LIGO/Virgo G297595

The LIGO Scientific Collaboration and the Virgo Collaboration report:

The gstlal CBC analysis (Messick et al. Phys. Rev. D 95, 042001, 2017)
identified candidate G297595 during real-time processing of data from
LIGO Hanford Observatory (H1),  LIGO Livingston Observatory (L1), and
Virgo Observatory (V1) at 2017-08-14 10:30:43 UTC (GPS time:
1186741861.5268).

G297595 is an event of interest because its false alarm rate, as
determined by the online analysis, is ~1/80000 years, passing our
stated alert threshold of ~1/month. The event's properties can be
found at this URL:
          https://gracedb.ligo.org/events/G297595

This event was also identified in real-time by another CBC pipeline,
PyCBC (Nitz, et al. 2017, arxiv 1705.01513), and the unmodeled burst
pipelines, cWB (Klimenko et al. Phys. Rev. D 93, 042004 (2016)) and
LIB (Lynch et al. Phys. Rev. D 95, 104046 (2017)).

The event appears consistent with the merger of two black holes at
this time, and there is little chance either component was a neutron
star. For more details on the source classification, please consult
this technical document: https://dcc.ligo.org/T1600571/public/main .

This is among the first GW event candidate detected in coincidence
with Advanced LIGO and Advanced Virgo, and the first event candidate
that registered loudly enough in Virgo to contribute significantly to
position reconstruction.

A rapid localization with distance information generated by the
BAYESTAR pipeline (e.g., Singer et al. 2016, ApJL 829, 15) is
available at this time and can be retrieved from the GraceDB event
page:
         bayestar.fits.gz,
using data from LIGO Hanford, LIGO Livingston, and Virgo, with
probability concentrated in a roughly elliptical region centered at
R.A.=02h44m, Dec.-45d29m. The 50% credible region spans about 22 deg2
and the 90% region about 97 deg2.

Marginalized over the whole sky, the a posteriori luminosity distance
estimate is 550 +/- 130 Mpc.

For comparison, using data from LIGO Hanford and LIGO Livingston
alone, the 50% credible region spanned 333 deg2 and the 90% area 1158
deg2.

Updates on our analysis of this event, including updated localizations
will be sent as they become available.

I. Bartos, S. Countryman (Columbia), C. Finley (U Stockholm), E. Blaufuss (U Maryland), R. Corley, Z. Marka, S. Marka (Columbia) on behalf of the IceCube Collaboration

In an analysis completed at 2017-08-14 11:31:35 UTC, we searched IceCube online track-like neutrino candidates (GFU) detected in a [-500,500] second interval about the LIGO-Virgo trigger G297595. We compared the candidate source directions of 12 temporally-coincident neutrinos to the BAYESTAR skymap, with the following parameters:

#            dt[s]     RA[deg]    Dec[deg]      E[TeV]  Sigma[deg]
------------------------------------------------------------------
1.         -442.72       117.9        30.6        0.95         1.2
2.         -362.65         6.8        49.6        1.20         0.9
3.         -358.50       240.1       -16.8       22.79         0.3
4.         -181.80       187.1       -66.2       35.08         0.3
5.         -143.66       215.1         6.2        1.56         1.4
6.          -42.69       264.3       -44.4       51.30         0.3
7.           99.62        85.0       -36.3       56.41         0.2
8.          174.83       280.2        22.6        1.05         0.9
9.          178.76       330.5        17.1        0.77         1.5
10.         202.04       291.7        36.2        0.78         0.8
11.         279.60       119.7       -15.8       18.31         0.7
12.         329.09       188.6        -5.4        1.30         1.0


(dt--time from GW in [seconds]; RA/Dec--sky location in [degrees]; E--reconstructed secondary muon energy in [TeV]; Sigma--uncertainty of direction reconstruction in [degrees])

The analysis found NO COINCIDENT ONLINE TRACK-LIKE NEUTRINO CANDIDATES detected by IceCube within the 500 second window surrounding G297595 within the BAYESTAR skymap.

A coincident neutrino-GW skymap has been posted to GraceDB (<https://gracedb.ligo.org/apiweb/events/G297595/files/coinc_skymap_initial_icecube.png,0>). A JSON-formatted list of the above neutrinos can be downloaded from GraceDB at: <https://gracedb.ligo.org/apiweb/events/G297595/files/IceCubeNeutrinoList.json,0>

In addition, we are performing coincident searches with other IceCube data streams, including the high-energy starting events (HESE) and Supernova triggers.  HESE events have typical energies > 60 TeV and start inside the detector volume, leading to a relatively pure event sample with a high fraction of astrophysical neutrinos.  The SN trigger system is sensitive to sudden increases in photomultiplier counts across the detector, which could indicate a burst of MeV neutrinos.  We will submit separate GCN circulars if coincident HESE or SN triggers are found.

The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica.  For a description of the IceCube realtime alert system, please refer to <http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1610.01814
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 >; for more information on joint neutrino and gravitational wave searches, please refer to <http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1602.05411
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 >.

A. Pozanenko (IKI), P. Minaev (IKI),
   E. Mazaeva (IKI), A. Volnova (IKI) report  on behalf of IKI-GW 
follow-up collaboration:

We investigated  data of SPI-ACS/INTEGRAL data around LIGO/Virgo trigger 
#G297595 (LIGO/Virgo collaboration). The small peak with duration of 
about 10 seconds starting 1.5 seconds before the time of the trigger 
2017-08-14 (UTC) 10:30:43 is detected. Significance of the peak is 3.5 
sigma and the significance is estimated using local background 
dispersion +/- 2000 seconds around the peak. The center of the 
LIGO/Virgo trigger localization (R.A.=02h44m  Dec.-45d29m ) is  off-axis 
of SPI detector of 78 degrees, which is nearly optimal for maximum 
sensitivity of the SPI-ACS detector. The fluence of the peak can be 
estimated as (4.0 +/- 1.2)*10^-7 erg/��m2. While the more accurate two 
parameter chance probability will be estimated we  note  that within 
investigated interval +/- 2000 s around the LIGO/Virgo trigger we do not 
find any more significant peak with the duration of 10 seconds.

The light curve of the peak can be found at 
http://grb.rssi.ru/GRB170814A/G297595_SPI-ACS_LC.png

F. Longo (Univ. Trieste and INFN Trieste), G. Piano, M.Cardillo (INAF/IAPS),
M. Pilia (INAF/OA-Cagliari), F. Verrecchia, C.Pittori (SSDC and INAF/OAR),
M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Bulgarelli
(INAF/IASF-Bo),  A.Ursi, G.Minervini, A. Argan, Y. Evangelista (INAF/IAPS),
N.Parmiggiani, A. Zoli, V. Fioretti (INAF/IASF-Bo), F. Lucarelli (SSDC and
INAF/OAR), I. Donnarumma (ASI), F. Fuschino (INAF/IASF-Bo), M. Marisaldi
(INAF/IASF-Bo and Bergen University),  A. Giuliani (INAF/IASF-Mi), A. Trois
(INAF/OA-Cagliari), report on behalf of the AGILE Team:

In response to the LIGO/Virgo GW event G297595 at T0 = 2017-08-14
10:30:43.527 UTC, a preliminary analysis of the AGILE MiniCALorimeter (MCAL)
data found no event candidates within a time interval covering approximately
-/+ 10 sec from the LIGO T0.

3-sigma ULs were computed for a 1 s integration time on different celestial
positions within the G297595 90% localization region, taking into consideration
the nearest triggered data acquisition (about 2.5 sec after the LIGO T0),
resulting in typical values of the fluence UL ranging from 4.2 e^-7 erg cm^-2
to 8.0 e^-7 erg cm^-2 (assuming as spectral model a power law with photon
index 1.4). The AGILE-MCAL detector is a CsI detector with a 4-pi FoV, working
in the range 0.4 - 100 MeV. Additional analysis of AGILE data is in progress.

V. Savchenko (ISDC, University of Geneva, CH)
on behalf of the INTEGRAL group:
S. Mereghetti (IASF-Milano, Italy),
C. Ferrigno ((ISDC, University of Geneva, CH),
E. Kuulkers (ESTEC/ESA, The Netherlands),
A. Bazzano (IAPS-Roma, Italy), E. Bozzo,
T. J.-L. Courvoisier (ISDC, University of Geneva, CH)
S. Brandt (DTU - Denmark) R. Diehl (MPE-Garching, Germany)
L. Hanlon (UCD, Ireland) P. Laurent (APC, Saclay/CEA, France)
A. Lutovinov (IKI, Russia) J.P. Roques (CESR, France)
R. Sunyaev (IKI, Russia) P. Ubertini (IAPS-Roma, Italy)

We investigated serendipitous INTEGRAL observations carried out at the
time of the LIGO/Virgo burst candidate G297595.  The satellite was
pointing at RA=240.554 Dec=-55.181, far from the high-probability area
of LIGO localization. For the full LIGO 90% confidence region the best
upper limit is set by the anti-coincidence shield of the spectrometer
on board of INTEGRAL (SPI/ACS). The localization of G297595 is close
to optimal for SPI-ACS observation.

The INTEGRAL Burst Alert System (IBAS) did not identify any unusual
transients in coincidence with the LIGO/Virgo trigger. The IBAS
inspects both ISGRI Field of View and all-sky SPI-ACS light curve.

We investigated the SPI-ACS, IBIS/Veto, and IBIS/ISGRI light curves
between -500 and +500 s from the trigger time (2017-08-14 10:30:43
UTC) on temporal scales from 0.1 to 100 s, and found no evidence for
any significant deviation from the background.  We estimate maximal 
3-sigma upper
limits of 6.6e-7 erg/cm2 (75-2000 keV) for 8s duration assuming Band
model parameters alpha=-1, beta=-2.5, and E_ peak = 300 keV.  To
derive a limit for a typical short burst with 1 s duration, we use a
harder cutoff power law spectrum with a photon index of -0.5 and an
Epeak = 500 keV. We find a limiting fluence of 2.1e-7 erg/cm2 (75-2000
keV) at 3 sigma c.l. Due to high particle background at the current
phase of the Solar Cycle, these upper limits are somewhat higher than
those that can be achieved by SPI-ACS in more favorable conditions.

We do not confirm the report by Pozanenko et al. 2017, GCN 21476
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 . The
fluctuation they report has an S/N marginally exceeding 3 sigma in an
optimized time bin used by the authors. In our systematic search, based
on predefined detection thresholds and time bins, this event is not
detected with a sufficiently high significance to justify a report. We
estimate post-trial significance of a long-timescale fluctuation
shortly following G297595 at 1.9 sigma.

INTEGRAL is scheduled to perform pointed follow-up observations of the
G297595 localization region.

M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (IFIC & APC), D.
  Dornic (CPPM/CNRS), A. Kouchner (APC/Universite Paris Diderot), T.
  Pradier (IPHC/Universite de Strasbourg) report on behalf of the ANTARES
  Collaboration:

  Using on-line data from the ANTARES detector, we have performed a
  follow-up analysis of the recently reported LIGO/Virgo G297595 event
  using the initial LIGO/Virgo Bayestar probability map at event time.
  The ANTARES visibility at the time of the alert
  together with the 90% contour of the probability map are shown
  in: https://www.cppm.in2p3.fr/~dornic/events/G297595/skymap_140817.png <https://www.cppm.in2p3.fr/~dornic/events/G297595/skymap_140817.png>
 (gwantares/GW@ANT30). Considering the location probability provided by the LIGO
  collaboration, there is a 98% chance that the GW emitter was in the
  ANTARES field of view.

  No up-going muon neutrino candidate events were recorded within the 90%
  contour during a +/- 500s time-window centered on the G297595 event
  time. The expected number of atmospheric background events in the
  region visible by ANTARES is ~1.2e-2 in the +/- 500s time window. An
  extended search during +/- 1 hour gives no up-going neutrino
  coincidence.

  An estimate of the upper limit on the associated neutrino fluence will
  be sent in a subsequent circular.

  ANTARES, being installed in the Mediterranean Deep Sea, is the largest
  neutrino detector in the Northern Hemisphere.  It is primarily
  sensitive to astrophysical neutrinos in the TeV-PeV energy range.  At
  10 TeV, the median angular resolution for muon neutrinos is below 0.5
  degrees.  In the range 1-100 TeV, ANTARES has the best sensitivity to a
  large fraction of the Southern sky.

D. Kocevski (NASA/Marshall), N. Omodei (Stanford), F. Longo (University and INFN, Trieste), S. Buson (NASA/GSFC), G.Vianello (Stanford), and J. McEnery (NASA/GSFC) report on behalf of the Fermi-LAT team: 

We have searched data collected by the Fermi Large Area Telescope (LAT) for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger G297595. 

At the time of the trigger (T0 = 2017-08-14 10:30:43.529 , 524399448.529 MET), 64% of the LIGO Bayestar probability map was in the LAT field of view, and we reached 100% cumulative coverage within 943 ks after the trigger. We define "instantaneous coverage" as the integral over the region of the LIGO probability map that is within the LAT field of view at a given time, and "cumulative coverage" as the integral of the instantaneous coverage over time. 

We performed a search for a transient counterpart within the 90% contour of the LIGO map in the time window from T0 to T0 + 10 ks, and no significant new sources are found. We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky. No significant candidate counterpart was found. 

The Fermi-LAT point of contact for this event is Daniel Kocevski (daniel.kocevski@nasa.gov) 

The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.

F. Longo (Univ. Trieste and INFN Trieste), F. Verrecchia (SSDC and INAF/OAR),
G. Piano (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), C.Pittori (SSDC and INAF/OAR),
M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Ursi, M. Cardillo, A.
Giuliani (INAF/IASF-Mi), A. Bulgarelli,  N. Parmiggiani, A.Zoli, V.Fioretti
(INAF/IASF-Bo), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), F. Lucarelli
(ASDC and INAF/OAR), G. Minervini (INAF/IAPS), F. Fuschino (INAF/IASF-Bo), Y.
Evangelista (INAF/IAPS), M. Marisaldi (INAF/IASF-Bo and Bergen University), A.
Argan (INAF/IAPS), A. Trois  (INAF/OA-Cagliari) report on behalf of the
AGILE Team:

In response to the LIGO/Virgo GW trigger G297595 (GCN #21474
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 ), we performed
an analysis of the AGILE Gamma-Ray Imaging Detector (GRID) data on different
timescales. On LIGO/VIRGO trigger time (T0=2017-08-14 10:30:43.527 UTC) the
GRID exposure has no coverage of the LIGO/VIRGO localization region (LR) due
to Earth occultation, from bayestar.fits.gz skymap in the GraceDB.

Data analysis in the energy range 50 MeV - 10 GeV was performed only at times
when the source region was not occulted by the Earth, from T0+500 to T0+600 sec,
when the AGILE-GRID exposure partially covered the LR (about 70% of it, observed
at off-axis angles between 0 and 42 deg).

Preliminary values of 3-sigma upper limits (UL) obtained within the
accessible G297595 LR are from 3.1e-08 to 3.9e-08 erg cm^2 s^-1.

These ULs apply to a large fraction of the GRID-exposed LIGO LR.

These measurements were obtained with AGILE observing a large portion of
the sky in spinning mode. Additional analysis of AGILE data is in progress.

T. Sakamoto (AGU), S.D. Barthelmy (NASA/GSFC), A. Y. Lien (GSFC/UMBC), 
D. M. Palmer (LANL), A. A. Breeveld (MSSL-UCL), A. P. Beardmore (U. Leicester),
D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC),
G. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB),
V. D'Elia(ASDC), S. Emery (UCL-MSSL), P. A. Evans (U. Leicester), 
P. Giommi (ASI), C. Gronwall (PSU), J. A. Kennea (PSU), 
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), 
F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), 
B. Mingo (U. Leicester), J. A. Nousek (PSU), S. R. Oates (Uni. of Warwick), 
P. T. O'Brien (U. Leicester), J. P. Osborne (U. Leicester), 
C. Pagani (U. Leicester), K. L. Page (U.Leicester), M. Perri (ASDC), 
J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU),
M. H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift team:

We report the search results in the BAT data within T0 +/- 100 s of the
LVC event G297595 (LIGO/VIRGO Collaboration GCN Circ. 21474
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 ), 
where T0 is the LVC trigger time (2017-08-14T10:30:43 UTC).

The BAT pointing position at T0 is
RA = 195.263 deg,
DEC = 27.016 deg,
ROLL = 255.372 deg.
The BAT Field of View (>10% partial coding) covers 0.0% of the integrated
LVC localization probability. That is, there is no overlap between the BAT
field of view and the LVC probability region at T0.

Within T0 +/- 100 s no significant detections (signal-to-noise ratio >~ 5 sigma) 
are found in the BAT raw light curves with time bins of 1 s and 1.6 s. There is 
a ~ 5.4 sigma spike at T0+27 s. However, since this spike is only seen in one 
single time bin and the 100-350 keV band, it is likely due to noise fluctuation.
We do not have event data around this time for further analysis. 
Assuming an on-axis (100% coded) short GRB with a typical spectrum in the BAT 
energy range (i.e., a simple power-law model with a power-law index of -1.32, 
Lien & Sakamoto et al. 2016), the 5-sigma upper limit in the 1-s binned light 
curve corresponds to a flux upper limit (15-350 keV) of ~ 7.68 x 10^-8 erg/s/cm^2.

BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 0.13% of the integrated LVC 
localization probability was outside of the BAT FOV but above the Earth's limb 
from Swift's location, and the corresponding flux upper limits for this region 
are within roughly an order of magnitude of those within the FOV.

A. Goldstein (USRA) reports on behalf of the GBM-LIGO Group:
L. Blackburn (CfA), M. S. Briggs (UAH), J. Broida (Carleton College), E.
Burns (NASA/GSFC), J. Camp (NASA/GSFC), T. Dal Canton (NASA/GSFC), N.
Christensen (Carleton College), V. Connaughton (USRA), R. Hamburg (UAH), C.
M. Hui (NASA/MSFC), P. Jenke (UAH), D. Kocevski (NASA/MSFC), N. Leroy
(LAL), T. Littenberg (NASA/MSFC), J. McEnery (NASA/GSFC), R. Preece (UAH),
J. Racusin (NASA/GSFC), P. Shawhan (UMD), K. Siellez (GATech), L. Singer
(NASA/GSFC), J. Veitch (Birmingham), P. Veres (UAH), C. Wilson-Hodge
(NASA/MSFC)

At the G297595 event time, GBM was taking data and viewing the entire
un-occulted sky approximately 67 degrees from Earth center (RA = 29.7, DEC
= +22.9), which includes 62% of the LIGO Bayestar LHV map.

There were no on-board triggers associated within a few hours of the GW
trigger time. The untargeted ground-based search of GBM data for
short-duration GRBs (Briggs et al., in prep) did not find any candidate
within an hour of the GW trigger.

The targeted search of the GBM data ([1], [2]) processes time scales of
0.256 to 8.192 s within 30 s of the LIGO event.  This search identified a
hard transient on the 2.048 s timescale 16.6 s after the GW trigger with an
initial estimated False Alarm Rate (FAR) of 7.1e-5 Hz (90% confidence).
Using the assumption that an EM signal closer in time to a GW event is more
likely to be associated, the initial False Alarm Probability (FAP) is
estimated at 2.5%  The localization of the event by the targeted search
(7700 sq. deg.; 90% containment) found that the LHV Bayestar map was
outside the 3 sigma statistical-only localization region. We can calculate
an associated FAR and FAP using this spatial information[2], however, the
FAR distribution that we have measured thus far assumes LIGO localizations
using L1 and H1, and may be different for the three-detector localization
maps. For completeness, we report the associated FAR including spatial
information as 1.7e-4 Hz (90% confidence) and FAP = 9.1%. The localization,
by itself, is highly suggestive of a Galactic source, encompassing the
location of two X-ray sources known to be currently active: Vela X-1 and
GRO J1008-57, however, the observed count spectrum is harder than typical
Galactic sources.

Although it has been determined that a systematic component to the GBM
localization uncertainty exists[3], this component has not yet been modeled
for un-triggered events. A follow-up human-in-the-loop inspection of the
lightcurve and the localization, incorporating the usual localization
systematic[3] for on-board triggered events, reveals that the un-occulted
LHV map is still outside the GBM 2-sigma region, but within the 3-sigma
region. A ten minute lightcurve shows some evidence for flaring with the
localization of the flares consistent with the localization of this
transient.


[1] L. Blackburn et al. 2015, ApJS 217, 8
[2] A. Goldstein et al. arXiv:1612.02395
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[3] V. Connaughton et al. 2015, ApJS 216, 32

David O. Cook (Caltech), Angela Van Sistine (UW Milwaukee), Leo Singer
(NASA/GSFC), and M. M. Kasliwal (Caltech)

report on behalf of the iPTF and GROWTH collaborations

We spatially cross-matched the LIGO/Virgo G297595 trigger (90% containment
volume; LVC GCN 21476
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 ) with our Census of the Local Universe (CLU; Cook et
al. in prep) galaxy catalog and found 82 galaxies. This catalog is a
compilation of galaxies with existing redshifts from many sources (e.g.,
NED, SDSS, etc) and new galaxies from a 3PI four-filter narrow-band survey
to look for redshifted Halpha emission out to 200 Mpc with the Palomar
Oschin 48-inch telescope. Since our catalog extends out to only ~200 Mpc
the resulting cross-matched galaxies cover only the nearest portion of the
full 90% localization volume. The narrow-band survey is limited to a
declination above -20 degrees, thus all galaxies within the 90% volume come
from the compiled CLU catalog with no Halpha overlap.

We list here the top 20 galaxies sorted by stellar mass (Mstar) for
galaxies whose location on the sky and distance falls in the 90% volume
reported by the bayestar probability sky map (Singer et al. 2016). The
total stellar mass located in the top 20 galaxies is 1.2e12 Msun, or 62% of
all mass in the 82 galaxies. We also list the dust-corrected star formation
rates (SFRs) for galaxies with GALEX FUV detections and a 'nan' for those
with no detection.

        name_NED           ra     dec    distmpc logsfr_fuv logmstar dm_kin
----------------------- ------- -------- ------- ---------- -------- ------
         ESO 198- G 008 35.5645 -51.1082  203.28        nan    11.22  36.54
2MASX J02235787-5058237 35.9912 -50.9733  203.55        nan    10.88  36.54
            2MFGC 01839 35.6649 -51.1009  210.38        nan    10.88  36.62
           FAIRALL 0726 36.8979 -51.2267  213.23        nan    10.87  36.64
  LCRS B025452.9-421921 44.1862 -42.1218  192.15        nan    10.87  36.42
           FAIRALL 0725 35.3950 -48.4925  271.12      0.138    10.84  37.17
         ESO 198- G 006 34.8638 -50.8529  209.43        nan    10.80  36.61
2MASX J02160149-5059094 34.0063 -50.9860  204.21        nan    10.78  36.55
  LCRS B025721.0-412315 44.8065 -41.1892  204.46        nan    10.78  36.55
2MASX J02270511-5117448 36.7714 -51.2958  202.12     -0.596    10.76  36.53
2MASX J03045777-4015102 46.2408 -40.2528  208.70     -0.638    10.69  36.60
2MASX J02411987-4534101 40.3329 -45.5695  180.75      0.144    10.65  36.29
      AM 0250-405 NED01 42.9935 -40.7236  199.58        nan    10.65  36.50
     APMBGC 247-025-101 43.1562 -43.0039  198.57        nan    10.64  36.49
2MASX J02504210-4323076 42.6755 -43.3855  198.81        nan    10.63  36.49
2MASX J02523735-4300107 43.1556 -43.0029  194.98        nan    10.62  36.45
  LCRS B025513.6-421400 44.2721 -42.0336  189.87        nan    10.59  36.39
2MASX J02251101-5039230 36.2958 -50.6564  208.82        nan    10.57  36.60
2MASX J02274395-5119348 36.9333 -51.3263  201.72        nan    10.54  36.52
2MASX J02143393-4953404 33.6416 -49.8946  200.55        nan    10.52  36.51


The SFRs are derived from GALEX all sky kron FUV magnitudes via the
prescription of Murphy et al. (2011) and have been corrected for internal
dust extinction using a combination of GALEX FUV and 22um ALLWISE fluxes
(Hao et al. 2011). The quoted stellar masses are derived from 3.4um ALLWISE
fluxes and a mass-to-light ratio of 0.5 (McGaugh & Schombert et al. 2015).

J. Y. Liao, C. K. Li, M. Y. Ge, Y. Huang, S. L. Xiong, Y. Liu,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU),
T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, H. Y. Wang, M. Wu, Y. P. Xu,
S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:

Insight-HXMT was taking data normally around the LIGO trigger time
(T0=2017-08-14 10:30:43 UTC). At T0, more than 95% of the LHV
localization region was covered by the Insight-HXMT without occultation
by the Earth. However, the general direction of the LHV localization is
almost perpendicular to HXMT detectors and thus the sensitivity of HXMT
is almost the worst.

Within T0 +/- 1000 s, no significant excess (SNR > 5) is found
in a search of the Insight-HXMT raw light curves with time bins of
20 ms, 50 ms, 0.2 s and 1 s, respectively. Within T0 +/- 100 s for
SNR>3, there is one 3.3 sigma excess only for the time bin of 0.2 s
at 10 s before T0, completely consistent with background fluctuations.

With the three typical GRB Band spectral models, three integration time
(1 s, 10 s, and 100 s) and the LHV localization region, the 3-sigma
upper-limit fluence (0.2 - 5 MeV, incident energy) are reported below:

Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV):
1s: 2.2e-07 to 3.3e-07 erg cm^-2
10s: 7.5e-07 to 1.2e-06 erg cm^-2
100s: 2.6e-06 to 4.1e-06 erg cm^-2

Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1s: 3.4e-07 to 5.0e-07 erg cm^-2
10s: 1.2e-06 to 1.7e-06 erg cm^-2
100s: 4.0e-06 to 5.9e-06 erg cm^-2

Band model 3 (alpha=0.0, beta=-1.5, Ep=1000 keV):
1s: 7.5e-07 to 9.9e-07 erg cm^-2
10s: 2.4e-06 to 3.2e-06 erg cm^-2
100s: 8.6e-06 to 1.0e-05 erg cm^-2

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

The analysis results presented above are preliminary;
refined results will be reported later.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and the Chinese
Academy of Sciences (CAS). More information about it could be found at:
http://www.hxmt.org/index.php/enhome .

K. C. Chambers (IfA), K. W. Smith (QUB), M. E. Huber (IfA),
S. J. Smartt, D. R. Young (QUB), M. Coughlin (Harvard), T.-W. Chen
(MPE), L. Denneau, H. Flewelling, A. Heinze, E. Kankare (QUB),
T. Lowe, E. A. Magnier (IfA), A. Rest (STScI), B. Stalder (IfA),
A. S. B. Schultz, C. W. Stubbs (Harvard) J. Tonry, C. Waters,
R. J. Wainscoat, H. Weiland, M. Willman (IfA), D. E. Wright (QUB)

Following Katsavounidis et al. (GCN 21474
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 ), we report Pan-STARRS
imaging observations of the skymap (bayestar.fits) of G297595, a GW
source with event time 2017/08/14 10:30:43.526780 == MJD
57979.43800378

We covered around 60 square degrees on the first night following the
release of the G297595 alert. We began taking data at 2017-08-14.564
UT (57979.564; 3hrs after the event detection, and 2.5hrs after the
alert).  We estimate that this first night of data coverage
corresponds to a probability of containing the source of around 60%,
(based on the bayestar.fits map; Singer et al. 2016, ApJL 829,
15). Our coverage map will be posted on GraceDB.  Note that we could
not go below dec=-48, and did not cover the most southern part of the
skymap.

Images were taken in the Pan-STARRS i-band filter in a series of
overlapping 45s exposures, with typically 4-6 images at each position.
Difference images were produced by subtracting the Pan-STARRS1 3Pi
reference image from these separate 45s exposures (Chambers et
al. arXiv:1612.05560
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 , and available at http://panstarrs.stsci.edu).
At airmass of 2.8 to 2.3, we reach i ~ 21 in the individual exposures.

Using techniques discussed in Smartt et al. (2016, MNRAS, 462, 4094),
we have located and vetted transients with quality filters and a
machine learning algorithm on the difference images.

Obvious variable sources which are likely AGN/QSOs or variable stars
have, as far as possible, been removed from this transient list
through catalogue matching.

We found 6 objects that are likely astrophysical transients, but all 6
are close to or coincident with the cores of resolved galaxies.  The
difference images are good quality and these are likely real, but
may be AGN activity. Given the recent interest in nuclear transients
and their nature we report them here for follow-up.

The ���prob countour��� gives the bayestar.fits map probability which
contains the transient.

We found no SN-like, or GRB-afterglow like candidates which are
associated with a galaxy and offset from the core, and 
similarly no orphan hostless transients to a limit of i ~ 21. 
Some of the following transients could be nuclear supernovae but
have no measurable offsets. 


name    ra           dec           mjd      disc mag   prob contour Notes  
PS17edg 02:51:44.91 -39:39:29.0    57979.568  20.29 i    70           1
PS17edm 02:54:18.07 -41:31:25.8    57979.576  20.62 i    40           2
PS17edh 02:54:07.09 -41:37:31.8    57979.576  18.36 i    40           3
PS17edn 02:55:45.77 -40:40:17.4    57979.576  20.78 i    50           4
PS17edl 02:52:48.23 -41:25:51.3    57979.578  20.51 i    40           5
PS17edj 02:30:45.31 -45:07:02.1    57979.587  18.39 i    90           6


1. The transient is associated with APMUKS(BJ) B024948.84-395146.3; a
20.03 mag galaxy found in the NED catalogue. It's located 0.34" S,
0.30" W from the galaxy centre.

2. The transient is associated with LCRS B025225.0-414335; a 18.86 mag
galaxy found in the NED catalogue. It's located 0.3" from the galaxy
core.

3.  The transient is associated with LCRS B025214.1-414941; a 17.26
mag galaxy found in the NED catalogue. It's located 0.3" (0.7 Kpc)
from the galaxy core. A host z=0.146 implies a transient M = -20.85.

4. The transient is associated with 02554579-4040171 ; a J=16.85 mag
stellar source found in the 2MASS PSC catalogue. It's located 0.4"
from the source core. The object appears slightly extended in the PS1
images and is likely a galaxy.

5. The transient is associated with 02524824-4125517 ; a J=16.72 mag
stellar source found in the 2MASS PSC catalogue. It's located 0.4"
from the source core. The object appears slightly extended in the PS1
images and is likely a galaxy.

6. The transient is synonymous with LCRS B022852.4-452018; a 18.45 mag
galaxy found in the NED catalogue. It's located 0.2" (0.5 Kpc) from
the galaxy core. A host z=0.143 implies a transient M = -20.56.

The LIGO Scientific Collaboration and the Virgo Collaboration report:

In GCN 21474
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 , we reported the identification of the GW binary merger
candidate G297595. The originally stated luminosity distance estimate of
550 +/- 130 Mpc (a posteriori mean +/- standard deviation) was incorrect
due to copying the value from a different GraceDB entry.

The correct luminosity distance estimate is 488 +/- 111 Mpc. The original
sky map that we sent in GCN 21474
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 , bayestar.fits.gz, contains the correct
value in the DISTMEAN and DISTSTD entries of its FITS header. Only the
circular was in error.

No further updates are available at this time.

The LIGO Scientific Collaboration and Virgo Collaboration report:

We have re-analyzed LIGO and Virgo data around the time of the compact binary
coalescence (CBC) event candidate G297595 (GCN 21474
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 ) taking into account
our current understanding of calibration uncertainties.

Parameter estimation has been performed using LALInference (Veitch et al.,
PRD 91, 042003) and a new sky map, LALInference.fits.gz, is available for
retrieval from the GraceDB event page:

https://gracedb.ligo.org/events/G297595

This is the preferred sky map at this time. The probability is
concentrated near R.A.=03h06m, Dec.=-44d36m. The 50% and 90% credible
regions span about 36 and 190 square degrees, respectively, somewhat
larger than the initial BAYESTAR sky map due to marginalizing over
calibration uncertainties. The 90% credible regions of the initial and
this updated localization have significant overlap, but the 50% credible
region is shifted east by its entire width.

[GCN OPS NOTE(17aug17): Per author's request, "We have re-analyzed LIGO data..."
was changed to "We have re-analyzed LIGO and Virgo data..."]

S. Sugita, N. Kawai (Tokyo Tech), M. Serino (RIKEN), H. Negoro (Nihon U.),
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai (JAXA),
T. Mihara, M. Sugizaki, S. Nakahira, W. Iwakiri, M. Shidatsu, M.
Matsuoka (RIKEN),
T. Yoshii, Y. Tachibana, S. Harita, Y. Muraki, K. Morita (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka, T. Hashimoto (AGU),
H. Tsunemi, T. Yoneyama (Osaka U.),
M. Nakajima, T. Kawase, A. Sakamaki (Nihon U.),
Y. Ueda, T. Hori, A. Tanimoto, S. Oda (Kyoto U.),
Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.),
M. Yamauchi, C. Hanyu, K, Hidaka (Miyazaki U.),
T. Kawamuro (NAOJ),
K. Yamaoka (Nagoya U.)
report on behalf of the MAXI team:

We examined the MAXI/GSC all-sky X-ray images (2-20 keV) obtained
in the orbit and the day after the LVC trigger
G297595 at 2017-08-14 10:30:43 UTC (GCN 21474
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 ).

At the trigger time of G297595,
the high-voltage of MAXI/GSC was off,
and it was turned on at T0+473 sec.
GSC scanned more than 74.1% of the whole sky in the 92-min orbit,
which includes 100% of the 90% region in the bayestar skymap
scanned from 10:56:11 to 10:59:42 UTC (T0+1528 to 1739 sec).
No significant new source was found in one-orbit and one-day images.
The 2-20 keV 1-sigma (3-sigma) averaged upper limits obtained
from the one-orbit and the one-day images in the bayestar skymap are
11(33) and 3(9) mCrab, respectively.

If you require information of X-ray flux by MAXI/GSC at specific coordinates,
please contact the submitter of this circular by email.

P. D'Avanzo (INAF-OAB), G. Greco (Urbino University/INFN Firenze), A. Melandri (INAF-OAB), M. Branchesi (GSSI), D. Fugazza, S. Covino (INAF-OAB), L. Amati (INAF-IASF Bo), L. A. Antonelli, (INAF-OAR), S. Ascenzi (INAF-OAR), S. Benetti (INAF-OAPD), M.T. Botticella (INAF-OAC),  S. Campana (INAF-OAB), E. Cappellaro (INAF-OAPD), V. D'Elia (INAF-ASDC), F. Getman (INAF-OAC), A. Grado (INAF-OAC), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), L. Nicastro (INAF-IASF Bo), E. Palazzi (INAF-IAFS Bo), E. Pian (SNS-Pisa), S. Piranomonte (INAF-OAR), L. Pulone (INAF-OAR), A. Rossi (INAF-IASF Bo), G. Stratta (Urbino University/INFN Firenze), G. Tagliaferri (INAF-OAB), V. Testa (INAF-OAR), L . Tomasella (INAF-OAPD), S. Yang (INAF-OAPD), E. Brocato (INAF-OAR) on behalf of GRavitational Wave Inaf TeAm report:


We carried out optical/NIR follow-up observations of the LIGO/Virgo GW trigger G297595 (LVC GCN Circ. 21474
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 ) with the 60-cm robotic telescope REM located at the La Silla Observatory (Chile). The observations were carried out on 2017 Aug 15 from 02:31:48 UT (i.e. 16 hours after the event detection) to 08:20:50 UT, simultaneously in the g, r, i, z and H bands. We observed 21 galaxies within the 50% probability region reported in LVC GCN Circ. 21474
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 . The targets were selected with a distance consistent with the one reported in the FITS header of the initial skymap (488 +/- 111 Mpc; see also LVC GCN Circ. 21489
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 ) and an absolute B-band magnitude brighter than -21.9 mag. The targets were selected using the information of distance and magnitude reported in the GLADE catalogue (Dalya et al. 2016). The pointing sequence was generated using the GWsky script (https://github.com/ggreco77/GWsky <https://github.com/ggreco77/GWsky>) starting from the high probability region of the skymap and taking into account the airmass:

RA(J2000)    Dec(J2000)    Distance (Mpc)    
02:33:12.75    -49:31:02.0    289.73 
02:34:00.15    -49:36:58.4    288.40*
02:39:27.05    -45:24:52.1    204.17* 
02:41:50.25    -46:51:52.1    396.28 
02:42:55.60    -44:21:38.0    442.59 
02:42:05.63    -45:20:14.8    432.51 
02:44:39.93    -47:29:02.5    409.26 
02:45:34.23    -44:32:22.5    316.23 
02:45:13.34    -46:27:19.4    413.05 
02:46:37.00    -42:22:01.5    307.61 
02:47:31.97    -41:50:11.4    642.69 
02:48:15.67    -41:39:12.3    295.12* 
02:48:54.66    -42:03:02.1    411.15 
02:48:03.81    -44:06:41.6    476.43 
02:48:33.66    -45:16:36.1    636.80 
02:49:44.35    -42:19:38.6    322.11 
02:51:39.04    -42:57:58.8    317.69 
02:53:45.59    -41:11:22.9    688.89 
02:54:07.10    -41:37:32.6    676.08 
02:56:35.81    -40:57:39.4    746.57 
02:56:03.08    -42:47:25.0    313.33 
*: no NIR images were collected for this target


A preliminary analysis (also based on visual comparison with the DSS) reveals no obvious optical/NIR candidate counterpart in the above galaxies down to the following magnitudes: r > 19.5, H > 17.3 (AB, 3sigma UL). We note that among our targets there is the host galaxy of the transient PS17edh reported by Chambers et al. (LVC GCN Circ. 21488
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 ). It is not possible, however, to resolve such object in our images.

Yousuke Utsumi (Hiroshima Univ.), Nozomu Tominaga (Konan Univ.),
Michitoshi Yoshida, Masaomi Tanaka, Tsuyoshi Terai (NAOJ),
Ryou Ohsawa, Tomoki Morokuma (Univ. of Tokyo),
Kouji Ohta (Kyoto Univ.), Koji S. Kawabata (Hiroshima Univ.)
on behalf of J-GEM collaboration

We report optical follow-up observations for G297595
with Hyper Suprime-Cam (HSC, 1.7 deg^2 FOV) attached to 8.2-m Subaru Telescope.

We performed Y-band imaging observations of the high probability region
using the updated skymap (LALInference.fits) on 2017-08-16 UT.
We covered about 40 deg^2 with 30 pointings.
Each field was visited twice with the total exposure time of 220 sec
(110 sec x 2).
An expected 5-sigma limiting magnitude is about 23 mag AB.

The observed fields are listed below.

ID UT                  RA          DEC          Exp    Filter
00 2017-08-16T12:32:25 03h19m45.9s -35d40m51.6s 110.0s HSC-Y
01 2017-08-16T12:34:46 03h16m57.2s -36d25m09.4s 110.0s HSC-Y
02 2017-08-16T12:37:07 03h14m08.5s -37d09m52.4s 110.0s HSC-Y
03 2017-08-16T12:39:27 03h11m19.8s -37d55m02.3s 110.0s HSC-Y
04 2017-08-16T12:41:48 03h19m46.0s -37d09m52.3s 110.0s HSC-Y
05 2017-08-16T12:44:08 03h16m57.3s -37d55m02.4s 110.0s HSC-Y
06 2017-08-16T12:46:29 03h14m08.6s -38d40m40.4s 110.0s HSC-Y
07 2017-08-16T12:48:50 03h11m19.9s -39d26m47.6s 110.0s HSC-Y
08 2017-08-16T12:51:11 03h08m31.2s -40d13m26.1s 110.0s HSC-Y
09 2017-08-16T12:53:32 03h05m42.5s -41d00m36.7s 110.0s HSC-Y
10 2017-08-16T12:55:53 03h19m46.1s -38d40m40.2s 110.0s HSC-Y
11 2017-08-16T12:58:15 03h02m53.8s -41d48m21.6s 110.0s HSC-Y
12 2017-08-16T13:00:35 03h16m57.4s -39d26m47.5s 110.0s HSC-Y
13 2017-08-16T13:02:57 03h14m08.7s -40d13m25.9s 110.0s HSC-Y
14 2017-08-16T13:05:18 03h00m05.2s -42d36m19.7s 110.0s HSC-Y
15 2017-08-16T13:07:39 03h11m20.0s -41d00m36.6s 110.0s HSC-Y
16 2017-08-16T13:09:59 03h08m31.3s -41d48m21.6s 110.0s HSC-Y
17 2017-08-16T13:12:20 03h05m48.0s -42d36m19.7s 110.0s HSC-Y
18 2017-08-16T13:14:41 03h19m46.2s -40d13m25.8s 110.0s HSC-Y
19 2017-08-16T13:17:02 03h16m57.5s -41d00m36.6s 110.0s HSC-Y
20 2017-08-16T13:19:23 03h02m59.4s -43d24m09.2s 110.0s HSC-Y
21 2017-08-16T13:21:44 03h14m08.9s -41d48m21.4s 110.0s HSC-Y
22 2017-08-16T13:24:04 03h00m05.3s -44d11m50.0s 110.0s HSC-Y
23 2017-08-16T13:26:25 03h11m30.9s -42d36m19.7s 110.0s HSC-Y
24 2017-08-16T13:28:46 02h57m05.4s -44d59m22.5s 110.0s HSC-Y
25 2017-08-16T13:31:06 03h08m47.8s -43d24m09.1s 110.0s HSC-Y
26 2017-08-16T13:33:28 02h53m59.3s -45d46m46.8s 110.0s HSC-Y
27 2017-08-16T13:35:49 03h05m59.4s -44d11m49.9s 110.0s HSC-Y
28 2017-08-16T13:38:10 03h17m13.7s -42d36m19.7s 110.0s HSC-Y
29 2017-08-16T13:40:31 03h03m05.4s -44d59m22.5s 110.0s HSC-Y
00 2017-08-16T13:42:59 03h19m36.4s -35d41m22.6s 110.0s HSC-Y
01 2017-08-16T13:45:20 03h16m47.6s -36d25m40.4s 110.0s HSC-Y
02 2017-08-16T13:47:41 03h13m58.8s -37d10m23.5s 110.0s HSC-Y
03 2017-08-16T13:50:01 03h11m10.0s -37d55m33.4s 110.0s HSC-Y
04 2017-08-16T13:52:22 03h19m36.3s -37d10m23.4s 110.0s HSC-Y
05 2017-08-16T13:54:43 03h16m47.5s -37d55m33.4s 110.0s HSC-Y
06 2017-08-16T13:57:04 03h13m58.7s -38d41m11.4s 110.0s HSC-Y
07 2017-08-16T13:59:25 03h11m09.9s -39d27m18.7s 110.0s HSC-Y
08 2017-08-16T14:01:46 03h08m21.1s -40d13m57.0s 110.0s HSC-Y
09 2017-08-16T14:04:07 03h05m32.3s -41d01m07.7s 110.0s HSC-Y
10 2017-08-16T14:06:30 03h19m36.2s -38d41m11.3s 110.0s HSC-Y
11 2017-08-16T14:08:51 03h02m43.5s -41d48m52.6s 110.0s HSC-Y
12 2017-08-16T14:11:12 03h16m47.4s -39d27m18.6s 110.0s HSC-Y
13 2017-08-16T14:13:34 03h13m58.6s -40d13m57.0s 110.0s HSC-Y
14 2017-08-16T14:15:55 02h59m54.6s -42d36m50.8s 110.0s HSC-Y
15 2017-08-16T14:18:17 03h11m09.8s -41d01m07.7s 110.0s HSC-Y
16 2017-08-16T14:20:38 03h08m21.0s -41d48m52.6s 110.0s HSC-Y
17 2017-08-16T14:22:59 03h05m37.5s -42d36m50.8s 110.0s HSC-Y
18 2017-08-16T14:25:20 03h19m36.1s -40d13m56.9s 110.0s HSC-Y
19 2017-08-16T14:27:41 03h16m47.3s -41d01m07.7s 110.0s HSC-Y
20 2017-08-16T14:30:02 03h02m48.8s -43d24m40.2s 110.0s HSC-Y
21 2017-08-16T14:32:23 03h13m58.5s -41d48m52.6s 110.0s HSC-Y
22 2017-08-16T14:34:44 02h59m54.5s -44d12m21.0s 110.0s HSC-Y
23 2017-08-16T14:37:05 03h11m20.4s -42d36m50.7s 110.0s HSC-Y
24 2017-08-16T14:39:26 02h56m54.4s -44d59m53.5s 110.0s HSC-Y
25 2017-08-16T14:41:48 03h08m37.2s -43d24m40.2s 110.0s HSC-Y
26 2017-08-16T14:44:08 02h53m48.3s -45d47m17.8s 110.0s HSC-Y
27 2017-08-16T14:46:29 03h05m48.6s -44d12m20.9s 110.0s HSC-Y
28 2017-08-16T14:48:50 03h17m03.2s -42d36m50.7s 110.0s HSC-Y
29 2017-08-16T14:51:11 03h02m54.4s -44d59m53.5s 110.0s HSC-Y

G. Greco (Urbino University/INFN Firenze), A. Grado (INAF-OAC), F. Getman
(INAF-OAC), E. Cappellaro (INAF-OAPD), M. Branchesi (GSSI), S. Covino
(INAF-OAB), P. D'Avanzo (INAF-OAB), A. Melandri (INAF-OAB), L. Amati
(INAF-IASF Bo), L. A. Antonelli, (INAF-OAR), S. Ascenzi (INAF-OAR), S.
Benetti (INAF-OAPD), M.T. Botticella (INAF-OAC),  S. Campana (INAF-OAB), V.
D'Elia (INAF-ASDC), D. Fugazza, L. Limatola (INAF-OAC), M. Lisi (INAF-OAR),
L. Nicastro (INAF-IASF Bo), E. Palazzi (INAF-IAFS Bo), E. Pian (SNS-Pisa),
S. Piranomonte (INAF-OAR), L. Pulone (INAF-OAR), A. Rossi (INAF-IASF Bo), P.
Schipani (INAF-OAC), G. Stratta (Urbino University/INFN Firenze), G.
Tagliaferri (INAF-OAB), V. Testa (INAF-OAR), L . Tomasella (INAF-OAPD), S.
Yang (INAF-OAPD), E. Brocato (INAF-OAR) on behalf of GRavitational Wave
Inaf TeAm report:



Observations of 81 square degrees of the skymap of the Advanced LIGO and
Virgo trigger G297595 (LVC GCN Circ. 21474
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 ) were performed with the VLT
Survey Telescope (VST - Proposal ID ESO 099.D-0568) at ESO-Paranal equipped
with OMEGACAM (FOV=1 square degree). The observations are divided in 9
regions, 3 x 3 square degrees each, centered on the following  coordinates
RA, Dec (ICRSd):



41.06842   -45.48795

36.78869   -45.48795

45.34815   -45.48795

42.42450   -42.48795

42.42450   -39.48795

39.71234   -48.48795

44.97423   -36.48795

46.17326   -33.80461

37.32240   -51.48795



The sequence of the VST pointings was generated using the GWsky script (
https://github.com/ggreco77/GWsky). Starting from the high probability
region of the skymap, the sequence was defined to maximize the contained
localization probability, to limit the airmass to 2, and to use the
available reference images. Fields with bright stars were excluded.



The images were taken in the r_SDSS filter with an exposure of 80s (split
in two dithered exposures of 40 s each). The observations started at
2017-08-15T 04:44:22 UTC and finished at 2017-08-15T 09:03:15 UTC.

The contained probability of the initial BAYESTAR sky map (LVC GCN Circ.
21474
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 ) covered by the VST observations is about 75%, while for the
LALinference sky map (LVC GCN Circ. 21493
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 ) it is about  25%.



Automatic data reduction with the VSTTube pipeline (Grado et al. 2012
Mem.SAIt 19, 362 ) was completed. The image analysis is ongoing. Further
observations of these fields are planned.

V.M.  Lipunov, E. Gorbovskoy, V.G.Kornilov, N.Tyurina, V.Shumkov, D.Kuvshinov, 
P.Balanutsa,  O.Gress, A.Kuznetsov, M.I.Panchenko, A.V.Krylov, I.Gorbunov
Lomonosov Moscow State University, Sternberg Astronomical Institute

R.Podesta, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA) , National University of San
Juan, Argentina

H. Levato, C. Saffe
Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE),
San Juan, Argentina

N.M. Budnev, O. Gress, K. Ivanov, S.Yazev
Irkutsk State University

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

D.Buckley, S. Potter, M. Kotze,
  South African Astronomical Observatory

R. Rebolo, M. Serra-Ricart, G. Israelian, N.Lodiu
The Instituto de Astrofisica de Canarias

A. Tlatov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory

Following Katsavounidis et al. (GCN 21474
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 ), we report two optical 
transients detected.



1) MASTER OT J030141.96-230037.8 discovery

During MASTER-OAFA inspection of LIGO GW G297595
MASTER-OAFA auto-detection system ( Lipunov et al., "MASTER Global Robotic 
Net",
Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 03h 
01m 41.96s -23d 00m 37.8s on 2017-08-16.31422 UT.
The OT unfiltered magnitude is 17.5m (mlim=19.7m).

The OT is seen in 2 image (MASTER inspection mode) at 2017-08-16 07:32:29 
and 2017-08-16 07:17:07UT

There is no minor planet at this place.

We have reference images without OT on 2017-03-10.01 UT with magnitude 
limit in unfiltered 18.6m.

Spectral observations are required.


The discovery and reference images are available 
at:http://master.sai.msu.ru/static/OT/030141.96-230037.8.png


2) MASTER OT J015849.50-230853.7 detection

MASTER-OAFA auto-detection system  discovered OT source at (RA, Dec) = 01h 
58m 49.50s -23d 08m 53.7s on 2017-08-15.27118 UT.

The OT unfiltered magnitude is 16.7m (mlim=19.3m).
The OT is seen in 3 images. There is no minor planet at this place.
We have reference image without OT on 2016-09-22.25362 UT with unfiltered 
magnitude limit is 18.4m.
There is  USNO-B1 star in 2" with known only B1=21.47,B2=20.96

Spectral observations are required.

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/015849.50-230853.7.png

This message can be citted.

D. Svinkin, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:

Konus-Wind (KW) was observing the whole sky at the time of the 
LIGO/Virgo event G297595 (2017-08-14 10:30:43.527 UTC, hereafter T0;
LIGO/Virgo Collaboration GCN Circ. 21474
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 ).

No triggered KW event happened from ~4 day before and up to ~1.3 days
after T0. The closest waiting-mode event was ~1.1 days after T0.
Using waiting-mode data within the interval T0 +/- 100 s,
we found no significant (> 5 sigma) excess over the background
in both KW detectors on temporal scales from 2.944 s to 100 s.

We estimate an upper limit (90% conf.) on the 10 keV ��� 10 MeV fluence
to 5.9x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having a
typical KW short GRB spectrum (an exponentially cut off power law with
alpha=-0.5 and Ep=500 keV). For a typical long GRB spectrum (the Band
function with alpha=-1, beta=-2.5, and Ep=300 keV), the corresponding
limiting peak flux is 2.2x10^-7 erg/cm^2/s (10 keV - 10 MeV, 2.944 s scale).

All the quoted values are preliminary.

P.A. Evans (U. Leicester), J.A. Kennea (PSU), S.D. Barthelmy
(NASA/GSFC), A.P. Beardmore (U. Leicester), A.A. Breeveld (UCL-MSSL),
D.N. Burrows (PSU), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC), G.
Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB),
V.D'Elia(ASDC), S.W.K. Emery (UCL-MSSL), P. Giommi (ASI), C. Gronwall
(PSU), H.A. Krimm (CRESST/GSFC/USRA), N.P.M. Kuin (UCL-MSSL), A.Y. Lien
(GSFC/UMBC), F.E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), J.A.
Nousek (PSU), S.R. Oates (U. Warwick), P.T. O'Brien (U. Leicester),
J.P. Osborne (U. Leicester), C. Pagani (U. Leicester), K.L. Page
(U.Leicester), D.M. Palmer (LANL), M. Perri (ASDC), J.L. Racusin
(NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M.H. Siegel (PSU), G.
Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/UMCP) report on behalf of
the Swift team:

Swift has performed a series of 535 observations, covering 535 separate
locations within the LVC error region for the GW trigger G297595 (LVC
Circ. 21474) convolved with the 2MPZ catalogue (Bilicki et al. 2014,
ApJS, 210, 9), using 530 fields from the 'bayestar' GW localisation map
and 5 fields from the 'LALInference' GW localisation map. As these are
3D skymaps, galaxy distances were taken into account in selecting which
ones to observe. The observations currently span from 31 ks to 222 ks
after the LVC trigger, and cover 54.6 sq degrees on the sky (corrected
for overlaps). This covers 13% of the probability in the 'LALInference'
skymap, and 17% after convolving with the 2MPZ galaxy catalogue, as
described by Evans et al., (2016, MNRAS,  462, 1591). Using the earlier
 'bayestar' skymap our observations covered 70% of the probability (70%
when convolved).

We have detected 7 X-ray sources. Each source is assigned a rank of 1-4
which describes how likely it is to be related to the GW trigger, with
1 being the most likely and 4 being the least likely. The ranks are
described at http://www.swift.ac.uk/ranks.php.

We have found:

  * 0 sources of rank 1
  * 0 sources of rank 2
  * 0 sources of rank 3
  * 7 sources of rank 4

For all flux conversions and comparisons with catalogues and upper
limits from other missions, we assumed a power-law spectrum with
NH=3e20 cm^2, and photon index (Gamma)=1.7


RANK 4 sources
==============

These are catalogued X-ray sources, showing no signs of outburst
compared to previous observations, so they are not likely to be related
to the GW trigger.
  
  Source 1:
  =============
    RA: 	 41.4741 ( = 02h 45m 53.78s) J2000
    Dec:	 -44.9939 ( = -44d 59' 38.0") J2000
    Error:	 +5.4 (arcsec, radius, 90% confidence).
    Peak Rate:	 8.1e-02 +/- 4.9e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 3.5e-12 +/- 2.1e-12 erg cm^-2 s^-1 (0.3-10 keV)
    Cat Source:  1SXPS J024554.1-445938 in the 1SXPS catalogue
    Separation:  3.9" from the XRT source
    Cat Rate:	 7.9e-02 +/- 4.7e-03 ct/sec 
    Cat Flux:	 3.4e-12 +/- 2.0e-13 erg cm^-2 s^-1 (0.3-10 keV)
       so the source is not above the catalogued flux.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `QSO B0244-452' is 3.5" away.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 2:
  =============
    RA: 	 38.6302 ( = 02h 34m 31.25s) J2000
    Dec:	 -46.5331 ( = -46d 31' 59.2") J2000
    Error:	 +6.3 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.1e-01 +/- 5.3e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 4.9e-12 +/- 2.3e-12 erg cm^-2 s^-1 (0.3-10 keV)
    Cat Source:  XMMSL2 J023431.2-463207 in the XMM-NEWTON/XMMSLEWCLN
catalogue
    Separation:  8.0" from the XRT source
    Cat Rate:	 9.0e-01 +/- 4.3e-01 ct/sec 
    Cat Flux:	 9.0e-12 +/- 4.3e-12 erg cm^-2 s^-1 (0.3-10 keV)
       so the source is not above the catalogued flux.
    The source may be fading, at the 0.2-sigma level.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `6dFGS gJ023431.3-463206' is 7.3" away.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 3:
  =============
    RA: 	 34.6059 ( = 02h 18m 25.42s) J2000
    Dec:	 -50.2247 ( = -50d 13' 28.9") J2000
    Error:	 +5.7 (arcsec, radius, 90% confidence).
    Peak Rate:	 1.7e-02 +/- 6.4e-03 ct/sec (0.3-10 keV)
    Peak Flux:	 7.5e-13 +/- 2.7e-13 erg cm^-2 s^-1 (0.3-10 keV)
    Cat Source:  1SXPS J021825.9-501330 in the 1SXPS catalogue
    Separation:  5.4" from the XRT source
    Cat Rate:	 2.0e-02 +/- 4.1e-04 ct/sec 
    Cat Flux:	 8.8e-13 +/- 1.8e-14 erg cm^-2 s^-1 (0.3-10 keV)
       so the source is not above the catalogued flux.
    There is no evidence for fading.
    There are 3 GWGC or 2MPZ galaxies within 200 kpc of the source.
      and consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `1RXS J021824.9-501335' is 7.7" away.
  
  Source 4:
  =============
    RA: 	 37.5016 ( = 02h 30m 0.38s) J2000
    Dec:	 -54.0222 ( = -54d 01' 19.9") J2000
    Error:	 +7.8 (arcsec, radius, 90% confidence).
    Peak Rate:	 4.6e-02 +/- 1.6e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 2.0e-12 +/- 6.7e-13 erg cm^-2 s^-1 (0.3-10 keV)
    Cat Source:  3XMM J023001.4-540115 in the XMM-NEWTON/XMMSSC
catalogue
    Separation:  10.5" from the XRT source
    Cat Rate:	 7.9e-01 +/- 1.0e-02 ct/sec 
    Cat Flux:	 7.9e-12 +/- 1.0e-13 erg cm^-2 s^-1 (0.3-10 keV)
       so the source is not above the catalogued flux.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 5:
  =============
    RA: 	 37.5869 ( = 02h 30m 20.86s) J2000
    Dec:	 -54.2524 ( = -54d 15' 08.6") J2000
    Error:	 +5.2 (arcsec, radius, 90% confidence).
    Peak Rate:	 3.4e-02 +/- 1.2e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 1.5e-12 +/- 5.0e-13 erg cm^-2 s^-1 (0.3-10 keV)
    Cat Source:  3XMM J023021.0-541506 in the XMM-NEWTON/XMMSSC
catalogue
    Separation:  2.3" from the XRT source
    Cat Rate:	 1.8e-01 +/- 4.7e-03 ct/sec 
    Cat Flux:	 1.8e-12 +/- 4.7e-14 erg cm^-2 s^-1 (0.3-10 keV)
       so the source is not above the catalogued flux.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
    There is 1 2MASS object within the source's 3-sigma error radius.
  
  Source 6:
  =============
    RA: 	 48.7127 ( = 03h 14m 51.05s) J2000
    Dec:	 -42.0480 ( = -42d 02' 52.8") J2000
    Error:	 +4.4 (arcsec, radius, 90% confidence).
    Peak Rate:	 3.6e-02 +/- 1.1e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 1.6e-12 +/- 4.8e-13 erg cm^-2 s^-1 (0.3-10 keV)
    Cat Source:  XMMSL2 J031450.4-420243 in the XMM-NEWTON/XMMSLEWCLN
catalogue
    Separation:  11.5" from the XRT source
    Cat Rate:	 1.6e+00 +/- 7.1e-01 ct/sec 
    Cat Flux:	 1.6e-11 +/- 7.1e-12 erg cm^-2 s^-1 (0.3-10 keV)
       so the source is not above the catalogued flux.
    There is no evidence for fading.
    NOTE: this source is NOT within 200 kpc of a GWGC or 2MPZ galaxy
      which is consistent (within 3-sigma) with the distance to the GW
object.
  
  Source 7:
  =============
    RA: 	 48.4264 ( = 03h 13m 42.34s) J2000
    Dec:	 -41.9943 ( = -41d 59' 39.5") J2000
    Error:	 +4.9 (arcsec, radius, 90% confidence).
    Peak Rate:	 3.5e-02 +/- 1.1e-02 ct/sec (0.3-10 keV)
    Peak Flux:	 1.5e-12 +/- 4.6e-13 erg cm^-2 s^-1 (0.3-10 keV)
    Cat Source:  1RXS J031342.2-415934 in the ROSAT/RASSBSC catalogue
    Separation:  5.7" from the XRT source
    Cat Rate:	 7.9e-02 +/- 1.6e-02 ct/sec 
    Cat Flux:	 2.2e-12 +/- 4.5e-13 erg cm^-2 s^-1 (0.3-10 keV)
       so the source is not above the catalogued flux.
    There is no evidence for fading.
    There is 1 GWGC or 2MPZ galaxy within 200 kpc of the source.

      and consistent (within 3-sigma) with the distance to the GW
object.
    A SIMBAD object `2MASS J03134233-4159362' is 3.3" away.
    There is 1 2MASS object within the source's 3-sigma error radius.

This circular is an official product of the Swift team.

C.M.Copperwheat (LJMU), A.S. Piascik (LJMU) and I.A.Steele (LJMU) report on behalf of

D.Bersier (LJMU), M.Bode (LJMU), C.Collins (LJMU), M.Darnley (LJMU), D.Galloway (Monash), A.Gomboc (Nova Gorica), S.Kobayashi (LJMU), A. Levan (Warwick), P.Mazzali (LJMU),  C.Mundell (Bath), E.Pian (Pisa), D. Pollacco (Warwick),  D. Steeghs (Warwick), N.Tanvir (Leicester), K. Ulaczyk (Warwick), K.Wiersema (Leicester)

and the GROWTH (Global Relay of Observatories Watching Transients Happen) collaboration.

---

We observed MASTER OT JJ015849.50-230853.7 originally reported in GCN #21499
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 , on 2017-08-17 at 04:45UT using the SPRAT spectrograph on the Liverpool Telescope. Using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024) we classify this transient as a SN Ia at around 13 days after peak, with a redshift of 0.035.

We also observed MASTER OT J030141.96-230037.8  on 2017-08-17 at 05:20UT. There is an extended object at these coordinates, but we detect no point source above the background level. The spectrum we obtained was featureless.

--
------------------------------------------------------
C.M.Copperwheat
Astrophysics Research Institute,
Liverpool John Moores University
------------------------------------------------------
http://telescope.livjm.ac.uk
------------------------------------------------------
Email: c.m.copperwheat@ljmu.ac.uk<mailto:c.m.copperwheat@ljmu.ac.uk>
Tel: +44 (0)151 231 2914
Fax: +44 (0)151 231 2921
------------------------------------------------------

________________________________
Important Notice: the information in this email and any attachments is for the sole use of the intended recipient(s). If you are not an intended recipient, or a person responsible for delivering it to an intended recipient, you should delete it from your system immediately without disclosing its contents elsewhere and advise the sender by returning the email or by telephoning a number contained in the body of the email. No responsibility is accepted for loss or damage arising from viruses or changes made to this message after it was sent. The views contained in this email are those of the author and not necessarily those of Liverpool John Moores University.

J. Alvarez-Muniz, F. Pedreira, E. Zas (Univ. Santiago de Compostela, Spain),
K. H. Kampert & M. Schimp (Bergische Universitat, Wuppertal, Germany)
on behalf of the Pierre Auger Collaboration.

In response to the LIGO/Virgo GW trigger G297595
(GCN #21474
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  ,T0=2017-08-14 10:30:43.527 UTC):

We searched for Ultra High Energy (UHE) neutrinos with energies
above ~ 1e17 eV in data collected with the Surface Detector (SD) of
the Pierre Auger Observatory in a [-500,500] second interval about
the LIGO-Virgo trigger G297595 as well as 1 day after it.

NO events survived the cuts applied to reject the background due to UHE
Cosmic Rays i.e. NO neutrino candidates were detected.

The field of view (fov) where the SD of Auger is sensitive to UHE neutrinos
(corresponding to inclined directions with respect to the vertical relative
to the ground) was NOT coincident with the updated LIGO 90% localization
region
at the time T0 of the merger alert. The LIGO 90% localization region
maximally
overlapped with the Auger fov for the first time at ~ T0+5.5 hours (i.e.
5.5 hr
after the merger) and remains fully in the Auger fov until ~ T0+8 hours.

The Pierre Auger Observatory is an UHE Cosmic Ray detector
located in the Mendoza Province in Argentina. It consists of an array
of Water Cherenkov detectors spread over a total surface of 3000 km^2
arranged in a triangular grid of 1.5 km side as well as Fluorescence
telescopes and other systems (see 10.1016/j.nima.2015.06.058
for more information).
For neutrino searches from GW events with Auger, please refer to:
https://journals.aps.org/prd/pdf/10.1103/PhysRevD.94.122007

M. de Naurois on behalf of the H.E.S.S. collaboration

The H.E.S.S. array of imaging atmospheric Cherenkov telescopes [1] was used to carry out follow-up observations of the GW trigger G297595 (GCN #21474
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 ) using the LALInference map (GCN #21493
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 ).
Observations started August 17 at 00:10 UTC and a total of 11 pointings were obtained over three consecutive nights. Each of the observations has a sensitivity of about 20% of the flux from the Crab nebula at 5 sigma. The observations cover about 80% of the LALInference localisation probability. A preliminary analysis with an energy threshold of about 500GeV did not reveal significant gamma-ray emission in any of the observed fields (within a field-of-view of ~2.5deg radius around the coordinates given below). Further analyses of the data are on-going.

The following regions-of-interests were observed. Given is the start time in UTC for each of the typically 28min long observations and the center of the ROI. 

     Time (UTC)              RA                  Dec
2017-08-17 00:10     2h38m19s     -48d43m12s
2017-08-17 00:40     3h03m07s     -45d35m24s
2017-08-18 00:10     2h36m58s     -51d15m59s 
2017-08-18 00:40     3h05m57s     -42d45m49s 
2017-08-18 01:10     3h13m53s     -39d46m14s   
2017-08-18 23:55     2h34m20s     -46d11m42s
2017-08-19 00:25     2h59m24s     -48d23m28s
2017-08-19 00:55     3h16m57s     -37d07m49s
2017-08-19 01:25     2h49m10s     -46d15m52s
2017-08-19 01:55     3h18m53s     -34d30m06s
2017-08-19 02:25     3h19m28s     -42d22m29s

H.E.S.S. is an array of five imaging atmospheric Cherenkov telescopes for the detection of very-high-energy gamma-ray sources and is located in the Khomas Highlands in Namibia. It was constructed and is operated by researchers from Armenia, Australia, Austria, the Czech Republic, France, Germany, Ireland, Netherlands, Japan, Poland, South Africa, Sweden, UK, and the host country, Namibia. For more details see https://www.mpi-hd.mpg.de/hfm/HESS/

G. P. Smith (Birmingham), M. Jauzac (Durham), M. Bianconi (Birmingham), 
J. Richard (Lyon), C. P. L. Berry (Birmingham), W. M. Farr (Birmingham), 
R. Massey (Durham), A. Robertson (Durham), K. Sharon (Michigan), A. 
Vecchio (Birmingham), J. Veitch (Glasgow)

The Gravitationally-lensed Gravitational Wave Hunters collaboration 
report observations of strong-lensing galaxy clusters located within the 
sky localisation of the LIGO/Virgo trigger G297595 (LVC GCN Circ. 21474
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 ).

Following Smith et al. (arXiv:1707.03412
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 ) we searched the initial 
(August 14th) and updated (August 16th) skymaps for strong-lensing 
galaxy clusters that lie within the 90% credible sky localisation.

Abell 3084 was the closest strong-lensing galaxy cluster to the peak 
probability in the initial skymap.  We observed this cluster through the 
i-band filter with GMOS on Gemini-South on the nights of August 14, 16, 
17, 20, 21, and with MUSE on VLT on the nights of August 16, and 18. 
GMOS spans a 5.5x5.5 arcminute field of view, and MUSE spans a 1x1 
arcminute field of view with a wavelength range of 4650-9300 Angstroms.

SMACSJ0304.3-4401 was the closest strong-lensing galaxy cluster to the 
peak probability in the updated skymap.  We observed this cluster 
through the i-band filter with GMOS on Gemini-South on the nights of 
August 17 and 20.

Analysis of these data is ongoing.  Colleagues with complementary data 
are welcome to contact us with a view to collaboration.

We thank the staff at ESO and Gemini for their outstanding support of 
our observing programmes.

V. Savchenko (ISDC, University of Geneva, CH)
on behalf of the INTEGRAL group:
C. Ferrigno, E. Bozzo ((ISDC, University of Geneva, CH),
E. Kuulkers (ESTEC/ESA, The Netherlands),
S. Mereghetti (IASF-Milano, Italy),
T. J.-L. Courvoisier (ISDC, University of Geneva, CH)
J. Chenevez, S. Brandt (DTU - Denmark)
R. Diehl (MPE-Garching, Germany)
L. Hanlon (UCD, Ireland)
P. Laurent (APC, Saclay/CEA, France), D. Gotz (DRF/Irfu/DAp Saclay/CEA)
J.P. Roques, E. Jourdain (IRAP, France)
P. Ubertini, A. Bazzano, J. Rodi (IAPS-Roma, Italy)
A. Lutovinov, R. Sunyaev (IKI, Russia)

INTEGRAL is an observatory with multiple instruments: a gamma-ray
spectrometer (20 keV -4 MeV, SPI), an imager (15 keV - 2 MeV, IBIS),
an X-ray monitor (3-25 keV, JEM-X), and an optical monitor (V band,
OMC). Our group requested and obtained pointed follow-up observations
of the LIGO/Virgo candidate BBH merger G297595 (GCN 21474
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 ).

The INTEGRAL follow-up observation was centered on RA=41.07
Dec=-45.49, close to the peak of the LIGO/Virgo localization
probability, taking into account observational constrains. This
observation spanned from 2017-08-16 at 10:04 to 2017-08-17 at 18:19
(starting about 47 hours after the LIGO/Virgo event), with a maximum
on-source time of 97.5 ks (depending on the instrument).

IBIS and SPI observed more than 92% of the of LIGO/Virgo localization
in the combined observation mosaic. JEM-X covered about 79%, owing to
its smaller Field of View.  INTEGRAL provides the most stringent
constraint on any possible emission associated with G297595, above 80
keV.  We searched IBIS/ISGRI and JEM-X data for new point sources in
the whole 90% LIGO/Virgo localization region, and did not find any. We
set the following 3-sigma upper limits for the average flux:

JEM-X:

3-10 keV: 2.0 mCrab (3.2e-11  erg/cm2/s )
10-25 keV: 1.0 mCrab (1.1e-11  erg/cm2/s )

ISGRI:

20-80 keV: 3.3 mCrab (4.9e-11 erg/cm2/s)
80-300 keV: 13.1 mCrab (1.5e-10 erg/cm2/s)


In the case of ISGRI (JEM-X), 82% (59%) of the of LIGO/Virgo
localization is covered with sensitivity no more than factor two worse
than the best.

During these observation online INTEGRAL/IBAS system identified
several weak triggers. After offline inspection, we consider these
triggers unrelated noise.

INTEGRAL/IBAS online search in the SPI-ACS identified a bright
GRB170816A on 2017-08-16 at 14:22:58. The location of this GRB is
inconsistent with the LIGO/Virgo 90% localization (GCN 21504
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 , 21517
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 ).

Finally, the BNS merger G298048 (GCN 21509
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 , 21513
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 ) candidate
counterpart (GRB 170817A, GCN 21506
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 , 21520
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 ) was detected in the
INTEGRAL data during this observation, as reported in GCN 21507
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 .

We have also inspected PICsIT spectral-timing data (200 - 2600 keV)
and did not find any evidence for significant variability.

Further analysis is ongoing.

We acknowledge the essential support by the teams at ESAC and ESOC for
the scheduling of this follow-up observation.

S. Allam (Fermilab), J. Annis (Fermilab), J.Garcia Bellido (IFT CSIC/UAM),
E. Berger (Harvard),
D. J. Brout (UPenn), D. Brown (Syracuse), R. E. Butler (Fermilab), H.-Y.
Chen (Harvard), R. Chornock (Ohio University), E. Cook (TAMU), P. S.
Cowperthwaite (Harvard), H. T. Diehl (Fermilab), A. Drlica-Wagner
(Fermilab), Z. Doctor (U. Chicago), M. R. Drout (Carnegie), B. Farr (U
Chicago), R. J. Foley (UCSC), W. Fong (Northwestern), D. Fox (Penn State),
J. Frieman (Fermilab/UChicago), M.S.S. Gill (Stanford), R. Gruendl (NCSA),
K. Herner (Fermilab), D. Holz (UChicago), R. Kessler (UChicago), H. Lin
(Fermilab), J. Marriner (Fermilab), R. Margutti (Northwestern), J. Marshall
(TAMU), E. Neilsen (Fermilab), F. Paz-Chincon (NCSA), M. Nicholl (Harvard),
A. Rest (STScI), M. Sako (UPenn), D. Scolnic (KICP), N. Smith (Arizona), M.
Soares-Santos (BrandeisU), D. Tucker (Fermilab), V. A. Villar (Harvard), A.
Walker (NOAO), B. Yanny (Fermilab), P. K. G. Williams (Harvard)

On behalf of the DESGW+community team:

We report on observations of LVC trigger G297595 conducted with the Dark
Energy camera (DECam) on the Blanco 4-m telescope at CTIO (program
2017B-0110, PI: Berger) for several nights starting on 2017-08-15 UT.
Observations consisted of 90 second exposures in i band.

On the first night observations started at 2017-08-15 06:00 UT (19 hours
after the GW detection). In 4 hours of observing time we performed two
tilings of the area and covered 90% of the localization probability given
by the LVC sky map available at the time. On the second night observations
started at 2017-08-16 06:00 UT. We performed a second visit of the area
covered in the previous night. At 07:02 UT a new map was released by LVC.
Our observations overlapped 49% of the probability on the new map. We
recomputed our sky footprint and, at 08:11 UT, started observations
covering a total of 84% of the new localization probability. On the third
night we performed a second tiling of the new area starting at 2017-08-17
06:30 UT. We revisited the new area 4 more times. The last visit of the
region was on the night of 2017-08-26 UT.

DECam has a 3 sq-deg field of view and typically reaches i,z = 23rd
limiting magnitudes for 90 second exposures. We have covered 160 sq-deg,
corresponding to 84% of the updated localization probability, to 23rd mag
in i band.

The table below lists the coordinates observed (first epoch only). Data
reduction is being performed using the DES software pipeline and an
independent pipeline on the Harvard Odyssey computer cluster. Difference
imaging is being performed using pre-existing DES exposures as templates.
Analysis is underway.


108 rows returned
expnumradecairmassseeingmag_limtime_since_trigger
667113 33.081017 -53.7447 1.36 1.131 22.70 19:29:38.500579
667114 34.526567 -47.6579 1.35 1.164 22.70 19:31:49.617109
667115 34.908854 -45.6289 1.35 1.232 22.64 19:33:49.704425
667116 37.8198 -40.5565 1.39 1.496 22.41 19:35:57.406561
667117 40.14195 -37.5131 1.43 1.4 22.46 19:37:56.378284
667118 41.501492 -50.7013 1.43 1.16 22.64 19:40:27.438763
667120 44.232871 -31.4262 1.52 1.179 22.59 19:45:04.830179
667121 46.071733 -28.3827 1.58 1.174 22.59 19:47:04.174300
667122 46.098692 -30.4117 1.55 1.118 22.66 19:49:01.944646
667123 46.386629 -44.6144 1.47 1.143 22.68 19:51:35.334292
667125 47.925883 -29.3972 1.56 1.312 22.46 19:56:11.468952
667126 47.993579 -31.4262 1.53 1.311 22.48 19:58:09.701798
667127 48.068325 -33.4551 1.5 1.323 22.46 20:00:09.554130
667128 48.151142 -35.4841 1.48 1.325 22.48 20:02:08.778424
667129 48.242654 -37.5131 1.46 1.252 22.56 20:04:07.371388
667130 48.343783 -39.542 1.45 1.194 22.59 20:06:06.372826
667131 42.266758 -34.4696 1.34 1.178 22.66 20:08:17.035111
667132 47.864804 -27.3683 1.48 1.222 22.54 20:10:30.827879
667133 33.620458 -51.7158 1.24 1.084 22.84 20:13:27.625683
667134 34.099333 -49.6868 1.23 1.049 22.89 20:15:26.147706
667135 36.02235 -52.7303 1.26 1.139 22.77 20:17:26.087003
667136 37.345425 -44.6144 1.23 1.516 22.48 20:19:48.078520
667137 37.594904 -42.5855 1.22 1.292 22.63 20:21:46.394679
667138 38.82525 -51.7158 1.26 1.175 22.73 20:24:09.877128
667139 39.859292 -41.571 1.24 1.205 22.68 20:26:33.378343
667140 40.007792 -39.542 1.23 1.127 22.77 20:28:32.514268
667141 42.130425 -38.5275 1.25 1.144 22.73 20:30:32.596601
667142 42.202033 -36.4986 1.25 1.076 22.81 20:32:32.148424
667143 44.089667 -47.6579 1.27 1.141 22.75 20:34:59.845293
667145 44.220629 -33.4551 1.25 1.242 22.64 20:39:28.326716
667146 46.12845 -32.4407 1.28 1.175 22.69 20:41:26.347140
667147 46.161358 -34.4696 1.26 1.135 22.73 20:43:27.175973
667148 46.197842 -36.4986 1.26 1.11 22.81 20:45:26.086710
667149 46.282604 -40.5565 1.25 1.065 22.83 20:47:28.378746
667150 46.331908 -42.5855 1.25 1.08 22.85 20:49:27.419364
667151 44.207146 -35.4841 1.21 0.952 22.96 20:51:56.583169
667153 36.758192 -48.6723 1.16 0.996 22.95 20:56:32.782815
667154 37.067833 -46.6434 1.15 0.97 22.97 20:58:31.339136
667155 39.080533 -49.6868 1.18 0.987 22.93 21:00:30.766293
667156 39.308158 -47.6579 1.16 0.984 22.97 21:02:28.452052
667157 39.511846 -45.6289 1.15 1.051 22.89 21:04:27.301000
667158 39.694696 -43.5999 1.14 1.112 22.83 21:06:25.419905
667159 41.636792 -48.6723 1.17 1.105 22.83 21:08:36.460086
667160 41.757629 -46.6434 1.16 1.01 22.91 21:10:34.758344
667161 41.866021 -44.6144 1.15 1.019 22.92 21:12:33.041454
667162 41.9634 -42.5855 1.14 0.992 22.94 21:14:31.312051
667163 42.051196 -40.5565 1.13 1.011 22.90 21:16:30.358284
667164 44.114746 -45.6289 1.16 1.007 22.92 21:18:37.993401
667165 44.137292 -43.5999 1.15 0.942 22.97 21:20:37.989628
667166 44.157496 -41.571 1.14 1.022 22.88 21:22:36.577622
667167 44.175796 -39.542 1.13 1.101 22.80 21:24:36.200377
667168 44.19225 -37.5131 1.13 1.04 22.88 21:26:35.962091
667169 46.238025 -38.5275 1.14 1.035 22.88 21:28:33.252666
667170 46.238025 -38.5275 1.14 1.042 22.86 21:30:33.628407
667637 36.02235 -52.7303 1.12 1.374 22.64 1 day, 21:41:03.836806
667638 36.411796 -50.7013 1.1 1.19 22.80 1 day, 21:43:01.770738
667639 36.758192 -48.6723 1.09 1.1 22.88 1 day, 21:44:59.834221
667640 37.067833 -46.6434 1.08 1.137 22.84 1 day, 21:46:58.881032
667641 38.537821 -53.7447 1.13 1.022 22.92 1 day, 21:49:14.047259
667642 39.511846 -45.6289 1.08 0.954 23.01 1 day, 21:51:35.282434
667643 39.694696 -43.5999 1.07 0.919 23.05 1 day, 21:53:32.996321
667644 41.349346 -52.7303 1.12 1.049 22.91 1 day, 21:55:58.142319
667645 41.9634 -42.5855 1.07 0.999 22.98 1 day, 21:58:24.355336
667646 44.175796 -39.542 1.07 0.949 23.05 1 day, 22:00:25.022154
667647 46.197842 -36.4986 1.07 1.018 22.99 1 day, 22:02:23.856376
667648 46.591183 -50.7013 1.12 1.138 22.84 1 day, 22:04:55.598562
667649 48.068325 -33.4551 1.07 1.033 22.94 1 day, 22:07:36.909732
667650 49.818992 -30.4117 1.08 1.013 22.95 1 day, 22:09:35.571894
667651 51.475817 -27.3683 1.09 1.035 22.92 1 day, 22:11:34.892573
667652 50.907329 -44.6144 1.1 1.151 22.84 1 day, 22:14:14.888743
667653 52.292954 -37.5131 1.09 1.103 22.89 1 day, 22:16:34.033753
667654 52.511683 -39.542 1.09 1.205 22.78 1 day, 22:18:32.990654
667655 38.82525 -51.7158 1.09 1.21 22.78 1 day, 22:21:07.325116
667656 39.080533 -49.6868 1.07 1.127 22.89 1 day, 22:23:05.824461
667657 39.308158 -47.6579 1.06 1.211 22.80 1 day, 22:25:03.367628
667658 41.501492 -50.7013 1.08 1.173 22.84 1 day, 22:27:03.333138
667659 41.636792 -48.6723 1.07 1.194 22.82 1 day, 22:29:01.859464
667660 41.757629 -46.6434 1.06 1.128 22.90 1 day, 22:30:59.623472
667661 41.866021 -44.6144 1.05 1.032 23.00 1 day, 22:32:57.799484
667662 44.030158 -51.7158 1.09 1.181 22.83 1 day, 22:35:36.632387
667663 44.157496 -41.571 1.04 1.062 22.94 1 day, 22:38:02.053494
667664 46.238025 -38.5275 1.03 1.125 22.91 1 day, 22:40:01.143328
667665 48.151142 -35.4841 1.03 1.04 22.95 1 day, 22:42:00.345576
667666 48.871258 -47.6579 1.07 1.082 22.91 1 day, 22:44:27.561412
667667 49.93155 -32.4407 1.03 1.047 22.97 1 day, 22:47:02.461422
667668 50.700404 -42.5855 1.05 1.039 22.97 1 day, 22:49:24.916068
667669 51.607892 -29.3972 1.03 1.071 22.92 1 day, 22:51:55.034195
667670 51.754275 -31.4262 1.03 1.071 22.94 1 day, 22:53:54.540442
667671 51.916125 -33.4551 1.03 1.155 22.86 1 day, 22:55:53.947934
667672 52.095046 -35.4841 1.03 1.091 22.96 1 day, 22:57:53.351123
667673 44.061646 -49.6868 1.07 1.16 22.88 1 day, 23:01:06.555281
667674 44.089667 -47.6579 1.05 1.151 22.88 1 day, 23:03:04.628618
667675 44.114746 -45.6289 1.04 1.135 22.89 1 day, 23:05:04.104997
667676 44.137292 -43.5999 1.03 1.16 22.86 1 day, 23:07:02.134092
667677 46.282604 -40.5565 1.02 1.139 22.91 1 day, 23:09:01.550370
667678 46.331908 -42.5855 1.03 1.207 22.84 1 day, 23:10:59.205759
667679 46.386629 -44.6144 1.04 1.294 22.77 1 day, 23:12:57.317365
667680 46.447529 -46.6434 1.05 1.258 22.81 1 day, 23:14:56.838481
667681 46.5153 -48.6723 1.06 1.339 22.73 1 day, 23:16:54.491556
667682 48.242654 -37.5131 1.01 1.423 22.69 1 day, 23:19:19.875913
667683 48.343783 -39.542 1.02 1.204 22.86 1 day, 23:21:19.338861
667684 48.455683 -41.571 1.02 1.166 22.91 1 day, 23:23:17.317086
667685 48.5799 -43.5999 1.03 1.237 22.83 1 day, 23:25:16.075497
667686 48.71775 -45.6289 1.04 1.19 22.85 1 day, 23:27:14.313076
667687 50.05605 -34.4696 1.01 1.143 22.92 1 day, 23:29:40.767316
667688 50.193629 -36.4986 1.01 1.28 22.80 1 day, 23:31:40.215267
667689 50.345717 -38.5275 1.01 1.177 22.89 1 day, 23:33:38.757192
667690 50.514 -40.5565 1.02 1.062 23.00 1 day, 23:35:36.910088

G. Hosseinzadeh, I. Arcavi (Las Cumbres Obs./UCSB), M. Zalzman, D.
Poznanski (TAU), L. P. Singer (NASA/GSFC), D. A. Howell, C. McCully, S.
Vasylyev (Las Cumbres Obs./UCSB), S. Valenti (UC Davis), T. Piran (HUJI),
D. Kasen, and J. Barnes (UC Berkeley) report optical follow-up observations
of GW170814 (GCN 21474
Loading...
 
 ) using Las Cumbres Observatory's 2-meter telescopes
at Haleakala Observatory (HO), Hawai'i, and Siding Spring Observatory
(SSO), Australia. We observed 16 nearby galaxies from the GLADE catalog
(Dalya et al. 2016, http://aquarius.elte.hu/glade/) prioritized by their
position in the localization region, their mass, and inversely with their
distance. A total of 49 images were obtained in the g, r, and i filters
using 300-second exposures (full list below). We calculated 3-sigma
limiting magnitudes by calibrating to nearby stars in the APASS catalog
(Henden et al. 2009, AAS, 214, 407.02). Further analysis is ongoing.

GLADE ID R.A.      Dec.       Dist. Date       Time     Site Filter Limit
         (deg)     (deg)      (Mpc) (UT)       (UT)                 (mag)
  723415 40.523499 -45.337452   433 2017-08-14 16:46:38 SSO  g      21.5
  723415 40.523499 -45.337452   433 2017-08-14 16:52:10 SSO  r      21.2
  723415 40.523499 -45.337452   433 2017-08-14 16:57:41 SSO  i      20.4
  721389 42.015915 -44.111561   476 2017-08-14 16:00:52 SSO  g      21.3
  721389 42.015915 -44.111561   476 2017-08-14 16:08:39 SSO  r      21.4
  721389 42.015915 -44.111561   476 2017-08-14 16:14:12 SSO  i      21.7
  787654 40.731670 -44.360573   443 2017-08-14 17:06:51 SSO  g      20.8
  787654 40.731670 -44.360573   443 2017-08-14 17:12:22 SSO  r      18.9
  787654 40.731670 -44.360573   443 2017-08-14 17:17:53 SSO  i      21.6
  556821 41.190659 -45.095711   441 2017-08-14 18:20:21 SSO  g      20.2
  556821 41.190659 -45.095711   441 2017-08-14 18:26:34 SSO  r      19.0
  556821 41.190659 -45.095711   441 2017-08-14 18:32:06 SSO  i      17.4
  625999 41.654194 -42.367088   308 2017-08-15 14:28:10 HO   g      21.8
  625999 41.654194 -42.367088   308 2017-08-15 15:08:26 HO   g      21.4
  625999 41.654194 -42.367088   308 2017-08-15 14:34:20 HO   r      22.0
  625999 41.654194 -42.367088   308 2017-08-15 14:39:52 HO   i      21.8
  706152 40.122471 -45.386868   494 2017-08-15 13:30:24 SSO  g      20.4
  706152 40.122471 -45.386868   494 2017-08-15 13:35:57 SSO  r      20.5
  706152 40.122471 -45.386868   494 2017-08-15 13:41:28 SSO  i      20.2
  752527 42.434814 -42.327412   322 2017-08-15 14:47:23 HO   g      *
  752527 42.434814 -42.327412   322 2017-08-15 14:52:54 HO   r      *
  752527 42.434814 -42.327412   322 2017-08-15 14:58:25 HO   i      *
 1066576 41.292435 -46.597050   399 2017-08-14 17:27:53 SSO  g      21.4
 1066576 41.292435 -46.597050   399 2017-08-14 17:33:24 SSO  r      21.5
 1066576 41.292435 -46.597050   399 2017-08-14 17:38:56 SSO  i      21.5
 1005823 42.079330 -44.054893   451 2017-08-15 14:10:58 SSO  g      20.5
 1005823 42.079330 -44.054893   451 2017-08-15 14:16:30 SSO  r      20.6
 1005823 42.079330 -44.054893   451 2017-08-15 14:22:02 SSO  i      20.3
 1031304 41.217548 -46.500435   402 2017-08-15 14:53:00 SSO  g      20.9
 1031304 41.217548 -46.500435   402 2017-08-15 14:58:31 SSO  r      20.8
 1031304 41.217548 -46.500435   402 2017-08-15 15:04:03 SSO  i      20.6
  622864 41.392635 -44.539589   316 2017-08-14 19:12:39 SSO  g      20.4
  622864 41.392635 -44.539589   316 2017-08-14 19:18:10 SSO  r      20.2
  622864 41.392635 -44.539589   316 2017-08-14 19:23:41 SSO  i      19.9
 1415752 42.418404 -44.226032   422 2017-08-15 13:49:58 SSO  g      20.4
 1415752 42.418404 -44.226032   422 2017-08-15 13:55:31 SSO  r      20.6
 1415752 42.418404 -44.226032   422 2017-08-15 14:01:02 SSO  i      20.3
 1181112 41.086727 -43.939903   452 2017-08-15 14:32:00 SSO  g      20.8
 1181112 41.086727 -43.939903   452 2017-08-15 14:37:31 SSO  r      20.7
 1181112 41.086727 -43.939903   452 2017-08-15 14:43:03 SSO  i      20.6
  806902 42.062664 -45.159618   447 2017-08-14 16:25:24 SSO  g      20.8
  806902 42.062664 -45.159618   447 2017-08-14 16:30:55 SSO  r      18.4
  806902 42.062664 -45.159618   447 2017-08-14 16:36:27 SSO  i      20.7
 1647694 42.000800 -46.319860   382 2017-08-14 18:52:50 SSO  g      21.5
 1647694 42.000800 -46.319860   382 2017-08-14 18:59:02 SSO  r      21.5
 1647694 42.000800 -46.319860   382 2017-08-14 19:04:33 SSO  i      20.5
   62667 41.574863 -44.984894   488 2017-08-15 15:14:03 SSO  g      20.8
   62667 41.574863 -44.984894   488 2017-08-15 15:19:34 SSO  r      20.9
   62667 41.574863 -44.984894   488 2017-08-15 15:25:06 SSO  i      20.5
*A limiting magnitude was not calculated for fields with very few APASS
stars visible.

Sheng Yang (INAF-OAPd, UC Davis), Stefano Valenti(UC Davis), David Sand (UA), Leonardo Tartaglia (UA, UC Davis), Enrico Cappellaro(INAF-OAPd), Dan Reichart, Josh Haislip (UNC) report on behalf of the Gravitational Wave Follow-Up by DLT40.

We report the observation of 24 galaxies within the LVC error region for the GW trigger GW170814 using the LIGO bayestar HLV localization map. We selected galaxies from the GWGC catalogue within 99.0% of the trigger error region, within a distance of 40.0 Mpc, brighter than -17.5 mag and at a Declination < 20 degree.
Those selected galaxies have been observed using the Prompt 5 telescope and they are part of the ongoing DLT40 search. The DLT40 search limit magnitude, for those galaxies is 19.0 (open filter scaled to r band). 

Below follow the list of galaxies observed:
Name RA(J2000) DEC(J2000) Dist(Mpc) BMAG KMAG OBS_WINDOW(JD)
NGC1097 41.57 -30.27 14.19 -20.74 -24.50 2457980.28-2457982.25                                                                                                                   
NGC0908 35.76 -21.23 15.78 -20.53 -23.76 2457980.28-2457982.25                                                                                                                   
NGC1232 47.43 -20.57 14.52 -20.42 -23.42 2457980.28-2457982.25                                                                                                                   
NGC0986 38.39 -39.04 23.12 -20.16 -24.04 2457980.28-2457982.25                                                                                                                   
NGC1302 49.96 -26.06 19.59 -20.06 -23.63 2457980.28-2457982.25                                                                                                                   
NGC1187 45.65 -22.86 18.36 -20.03 -23.21 2457980.28-2457982.25                                                                                                                   
NGC1201 46.03 -26.06 19.33 -20.01 -23.75 2457980.28-2457982.25                                                                                                                   
NGC1309 50.52 -15.4 23.12 -19.92 -22.71 2457980.28-2457982.25                                                                                                                    
NGC1300 49.92 -19.41 14.52 -19.86 -23.24 2457980.28-2457982.25                                                                                                                   
NGC1255 48.38 -25.72 17.7 -19.83 -22.86 2457980.28-2457982.25                                                                                                                    
PGC012664 50.72 -11.20 34.67 -19.73 -21.10 2457980.28-2457982.25                                                                                                                
NGC1325 51.10 -21.54 19.95 -19.72 -22.87 2457980.28-2457982.25                                                                                                                   
NGC1297 49.80 -19.10 28.58 -19.68 -23.34 2457980.28-2457982.25                                                                                                                   
PGC012633 50.57 -7.09 33.89 -19.24 -22.34 2457980.28-2457982.25                                                                                                                 
NGC1292 49.56 -27.61 18.97 -19.19 -21.99 2457980.28-2457982.25
ESO545-005 35.02 -19.75 30.2 -19.15 -21.79 2457980.28-2457982.25
PGC013359 54.30 1.86 22.59 -19.15 -20.80 2457980.28-2457982.25
NGC0988 38.86 -9.356 17.3 -18.98 -24.19 2457980.28-2457982.25
PGC1075354 52.67 -3.163 24.72 -18.94 -21.04 2457980.28-2457982.25
NGC1337 52.02 -8.388 11.91 -18.86 -21.16 2457980.28-2457982.25
IC1892 47.11 -23.05 34.67 -18.85 -19.73 2457980.28-2457982.25
IC1898 47.58 -22.40 19.5 -18.39 -21.41 2457980.28-2457982.25
ESO300-014 47.40 -41.03 10.86 -18.32 -16.32 2457980.28-2457982.25
ESO481-018 49.63 -25.83 18.53 -18.28 -20.64 2457980.28-2457982.25

M. Im, C. Choi, H. M. Lee (SNU), on behalf of the KU collaboration

We report the observation of galaxies in the LVC error region for
 G297595/GW170814 (GCN 21474
Loading...
 
 ) The following galaxies were observed as a
part of the ongoing galaxy monitoring program one to two days before or
after the reported time of the event of 2017-08-14 10:30:43 UTC (GCN21474
Loading...
 
 ).
The Lee Sang Gak Telescope (LSGT), a 0.43m telescope at the Siding Spring
Observatory, was used for the observation (Im et al. 2015).

NGC 1097

NGC 1309

NGC 1365

NGC 1395

NGC 1672

2MASX J02451334-4627194

LCRS B025857.5-382242

2MASX J03171288-435821

LCRS B031640.4-421205

 No credible transient has been found around these galaxies, except for NGC
1672 where a young supernova, SN 2017gax, is detected in the images taken
on both August 13 and 14, making it not associated with G297595/GW170814.

D. Roberts, U. Kolb & M.Morrell (The Open University) reporting on behalf of the PIRATE group:


We observed 15 separate fields within the LALInference update skymap of the LIGO/Virgo candidate G297595 using our 0.43m robotic telescope at Teide Observatory, Tenerife, Spain. We acquired 118 images across 7 nights of observations, all images were obtained using the R filter and 100s exposure length. Initial observations began at 2017-08-17T04:45:22, approximately 15hrs after receiving the updated alert, and 2.75 days after the initial trigger. A detailed list of all the fields observed can be found on GraceDB under the EMObservations tab. A high number of poor quality images (19) and low cadence made transient searches difficult but our initial analysis suggests no new transients were detected in any of the observing fields down to a limiting magnitude ~17. Further analysis is ongoing.

-- The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England & Wales and a charity registered in Scotland (SC 038302). The Open University is authorised and regulated by the Financial Conduct Authority in relation to its secondary activity of credit broking.

S. Rosetti, N. R. Tanvir, A. J. Levan, C. Gonzalez-Fernandez, D. Steeghs,
K. Wiersema report on behalf of the VINROUGE collaboration:

NIR follow-up observations were carried out using the 4m ESO/VISTA 
telescope at the Paranal Observatory (Cerro Paranal, Chile) in response 
to the LIGO/Virgo trigger G297595/GW170814 (GCN� 21474). 
The observations took place between 05:37:37 UT on 14 August 2017 
and 09:47:17.6 UT on 16 August 2017. 22 tiles were produced for each 
filter (Ks, J and Y), each covering a 1.5 square degree area. Analysis
is ongoing.  The targeted areas are listed as follows:


UT(DAY MIN:SEC)	RA (J2000)	 Dec (J2000)    Filter
��������������������������
20170814 347:41.0 	02:38:41.2 	-44:24:38.8  	J       
20170814 337:37.0 	02:38:41.2 	-44:24:39.4  	Ks      
20170814 357:17.0 	02:38:41.2 	-44:24:38.8  	Y       
20170814 397:03.6 	02:35:19.1 	-45:51:33.8  	J       
20170814 380:06.0 	02:35:19.0 	-45:51:34.3  	Ks      
20170814 409:21.0 	02:35:19.1 	-45:51:33.8  	Y       
20170814 436:38.6 	02:34:37.4 	-47:19:04.0  	J	       
20170814 426:25.0 	02:34:37.4 	-47:19:04.6  	Ks      
20170814 446:18.6 	02:34:37.4 	-47:19:04.0  	Y       
20170814 468:36.0 	02:47:25.1 	-42:57:16.9  	J       
20170814 458:22.6 	02:47:25.1 	-42:57:17.5  	Ks      
20170814 480:14.0 	02:47:25.1 	-42:57:16.9  	Y       
20170814 511:52.0 	02:34:48.7 	-48:46:33.8  	J       
20170814 490:19.6 	02:34:48.6 	-48:46:34.4  	Ks      
20170814 523:49.0 	02:34:48.7 	-48:46:33.8  	Y       
20170814 548:35.0 	02:51:26.4 	-41:29:06.0  	J       
20170814 536:30.0 	02:51:26.4 	-41:29:06.5  	Ks      
20170814 560:49.0 	02:51:26.4 	-41:29:06.0  	Y  
20170814 583:24.6 	02:39:15.5 	-47:19:02.9  	J       
20170814 570:45.6 	02:39:15.4 	-47:19:03.5  	Ks     
20170814 593:07.0 	02:39:15.5 	-47:19:02.9  	Y  
��������������������������
20170815 337:34.6 	02:40:38.7 	-45:51:37.0  	J       
20170815 327:33.6 	02:40:38.6 	-45:51:37.6  	Ks      
20170815 347:10.0 	02:40:38.7 	-45:51:37.0  	Y       
20170815 369:18.0 	02:44:30.7 	-45:51:37.7  	J       
20170815 359:08.6 	02:44:30.6 	-45:51:38.3  	Ks      
20170815 381:10.0 	02:44:30.7 	-45:51:37.7  	Y       
20170815 405:29.0 	02:44:11.3 	-44:24:41.7  	J	       
20170815 391:23.6 	02:44:11.2 	-44:24:42.3 	Ks      
20170815 416:17.0 	02:44:11.3 	-44:24:41.7  	Y      
20170815 440:25.0 	02:49:23.3 	-44:24:41.7  	J       
20170815 426:08.6 	02:49:23.2 	-44:24:42.3  	Ks     
20170815 450:37.0 	02:49:23.3 	-44:24:41.7  	Y       
20170815 474:00.0 	02:52:28.9 	-42:57:09.0  	J      
20170815 463:44.0 	02:52:28.8 	-42:57:09.5  	Ks      
20170815 486:23.6 	02:52:28.9 	-42:57:09.0  	Y       
20170815 509:14.0 	02:54:20.3 	-41:29:07.1  	J       
20170815 496:34.6 	02:54:20.3 	-41:29:07.6  	Ks      
20170815 518:55.6 	02:54:20.3 	-41:29:07.1  	Y       
20170815 542:40.6 	02:50:08.7 	-45:51:32.7  	J       
20170815 531:52.6 	02:50:08.6 	-45:51:33.3  	Ks      
20170815 553:59.0 	02:50:08.7 	-45:51:32.7  	Y      
20170815 575:29.0 	02:43:33.1 	-47:19:06.8  	J       
20170815 564:29.0 	02:43:33.0 	-47:19:07.5  	Ks      
20170815 585:24.6 	02:43:33.1 	-47:19:06.8  	Y       
��������������������������
20170816 367:55.0 	03:05:18.2 	-44:24:41.0  	J     
20170816 358:02.0 	03:05:18.2 	-44:24:41.5  	Ks     
20170816 377:26.0 	03:05:18.2 	-44:24:41.0  	Y      
20170816 399:22.6 	03:10:48.2 	-44:24:41.0  	J      
20170816 389:15.0 	03:10:48.2 	-44:24:41.5  	Ks     
20170816 410:03.0 	03:10:48.2 	-44:24:41.0  	Y      
20170816 431:04.6 	02:59:47.3 	-44:24:41.7  	J      
20170816 421:00.0 	02:59:47.2 	-44:24:42.3  	Ks     
20170816 440:36.0 	02:59:47.3 	-44:24:41.7  	Y      
20170816 462:34.6 	03:07:06.8 	-42:57:13.0  	J      
20170816 452:29.0 	03:07:06.7 	-42:57:13.5  	Ks     
20170816 474:18.6 	03:07:06.8 	-42:57:13.0  	Y      
20170816 495:41.6 	03:01:24.9 	-45:51:34.8  	J      
20170816 484:19.6 	03:01:24.9 	-45:51:35.4  	Ks     
20170816 505:18.0 	03:01:24.9 	-45:51:34.8  	Y      
20170816 530:22.6 	03:06:43.4 	-45:51:35.9  	J      
20170816 520:16.6 	03:06:43.4 	-45:51:36.5  	Ks     
20170816 539:55.6 	03:06:43.4 	-45:51:35.9  	Y      
20170816 568:38.6 	03:15:04.6 	-44:24:41.7  	J      
20170816 558:28.0 	03:15:04.5 	-44:24:42.3  	Ks     
20170816 579:28.0 	03:15:04.6 	-44:24:41.7  	Y

The LIGO Scientific Collaboration and the Virgo Collaboration report:

We have re-analysed offline noise-subtracted data for the LIGO Hanford
Observatory (H), LIGO Livingston Observatory (L), and Virgo (V) detectors
around the time of the binary black hole event G297595 / GW170814 (GCNs
21474
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 , 21493
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 ) taking into account our most up-to-date understanding of
both calibration and waveform modelling uncertanties.

Parameter estimation has been performed using LALInference (Veitch et al.,
PRD 91, 042003) and a new sky map, LALInference_v1.fits.gz, is available
for retrieval from the GraceDB event page:

https://gracedb.ligo.org/events/G297595

The 50% and 90% credible regions span about 13 and 62 square degrees,
respectively.

This is the preferred sky map at this time, and the version that will
appear in LVC 2017 (Physical Review Letters, in press).