LIGO/Virgo G194575

Leo Singer (NASA/GSFC), Peter Shawhan (UMD), Nipuni Palliyaguru (TTU), B.
S. Sathyaprakash (Cardiff), Alex Urban (UWM), Jeff Bartlett (LIGO
Hanford), Travis Sadecki (LIGO Hanford), Mike Landry (LIGO Hanford), Joe
Hanson (LIGO Livingston), Bryan Smith (LIGO Livingston), Brian O'Reilly
(LIGO Livingston), Kipp Cannon (CITA), Gianluca Guidi (Urbino), Andy
Lundgren (AEI/Hannover), Laura Nuttall (Syracuse), T. J. Massinger
(Syracuse), Jessica McIver (Caltech), and Joshua Smith (Fullerton) report
on behalf of the LIGO Scientific Collaboration and Virgo:

The gstlal CBC analysis, which is sensitive to binary coalescence events
from systems containing at least one neutron star, identified candidate
G194575 during real-time processing of data from LIGO Hanford Observatory
(H1) and LIGO Livingston Observatory (L1) at 2015-10-22 13:33:19.942 UTC
(GPS time: 1129556016.942). Both the H1 and L1 detectors were in
observation mode and operating normally.

G194575 is an event of interest because its false alarm rate, as
determined by the online analysis, is 9.65e-08 Hz or about one in 4
months, passing our stated alert threshold of ~1/month for CBC candidates.
The event's properties can be found at this URL:

https://gracedb.ligo.org/events/G194575

Fermi triggered (bn151022577) about 1 ks after the LIGO candidate, and
Swift detected GRB 151022A (D���Avanzo et al., GCN 18436
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 ) about 2 ks after.
Neither gamma-ray trigger���s localization is consistent with the rapid
position reconstruction of the LIGO candidate. Based on the separation in
time and sky position, we infer that these high-energy triggers are
unrelated.

One sky map is available at this time and can be retrieved from the
GraceDB event page: skymap.fits.gz, an initial localization generated by
BAYESTAR. The probability is concentrated in two main equatorial regions
around right ascensions of 1h and 13h. About 30% of the probability is
confined to the top 500 deg2.

Updates on our analysis of this event will be sent as they become
available.

S.J. Smartt (Queen���s University Belfast), K. Chambers 
(IfA, University of Hawaii), K. W. Smith,  (QUB), M. Huber, E. Magnier,
H. Flewelling, C. Waters, J. Tonry, A. Schultz, N. Primak 
A. Heinze, B. Stalder, L. Denneau, A. Sherstyuk (IfA), D. Young, 
D. Wright, (QUB), C. Stubbs, M. Coughlin (Harvard), A. Rest (STScI)

Report several transients discovered in and around the 
RA=1hr DEC=+4deg error region as defined in the BAYESTAR 
skymap.fits file. 

This area has been covered in the w and i-bands 
during the routine course of the Pan-STARRS Survey for Transients
(see Huber et al. 2015, ATel 7153 and http://star.pst.qub.ac.uk/ps1threepi/psdb/)
and around 10 supernova candidates are known from the last 
7 days of observations in this region. These are almost certainly all 
unrelated to the GW trigger, as they were discovered days before the 
LIGO/Virgo detection. Details are available on the public webpage above. 

For example, the most recent discovery is a i=18.6 supernova candidate at 
7.2��� from the core of MCG -01-59-024 at z=0.033. This was discovered on 57315.31, 
54h before the GW trigger (at position 23:28:24.29 -02:47:57.8)

Pan-STARRS was observing the RA=1hr localisation region (south of dec=0), 
during the night of 2015-10-22. However the observations were taken 5-6hrs
before the LIGO/Virgo detection. Difference imaging and transient searches
are underway and further observations are planned for the 
coming nights. We plan to cover this RA=1hr region with the PS1 1.8m
telescope, 7 sq degree camera, in i and z bands.

S.Karpov, G.Beskin (SAO RAS and Kazan Federal University,
Russia), S.Bondar, E.Ivanov, E.Katkova, A.Perkov (OJS RPC PSI,
Russia), A.Biryukov (SAI MSU and Kazan Federal University,
Russia), V.Sasyuk (Kazan Federal University, Russia)

Following GCN #18442
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  on the possible GW event G194575, we
observed its secondary probability density region with
Mini-MegaTORTORA nine-channel wide-field monitoring system
(located at Special Astrophysical Observatory near Russian 6-m
telescope) starting on 2015-10-22 22:33:24 UT under bad weather
conditions.

The system field of view has been centered on RA, Dec = 16.8, 5.7
covering roughly 900 square degrees simultaneously. Coverage map
of all nine channels is shown at
http://mmt.favor2.info/scheduler/761/lvc

Every channel acquired 10 x 60s exposure images in white light
between 2015-10-22 22:33:24 UT and 2015-10-22 22:42:31 UT,
further observations interrupted due to heavy clouds. The
footprints of acquired images are uploaded to GraceDB.

Quick-look analysis did not reveal any transient brighter than
V~13.5 magnitude in the data.

LIGO/Virgo G194575:  Fermi GBM Observations

Lindy Blackburn (CfA), Michael S. Briggs (UAH), Eric Burns (UAH), Jordan Camp (NASA/GSFC), 
Nelson Christensen (Carleton College), Valerie Connaughton(USRA), Tito Dal Canton (MPG), 
Adam Goldstein (NASA/MSFC), Peter Jenke (UAH), Tyson Littenberg (USRA/UAH), 
Judith Racusin (NASA/GSFC), Peter Shawhan (UMD), Leo Singer (NASA/GSFC), 
John Veitch (Birmingham), Binbin Zhang (UAH)

The region around 13h in Right Ascension, containing most of the probability for the LIGO CBC 
candidate G194575 reported by Singer et al. GCN 18442
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 , was observed by Fermi GBM during 
the GW event.  The region around 01h was occulted by the Earth.

A search of the GBM Time-Tagged Event data between 8 keV and 40 MeV from 64 s before to 
82 s after the CBC candidate event revealed no significant emission on search timescales in 
factors of 2 from 64 ms to 2.048 s.

[GCN OPS NOTE(26oct15):  In the FROM-line the SB was replaced with VC.
SB manually processed the submission due to problems with VC's entry
in the vetting list.  The record has now been corrected.]

[GCN OPS NOTE(15jun16):  If you are looking for the P.Evans circ 18448
("GRB 151022A: Swift-XRT refined Analysis"), please note that the ID
for that circular has been changed to "18448a".]

K. Chambers, M. Huber, (IfA, University of Hawaii), K. W. Smith, 
D. Young, D. Wright, S.J. Smartt (Queen���s University Belfast), (QUB) E. Magnier,
H. Flewelling, C. Waters, J. Tonry, A. Schultz, N. Primak 
A. Heinze, B. Stalder, L. Denneau, A. Sherstyuk (IfA), C. Stubbs, M. Coughlin (Harvard), A. Rest (STScI)

Further to GCN 18445
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 , we report that 7 transients were discovered within 
the 45% probability contour of the RA=1hr blob between the dates 
2015-10-16 and 2015-10-21. G194575 was reported with a time stamp of
2015-10-22 13:33:20 UTC, hence these first detections are a few
days before. They should be useful to other surveys to weed out any freshly 
appearing transients from existing ones. 

These are all likely supernova with identifications :  
PS15ckv, PS15clm, PS15cmc, PS15cll, PS15ckt, PS15cmj and PS15cng. 

All details for these transients are on 
http://star.pst.qub.ac.uk/ps1threepi/psdb/
We note the bright transient PS15cng (i=18.6) in MCG -01-59-024 (145 Mpc)

In addition, two new transients were detected at 2015-10-22 07:34 UTC and 
2015-10-22 07:32 UTC (6hrs before the GW event) 

PS15coc	00:28:48.57 -02:42:35.8 18.18(i)
PS15coa	00:16:47.00 -02:25:10.0 20.28(i)

They are both offset from obvious SDSS host galaxies by 7��� and 5.5���, but
no catalogued redshifts are available. Again, these are likely to be unrelated field supernovae
given their discovery before the GW event, and unrestrictive limits on their explosion epochs. 
Further analysis and observations are ongoing.

Nat Butler (ASU), Neil Gehrels (GSFC), V. Zach Golkhou (ASU), Alexander
Kutyrev (GSFC), William H. Lee (UNAM), Eleonora Troja (GSFC), Alan M.
Watson (UNAM) report:

We observed 26 nearby galaxies (D<10 Mpc) within the GWGC catalog (White,
et al. 2011) and also contained with the LIGO/Virgo G194575 1-sigma
confidence interval (Singer, et al. GCN 18442
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 ) between RA 23.1 hours and RA
1.5 hours (J2000) with the Reionization and Transients Infrared Camera
(RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the
Observatorio Astron��mico Nacional on Sierra San Pedro M��rtir on the night
of 2015/10/23.

We obtained a total exposure of 8 minutes on each field, reaching typical
depths of r and i = 21 mag, and z = 17 mag (10-sigma).  These magnitudes
are in the AB system and are not corrected for Galactic extinction.  Each
field, centered upon one GWGC galaxy, has a size of approximately 5 by 5
arcmin^2.  Analysis is ongoing.

We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.

Continued observations are planned.

[GCN OPS NOTE(26oct15):  In the FROM-line the SB was replaced with NB.
SB manually processed the submission due to problems with NB's entry
in the vetting list.  The record has now been corrected.]

[GCN OPS NOTE(27oct15):  The Trigger number was changed from "G19457"
to "G194575" in the Subject-line and the first paragraph.]

[GCN OPS NOTE(15jun16):  If you are looking for the V.Savchenko circ 18453
("LIGO/Virgo G194575: INTEGRAL search of temporally coincident prompt hard X-ray emission"),
please note that the ID for that circular has been changed to "18453a".]

V. Savchenko (APC, Paris, France), S. Mereghetti (IASF-Mi, Italy), C.
Ferrigno, E. Bozzo, T. J.-L. Courvoisier (ISDC, University of Geneva,
CH),  E. Kuulkers (ESAC/ESA, Madrid, Spain), A. Bazzano (IAPS-Roma,
Italy)

The anti-coincidence shield of the spectrometer on board of INTEGRAL
(SPI/ACS) is sensitive to photons above ~50 keV, but without directional
information.

We investigated the SPI/ACS light curve at -1000 +1000 s from the trigger time
(2015-10-22 13:33:19 UTC) on temporal scales from 0.1 to 100 s. The
nearest excess on the constant background is at 2015-10-22 13:36:54, i.e.
215 seconds after the LIGO/Virgo trigger. The excess has a duration of
less than 0.05 seconds and a post-trial significance of 5.1 sigma. This
event is compatible with particle effects in SPI-ACS. We estimate the
chance of a particle effect to happen in the 200 seconds following the
trigger to be 20%. However, with SPI-ACS data alone we can not exclude
a cosmic origin of this excess.

The SPI/ACS light curves, binned at 50 ms, are derived from 91
independent detectors with different lower energy thresholds (mainly
between 50 keV and 150 keV) and an upper threshold at about 100 MeV. The
ACS response varies as a function of the incident angle. The highest
probability sky location of the LIGO trigger is in the direction of the
satellite Z-axis (the direction pointing to the Sun, where the SPI/ACS
has reduced sensitivity). For this direction we estimate a  3-sigma
upper limits corresponding to fluences in the 75-1000 keV band of 4e-6 erg/cm2
for a 100 s duration, 1.8e-6 erg/cm2 for 10 s, 5.8e-7 erg/cm2 for 1 s,
and 2.1e-7 erg/cm2 for 0.1 s. The upper limits assume a typical GRB
spectrum with Band model parameters alpha=1, beta=2.5 and E0 ~ 500 keV.
For the other probability region, the estimated upper limits are roughly
a factor three tighter. Given the same assumptions, if the excess at
2015-10-22 13:36:54 were of cosmic origin, it would have a fluence of 3.2e-7
erg/cm2 in the 75-1000 keV energy range.

We also searched for transient events in time coincidence with the LIGO
trigger in the data of the coded-mask imager IBIS, which at the time of
the trigger was pointed at R.A.=297.1 deg, Dec.=+29.3 deg (i.e., more
than 90 degrees from both LIGO highest probability regions). No
significant events were found on timescales from 2 ms to 100 s.
Typically, the minimum peak flux on 1 s time scale of gamma-ray
bursts detected with IBIS is 0.1 ph/s/cm2 in the 20-200 keV energy band,
in the central 9x9 deg of the field of view, which has zero response at 29x29 degrees.
However, due to the presence of the bright and variable source Cyg X-1  in the
field of view, we estimate that the sensitivity in the current
observation might be at least a factor 3 worse.

[GCN OPS NOTE(26oct15):  Because of a processing error, two circulars
received the same ID Number.  The second was given an "a' suffix.]

GCN OPS NOTE: The new GCN database requires the GCN Circular ID to be a number. 
Therefore, the previous GCN number assigned as 18453a was modified to 18448.5 
during the GCN Circulars migration in April 2023.

Nat Butler (ASU), Neil Gehrels (GSFC), V. Zach Golkhou (ASU), Alexander
Kutyrev (GSFC), William H. Lee (UNAM), Eleonora Troja (GSFC), Alan M.
Watson (UNAM) report:

We observed 26 nearby galaxies (D<10 Mpc) within the GWGC catalog (White,
et al. 2011) and also contained with the LIGO/Virgo G194575 1-sigma
confidence interval (Singer, et al. GCN 18442
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 ) between RA 23.1 hours and RA
1.5 hours (J2000) with the Reionization and Transients Infrared Camera
(RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the
Observatorio Astron��mico Nacional on Sierra San Pedro M��rtir on the night
of 2015/10/23.

We obtained a total exposure of 8 minutes on each field, reaching typical
depths of r and i = 21 mag, and z = 17 mag (10-sigma).  These magnitudes
are in the AB system and are not corrected for Galactic extinction.  Each
field, centered upon one GWGC galaxy, has a size of approximately 5 by 5
arcmin^2.  Analysis is ongoing.

We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.

Continued observations are planned.

[GCN OPS NOTE(27oct15):  The Trigger number was changed from "G19457"
to "G194575" in the Subject-line and the first paragraph.]

[GCN OPS NOTE(27oct15):  This is a duplicate of LVC Circ 18453.]

A. Rowlinson (UvA, ASTRON), J. Broderick (ASTRON),
P.G. Jonker (SRON/RU), R.P. Fender (Oxford), R.A.M.J. Wijers (UvA),
B.W. Stappers (Manchester), A. Shulevski (ASTRON) report on behalf of
the LOFAR Transients Key Science project

On Oct 23, 2015, starting at 11:01 (UTC), we observed a large fraction
of the localization error range of the Advanced LIGO trigger G194575
with the ILT (International Low-Frequency Array [LOFAR] Telescope) as
part of a test observation. Due to the low elevation and proximity to the
Sun of these observations, we note that LOFAR will not be at optimal
performance. The quality of these observations will determine the
feasibility of further LOFAR follow-up of Advanced LIGO trigger
G194575.

The observations were obtained with the High-Band Antennas (HBA) at a
centre frequency of 145 MHz (bandwidth 7.8 MHz). In this configuration,
the ILT can provide 8 simultaneous beams on the sky, where each beam
has a field of view of approximately 12 deg^2 (beam FWHM 3.9 degrees).
The beam centres are given below:

1) 204.648425	-4.457881 13:38:35.62 -04:27:28.4
2) 207.424367	-4.457881 13:49:41.85 -04:27:28.4
3) 201.872483	-4.457881 13:27:29.40 -04:27:28.4
4) 206.036396	-2.053845 13:44:08.74 -02:03:13.8
5) 203.260454	-2.053845 13:33:02.51 -02:03:13.8
6) 206.036396	-6.861917 13:44:08.74 -06:51:42.9
7) 203.260454	-6.861917 13:33:02.51 -06:51:42.9
8) 196.154938	-15.286953 13:04:37.19 -15:17:13.0

The observations cover roughly 50 square degrees in total.  Each field
was observed for a total of 0.5 hr with 10s time resolution after
pre-processing. Analysis is ongoing.

Possible Fermi-LAT Gamma-ray counterpart for LIGO/Virgo G194575

G. Vianello (Stanford), N. Omodei (Stanford) and Julie McEnery (GSFC)

report on behalf of the Fermi-LAT team:

We report the detection of a possible gamma-ray counterpart for the 
LIGO/VIRGO candidate G194575 in the data of the Fermi Large Area Telescope.

We performed a search for a gamma-ray counterpart above 200 MeV on 
various timescales for 10,000s after the LIGO trigger. The entire 
G194575 error region came within the LAT FOV for some time during this 
interval. In this search we found a new gamma-ray transient, which was 
within the LAT FoV between 1000 and 3500 s after the trigger (from 
2015-10-22 13:53:19 UTC to 2015-10-22 14:36:39 UTC)

The transient is faint and localized on the border of the LIGO/VIRGO 
confidence region. Its significance is around 4 sigma pre-trials. The 
best localization for the possible LAT counterpart is a circle centered on :

(R.A., Dec.) = (221.69, -3.246) deg (J2000)

with a 90% containment radius of 0.52 deg (statistical only).

The significance of this putative excess is below our standard reporting 
threshold of 5 sigma (pre-trials). We cannot confirm nor exclude at this 
stage that the source is not a background fluctuation and  is related to 
the LIGO/VIRGO candidate. Further analysis is ongoing.

However, follow up is strongly encouraged.

The Fermi-LAT point of contact for this candidate is Giacomo Vianello 
(giacomov@stanford.edu).

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.

M. Im, H. M. Lee, C. Choi, Y. Taak (SNU), S. Pak (KHU), H.-I. Sung (KASI),
S. Ehgamberdiev (UBAI) on behalf of the KU (Korea-Uzbekistan) collaboration
report:

 We observed several nearby bright galaxies within the error region of the
possible GW event G194575 (GCN #18442
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 ), with the CQUEAN instrument on the
McDonald observatory's 2.1m telescope (Park et al. 2012, PASP, 124, 839)
and LOAO (Mt. Lemmon Astronomy Observatory) 1-m telescope (Lee et al. 2010,
JKAS, 43, 95). CQUEAN covers a field of view of 4.7' by 4.7' centered on
each galaxy and LOAO 1-m's field of view is 20' by 20'. The observations
started at 2015-10-23 02:28 (UT) for CQUEAN, and 2015-10-23 07:08 (UT) for
LOAO. Five galaxies were observed so far in R and I filters with 3 min
exposure per filter.

Name            RA (J2000)   Dec (J2000)    Facility
NGC 0099     00:23:59.4   +15:46:13      CQUEAN
UGC 00099   00:10:40.9   +13:42:33      CQUEAN
UGC 00119   00:13:03.1   +14:24:36      CQUEAN
PGC 00282   00:04:01.5   -11:10:27      CQUEAN
Arp  256       00:18:50.9  -10:22:36       CQUEAN
NGC 337      00:59:50.1  -07:34:41       LOAO

No obvious transient was found in the data taken so far. We plan to
continue the observation of these and other nearby galaxies with our
 facilities. We thank the staff of LOAO for carrying out the observation.

P.A. Evans (U. Leicester), J.A. Kennea (PSU), Scott Barthelmy
(NASA/GSFC), Dave Burrows (PSU), Sergio Campana (INAF-OAB), Brad Cenko
(NASA/GSFC), Neil Gehrels (NASA/GSFC), Paolo Giommi (ASI), Frank
Marshall (NASA/GSFC), John Nousek (PSU), Paul O'Brien (U. Leicester),
Julian Osborne (U. Leicester), David Palmer (LANL), Matteo Perri
(ASDC), Judy Racusin (NASA/GSFC), Mike Siegel (PSU), Gianpiero
Tagliaferri (INAF-OAB) report on behalf of the Swift team:

Swift has performed follow up of LVC trigger G194575 (Singer et al., GCN
Circ. 18442
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 ). Unfortunately, most of the error region is in Sun
constraint and cannot be observed. We have observed the locations
(observation centres) listed below. No X-ray sources have been found,
nor have any new sources been seen in UVOT. The typical limiting
magnitude is about 18.9 in the u band. In the XRT the 3-sigma upper
limit is in the range 0.007 to 0.015 ct/s, corresponding to a 0.3-10 keV
flux of 3e-13 to 6e-13 erg/cm^2/s.

RA=188.117, Dec=-70.759, exposure=925 s
RA=187.167, Dec=-70.759, exposure=349 s
RA=81.8355, Dec=-4.69639, exposure=880 s
RA=9.77883, Dec=26.2998, exposure=988 s
RA=0.64059, Dec=-60.74, exposure= 993 s

This circular is an official product of the Swift team.

M. Serino (RIKEN), H. Negoro (Nihon U.), N. Kawai (Tokyo Tech),
S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, 
Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Shidatsu, 
J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), 
M. Arimoto, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech), 
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), 
H. Tsunemi, R.Imatani (Osaka U.), 
M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), 
Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.), 
Y. Tsuboi, S. Kanetou (Chuo U.), 
M. Yamauchi, D. Itoh (Miyazaki U.), 
K. Yamaoka (Nagoya U.), M. Morii (ISM)
report on behalf of the MAXI team:
 
We examined the MAXI/GSC all-sky X-ray image (2-10 keV) obtained in the orbit
immediately following the LVC trigger G194575 (Singer et al. GCN 18442
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 ).
Due to proximity to the sun, about half of the candidate region around 13h 
in R.A. and half of the region around 13.5h were not observed.  
We did not detect new sources with the following upper limits for the 2-10 keV
X-ray flux in the these regions examined.  
The scan transit times of the centers of these regions are also shown.

Region Center Transit UT  3-sigma UL
------------  ----------  ----------
(13h,  -15.)   14:01:01    23 mCrab  
(13.5h, -5.)   14:06:53    22 mCrab
(01h,   +5.)   14:50:55    29 mCrab
------------  ----------  ----------

A. �wiek (NCBJ), A. F. �arnecki (UW), A. Mankiewicz (CFT PAS), A. Zadro�ny (NCBJ) on behalf of the Pi of the Sky

On night starting 22rd of October we scheduled observations from our observatory Pi of the Sky South located in San Pedro de Atacama in Chile. The observations are performed with two cameras: one observing in R filter and one with wide-band White filter. Two expositions times are used 10s and 100s. For 10s exposition time we expect limiting brightness 12mag, and 13mag for 100s. Each exposition taken cover area of approximately plus/minus 10 deg from coordinates set on center of the frame. For observations related to G194575 we are using following pointings:

1) 0.889 h 2.29 deg
2) 0.558 h -2.71 deg

On first night 100 images were taken from both cameras. Each image taken covers approximately 400 square degrees. We are currently analyzing taken images.

We continue observations during following nights.

R. Itoh, T. Nakaoka, M. Yoshida, K. S. Kawabata (Hiroshima Univ.)
on behalf of the J-GEM collaboration

We made optical follow-up observations of G149575 with HOWPol
(Hiroshima Optical Wide-field Polarimeter) attached to the 1.5m
Kanata telescope at Higashi-hiroshima Observatory. The instrument
has a circular field-of-view whose diameter is 15'. Nearby galaxies
selected from GWGC within 10 degree in radius from the skymap peak
in the anti-Sun direction (RA=01:02:00 and DEC=+04:25:00).
We performed R and I bands imaging observations for each galaxy.

The observed galaxies and the limiting magnitudes of R and I bands
(Rlim and Ilim) are listed below. No new optical transient was found
in these data.

#############################################################
# START-TIME         EXP-T RA      DEC    Rlim Ilim OBJECT
#############################################################
2015-10-23T09:46:35  270.0 12.0958 4.0917 18.3 18.7 IC0052
2015-10-23T09:59:36  270.0 13.1375 6.0025 19.2 19.6 UGC00537
2015-10-23T10:10:09  270.0 13.3625 5.7703 18.8 19.4 IC1592
2015-10-23T10:20:41  270.0 13.5792 6.1975 20.6 20.6 PGC003199
2015-10-23T10:31:15  270.0 12.9292 3.1714 17.7 19.5 UGC00526
2015-10-23T10:42:12  270.0 13.6708 5.7739 19.6 ---- IC1598
2015-10-23T10:52:43   90.0 12.9542 3.1056 16.2 20.4 UGC00527
2015-10-23T11:03:12  270.0 13.3833 2.9236 18.6 18.7 UGC00544
2015-10-23T11:13:44  270.0 13.2792 2.6206 18.4 18.3 PGC1232627
2015-10-23T11:24:16  270.0 14.0625 4.4094 18.8 19.4 UGC00574
2015-10-23T11:34:57  270.0 13.3667 2.7739 18.9 19.0 PGC003137
2015-10-23T11:45:43  270.0 14.6250 4.8956 19.0 19.1 PGC003495
2015-10-23T11:56:21  270.0 15.0875 4.6653 19.3 18.8 PGC003600
2015-10-23T12:06:48  270.0 14.6583 3.0289 19.5 19.3 PGC003500
2015-10-23T12:17:38  270.0 16.2375 5.6528 18.6 18.7 UGC00667
2015-10-23T12:28:09  270.0 16.2208 4.7672 18.3 19.0 IC0073
2015-10-23T12:38:41  270.0 15.4417 3.0817 19.8 19.2 UGC00637
2015-10-23T12:49:14  270.0 16.4792 4.0900 20.0 20.0 IC0074
2015-10-23T12:59:45  270.0 16.5583 3.5742 19.9 19.4 UGC00678
2015-10-23T13:10:14  270.0 17.6708 3.6136 18.9 19.2 PGC004199
2015-10-23T13:20:42  270.0 16.6792 2.8219 19.1 19.2 PGC1238390
2015-10-23T13:31:11  270.0 17.2208 3.1358 19.9 20.2 PGC1245956
2015-10-23T13:41:54  270.0 15.9333 2.2831 20.0 19.8 UGC00656
2015-10-23T13:52:27  270.0 16.2250 2.1331 20.2 19.9 IC1613
2015-10-23T14:02:57  270.0 14.4833 0.8689 19.2 19.0 PGC1177707
2015-10-23T14:13:30  270.0 14.9250 0.9164 19.2 19.1 UGC00618
2015-10-23T14:24:03  270.0 14.7292 1.0047 19.6 19.4 PGC003524
2015-10-23T14:34:31  270.0 14.7667 1.0011 19.9 19.8 PGC003530
2015-10-23T14:44:58  270.0 15.6292 1.3436 19.6 19.5 PGC003718
2015-10-23T16:04:32  270.0 17.1500 1.6417 18.9 19.0 UGC00711
2015-10-23T16:15:10  270.0 16.7250 1.9453 20.0 20.1 PGC003943
#############################################################

K. Yanagisawa, D. Kuroda (OAO/NAOJ), Y. Utsumi, M. Yoshida (Hiroshima),
K. Ohta(Kyoto) and N. Kawai(Tokyo Tech.) on behalf of the J-GEM
collaboration.

We carried out J-band imaging observations of 32 nearby galaxies to
search for new point sources associated with the objects, in response
to G194575. The target galaxies were selected from nearby galaxies
listed in GWGC, close to the anti-solar direction.

The observations were made on 23rd and 24th October 2015, with a
wide-field infrared camera (D=0.91 m), OAOWFC, of Okayama Astrophysical
Observatory of NAOJ.

We could find no new point sources brighter than the limiting magnitude
of J=17-18(S/N=3) in Vega system. The photometric calibration was made
against 2MASS field stars.

Summary of the observations are listed below.

#-----------------------------------------
#Object    UT Start         Exp  Limit J
#                          (min)  (S/N=3)
#-----------------------------------------
UGC00637   2015-10-23 09:15  15    17.2
PGC003718  2015-10-23 09:35  20    17.5
UGC00656   2015-10-23 10:02  15    17.7
IC0073     2015-10-23 10:22  15    17.6
IC1613     2015-10-23 10:42  15    17.8
UGC00667   2015-10-23 11:02  15    17.9
IC0074     2015-10-23 11:22  15    18.1
UGC00678   2015-10-23 11:41  29    18.2
PGC1238390 2015-10-23 12:42  13    18.1
UGC00711   2015-10-23 13:50  20    18.4
PGC1245956 2015-10-23 14:17  15    18.3
PGC004199  2015-10-23 14:37  15    18.2
IC0052     2015-10-23 14:57  15    18.2
UGC00526   2015-10-23 15:17  15    18.2
UGC00527   2015-10-23 15:37  15    18.2
UGC00537   2015-10-23 15:57  15    18.2
PGC1232627 2015-10-23 16:17  15    18.2
IC1592     2015-10-23 16:36  15    18.2
PGC003137  2015-10-23 16:56  15    18.1
UGC00544   2015-10-23 17:16  15    17.8
PGC003199  2015-10-23 17:36  15    17.9
IC1598     2015-10-23 17:56  15    17.7
UGC00574   2015-10-23 18:16  15    17.6
PGC1177707 2015-10-23 18:36  09    17.1
PGC003495  2015-10-24 09:56  15    17.7
PGC003500  2015-10-24 10:16  15    17.9
PGC003524  2015-10-24 10:36  15    17.9
PGC003530  2015-10-24 10:56  15    17.9
UGC00618   2015-10-24 11:16  15    17.7
PGC003600  2015-10-24 11:36  15    17.9
UGC00637   2015-10-24 11:55  15    18.0
PGC003718  2015-10-24 12:15  15    17.8
#-----------------------------------------

D. Rabinowitz, C. Baltay, N. Ellman, E. Woodward (Yale), P. Nugent (LBNL)

The La Silla-QUEST survey operating the 10-sq-deg QUEST camera on the 1.0m ESO Schmidt at La Silla, Chile searched the following ~250 sq. deg area centered on the lobe of the  ~90% confidence area of LVC event G19457 near at 1 h RA.

RA 0.3 to 1.4 h;. Dec -4.5 to + 10.0 deg

One new source (not appearing in deep reference images taken ~1 yr previously) has been detected with high confidence near the center of the LSQ area coverage :

LSQ Desig   V-mag    hh:mm:ss   dd:mm:ss
______________________________________________
LSQ15bjb     18.2    00:11:27.60 -06:25:38.28

LSQ15bjb appears 0.2 arcmin north of GALEXASC J001127.51-062549.8. Observations made 2015 Oct 23 and 24 (V mag 18.7 on JD 2457318.64 and 18.2 mag on JD 2457319.63) indicate at rapidly brightening intensity (by factor ~1.5 per day). 

Followup observations are strongly encouraged.

P. D'Avanzo, A. Melandri (INAF-OAB), S. Piranomonte (INAF-OAR), E. Palazzi (INAF-IAFS Bo), M. Branchesi (Urbino University/INFN Pisa), G.Greco (Urbino University/INFN Firenze), E. Brocato (INAF-OAR), S. Campana (INAF-OAB), E. Cappellaro (INAF-OAPd), S. Covino (INAF-OAB), F. Getman (INAF-OAC), A. Grado (INAF-OAC), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), L. Nicastro (INAF-IASF Bo), E. Pian (SNS-Pisa), L. Pulone (INAF-OAR), G. Stratta (Urbino University/INFN Firenze), V. Testa (INAF-OAR), A. Fiorenzano, W. Boschin, D. Carosati (INAF-TNG), on behalf of the INAF Gravitational Astronomy group report:

We observed the optical transient reported by Rabinowitz et al. (LSQ15bjb; LIGO/Virgo Circular #18473), located in the skymap of the avanced LIGO and Virgo trigger G194575 (Singer et al., LIGO/Virgo Circular #18442). The observations were carried out with the 3.6m Italian TNG telescope, located in Canary Islands (Spain), equipped with the DOLORES camera in both imaging and spectroscopic mode on 2015 Oct 26. 
The optical transient is clearly detected. At a mean time of 21:24:10 UT we measure a magnitude of i' = 17.48 +/- 0.05 (AB), calibrated with respect of the SDSS DR10. 
Spectroscopic analysis is ongoing

K. Bannister (CSIRO), J. Marvil (CSIRO), I. Heywood (CSIRO), R. Wark 
(CSIRO), B. Indermuehle (CSIRO), M. Bell (CSIRO), T. Murphy (University 
of Sydney), D. Kaplan (UWM) on behalf of the ASKAP/VAST team

We observed the Southern probability maximum with BETA - the ASKAP 
engineering test array. The observations cover a 7x7 degree square 
centered on 13h02m00s -14d40m00s with 8 pointings, each comprising 9 
beams. We observed at center frequency of 863.5 MHz with a a bandwidth 
of 300 MHz. Observing began at 2015-10-22 22:35:51 UT and continued for 
10 hrs. Due to the proximity of the Sun, we expect worse than normal 
imaging fidelity.

Analysis of these data are ongoing.
-- 
KEITH BANNISTER | Bolton Fellow
CSIRO Astronomy and Space Science
T +61 2 9372 4295
E keith.bannister@csiro.au

K. W. Smith, D. Wright, S. J. Smartt (Queen�s University Belfast),  
K. Chambers, M. Huber, (IfA, University of Hawaii), E. Magnier, 
H. Flewelling, C. Waters, J. Tonry, A. Schultz, N. Primak, A. Heinze, 
B. Stalder, L. Denneau, A. Sherstyuk (IfA), C. Stubbs, 
M. Coughlin (Harvard), A. Rest (STScI)

Further to GCN 18445
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 , we report that 2 further transients were discovered within 
the 45% probability contour of the RA=1hr blob. These transients are listed
below along with their discovery dates. We also recovered LSQ15bjb on
MJD=57316 (i=19.55) and MJD=57317 (i=19.03), as PS transient PS15cog. 
Our first detection is 29.14 hrs before the GW trigger, hence although we
confirm the LSQ result that this is indeed a fast rising and bright transient, 
it exploded before the LIGO/Virgo detection trigger.

Name         RA (J2000)    Dec (J2000)   Disc. Date   Disc Mag  filter   Notes

LSQ15bjb   00 11 27.61   -06 25 38.4      20151021     19.55       i       (1)

PS15coe     00 29 00.31   -01 34 53.6     20151023     20.69       i       (2)

PS15cof      00 32 03.01   -05 51 46.9     20151023     21.02       i       (3)

(1) LSQ15bjb = PS15cog.  The PS1 photometry shows it to be visible 29.14 
hours prior to the G194575 event, hence can probably be ruled out as unrelated.  
SDSS DR12 reports that the likely host (12.34" away) is 
SDSS J001127.44-062549.5, with photometric redshift of ~0.06.
(2) DR12 reports that the likely host (2.2" away) is SDSS J002900.23-013451.7,
with photometric redshift of ~0.15.
(3) DR12 reports that the likely host (3.17" away) is SDSS J003203.21-055146.6, 
with photometric redshift of ~0.11.

Jochen Greiner (MPE Garching), Sylvio Klose (TLS Tautenburg), and Phil 
Wiseman (MPE Garching) report:

We observed the optical transient LSQ15bjb (Rabinowitz et al., GCN 18473
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 ) 
simultaneously in g'r'i'z'JHK using the multi-channel imager GROND 
(Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at 
ESO La Silla Observatory (Chile). Observations started on October 27 at 
01:09 UT. In total 18 short exposures were taken until 06:40 UT.

At a mean time of 01:34 UT we measure the following AB magnitudes:

g' = 16.8  +/-  0.1,
r' = 17.1  +/-  0.1,
i' = 17.4  +/-  0.1,
z' = 17.5  +/-  0.1,
J  = 18.2  +/-  0.1,
H  = 19.0  +/-  0.2,
K  = 19.8  +/-  0.3,

calibrated against SDSS in the optical and 2MASS in the NIR.

The source appears very blue. After correcting for the (tiny) Galactic 
reddening along the line of sight, E(B-V) = 0.03 mag (Schlegel et al. 
1998), the spectral energy distribution (SED) can be fit with a power law 
(F_nu \sim nu**(-beta) ), with a slope beta = -0.33 +/- 0.02, consistent 
with an accretion disk spectrum (and ruling out a GRB afterglow SED, which 
would have beta > 0).

Despite the still fast rise with respect to earlier observations 
(Rabinowitz et al., GCN 18473
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 , Smith et al., GCN 18484
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 ) the source appears 
to be constant within +/- 0.05 mag over the course of our 5.5 hrs 
observation (consistent with D'Avanzo et al., GCN 18476
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 ).

Assuming SDSS upper limits of g'>23.1, r'>24.2, i'>23.6 and z'>22.3 (based 
on some residual flux of the nearby galaxy), we note that LSQ15bjb 
exhibits a >7 mag amplitude. Typically, such amplitudes and several days 
time scale are found only in novae, black hole transients ("X-ray novae"), 
or tidal disruption events. The latter is an unlikely explanation due to 
the offset to the galaxy. Even if this source is unrelated to G194575, its 
light curve evolution appears to be peculiar.

S. Piranomonte (INAF-OAR), P. D'Avanzo, A. Melandri (INAF-OAB), E. Palazzi (INAF-IAFS Bo), M. Branchesi (Urbino University/INFN Pisa), G.Greco (Urbino University/INFN Firenze), P. Astone (INFN-Roma), E. Brocato (INAF-OAR), S. Campana (INAF-OAB), E. Cappellaro (INAF-OAPd), S. Covino (INAF-OAB), F. Getman (INAF-OAC), G. Giuffrida (ASDC), A. Grado (INAF-OAC), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), L. Nicastro (INAF-IASF Bo), E. Pian (SNS-Pisa), L. Pulone (INAF-OAR), F. Ricci (Sapienza University), G. Stratta (Urbino University/INFN Firenze), V. Testa (INAF-OAR),  L. Tomasella (INAF-OAPd), A. Fiorenzano, W. Boschin, D. Carosati (INAF-TNG), on behalf of the INAF Gravitational Astronomy group report: 

We report the result of the analysis of the spectrum of the optical transient reported by Rabinowitz et al. (LSQ15bjb; LIGO/Virgo Circular #18473), located in the skymap of the advanced LIGO and Virgo trigger G194575 (Singer et al., LIGO/Virgo Circular #18442) and observed with the 3.6m Italian TNG telescope (Canary Islands, Spain), equipped with DOLORES (D'Avanzo et al. LIGO/Virgo Circular #18476).

Based on a preliminary calibration, the spectrum, obtained on 2015 Oct 26 of 21:59:10 UT, shows that the transient is a supernova of type Ia. The best fit obtained using SNID (Blondin & Tonry 2007, ApJ 666,1024) is with SN 1990N (Mazzali et al. 1993 A&A 269, 423), 6 days days before maximum and placed at a redshift z~0.03. Assuming this redshift, the ejecta expansion velocity measured from the SiII 6355 absorption is about 10900 km/s.

P.A. Evans (U. Leicester), Frank Marshall (NASA/GSFC), J.A. Kennea
(PSU), B. Sbarufatti (INAF-OAB/PSU), Scott Barthelmy (NASA/GSFC), Dave
Burrows (PSU), Sergio Campana (INAF-OAB), Brad Cenko (NASA/GSFC), Neil
Gehrels (NASA/GSFC), Paolo Giommi (ASI), John Nousek (PSU), Paul O'Brien
(U. Leicester), Julian Osborne (U. Leicester), David Palmer
(LANL), Matteo Perri (ASDC), Judy Racusin (NASA/GSFC), Mike Siegel
(PSU), Gianpiero Tagliaferri (INAF-OAB) report on behalf of the Swift team:

Swift performed follow-up observations of the rapidly-brightening
optical transient LSQ15bjb reported by Rabinowitz et al (GCN Circ.
18473
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 ) inside the LIGO error region for trigger G194575. The
observations began at 01:20 UT on October 27.

No X-ray sources are found in the image. At the location of the La
Silla-QUEST source there are no events recorded in 2ks of exposure time.
The 3-sigma upper limit deduced from these data is 3.5e-3 ct/sec,
corresponding to an approximate flux of 1.4e-13 erg/cm^2/s.

UVOT took an exposure of 1370 s with the U filter starting at 01:20:05
UT, and a second exposure of 585 s with the U filter starting at
02:36:43. The source LSQ15bjb is detected with a preliminary u magnitude
of 16.79 �� 0.07 in the UVOT photometric system (Breeveld et al. 2011,
AIP Conf. Proce. 1358, 373) in the first exposure and 16.73 �� 0.07 in
the second. We caution that the source is not well separated from the
nearby galaxy.

The magnitudes are not corrected for the Galactic extinction due to the
reddening of E(B-V) = 0.03 in the direction of the source (Schlegel et
al. 1998).

This circular is an official product of the Swift team.

V.M. Lipunov (Lomonosov Moscow State University, SAI MSU), E.S. Gorbovskoy
(SAI Lomonosow MSU), R.Rebolo (IAC), N.Budnev (API Irkutsk State Uni),
A.Tlatov (Kislovodsk Solar Station, Pulkovo), V.V.Yurkov (Blagoveschensk
State Pedagogical University)
 and D. Buckley(SAAO) behalf MASTER-team.

MASTER-Net of robotic telescope spent a great sky survey for research LVC
trigger G194575.
We have not received an automatic socket messages through GCN.
Therefore, we were not able to immediately start automatically survey
inside error box  and began  it in the manual mode at 2015-10-22 23:17:52
on the MASTER-Kislovodsk telescope,
which at that time had suitable weather condition. In the subsequent time
MASTER-II  telescopes SAAO (South Africa), IAC (Tenerife), Tunka (Baykal),
Blagoveschensk and Kislovodsk  cover approximately 9000 sq. degree of sky
due to very flat probability distributuion (which actually includes all the
sky).  The observations inside on the lobe nead 1 h RA  were greatly
complicated by the proximity of the moon. It was finally covered 87% of the
lobe nead 1 h RA and 14% of full probability. The remaining 13% of 1h lobo
are overexposed background light of the moon. 3 sigma upper limit in our
survey ranged from 17 to 20 depending on the distance to the moon and
weather conditions. The best limit, which is obtained in our survey shows
a color on a coverage map:

http://master.sai.msu.ru/static/G194575/limits2.png

We found following transitents during this survey:



1) MASTER OT J194142.51-563815.7 discovery ��� dwarf nova outburst, Amplitude
more then 4.9m.

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 19h
41m 42.51s -56d 38m 15.7s on 2015-10-25.80803 UT.
The OT unfiltered magnitude is m_OT=17.1 (the limit is 18.5m, 6 images),
m_OT=17.4 on 2015-10-26 18:38:50.366UT(2 images). There is no minor planet
at this place. We have reference image without OT on 2015-03-23.04023 UT
with unfiltered magnitude limit 20.2m.
There is no known optical source at this place (VIZIER database, POSS limit
is 22m). There is only Allwise source with W1=17.109, W2=17.373, W3=12.745.
So there is a dwarf nova outburst with Amplitude more then 4.9m.

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/194142.51-563815.7_1.png

2) MASTER OT J184709.24-495633.9 discovery ��� dwarf nova outburst with
Amplitude more then 3.4m

MASTER-SAAO auto-detection system discovered OT source at (RA, Dec) = 18h
47m 09.24s -49d 56m 33.9s on 2015-10-25.79044 UT.
The OT unfiltered magnitude is 17.2m (limit is 18.3m, 4 images). There is
no minor planet at this place.
MASTER-SAAO reobserved it on 2015-10-26 18:06:20.857 , m_OT=17.7 (2
images). We have reference image without OT on 2015-02-17.102UT with
unfiltered magnitude limit 19.4m. There is USNO B1 star with B2=20.83,
R2=20.58. So there is classic dwarf nova outburst with amplitude more then
3.4m.
The discovery and reference images are available at
http://master.sai.msu.ru/static/OT/184709.24-495633.9.png


3) MASTER OT J020836.79-104018.8 discovery

MASTER-IAC auto-detection system discovered OT source at (RA, Dec) = 02h
08m 36.79s -10d 40m 18.8s on 2015-10-23.07405 UT.
The OT magnitude in I-band is 17.0m (limit 18.4m). The OT is seen in 3
images. There is no minor planet at this place. We have reference image
without OT on 2015-10-21.07257 UT with unfiltered magnitude limit 21.1m.

There is 2MASS and WISE source with J=14.873, H=14.243, K=13.851
http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=&-out.add=_r&-out.add=_RAJ%2C_DEJ&-sort=_r&-to=&-out.max=20&-meta.ucd=2&-meta.foot=1&-c=32.153291666667+-10.671888888889&-c.rs=5

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/020836.79-104018.8.png


4). MASTER OT J060553.93+283325.6 discovery  -dwarf nova outburst with
Amplitude more then 3.9m

MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 06h
05m 53.93s +28d 33m 25.6s on 2015-10-25.75079 UT.
The OT unfiltered (W=0.2B+0.8R, calibrated to USNO-B) magnitude is 15.5m
(the limit is 18.0m).
The OT is seen in 9 images.
We have reference image without OT on 2013-12-01.66689 UT with unfiltered
magnitude limit 18.9m.
There is USNO-B1 star with B2=20.53,R2=19.10,I=17.9, no JHK, so this OT is
dwarf nova outburst with Amplitude more then 3.9m.

Spectral observations are required. The discovery and reference images are
available at
http://master.sai.msu.ru/static/OT/MASTEROTJ060553.93+283325.6.jpg


5). MASTER-IAC automaticaly found the QUEST optical transient reported by
GCN Circ.18473
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  (Rabinovich et al.) inside the LIGO error region for trigger
G194575.

MASTER-IAC auto-detection system detected OT source at (RA, Dec) = 00h 11m
27.62s -06d 25m 38.0s on 2015-10-26.97009 UT  with unfiltered magnitude
m_OT= 17.0 m +-0.3 (W=0.2B+0.8R calibrated to USNO-B1). Photometry is not
very good because proximity of the Moon.

The OT is seen in 5 images. There is no minor planet at this place. We have
reference image without OT on 2015-10-09.09056 UT with 19.9 unfiltered
magnitude limit.

L. P. Singer (NASA/GSFC), M. M. Kasliwal (Caltech), R. Ferretti
(Stockholm), S. B. Cenko (NASA/GSFC), T. Barlow (Caltech), Y. Cao
Caltech), R. Laher (IPAC), and J. Rana (IUCAA) report on behalf of the
intermediate Palomar Transient Factory (iPTF) collaboration:

We have performed tiled observations of LIGO/Virgo G194575 using the
Palomar 48-inch Oschin telescope (P48). The anti-sun probability island
from the BAYESTAR localization was observable from Palomar for most of the
night and weather conditions were good. Starting at 2015-10-23 03:26 UTC,
about 14 hours after the GW trigger, we imaged 160 fields spanning 1114
deg2. We estimate a 17% prior probability that these fields contain the
true location of the source.

Sifting through candidate variable sources using image subtraction by both
our NERSC and IPAC pipelines, and applying standard iPTF vetting
procedures, we flagged the following optical transient candidates for
further follow-up:

   name       RA       Dec     time  mag 
--------- --------- --------- ----- -----
iPTF15dkm 354.32375  -3.53254 03:39 18.66
iPTF15dlc  16.14909  -2.54011 08:15 16.17
iPTF15dld  14.55532  -3.66397 08:15 18.50
iPTF15dlj  19.76198 +10.00134 09:22 18.14
iPTF15dln  14.58195  +7.23471 09:15 18.81
iPTF15dmk  21.22653  +0.61874 10:58 19.60
iPTF15dmn   7.23638 -11.40550 09:07 18.37
iPTF15dmq 353.87809  +6.45032 04:36 18.64
iPTF15dni  21.26675  -4.70845 10:23 17.72
iPTF15dkv   7.77118  -2.65228 07:08 18.84
iPTF15dkn 357.54623  +0.09660 05:34 19.17
iPTF15dkk 357.57171  -3.16660 05:38 19.43
iPTF15dnh  14.90946 -14.19912 10:01 19.45
iPTF15dlb  16.18149  +2.06164 08:25 19.21 = (PS15byt)
iPTF15dmv  21.02204 -10.50270 10:20 19.85
iPTF15dkt   7.20239  -2.70993 07:08 18.05 = (PS15coc)
iPTF15dmt  97.71723 +39.31086 13:01 19.17
iPTF15dmu  22.59586  -4.41018 10:25 19.35
iPTF15dms  98.41981 +37.30400 13:00 19.97
iPTF15dmp  16.28538  -9.74387 09:59 20.05
iPTF15dmf  15.40890  -3.94111 08:15 18.48
iPTF15dmb  18.31767  -6.51451 10:09 19.45
iPTF15dlz  22.25290  -4.36629 10:25 19.22
iPTF15dlv  20.54769  -2.00612 10:26 19.18
iPTF15dlu  22.85842  -8.89533 10:21 19.40
iPTF15dlr  18.56416  +3.32916 10:03 19.14 (= PS1-14aen)
iPTF15dlp  15.49983  +9.50920 09:14 19.11
iPTF15dlg   3.68611 -11.70795 09:05 19.10
iPTF15dla  14.73492  +1.74302 08:25 18.28
iPTF15dkj 359.67964  -7.68101 05:41 19.47
iPTF15dku   2.86523  -6.42730 07:11 17.74 (= LSQ15bjb, PS15cog)
iPTF15dmr   6.96306 -11.47793 09:05 18.82 (= PS15bww)
iPTF15dmj  21.09391  +3.58754 11:02 16.10 (= PS15cku)
iPTF15dls  19.93774  +4.08302 10:03 19.34
iPTF15dlo  18.11055  +5.07488 09:26 19.17
iPTF15dlm  15.73540  +5.54822 09:17 18.90
iPTF15dll  16.22272  +4.76531 09:17 17.63 (= PS15byu)
iPTF15dli  18.13482 +10.49597 09:22 19.68 (= PS15buq)
iPTF15dlk  17.44493 +13.30794 09:21 16.34
iPTF15dko   3.41903  +8.90473 06:51 19.34
iPTF15dma  22.39782 -15.50700 10:16 19.93
iPTF15dlx  22.44977 -15.14902 10:16 19.39

Where relevant, we have given equivalent designations by Pan-STARRS
(Smartt et al., GCN 18451
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 , GCN 18484
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 ) and La Silla-QUEST (Rabinowitz et
al., GCN 18473
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 ).

The following sources are coincident with galaxies with redshifts
(spectroscopic or photometric) < 0.1: iPTF15dkm, iPTF15dlc, iPTF15dld,
iPTF15dlj, iPTF15dln, iPTF15dmn, iPTF15dni, iPTF15dkv, iPTF15dkn,
iPTF15dkk, iPTF15dnh.

iPTF15dlc may be a variable star superimposed on a nearby galaxy.

iPTF15dni appeared to fade by 0.5 mag in one day, but its position in the
nucleus of its host galaxy makes the host-subtracted photometry
questionable. We will obtain further follow-up to confirm the fading.

iPTF15dmk and iPTF15dmq lacked any plausible host galaxy or quiescent
counterpart in SDSS or archival iPTF images, but showed no significant
intra-night photometric evolution.

iPTF15dlb (our designation of PS15byt) is a known nova in the galaxy IC
1613 (Williams & Darnley, ATel #8061).

The following candidates coincided with galaxies with redshifts > 0.1:
iPTF15dmv, iPTF15dkt.

The following sources had no known redshift but showed unremarkable
photometric evolution: iPTF15dmt, iPTF15dmu, iPTF15dms, iPTF15dmp,
iPTF15dmf, iPTF15dmb, iPTF15dlz, iPTF15dlv, iPTF15dlu, iPTF15dlr,
iPTF15dlp, iPTF15dlg, iPTF15dla, iPTF15dkj.

The following sources were previously known SNe or AGNs: iPTF15dku,
iPTF15dmr, iPTF15dmj, iPTF15dls, iPTF15dlo, iPTF15dlm, iPTF15dll,
iPTF15dli, iPTF15dlk, iPTF15dko.

iPTF15dku is our designation for LSQ15bjb. We report the following
additional photometry:
  -377.25 days: R < 20.21
    +0.71 days: R = 18.62 +/- 0.13
    +1.71 days: R = 18.15 +/- 0.15

In summary, we encourage further follow-up of iPTF15dkm, iPTF15dld,
iPTF15dlj, iPTF15dln, iPTF15dmn, iPTF15dni, iPTF15dkv, iPTF15dkn,
iPTF15dkk, iPTF15dnh, iPTF15dmk, iPTF15dmq.

Positions are stated in the ICRS. Times are in UTC. Magnitudes are based
on image subtraction; they are in the Mould R filter and in the AB system,
calibrated with respect to point sources in SDSS as described in Ofek et
al. (2012, http://dx.doi.org/10.1086/664065
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 ).

The diagram https://gracedb.ligo.org/apiweb/events/G194575/files/iptf.pdf
shows the locations of our candidates and the P48 fields in relation to
the LIGO/Virgo localization.

V. Zach Golkhou (ASU), Nat Butler (ASU), Neil Gehrels (GSFC), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Eleonora Troja (GSFC), and Alan M. Watson (UNAM) report:

We observed the La Silla Quest candidate (GCN 18473
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 ; RA = 2.865, DEC = -6.4273), with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio 
Astron�mico Nacional on Sierra San Pedro M�rtir from 2015/10 27.11 to 2015/10 27.13 UTC. We obtained a total exposure of 24 minutes on this target.

The source is cleanly detected in the r, i, and z bands.  We find r = 17.14 +/- 0.01, i =  17.37 +/- 0.01, and z = 17.39 +/- 0.06.  These magnitudes are in the AB system and are not corrected for Galactic 
extinction.

We thank the staff of the Observatorio Astron�mico Nacional in San Pedro M�rtir.

Nipuni Palliyaguru (TTU) and Alessandra Corsi (TTU) report on behalf of a
larger collaboration:

We imaged the position of several iPTF transients (complete list reported
at the end of this message; Singer et al. GCN 18497
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 ) located in the error
region of LIGO/Virgo G194575 (Singer et al. GCN 18442
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 ), with the Karl G.
Jansky Very Large Array (VLA) in its D configuration. The observations
started on 15-Oct-29 02:51:05 UT, ended on 15-Oct-29 04:35:48 UT, and were
carried out in C-band (central frequency of about 6 GHz). Analysis is
ongoing.


List of followed-up iPTF transients

iPTF name   RA         Dec
 --------------------------
iPTF15dmk 21.22653  +0.61874
iPTF15dld 14.55532  -3.66397
iPTF15dlj 19.76198 +10.00134
iPTF15dln 14.58195  +7.23471
iPTF15dmn  7.23638 -11.40550
iPTF15dni 21.26675  -4.70845
iPTF15dkv  7.77118  -2.65228
iPTF15dkn 357.54623 +0.09660
iPTF15dkk 357.57171 -3.16660
iPTF15dnh 14.90946 -14.19912
iPTF15dmk 21.22653  +0.61874
iPTF15dmq 353.87809 +6.45032

P. D'Avanzo, A. Melandri (INAF-OAB), S. Piranomonte (INAF-OAR), E. Cappellaro, L. Tomasella (INAF-OAPd), E. Brocato (INAF-OAR), M. Branchesi (Urbino University/INFN Firenze), E. Palazzi (INAF-IAFS Bo), L. A. Antonelli, (INAF-OAR), P. Astone (INFN-Roma), S. Campana (INAF-OAB), E. Cappellaro (INAF-OAPd), S. Covino (INAF-OAB), V. D'Elia (INAF-ASDC), F. Getman (INAF-OAC), G. Giuffrida (INAF-ASDC), A. Grado (INAF-OAC), G.Greco (Urbino University/INFN Firenze), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), S. Marinoni (INAF-ASDC), P. Marrese (INAF-ASDC), L. Nicastro (INAF-IASF Bo),  Pian (SNS-Pisa), L. Pulone (INAF-OAR), F. Ricci (Sapienza University), G. Stratta (Urbino University/INFN Firenze), V. Testa (INAF-OAR), A. Fiorenzano, W. Boschin, Albar Garcia de Gurtubai Escudero (INAF-TNG), on behalf of the INAF Gravitational Astronomy group report: 

We report the result of the analysis of the optical transients iPTF15dkm and iPTF15dlj reported by Singer et al. (LIGO/Virgo Circular #18497), located in the skymap of the advanced LIGO and Virgo trigger G194575 (Singer et al., LIGO/Virgo Circular #18442).
We observed with the 3.6m Italian TNG telescope (Canary Islands, Spain), equipped with DOLORES  camera in both imaging and spectroscopic mode on 2015 Oct 29. 

The optical transients are clearly detected. At a mean time of 20:07:03 UT and 20:50:24 UT we measure a magnitude of r = 17.95  +/-   0.23 (AB) and r = 16.64  +/-   0.35 (AB) for iPTF15dkm and iPTF15dlj respectively.

Based on a preliminary calibration, the spectrum of iPTF15dkm,  obtained on
2015 Oct 29 at 20:57:30 UT, shows that the transient is a Type II SN
about ten days after explosion at z~0.026, as derived from the position of
the SN main features. The best fit is with SN2006bp (Quimby et al. 2007, ApJ 666, 1093).
The transient is close to SDSS galaxy SDSS J233717.65-033159.2,
with photometric redshift z~0.036.

The spectrum of iPTF15dlj, obtained on Oct 29 at 21:37:46 UT, shows that
the transient is a type II SN about 2-3 weeks after explosion, around z~0.01.
The best match is with SN 2005cs  (Pastorello et al. 2006,
MNRAS, 370, 1752). The transient is close to the galaxy J011902.90+100005.5
(photometric redshift z~0.05 from SDSS).

Classification was done with GELATO (Harutyunyan et al. 2008, A&A, 488, 383)
and SNID (Blondin and Tonry 2007, ApJ, 666, 1024).

I.A. Steele, C.M. Copperwheat, A. S. Piascik (Liverpool JMU) report on behalf of
a larger collaboration:

Observations of 7 of the proposed iPTF candidates (GCN 18497
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 ) using the��
SPRAT spectrograph of the 2.0 metre Liverpool Telescope (La Palma)��have been obtained. ��
The spectral ��resolution was R~350 and the wavelength range 4000 - 8000 Angstroms.

iPTF-15dln was observed��on 2015-10-28 at 00:24UT. ��The transient can not be obviously��
distinguished��from the host��galaxy in our acquisition images. ��Our spectrum shows��absorption��
lines of the host galaxy with��redshift z=0.051.

iPTF-15dkk was observed��on 2015-10-28 at 20:34UT. ��The transient can not be obviously��
distinguished��from the host��galaxy in our��acquisition images. ��Our spectrum shows��absorption��
lines of the host galaxy with��redshift z=0.061.

iPTF-15dkn was observed��on 2015-10-28 at 21:09UT. ��The transient can not be distinguished
from the host��galaxy in our��acquisition images.�� Our spectrum shows��absorption lines of the��
host galaxy with��redshift z=0.074.

iPTF-15dkm was observed��on 2015-10-28 at 21:41UT. ��Our spectrum shows broad H-alpha��
emission and is consistent with a Supernova as reported in GCN 18536
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 . ��

iPTF-15dmn was observed��on 2015-10-28 at 22:15UT. ��Our spectrum shows narrow emission��
line features typical of an AGN at redshift z=0.056.

iPTF-15dni was observed��on 2015-10-28 at 23:08UT. ��The spectrum shows��weak H-alpha emission��
and typical galaxy absorption lines. ��Both the H-alpha emission and the absorption spectra��have��
redshift z=0.020.

iPTF-15dnh was observed��on 2015-10-29 at 01:16UT. ��The transient can not be obviously��
distinguished��from the host��galaxy in our��acquisition images. ��Our spectrum shows��absorption��
lines of the host galaxy with��redshift z=0.056.

Further��analysis is ongoing.

DisclaimerNone��

I.A. Steele, C.M. Copperwheat, A.S. Piascik (Liverpool JMU) report on behalf
of a larger collaboration:

A spectrum of the iPTF candidate iPTYF-15dmk (GCN 18497
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 ) was obtained with the
SPRAT spectrograph on the Liverpool Telescope on 2015-11-02 at 23:37UT.  The
wavelength range is 4000-8000 Angstroms and the spectral resolution R=350.

Classification using SNID indicates the transient is a Type II supernova with
redshift z=0.065 and near maximum light.

DisclaimerNone

M. Serino (RIKEN), H. Negoro (Nihon U.), N. Kawai (Tokyo Tech),
S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, 
Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Shidatsu, 
J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), 
M. Arimoto, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech), 
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), 
H. Tsunemi, R.Imatani (Osaka U.), 
M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), 
Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.), 
Y. Tsuboi, S. Kanetou (Chuo U.), 
M. Yamauchi, D. Itoh (Miyazaki U.), 
K. Yamaoka (Nagoya U.), M. Morii (ISM)
report on behalf of the MAXI team:

We analyzed the MAXI/GSC all-sky X-ray data (2-10 keV) for the two days
following the LVC trigger G194575 (Singer et al. GCN 18442
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 ).

We did not detect new sources in the LIGO candidate regions.
The 3-sigma upper limits are shown below for the two 24-hour 
integrations after the trigger.

Region Center   0-24h     24h-48h
------------  ---------  ----------
(13h,  -15.)   8 mCrab     9 mCrab  
(13.5h, -5.)   8 mCrab     9 mCrab  
(01h,   +5.)  12 mCrab    12 mCrab  
------------  ---------  ----------

As in the previous report for the single orbit image (Serino et al. 
GCN 18467
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 ), about half of the candidate region around 13h in R.A. 
and half of the region around 13.5h were not observed to avoid the sun.

Nipuni Palliyaguru (TTU) and Alessandra Corsi (TTU) report on behalf of a
larger collaboration:

We reobserved the position of several iPTF transients (all of the ones
reported in
Palliyaguru et al. GCN 18528
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  except for iPTF15dmn) located in the error
region of
LIGO/Virgo G194575 (Singer et al. GCN 18442
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 , 18497
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 ), with the Karl G.
Jansky Very Large
Array (VLA) in its D configuration. The observations started on 15-Nov-04
03:06:16 UT,
ended on 15-Nov-4 05:15:56 UT, and were carried out in C-band (central
frequency ~6 GHz). Analysis is ongoing and further observations are planned.

L. Tomasella, E. Cappellaro, (INAF-OAPd), E. Brocato (INAF-OAR), M. Branchesi (Urbino University/INFN Firenze),   L. A. Antonelli, (INAF-OAR), P. Astone (INFN-Roma), S. Campana (INAF-OAB), S. Covino (INAF-OAB), P. D'Avanzo,  V. D'Elia (INAF-ASDC), F. Getman (INAF-OAC), G. Giuffrida (INAF-ASDC), A. Grado (INAF-OAC), G.Greco (Urbino University/INFN Firenze), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), S. Marinoni (INAF-ASDC), P. Marrese (INAF-ASDC), A. Melandri (INAF-OAB), L. Nicastro (INAF-IASF Bo), E. Palazzi (INAF-IAFS Bo), E. Pian (SNS-Pisa), S. Piranomonte, L. Pulone (INAF-OAR), F. Ricci (Sapienza University), G. Stratta (Urbino University/INFN Firenze), G. Tagliaferri (INAF-OAB), V. Testa (INAF-OAR) on behalf of the INAF Gravitational Astronomy group report: 


We report on the results of the observations of three optical transients from the list of Singer et al. (LIGO/Virgo Circular #18497), located in the skymap of the advanced LIGO and Virgo trigger G194575 (Singer et al., LIGO/Virgo Circular #18442).
Observation were obtained with the Asiago 1.82 m Copernico Telescope + AFOSC on 2015 Nov 4, under excellent sky conditions.

1- the spectrum of iPTF15dld (range 340-820 nm; resolution 1.4 nm) shows narrow emission lines of the H Balmer series, [OIII] doubled and SiII that are typical of Seyfert 2 at redshift z=0.046.  Preliminary photometry gives g=19.52(0.04), r=19.35(0.03), i=19.23(0.04).

2- the spectrum of  iPTF15dkv (same configuration as before) show  narrow Halpha/NII emissions consistent with that of a giant HII region at  redshift z=0.081 that indicates heavy contamination from the host galaxy.

3- photometry iPTF15dmq indicates a magnitude r~21.5. This is consistent with the magnitude reported by SDSS for SDDSJ233530.88+062710.7that is  r=21.63. Therefore, if  transient was present it already declined below our detection limit.

S. Benetti, L. Tomasella, E. Cappellaro, (INAF-OAPd), E. Brocato (INAF-OAR), M. Branchesi (Urbino University/INFN Firenze),  L. A. Antonelli, (INAF-OAR), P. Astone (INFN-Roma), S. Campana, S. Covino, P. D'Avanzo (INAF-OAB), V. D'Elia (INAF-ASDC), F. Getman (INAF-OAC), G. Giuffrida (INAF-ASDC), A. Grado (INAF-OAC), G. Greco (Urbino University/INFN Firenze), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), S. Marinoni (INAF-ASDC), P. Marrese (INAF-ASDC), A. Melandri (INAF-OAB), L. Nicastro (INAF-IASF Bo), E. Palazzi (INAF-IAFS Bo), E. Pian (SNS-Pisa), S. Piranomonte, L. Pulone (INAF-OAR), F. Ricci (Sapienza University), G. Stratta (Urbino University/INFN Firenze), G. Tagliaferri (INAF-OAB), V. Testa (INAF-OAR) on behalf of the INAF Gravitational Astronomy group report:

We have re-analysed the spectra of PTF15dkv and PTF15dld taken on 2015 Nov 4 with the Asiago 1.82 m Copernico Telescope + AFOSC, for which preliminary information were reported in Tomasella et al. (GCN18561
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 ).

After careful minimisation of  the strong background contamination, low S/N spectra of supernovae emerge. In particular:

The spectrum of PTF15dkv, given the redshift reported in GCN18561
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  (z=0.081), is consistent with those shown by Type Ia Supernovae, about a week after the B  maximum light.

More interesting, the spectrum of PTF15dld, given the redshift  (z=0.046), is consistent with those of broad-line Type Ic Supernovae, close to maximum light. In particular, the spectrum closely resembles that of SN 2006aj (Pian et al 2006, Nature 442, 1011), which has been associated with the GRB 060218 (Campana et al. 2006, Nature 442, 1008). These are rare events (<1% of all core collapse SNe) and are likely associated to jet-like core collapse.

For the latter object follow-up observations have been activated.

L. Tomasella, E. Cappellaro (INAF-OAPd), P. D'Avanzo (INAF-OAB), S. Piranomonte (INAF-OAR), M. Branchesi (Urbino University/INFN Firenze), S. Campana (INAF-OAB), S. Benetti (INAF-OAPd), E. Brocato (INAF-OAR),  L. A. Antonelli, (INAF-OAR), P. Astone (INFN-Roma), S. Covino (INAF-OAB), V. D'Elia (INAF-ASDC), F. Getman (INAF-OAC), G. Giuffrida (INAF-ASDC), A. Grado (INAF-OAC), G. Greco (Urbino University/INFN Firenze), L. Limatola (INAF-OAC), M. Lisi (INAF-OAR), S. Marinoni (INAF-ASDC), P. Marrese (INAF-ASDC), A. Melandri (INAF-OAB), L. Nicastro (INAF-IASF Bo), E. Palazzi (INAF-IAFS Bo), E. Pian (SNS-Pisa), L. Pulone (INAF-OAR), F. Ricci (Sapienza University), G. Stratta (Urbino University/INFN Firenze), G. Tagliaferri (INAF-OAB), V. Testa (INAF-OAR), W. Boschin, D. Carosati, L. Di Fabrizio (INAF-TNG),  on behalf of the INAF Gravitational Astronomy group report:

Following the observations reported by Tomasella et al. (GCN 18561
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 ) and Benetti et al. (GCN 18563
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 ), we re-observed the optical transient iPTF15dld reported by Singer et al. (GCN 18497
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 ), located in the skymap of the advanced LIGO and Virgo trigger G194575 (Singer et al., GCN 18442
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 ).

Optical spectroscopic observations were carried out at a mid time of 2015 Nov 6.949 UT with the 3.6m Italian TNG telescope (Canary Islands, Spain), equipped with the DOLORES camera using the grism LR-B (wavelength range 3000-8000 AA). Optical imaging observations were carried out with the Italian Asiago 1.82 m Copernico Telescope equipped with the AFOSC camera in the uBVriz filters at a mid time of 2015 Nov 6.870. 

Data analysis is ongoing and further observations are planned.

Phil A. Evans (U. Leicester), Jamie A. Kennea (PSU), Scott Barthelmy
(NASA/GSFC), Dave Burrows (PSU), Sergio Campana (INAF-OAB), Brad Cenko
(NASA/GSFC), Neil Gehrels (NASA/GSFC), Paolo Giommi (ASI), Frank
Marshall (NASA/GSFC), John Nousek (PSU), Paul O'Brien (U. Leicester),
Julian Osborne (U. Leicester), David Palmer (LANL), Matteo Perri
(ASDC), Judy Racusin (NASA/GSFC), Mike Siegel (PSU), Gianpiero
Tagliaferri (INAF-OAB) on behalf of the Swift team:

P. D'Avanzo (INAF-OAB), S. Piranomonte (INAF-OAR), E. Cappellaro 
(INAF-OAPd), M. Branchesi (Urbino University/INFN Pisa), E. Brocato 
(INAF-OAR) on behalf of the INAF-GW collaboration:

Alessandra Corsi (Texas Tech), Shri Kulkarni (Caltech), Mansi Kasliwal 
(Caltech), Dale Frail (NRAO) Avishay Gal-Yam (Weizmann Institute) on 
behalf of the iPTF team:

Swift has observed the location of iPTF15dld (Singer at al., LVC Circ. 
18497), which may be a type Ic supernova (Benetti et al., LVC Circ. 
18563). The observations were gathered from 15.4 d to 15.9 d after the 
aLIGO trigger, for a total of 10 ks observing time.

No X-ray emission is detected from iPTF15dld, with a 3-sigma upper limit 
of 9.8e-4 ct/sec; this corresponds to an approximate 0.3-10 keV flux 
limit of 4.9e-14 erg cm^-2 s^-1.

Swift-UVOT detected a bright source with a magnitude of 17.51 +/- 0.10 
in the uvw1 filter, however this lies within the host galaxy, whose uvw1 
magnitude is not known, thus the above magnitude is a combination of 
host+source. Once the transient has faded, we will perform repeat 
observations to measure the host flux and determine the correct 
transient magnitude.

These Swift observations were performed in part through the Swift-GI 
program 1114155 (PI: Corsi).

This circular is an official product of the Swift GW follow-up team.

D. Rabinowitz, C. Baltay, N. Ellman, E. Woodward (Yale), P. Nugent (LBNL)
S. J. Smartt, K. W. Smith, D. Wright D. Young,(Queen���s University Belfast),  
K. Chambers, M. Huber, E. Magnier, H. Flewelling, C. Waters, J. Tonry,
A. Schultz, N. Primak, A. Heinze, B. Stalder, L. Denneau, A. Sherstyuk (IfA Hawaii),
C. Stubbs, M. Coughlin (Harvard), A. Rest (STScI), M. Dennefeld (IAP),
J. Harmanen S. Mattila (Turku), L. Galbany (U de Chile), C. Inserra (QUB),
E. Kankare (QUB), K. Maguire (QUB),  M. Sullivan (Southampton),
S. Valenti (LCOGT), O. Yaron (Weizmann)

We report independent La Silla-QUEST and Pan-STARRS observations of 
iPTF15dld as reported by Singer et al. (GCN18497
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 ), and the follow-up 
observations of  Benetti et al. (GCN18563
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 ). Benetti et al. reported that this 
object was a broad lined type Ic SN. 

La Silla QUEST  operates the 10-sq-deg QUEST camera on the 1.0m 
ESO Schmidt at La Silla (Baltay et al. 2013), and feeds targets to the 
PESSTO spectroscopy programme (Smartt et al. 2015). As part of
routine surveying, a region of G194575 localisation area at
RA~1hr was scanned in the weeks before the trigger and targets
were ingested into the PESSTO marshall.  The object LSQ15bfp was 
discovered on 2015-10-05 at V=19.5 and is the same object as iPTF15dld.
An LSQ pre-discovery detection is visible on 2015-10-03 at V=20.2
It showed an early rising lightcurve of 0.7 mag in two days.  
Hence this object exploded 19 days before the trigger of 
G194575 (2015-10-22 13:33:19.942 UTC Singer et al. GCN18442
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 ).
LSQ has a non-detection of LSQ15bfp on 2015-09-08. 

The object was also detected by Pan-STARRS as PS15crl in 6 separate 
exposures on 2015 10 23.48 +/- 0.2 (UT),  +22hrs after the G194575 
trigger (see Smith et al. GCN 18484
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 , Smartt et al. GCN 18445
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 ). 
PS15crl was measured at i=18.8 +/- 0.04, on each image with no 
significant intra-night variation. 

The reported coordinates of the object are :

LSQ coordinates of LSQ15bfp  : 00:58:13.27 -03:39:50.1
Pan-STARRS coordinates of PS15crl : 00:58:13.27 -03:39:50.2
iPTF coordinates of iPTF15dld :   00:58:13.28  -03:39:50.3

As in SDSS, the Pan-STARRS reference images show a very blue
host galaxy that is superimposed on a larger spiral. These are
probably distinct galaxies. 

Benetti et al.���s note that broad lined Ic SNe are relatively rare, and its 
location within the central 30% probability region make it an appealing 
target for further follow-up (see GCN18563
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 ). However the LSQ 
discovery date makes it unlikely to be related to G194575. 
Nevertheless PESSTO (www.pessto.org) will take a number of 
spectra for follow-up (the first epoch was taken on 2015-11-08).

I.A. Steele, C.M. Copperwheat, A.S. Piascik (Liverpool JMU) report on behalf
of a larger collaboration:

We report Liverpool Telescope (La Palma) observations of iPTF-15dld and iPTF-15dni.

SPRAT Spectroscopy and IO:O broad band optical photometry of iPTF-15dld was obtained on the
night of 2015-11-06. ��Interpolating over the host galaxy emission lines in the spectrum reveals
a continuum with broad emission features. ��With the data to hand we are
not confident in subtraction of the host galaxy continuum from that of the transient. ��The
spectrum is broadly consistent with the identification made as a Type Ic broad line
supernova in GCN18632
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  but we are not able to constrain the redshift or age. ��Depending
on observation priorities we may schedule some further spectroscopy and photometry
at later times.

SPRAT Spectroscopy and IO:O redshifted H-alpha optical imaging of iPTF-15dni
was obtained on the night of 2015-11-05. ��Comparison of the spectrum with our
earlier spectrum obtained on 2015-10-28 and reported in GCN18549
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  shows no
significant change in the H-alpha emission line. ��Our H-alpha images show the galaxy
has many apparent star forming regions, although we can not resolve the location of the��
transient in H-alpha from the galaxy core without a reference image at this time. ����
Depending on observation priorities we may schedule some further spectroscopy��
and photometry at later times.

DisclaimerNone

Nipuni Palliyaguru (TTU) and Alessandra Corsi (TTU) report on behalf of a
larger collaboration:

We observed the position of the Fermi-LAT transient detected in the error
region of LIGO/Virgo G194575 (Vianello et al. GCN 18458
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 ) with the Karl G.
Jansky Very Large Array (VLA) in its D configuration. The observations were
carried out in S band (3 GHz; primary beam ~15 arcmin), started on
5-Nov-2015 22:09:18 UT, and ended on 5-Nov-2015 23:09:05. We obtained 5
images centered at the positions listed below (all located within the
Fermi/LAT 0.5 deg statistical error circle). Although the VLA calibration
pipeline failed in some of the data quality scores, careful inspection and
flagging allowed us to obtain calibrated images. Further observations are
planned: we will attempt to use the images collected during this first
epoch as references for identifying variable sources in the imaged area.

RA Dec

14h46m45.59s   -3d15'15.60"

14h47m28.80s   -3d3'57.60"

14h46m2.40s     -3d3'57.60"

14h47m28.80s   -3d5'33.60"

14h46m2.40s     -3d25'33.60"

Old message: Resending so that it appears in GCN archive�

LIGO/Virgo G194575:  Fermi GBM Observations

Lindy Blackburn (CfA), Michael S. Briggs (UAH), Eric Burns (UAH), Jordan Camp (NASA/GSFC), 
Nelson Christensen (Carleton College), Valerie Connaughton(USRA), Tito Dal Canton (MPG), 
Adam Goldstein (NASA/MSFC), Peter Jenke (UAH), Tyson Littenberg (USRA/UAH), 
Judith Racusin (NASA/GSFC), Peter Shawhan (UMD), Leo Singer (NASA/GSFC), 
John Veitch (Birmingham), Binbin Zhang (UAH)

The region around 13h in Right Ascension, containing most of the probability for the LIGO CBC 
candidate G194575 reported by Singer et al. GCN 18442
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 , was observed by Fermi GBM during 
the GW event.  The region around 01h was occulted by the Earth.

A search of the GBM Time-Tagged Event data between 8 keV and 40 MeV from 64 s before to 
82 s after the CBC candidate event revealed no significant emission on search timescales in 
factors of 2 from 64 ms to 2.048 s.

The LIGO Scientific Collaboration and Virgo report:

The routine offline compact binary coalescence (CBC) analysis of the span
of data containing the gravitational-wave candidate G194575 (GCN 18442
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 )
has completed. The offline CBC analysis consists of a pair of matched
filter search pipelines, gstlal and pycbc. They are similar to the
low-latency CBC searches that generate real-time alerts, but analyze the
data in discrete two-week chunks, are sensitive to both neutron star and
black hole binary mergers, use additional data quality vetoes, and employ
more live time to estimate the significance of candidates.

In our initial circular, we had reported the false alarm rate (FAR)
estimated by the low-latency gstlal search, 9.654e-08, or about 1/120
days. As estimated by the offline gstlal search, the candidate has a FAR
of 5.87e-06 Hz, or 1/1.97 days. As estimated by the offline pycbc
search, G194575 has a FAR of 8.19e-6 Hz, or 1/1.41 days.

Though the low-latency FAR estimate for this event met our threshold for
distribution of an alert, from the offline analysis we conclude that
G194575 is no longer an event of interest.

Zhang, Yu (XAO); Zhang, Xuan (XAO); Niu, Hubiao (XAO); Pu, guangxin (XAO); Ma, shuguo (XAO); Yang, taozhi (XAO); Song, fangfang(XAO)

Liu Jinzhong (XAO), on behalf of the NOWT group report:
We followed up the GraceDB event (event ID: G194575) with Nanshan One-meter Wide field Telescope (NOWT) from Xinjiang Astronomical observatory (XAO). The first observation was observed at 10/29/2015, GMT 19/15/51. The first observation reached an exposure time of 120 seconds with V band and approached a limiting magnitude of 20.3 magnitude. 40 of *.fit files of this field were obtained and the time of duration was 1680 s. We only report the first observation here, more information will be reported later.


We monitored the sky region constantly since the event, and we anticipated to continue the observation. We observed the range (just about FOV of 15 sqr deg due to very small possibility-map at northern sky) and here reported a non-detection of EM-trigger with a time span of 2.48 h  with limiting magnitude of 20.3


=========================
Detailed information about the observation is listed below
   RA               DEC       EXP       UTC        number     total(s)    limit_mag   filter
  01:59:59.07    +15:31:46.6  120s  20151029191551   40        1680         20.3        V
  01:59:59.07    +14:13:46.6  12s   20151029192409   36        1500         15.3        V
  01:59:59.07    +12:55:46.6  30s   20151029193227   30        1260         16.7        V
  01:59:59.07    +11:37:46.6  30s   20151029194044   30        1260         17.1        V
  01:59:59.07    +10:19:46.6  12s   20151029194902   30        1260         15.0        V
  01:59:59.07    +09:01:46.6  12s   20151029195720   30        1260         15.0        V
  00:54:24.3     +00:39:59.0  40s,  20151217131620    6        360          17.8        V
  01:54:38.0     +00:43:00    35s   20160122125821   10        360          15.6        V




--
N: Jinzhong Liu, PhD
O: Main building, 213
P: 150, Science 1-Street, Urumqi, Xinjiang 830011, China
T: 86 991 3689027
D: 2012-07-14
E: optics@xao.ac.cn