LIGO/Virgo S190930t
GCN Circular 25874
Subject
LIGO/Virgo S190930t: Upper limits from IceCube neutrino searches
Date
2019-09-30T15:05:09Z (6 years ago)
From
Raamis Hussain at IceCube <raamis.hussain@icecube.wisc.edu>
IceCube Collaboration (http://icecube.wisc.edu/) reports:
Searches [1,2] for track-like muon neutrino events detected by IceCube
consistent with the sky localization of gravitational-wave candidate
S190930t
in a time range of 1000 seconds [3] centered on the alert event time
(2019-09-30 14:25:47.685 UTC to 2019-09-30 14:42:27.685 UTC) have been
performed. During this time
period IceCube was collecting good quality data. No significant track-like
events are found in spatial coincidence of S190930t calculated from the map
circulated in the 2-Initial notice.
IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino
point sources within the locations spanned by the 90% spatial containment
of S190930t ranges from 0.029 to 1.150 GeV cm^-2 in a 1000 second
time window.
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector
operating at the geographic South Pole, Antarctica. The IceCube realtime
alert point of contact can be reached at roc@icecube.wisc.edu
[1] Bartos et al. arXiv:1810.11467 (2018) and Countryman et
al.arXiv:1901.05486 (2019)
[2] Braun et al., Astroparticle Physics 29, 299 (2008)
[3] Baret et al., Astroparticle Physics 35, 1 (2011)
GCN Circular 25875
Subject
LIGO/Virgo S190930t: Global MASTER-Net observations report
Date
2019-09-30T15:25:13Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin,
V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
H.Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova
(Irkutsk State University, API),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko
(Blagoveschensk Educational State University)
MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the LIGO/Virgo S190930t errorbox 146 sec after trigger time at 2019-09-30 14:36:33 UT, with upper limit up to 17.8 mag. The observations began at zenit distance = 53 deg. The sun altitude is -41.8 deg.
The galactic latitude b = -60 deg., longitude l = 98 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10861
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
236 | 2019-09-30 14:36:33 | MASTER-Amur | (21h 37m 57.259s , +04d 14m 22.62s) | C | 180 | 17.2 |
446 | 2019-09-30 14:40:02 | MASTER-Amur | (21h 27m 36.298s , +02d 14m 13.90s) | C | 180 | 17.8 |
666 | 2019-09-30 14:43:42 | MASTER-Amur | (21h 26m 50.955s , +00d 13m 52.57s) | C | 180 | 17.6 |
1073 | 2019-09-30 14:50:30 | MASTER-Amur | (21h 13m 54.694s , +04d 13m 40.66s) | C | 180 | 17.8 |
1287 | 2019-09-30 14:54:03 | MASTER-Amur | (21h 11m 37.617s , +02d 13m 43.23s) | C | 180 | 17.6 |
1924 | 2019-09-30 15:04:40 | MASTER-Amur | (21h 27m 38.532s , +02d 13m 57.91s) | C | 180 | 17.3 |
2138 | 2019-09-30 15:08:14 | MASTER-Amur | (21h 35m 39.297s , +02d 13m 55.29s) | C | 180 | 17.4 |
2349 | 2019-09-30 15:11:45 | MASTER-Amur | (21h 26m 53.129s , +00d 13m 45.37s) | C | 180 | 17.3 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 25876
Subject
LIGO/Virgo S190930t: Identification of a GW compact binary merger candidate
Date
2019-09-30T15:29:21Z (6 years ago)
From
Olivier Minazzoli at LIGO Virgo Collaboration <olivier.minazzoli@ligo.org>
The LIGO Scientific Collaboration and the Virgo Collaboration report:
We identified the compact binary merger candidate S190930t during real-time
processing of data from LIGO Livingston Observatory (L1) at 2019-09-30
14:34:07.685 UTC (GPS time: 1253889265.685). The candidate was found by the
GstLAL [1] analysis pipeline.
S190930t is an event of interest because its false alarm rate, as estimated
by the online analysis, is 1.5e-08 Hz, or about one in 2 years. The event's
properties can be found at this URL:
https://gracedb.ligo.org/superevents/S190930t
The classification of the GW signal, in order of descending probability, is
NSBH (74%), Terrestrial (26%), BNS (<1%), BBH (<1%), or MassGap (<1%).
Assuming the candidate is astrophysical in origin, there is strong evidence
for the lighter compact object having a mass < 3 solar masses (HasNS:
>99%). Using the masses and spins inferred from the signal, there is strong
evidence against matter outside the final compact object (HasRemnant: <1%).
Data from the LIGO-Livingston detector at the time of the trigger exhibits
non-stationarity that is consistent with a known class of transient noise
[2]. Investigations are ongoing as to the possible impact of this noise
feature on the significance, classification, and distance estimate of the
reported trigger.
One sky map is available at this time and can be retrieved from the GraceDB
event page: * bayestar.fits.gz,0, an updated localization generated by
BAYESTAR [5], distributed via GCN notice about 6 minutes after the
candidate trigger time. For the bayestar.fits.gz,0 sky map, the 90%
credible region is 24220 deg2. Marginalized over the whole sky, the a
posteriori luminosity distance estimate is 108 +/- 38 Mpc (a posteriori
mean +/- standard deviation).
For further information about analysis methodology and the contents of this
alert, refer to the LIGO/Virgo Public Alerts User Guide <
https://emfollow.docs.ligo.org/userguide/>.
[1] Messick et al. PRD 95, 042001 (2017)
[2] Abbott et al. CQG 33, 134001 (2016)
GCN Circular 25880
Subject
LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
Date
2019-09-30T15:56:34Z (6 years ago)
From
Maeve Doyle at U College Dublin, Ireland <maeve.doyle.1@ucdconnect.ie>
Maeve Doyle (UCD, Ireland), Diego Gotz (CEA, Saclay)
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
J. Rodi (IAPS-Roma, Italy)
A. Coleiro (APC, France)
S. Mereghetti (INAF IASF-Milano, Italy)
on behalf of the INTEGRAL multi-messenger collaboration:
https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration
Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed
a search for a prompt gamma-ray counterpart of S190930t (GCN 25876).
At the time of the event (2019-09-30 14:34:07 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 139 deg with respect to
the spacecraft pointing axis. This orientation implies strongly
suppressed (3.4% of optimal) response of ISGRI, somewhat suppressed
(64% of optimal) response of IBIS/Veto, and strongly suppressed (40%
of o ptimal) response of SPI-ACS.
The background within +/-300 seconds around the event was rather
stable (excess variance 1.2).
We have performed a search for any impulsive events in INTEGRAL SPI-
ACS (as described in [2]) data.
We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 3.3e-07 erg/cm^2 (within the
50% probability containment region of the source localization) for a
burst lasting less than 1 s with a characteristic short GRB spectrum
(an exponentially cut off power law with alpha=-0.5 and Ep=600 keV)
occurring at any time in the interval within 300 s around T0. For a
typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and
Ep=300 keV), the derived peak flux upper limit is ~3e-07 (6.2e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.
For the mean reported distance 108.0 Mpc this corresponds to the limit
on the total isotropic equivalent energy in 1 s of 4.6e+47 erg for
the short GRB spectrum and for a long GRB spectrum isotropic
equivalent luminosity in 1 s (8 s) of 2.2e+47 erg/s (8.8e+46 erg/s)
We report for completeness and in order of FAP, all excesses
identified in the search region. We find 4 likely background
excesses:
scale | T | S/N | luminosity ( x 1e+48 erg/s) | FAP
4.5 | -58.1 | 3.5 | 3.97 +/- 1.68 +/- 3.84 | 0.0998
6 | -133 | 3.6 | 3.84 +/- 1.45 +/- 3.71 | 0.13
0.05 | -1.19 | 3.1 | 3.27 +/- 1.63 +/- 3.17 | 0.424
0.15 | 20.1 | 3.6 | 21.7 +/- 9.31 +/- 21 | 0.845
Note that FAP estimates (especially at timescales above 2s) may be
possibly further affected by enhanced non-stationary local background
noise. This list excludes any excesses for which FAP is close to
unity.
All results quoted are preliminary.
This circular is an official product of the INTEGRAL Multi-Messenger
team.
[1] Savchenko et al. 2017, A&A 603, A46
[2] Savchenko et al. 2012, A&A 541A, 122S
GCN Circular 25882
Subject
LIGO/Virgo S190930t : no neutrino counterpart candidate in ANTARES search
Date
2019-09-30T16:07:00Z (6 years ago)
From
Damien Dornic at CPPM,France <dornic@cppm.in2p3.fr>
M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (APC/Universite de Paris), M. Colomer (APC/Universite de Paris), D. Dornic (CPPM/CNRS), A. Kouchner (APC/Universite de Paris), 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 S190930t event using the 90% contour of the Initial bayestar probability
map provided by the GW interferometers (GCN#25876). The ANTARES visibility at the time of the
alert, together with the 50% and 90% contours of the probability map are shown at http://antares.in2p3.fr/GW/S190930t_Initial.png <http://antares.in2p3.fr/GW/S190930t_Initial.png>.
Considering the location probability provided by the LIGO/Virgo collaborations, there is a
50.0% chance that the GW emitter was in the ANTARES **upgoing** field of view at the time of
the alert.
No up-going muon neutrino candidate events were recorded in the ANTARES sky during a
+/-500s time-window centered on the time 2019-09-30 14:34:07 and in the 90% contour of the S190930t
event. The expected number of atmospheric background events in the region visible by ANTARES is
5.9e-03 in the +/- 500s time window. An extended search during +/- 1 hour gives no
up-going muon neutrino coincidence. The expected number of atmospheric background events in the
region visible by ANTARES is 4.2e-02 in this larger time window.
ANTARES is the largest undersea neutrino detector, installed in the Mediterranean Sea, and it is
primarily sensitive to neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular
resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a
competitive sensitivity to this position in the sky.
GCN Circular 25885
Subject
LIGO/Virgo S190930t: No counterpart candidates in HAWC observations
Date
2019-09-30T18:08:05Z (6 years ago)
From
Israel Martinez-Castellanos at UMD/HAWC <imc@umd.edu>
The HAWC Collaboration (https://www.hawc-observatory.org) reports:
The HAWC Collaboration performed a follow-up of the gravitational wave
trigger S190930t (GCN #25876). At the time of the trigger the HAWC
local zenith was oriented towards (RA, Dec) = (130.0 deg, 19.1deg).
31% of the GW candidate sky location probability fell within our
observable field of view (0-45 deg zenith angle).
We performed a search for a short timescale emission using 6 sliding
time windows (dt = 0.3s, 1s, 3s, 10s, 30s and 100s), shifted forward
in time by 20% of their width. We searched the 95% probability
containment area in a timescale-dependent time period, from t0-5dt to
t0+10dt, where t0 is the time of the GW trigger.
No significant gamma-ray detection above the background was observed.
The sensitivity of this analysis is greatly dependent on zenith angle,
ranging from 0 deg to 45 deg for the area searched in this
analysis. The 5sigma detection sensitivity to a 1s (100s) burst in the
80-800GeV energy range goes from 1.1e-6 erg/cm^2 to 1.1e-4 erg/cm^2
(6.4e-6 erg/cm^2 to 5.0e-4 erg/cm^2), depending on the zenith
angle.
HAWC is a TeV gamma ray water Cherenkov array located in the state of
Puebla, Mexico. It is sensitive to the energy range ~0.1-100TeV, and
monitors 2/3 of the sky every day with an instantaneous field-of-view
of ~2 sr.
GCN Circular 25887
Subject
LIGO/Virgo S190930t: Upper limits from Fermi-GBM Observations
Date
2019-09-30T20:01:02Z (6 years ago)
From
Joshua Wood at MSFC/Fermi-GBM <joshua.r.wood@nasa.gov>
J. Wood (NASA/MSFC) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group
For S190930t and using the initial bayestar.fits.gz skymap, Fermi-GBM was observing 58.5% of the localization probability at event time.
There was no Fermi-GBM onboard trigger around the event time of the LIGO/Virgo detection of GW trigger S190930t (GCN 25876). An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM also identified no counterpart candidates. The GBM targeted search, the most sensitive, coherent search for GRB-like signals, was run from +/-30 s around merger time, and also identified no counterpart candidates.
We therefore set upper limits on impulsive gamma-ray emission. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, we set the following 3 sigma flux upper limits over 10-1000 keV, weighted by GW localization probability (in units of 10^-7 erg/s/cm^2):
Timescale Soft Normal Hard
------------------------------------
0.128 s: 2.8 4.1 8.8
1.024 s: 0.8 1.2 2.6
8.192 s: 0.3 0.4 0.8
Assuming the median luminosity distance of 108 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^47 erg/s):
Timescale Soft Normal Hard
------------------------------------
0.128 s: 5.93 8.13 28.7
1.024 s: 1.61 2.38 8.47
8.192 s: 0.64 0.83 2.57
GCN Circular 25888
Subject
LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
Date
2019-10-01T01:12:03Z (6 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
S. D. Barthelmy (NASA/GSFC), A. Y. Lien (GSFC/UMBC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
A. P. Beardmore (U. Leicester), M. G. Bernardini (INAF-OAB),
A. A. Breeveld (MSSL-UCL), 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 (ASI-SSDC), S. Emery (UCL-MSSL),
P. A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU),
D. Hartmann (Clemson U.), J. A. Kennea (PSU),
N. Klingler (PSU), H. A. Krimm (NSF),
N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),
A. Melandri (INAF-OAB), 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. J. Page (UCL-MSSL), M. Perri (ASDC),
J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU),
M. H. Siegel (PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (Toronto),
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 S190930t (LIGO/VIRGO Collaboration GCN Circ. 25876),
where T0 is the LVC trigger time (2019-09-30T14:34:07.685 UTC).
The center of the BAT field of view (FOV) at T0 is
RA = 213.258 deg,
DEC = -65.410 deg,
and the roll angle is 320.260 deg.
The BAT FOV (>10% partial coding) covers 10.31% of the integrated
LVC localization probability, and 7.34% of the galaxy convolved
probability (Evans et al. 2016). Note that the sensitivity in the BAT FOV
changes with the partial coding fraction. Please see the BAT FOV figure
in the summary page (link below) for the specific location of the LVC
region relative to the BAT FOV.
Within T0 +/- 100 s, no significant detections (signal-to-noise
ratio >~ 5 sigma) from astrophysical origins are found in the
BAT raw light curves with time bins of 64 ms, 1 s, and 1.6 s.
The short spike at ~T+4.9 s in the 15-25 keV light curve is due
to a detector glitch (see more explanation in the "Investigation
of the detector glitch" section in the link below). The background
changes from ~T-200 s to ~T-80 s is likely due to spacecraft slews.
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 ~ 1.17 x 10^-7 erg/s/cm^2.
Assuming a luminosity of ~ 2 x 10^47 erg/s (similar to GW170817)
and an average Epeak of ~ 400 keV for short GRBs (Bhat et al. 2016),
this flux upper limit corresponds to a distance of ~ 66.57 Mpc.
Event data analysis is available from T0-101.407 s to T+98.543 s.
No significant detections are found in the 15-350 keV images created
using intervals of T0 to T0+0.1 s, T0-2 s to T0+8 s, and the whole
event data range from T0-79.0 s to T0+98.543 s (i.e. the interval that
does not include the spacecraft slew period).
BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 66.38% 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 higher than those
within the FOV.
The results of the BAT analysis are available at
https://swift.gsfc.nasa.gov/results/BATbursts/team_web/S190930t/web/source_public.html
GCN Circular 25890
Subject
LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
Date
2019-10-01T03:55:30Z (6 years ago)
From
Motoko Serino at RIKEN/MAXI <motoko@crab.riken.jp>
M. Serino, S. Sugita (AGU),
N. Kawai (Tokyo Tech), H. Negoro (Nihon U.),
M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.),
T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, H. Nishida, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.),
M. Shidatsu (Ehime U.), M. Oeda, K. Shiraishi (Tokyo Tech),
S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, N. Isobe, R. Shimomukai, M. Tominaga (JAXA),
Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.),
H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.),
M. Yamauchi, S. Iwahori, Y. Kurihara, K. Kurogi, K. Miike (Miyazaki U.),
T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC)
report on behalf of the MAXI team:
We examined MAXI/GSC all-sky X-ray images (2-20 keV)
after the LVC trigger S190930t at 2019-09-30 14:34:07.685 UTC (GCN 25876).
At the trigger time of S190930t, the high-voltage of MAXI/GSC was on.
The instantaneous field of view of GSC at the GW trigger time covered 2% of the 90% credible region
of the bayestar sky map, in which we found no significant new X-ray source.
The first one-orbit (92 min) scan observation with GSC after the event covered 75%
of the 90% credible region of the bayestar skymap from 14:34:07 to 16:06:04 UTC (T0+0 to T0+5517 sec).
No significant new source was found in the region in the one-orbit scan observation.
A typical 1-sigma averaged upper limit obtained in one scan observation
is 20 mCrab at 2-20 keV.
If you require information about X-ray flux by MAXI/GSC at specific coordinates,
please contact the submitter of this circular by email.
GCN Circular 25892
Subject
LIGO/Virgo S190930t: Upper limits from CALET observations.
Date
2019-10-01T04:42:27Z (6 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
Y. Kawakubo (LSU), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka,
S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger
time of S190930t T0 = 2019-09-30 14:34:07.685 UT (The LIGO Scientific
Collaboration and Virgo Collaboration, GCN Circ.25876).
No CGBM on-board trigger occurred around the event time. Based on the
LIGO-Virgo localization sky map, the summed LIGO probabilities inside
the CGBM HXM (7 - 3000 keV) and SGM (40 keV - 28 MeV) fields of view
are 19 % and 50 %, respectively (and 74 % credible region of the
initial sky map was above the horizon). The HXM and SGM fields of
view were centered at RA = 225.9 deg, Dec = 43.7 deg and RA = 235.2
deg, Dec = 36.7 deg at T0, respectively.
Based on the analysis of the light curve data with 0.125 sec time
resolution from T0-60 sec to T0+60 sec, we found no significant
excess around the trigger time in either the HXM or the SGM data.
The CALET Calorimeter (CAL) was operating in the high energy trigger
mode at the trigger time of S190930t. Using the CAL data, we have
searched for gamma-ray events in the 10-100 GeV band from -60 sec to
+60 sec from the GW trigger time and found no candidates in the
overwrap region with the LIGO-Virgo high probability localization
region.
The 90% upper limit of CAL is 1.7x10^-5 erg/cm^2/s (10-100 GeV) when
the summed LIGO-Virgo probability reaches 5%.
The CAL FOV was centered at RA= 235.5 deg, DEC= 36.3 deg at T0.
GCN Circular 25897
Subject
LIGO/Virgo S190930t and S190930s: MASTER optical observation and optical transient
Date
2019-10-01T13:32:24Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tiurina, F.Balakin,P.Balanutsa,A.Kuznetsov, V.Vladimirov, D. Vlasenko, I.Gorbunov,
D.Zimnukhov,V.Senik, T.Pogrosheva, K.Pozdnyakov, A.Chasovnikov, V.Topolev,D.Kuvshinov(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA),
H.Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova(Irkutsk State University, API),
A. Tlatov, D. Dormidontov(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University)
MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al.,2010,Advances in Astronomy, vol.2010, 30L)
started inspect of LIGO/Virgo S190930t (LVC GCN 25876)
146 sec after trigger time at 2019-09-30 14:36:33 UT (Lipunov et al. GCN 25875)
and observed it at MASTER-Amur, -Tunka, -Kislovods, -Tavrida, -SAAO,
-OAFA), see real-time coverage map at
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10861
During this inspect we found OT, but there are 2 PanSTARR sources in 1.6" and 1.8",
and the blue one can be CV, but
it is also inside LIGO/Virgo S190930s (LVC GCN 25871, Lipunov et al. GCN25870)
and we need a Spectrum
MASTER 205329.99+224421.2 discovery
MASTER-IAC auto-detection system discovered OT source at
(RA, Dec) = 20h 53m 29.99s +22d 44m 21.2s on 2019-09-30.90192 UT.
The OT unfiltered magnitude is 18.1m (limit 19.3m).
The OT is seen in 3 images. There is no minor planet at this place.
We have reference image without OT on 2016-09-23.93716 UT with unfiltered magnitude limit 20.1m.
Spectral observations are required.
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/205329.99224421.2.png
GCN Circular 25898
Subject
LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
Date
2019-10-01T14:54:58Z (6 years ago)
From
Magnus Axelsson at Stockholm U. <magaxe@kth.se>
M. Kovacevic (INFN Perugia), L. Scotton (Univ. and INFN, Torino), M. Axelsson (KTH and Stockholm Univ.), F. Longo (Univ. and INFN Trieste), E. Bissaldi (Politecnico and INFN Bari), N. Omodei (Stanford Univ.), M. Arimoto (Kanazawa Univ.) and D. Kocevski (NASA/MSFC) report on behalf of the Fermi-LAT Collaboration:
We have searched data collected by the Fermi Large Area Telescope (LAT) on Sep 30, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S190930t (GCN 25876).
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. Fermi-LAT had an instantaneous coverage of ~30% of the LIGO probability region at the time of the trigger (T0 = 2019-09-30 14:34:07.685 UTC) and reached ~95% cumulative coverage at approximately T0 + 5.2 ks. The remaining area was not observed within 10 ks after the trigger.
We performed a search for a transient counterpart within the observed region of the 90% contour of the LIGO map in a fixed time window from T0 to T0 + 10 ks. No significant sources were found.
We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky, and no additional excesses were found.
Energy flux upper bounds between 100 MeV and 1 GeV for the fixed time interval of this search vary between 1.2e-10 and 4.0e-6 [erg/cm^2/s].
The Fermi-LAT point of contact for this event is Nicola Omodei (nikomo@stanford.edu<mailto:nikomo@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.
GCN Circular 25899
Subject
LIGO/Virgo S190930t: Candidates from the Zwicky Transient Facility
Date
2019-10-01T16:26:31Z (6 years ago)
From
Robert Stein at DESY <robert.stein@desy.de>
Robert Stein (DESY), Mansi M. Kasliwal (Caltech), Erik Kool (OKC), Eric Bellm (UW), Igor Andreoni (Caltech), Tomas Ahumada (UMD), Michael Coughlin (Caltech), Shreya Anand (Caltech), Leo Singer (NASA GSFC), Brad Cenko (NASA GSFC), Albert Kong (NTHU), Kunal Deshmukh (IITB), Maitreya Khandagale (IITB), Gaurav Waratkar(IITB), Varun Bhalerao (IITB), G C Anupama (IIA)
On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations
We observed the localization region of the gravitational wave trigger S190930t (LVC et al. GCN 25876) with the Palomar 48-inch telescope equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). Some observations were serendipitously obtained as part of the public ZTF survey. We enhanced this coverage with additional tiles that were optimally determined and triggered using the GROWTH Target of Opportunity marshal (Coughlin et al. 2019a, Kasliwal et al. 2019b). We started obtaining observations in the g-band and r-band beginning at UT 2019-10-01T02:29:18, approximately 11.9 hours after merger time. We covered 55% of the enclosed probability (44.5% observed twice). This estimate does not account for chip gaps. Each exposure was 30s with a typical depth of ~20.4 mag.
The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019) was used to search the alerts database for candidates. After rejecting stellar sources (Tachibana and Miller 2018) and moving objects and applying machine learning algorithms (Mahabal et al. 2019), and after removing candidates with history of variability prior to the merger time, 31 high-significance transient candidates were identified by our pipeline in the 95% localization of the bayestar map. We highlight two candidates whose putative host galaxies are nearby and have a distance consistent within 2-sigma of the GW localization.
+------------------------------------------------------------------------------+
| ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr |
+------------------------------------------------------------------------------+
| ZTF19acbpqlh | AT2019rpn | 319.9216636| +37.5220721 | r | 20.02 | 0.15 |
| ZTF19acbwaah | AT2019rpp | 162.3277489| +22.9827302 | r | 17.68 | 0.09 |
+------------------------------------------------------------------------------+
In addition, we detected a candidate first reported to TNS by ATLAS:
+------------------------------------------------------------------------------+
| ATLAS19wyn | AT2019rpj | 339.8367397| +31.4916262 | r | 19.56 | 0.09 |
+------------------------------------------------------------------------------+
ZTF19acbpqlh, first detected 13.4 hours after merger, was not detected 3.0 days prior to a depth of 20.77. It is located at a galactic latitude of -8.49 degrees, but has an apparent host at redshift z=0.026, giving an absolute magnitude of -14.91. ZTF19acbwaah, first detected 22.0 hours after merger, is offset from a possible host at redshift z=0.03182. This would give an absolute magnitude of -18.069. AT2019rpj (ZTF19acbpsuf), detected by ZTF 13.8 hours after merger, was first reported to the TNS by ATLAS. Their reported discovery date is also post-merger, 4 hours after the ZTF detection. It was not detected by ZTF 5.9 days prior to a depth of 20.42. It has a host at redshift z=0.0297, giving an absolute magnitude of -15.987.
We strongly encourage photometric and spectroscopic follow-up to confirm the nature of these transients.
ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IIT-B, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering and follow-up co-ordination is being undertaken by the GROWTH marshal system (Kasliwal et al. 2019).
GCN Circular 25900
Subject
LIGO/Virgo S190930t and S190930s: MASTER PSN in unknown disk galaxy
Date
2019-10-01T16:32:23Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tiurina, F.Balakin,P.Balanutsa,A.Kuznetsov, V.Vladimirov, D. Vlasenko, I.Gorbunov,
D.Zimnukhov,V.Senik, T.Pogrosheva, K.Pozdnyakov, A.Chasovnikov, V.Topolev,D.Kuvshinov(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA),
H.Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova(Irkutsk State University, API),
A. Tlatov, D. Dormidontov(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State
University)
MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al.,2010,Advances in Astronomy, vol.2010, 30L)
is inspecting 2 LVC error-boxes:
LIGO/Virgo S190930t (LVC GCN 25876, Lipunov et al. GCN 25875)
and
LIGO/Virgo S190930s (LVC GCN 25871, Lipunov et al. GCN25870)
MASTER OT J205529.78+220725.5 discovery - PSN in unknown galaxy
(=AT2019rpr)
MASTER-IAC auto-detection system discovered OT source at
(RA, Dec) = 20h 55m 29.78s +22d 07m 25.5s on 2019-09-30.90192 UT.
The OT unfiltered magnitude is 18.3m (limit 19.3m).
The OT is seen in 2 images on 2019-09-30 and on 6 images on 2019-10-01 (now). There is no minor planet at this place.
We have reference image without OT on 2016-09-23.93716 UT with unfiltered magnitude limit 20.1m.
Spectral observations are required.
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/205529.78220725.5.png
GCN Circular 25901
Subject
LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
Date
2019-10-01T17:25:07Z (6 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (Uni. of Warwick), A. A. Breeveld (MSSL-UCL), N. P. M. Kuin (UCL-MSSL),
F. E. Marshall (NASA/GSFC), P. Brown (TAMU), C. Gronwall (PSU),
M. J. Page (UCL-MSSL), M. De Pasquale (Istanbul U.), M. H. Siegel (PSU),
A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), S. D. Barthelmy (NASA/GSFC),
A. P. Beardmore (U. Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB),
S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), V. D'Elia(ASDC),
P. A. Evans (U. Leicester), P. Giommi (ASI), D. Hartmann (Clemson U.),
J. A. Kennea (PSU), N. J. Klingler (PSU), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC),
D. B. Malesani (DTU Space), A. Melandri (INAF-OAB), J. A. Nousek (PSU),
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), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU),
G. Tagliaferri (INAF-OAB), A. Tohuvavohu (U Toronto), and
E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:
We report a candidate transient found in the UVOT search results of the
LVC event S190930t (LIGO/VIRGO Collaboration GCN Circ. 25876).
On 2019-09-30 at 18:33:40 UT Swift UVOT took a 74 s exposure in the
u band with exposure ID uu591561225I (target ID 07021582001). The new source is
not listed in the USNO-B1, Gaia DR1, GSC2.3 or 2MASS and is not listed as a minor planet.
The UVOT position is
RA (J2000) 22:19:51.82 = 334.96592
Dec (J2000) -48:42:40.1 = -48.71114
with an estimated uncertainty of 0.7 arcsec (radius, 90% confidence).
The magnitude using the UVOT photometric system (Breeveld et al. 2011, AIP
Conf. Proc. 1358, 373) is u = 18.47 +/- 0.20 mag (Vega).
A faint unresolved counterpart consistent with this position is identified in
the DSS archival image and in the Dark Energy Camera Legacy Survey (DECaLS; http://legacysurvey.org/decamls/),
with reported magnitudes g = 22.76, r = 21.18, and z = 20.29. A source is also
observed at this position in VISTA archival images with magnitudes of J = 18.82,
H = 18.35, Ks = 17.88. The infra-red archival detection may indicate
that this source is a flare of a red dwarf star.
In 72 s of XRT data, there is no X-ray source detected, with a 3-sigma
upper limit of 0.12 count s^-1 (corresponding to an observed flux of
~5e-12 erg cm^-2 s^-1, assuming a typical power-law spectrum).
This circular is an official product of the Swift team.
[GCN OPS NOTE(01oct19): Per author's request, the extra copy of the Notice
in development was removed from the end of this Circular as submitted.
And N. J. Klingler was added to the author list.]
GCN Circular 25907
Subject
LIGO/Virgo S190930t: Upper limits on the two of the ZTF/GROWTH candidates
Date
2019-10-01T19:16:47Z (6 years ago)
From
Tomoki Morokuma at U of Tokyo <tmorokuma@ioa.s.u-tokyo.ac.jp>
Morokuma, T. (U. Tokyo); Utsumi, Y. (Stanford/SLAC) on behalf of J-GEM
collaboration
We report optical follow-up imaging observations for the electromagnetic
counterpart candidates of the gravitational wave event S190930t (The
LIGO Scientific Collaboration and the Virgo Collaboration, GCN Circ.
25876) reported by Stein et al. (GCN Circ. 25899).
We took 12 contiguous frames of 0.5-second exposures 19-22 hours from
the possible neutron star and black hole merger for the regions around
ZTF19acbpqlh (AT2019rpn) and ATLAS19wyn (AT2019rpj) with Tomo-e Gozen
(Sako et al. 2018, SPIE, 10702, 107020J) on the 1.05-m Kiso Schmidt
telescope. No filters are used and the data are calibrated relative to
r-band data from Pan-STARRS DR2. We find no transients at the reported
locations down to depths in the AB system shown below.
| MJD | AT | depth (5 sigmas) |
| 58757.40871 | ZTF19acbpqlh (AT2019rpn) | 18.69 |
| 58757.51431 | ZTF19acbpqlh (AT2019rpn) | 17.66 |
| 58757.43221 | ATLAS19wyn (AT2019rpj) | 18.53 |
| 58757.52506 | ATLAS19wyn (AT2019rpj) | 18.04 |
We note that the ZTF/GROWTH reported magnitudes are 1.0-2.4 magnitudes
fainter than our detection limits above.
GCN Circular 25908
Subject
LIGO/Virgo S190930t and S190930s: MASTER OT J205529.78+220725.5/AT2019rpr further analysis
Date
2019-10-01T19:30:08Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tiurina,F.Balakin,P.Balanutsa,A.Kuznetsov, V.Vladimirov, D. Vlasenko, I.Gorbunov,
D.Zimnukhov,V.Senik, T.Pogrosheva, K.Pozdnyakov, A.Chasovnikov,V.Topolev,V.Shumkov, D.Kuvshinov(Lomonosov Moscow State University, SAI, Phys.Dep.),
R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar of San Juan Natioal Univeristy, OAFA Argentina ),
H.Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE SJNU),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova(Irkutsk State University, API),
A. Tlatov, D. Dormidontov(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University)
MASTER OT J205329.99+224421.2 (GCN 25900) - optical transient discovered
at 2019-09-30 21:38:47UT in anonymous edge-on galaxy
is located in the center of LVC S190930s error-box (mass gap event at 752 +- 223 Mpc, Ttrig=2019-09-30 14:34:07 UT
LVC GCN #25871, Lipunov et al. GCN 25870; Lipunov et al.GCN 25900, Balanutsa et al., ATel 13151)
and also
inside LIGO/Virgo NS+BH S190930t (108 +-37Mpc, Ttrig=2019-09-30 13:35:41 UT
LVC GCN #25871, Lipunov et al. GCN #25870).
MASTER inspects both LVC error-boxes (PSN location is marked by *):
LIGO/Virgo S190930t real-time cover map https://master.sai.msu.ru/site/master2/ligo_1.php?id=10866
LIGO/Virgo S190930s cover map https://master.sai.msu.ru/site/master2/ligo_1.php?id=10856
We reobserved MASTER OT J205529.78+220725.5 in MASTER-Tavrida,
it became brighter on 6 images 2019-10-01 16:51:37- 18:15:11UT, m_OT~17.8.
In accordance with the distances for gavitational-wave alerts, we obtain
the following distance modulus and absolute magnitudes
LVC_alert Dist,Mpc Dist.modulus Mag (absolute)
S190930t (min) 71 34.3 -15.5
S190930t (max) 145 35.8 -17.0
S190930s (min) 528 38.6 -19.8
S190930s (max) 976 39.9 -21.2
GCN Circular 25916
Subject
LIGO/Virgo S190930t: Lulin Follow-up Observations of AT2019rpn and AT2019rpj
Date
2019-10-01T23:55:00Z (6 years ago)
From
Albert Kong at NTHU <akhkong@gmail.com>
Han-Jie Tan (NCU), Albert Kong (NTHU), Chow-Choong Ngeow (NCU),
Wing-Huen Ip (NCU)
On behalf of the Global Relay of Observatories Watching Transients
Happen (GROWTH) collaborations
We report the photometric measurements of two optical counterpart
candidates ZTF19acbpqlh (AT2019rpn) and ATLAS19wyn/ZTF19acbpsuf
(AT2019rpj) associated with the gravitational wave event S190930t (GCN
#25876, #25899) using the Lulin One-meter Telescope (LOT) in Taiwan.
The observations were conducted using g, r, i filters starting at
2019-10-01 14:12:14 UT. Preliminary photometry was obtained by
calibrating with the Pan-STARRS catalog.
Summary of ZTF19acbpqlh:
UT Filter Exp(s) Mag (AB)
2019-10-01 14:14:56 g 300 20.80+/-0.25
2019-10-01 14:20:16 r 300 20.67+/-0.33
2019-10-01 14:25:36 i 300 20.80+/-0.39
Summary of ATLAS19wyn/ZTF19acbpsuf:
2019-10-01 14:31:53 g 300 19.65+/-0.08
2019-10-01 14:37:14 r 300 19.58+/-0.09
2019-10-01 14:42:35 i 300 19.55+/-0.12
We would like to thank the staff in Lulin Observatory for helping the
observations.
GCN Circular 25917
Subject
LIGO/Virgo S190930t: HCT observations of ZTF19acbpsuf
Date
2019-10-02T02:01:26Z (6 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
Brajesh Kumar, D. K. Sahu, G. C. Anupama (IIA), V. Bhalerao (IITB) report on behalf of the GROWTH collaboration:
We observed ZTF19acbpsuf with the 2-m Himalayan Chandra Telescope (HCT) located at the Indian Astronomical Observatory, Hanle, India. The observations started on 2019-10-01 (17:31:33 UT). Multiple frames in Bessell VRI-bands (each exposure 300 sec) were obtained. The object is clearly visible in all frames. The preliminary PSF magnitudes of initial images (calibrated using USNO-B1.0 catalogue) are following:
UT-mid Filter Mag
------------------- ---------- --------------
2019-10-01 17:33:15 R 19.56 +/- 0.10
2019-10-01 17:39:51 I 19.48 +/- 0.10
2019-10-01 17:45:28 V 19.08 +/- 0.10
Further monitoring is planned.
GCN Circular 25920
Subject
LIGO/Virgo S190930t: J-GEM follow-up observations for AT2019rpj
Date
2019-10-02T06:33:59Z (6 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
Murata, K. L. (Tokyo Institute of Technology); Sasada, M. (Hiroshima); Morokuma, T. (U. Tokyo) Utsumi, Y. (Stanford/SLAC) on behalf of J-GEM collaboration
We report an optical follow-up observation for the electromagnetic counterpart candidate of the gravitational wave event S190930t (The LIGO Scientific Collaboration and the Virgo Collaboration, GCN Circ. 25876) reported by Stein et al. (GCN Circ. 25899).
We observed one of the EM counterpart candidates of neutron star and black hole merger, AT2019rpj/ATLAS19wyn/ZTF19acbpsuf, using 50 cm MITSuME telescope at Akeno Observatory and a 3 color imager. The brightness of the candidate on 2019-10-01 at 18:44:02 UTC (MJD 58757.780578) is
g'=19.8 +/- 0.5
Rc=19.3 +/- 0.3
Ic=19.1 +/- 0.3
in AB magnitude system by PSF photometry compared with the nearby star at (RA, Dec)=(339.82556, +31.50232) with Pan-STARRS DR1 catalog (Chambers et al. 2016).
GCN Circular 25921
Subject
LIGO/Virgo S190930t: Palomar 200-in DBSP follow-up of ZTF19acbpqlh and ATLAS19wyn
Date
2019-10-02T07:58:46Z (6 years ago)
From
Kishalay De at Caltech, GROWTH <kde@astro.caltech.edu>
V. Karambelkar, K. De, J. Van Roestel, M. M. Kasliwal (Caltech)
On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of
Observatories Watching Transients Happen (GROWTH) collaborations
On 2019 Oct 2 UT, we obtained spectra of ZTF19acbpqlh/AT2019rpn and
ATLAS19wyn/AT2019rpj (Stein et al. GCN 25899) with the Double Beam
Spectrograph on the Palomar 200-in telescope. For ATLAS19wyn, we
identify strong Balmer P-Cygni features at z~0.03 and classify as a
young Type II supernova. For ZTF19acbpqlh, we see a blue, mostly
featureless continuum with a tentative identification of a weak, broad
feature around H-alpha suggesting this may also be a core-collapse
supernova.
GCN Circular 25922
Subject
LIGO/Virgo S190930t: Candidates from ATLAS observations and constraints on AT2019rpr and AT2019rpn
Date
2019-10-02T08:40:20Z (6 years ago)
From
Stephen Smartt at Queen's U/Belfast <s.smartt@qub.ac.uk>
S. J. Smartt, S. Srivastav, K. W. Smith (QUB), T.-W. Chen (MPE), D. R.
Young, M. Fulton, (QUB) L. Denneau, H. Flewelling, A. Heinze, J.
Tonry, H. Weiland (IfA, Univ. Hawaii), A. Rest (STScI), B. Stalder
(LSST), C. Stubbs (Harvard), O. McBrien, M. Dobson, J. Gillanders, D.
O'Neil, P. Clark, S. Sim (QUB)
We report observations of the Bayestar skymap of the NSBH event
S190930t (The LIGO Scientific Collaboration and the Virgo
Collaboration, GCN 25876) with the ATLAS telescope system (Tonry et
al. 2018, PASP, 13, 164505). ATLAS is a twin 0.5m telescope system on
Haleakala and Mauna Loa employing two filters - cyan and orange. While
carrying out the primary mission for Near Earth Objects, we can adjust
the schedule rapidly to point at LVC gravitational wave skymaps. The
survey provides coverage from declination -40 to +80 every 2 nights to
typical depths of 19.5 mag in the o-band.
In this case we did not perturb the normal ATLAS sky survey footprint,
given the large area of the Bayestar skymap. We estimate coverage
of the 90% contour of 2451 square degrees and 14% of the total
probability between MJD 58756.607097 and 58757.555924 (for reference,
S190930t is reported with a discovery time 58756.60703339205 from the
FITS header of bayestar.fits.gz).
Normal survey operations provided a sequence of quads (4 x 30 sec) at
each pointing position. The images were processed with the ATLAS
pipeline and reference images subtracted from each one. Transient
candidates were run through our standard filtering procedures,
combined with machine learning algorithms (e.g. Wright et al. 2015,
MNRAS, 449, 451). Candidates were spatially cross-matched with known
minor planets, and star, galaxy, AGN and multi-wavelength catalogues
(as described in Smartt et al. 2016, MNRAS, 462 4094; Stalder et al.
2017, ApJ, 850, 149).
We have reported all candidates to the IAU Transient name server.
Candidates of note are :
Name | ATLAS Name | RA (J2000) | Dec (J2000) | Disc. MJD | Disc Mag | Notes
AT2019rpq | ATLAS19wzl | 08:59:22.13 | -00:53:53.6 | 58756.61 | 17.81 o | 1.
AT2019rpi | ATLAS19wym | 07:41:17.77 | +03:37:18.6 | 58756.61 | 18.85 o | 2.
AT2019rog | ATLAS19wxr | 20:20:47.61 | +15:05:03.1 | 58757.29 | 16.77 o | 3.
AT2019rpt | ATLAS19xas | 08:23:32.96 | +21:20:24.7 | 58757.57 | 17.60 o | 4.
AT2019rpj | ATLAS19wyn | 22:39:20.79 | +31:29:30.0 | 58753.49 | 19.93 o | 5.
Notes on objects :
1. Host probably 2MASS 07411836+0337242; a J=14.60 mag galaxy found in
the 2MASS XSC catalogue. It's located 5.65" S, 8.93" W, but could also
be associated with a fainter galaxy which is closer. No previous
observations in last 30 days due to RA and solar conjunction.
2. No host detected. No previous observations in last 30 days due to RA
and solar conjunction.
3. Very fast decline, 1 mag in 30 minutes. No host star in Pan-STARRS1 3Pi. Decline is
similar to M-dwarf flare decline rate.
4. Host is PGC023546: transient is located 26.77" S, 17.48" W (11.7
Kpc) from the galaxy centre. A host z=0.018 implies a distance of
74Mpc. The distance modulus m - M = 34.46, implies M > -17, which is
SN like.
5. Detected also by ZTF in GCN 25899. We have Clear detections 3 days
before S190930t. Host is AGC321427. Transient is located 21.00" S,
16.40" W (17.2 Kpc) from the galaxy centre. A host distance of 133.5
Mpc(z=0.030). Has been confirmed as type II SN (Karambelkar et al. GCN 25921).
Comments on other objects reported:
AT2019rpr (MASTER OT J205529.78+220725.5) reported by Lipunov et al. GCN 25900
is a recurring variable/outbursting object in ATLAS and likely a Galactic CV.
AT2019rpn (ZTF19acbpqlh) has no previous detections in ATLAS. We
observed the field on 58754, 58755, 58756, 58757, 58758 and there are
no clear >5sigma detections above o ~ 19.5. The object is not rapidly
rising (Tan et al. GCN 25916). Karambelkar et al. (GCN 25921) report
possible broad H-alpha. Stacking of the ATLAS data is underway.
GCN Circular 25923
Subject
LIGO/Virgo S190930t: ATLAS Forced photometry of ZTF19acbpqlh (AT2019rpn)
Date
2019-10-02T13:02:40Z (6 years ago)
From
Stephen Smartt at Queen's U/Belfast <s.smartt@qub.ac.uk>
S. J. Smartt, K. W. Smith (QUB), S. Srivastav, T.-W. Chen (MPE), D. R.
Young, M. Fulton, (QUB) L. Denneau, H. Flewelling, A. Heinze, J.
Tonry, H. Weiland (IfA, Univ. Hawaii), A. Rest (STScI), B. Stalder
(LSST), C. Stubbs (Harvard), O. McBrien, M. Dobson, J. Gillanders, D.
O'Neil, P. Clark, S. Sim (QUB)
The transient ZTF19acbpqlh (AT2019rpn) was reported by Stein et al.
(GCN 25899) at r = 20.02 within the 95% localisation bayestar map (LVC
et al. GCN 25876).
ATLAS covered this region on 6 recent epochs, and forced PSF
photometry on the difference images at the position of this transient
gives the following 3-sigma limiting magnitudes and two 4-sigma detections.
58752.21516 c < 18.24
58754.21109 o < 18.71
58755.35411 c < 21.00
58756.60703339205 == s190930t discovery
58756.2132 c < 19.47
58757.23448 o 19.84 +/- 0.26
58758.21185 o 19.68 +/- 0.27
All mags are AB.
c = cyan filter (a g+r composite)
o = orange filter (a i+r composite)
Tan et al. (GCN 25916) reported r = 20.7 +/- 0.3 which could imply a
significant fade, although the uncertainty is significant. Our
measurements imply the transient is flat or slowly rising.
Karambelkar et al (GCN 25921) give a tentative identification of broad
H-alpha in their blue spectrum. Our ATLAS photometry would support
their conclusion of a young, relatively faint, type II SN. But further
data are required to confirm.
GCN Circular 25925
Subject
LIGO/Virgo S190930t: No neutrino candidates at Pierre Auger Observatory
Date
2019-10-02T15:02:56Z (6 years ago)
From
Jaime Alvarez-Muniz at Pierre Auger Observatory <jaime.alvarezmuniz@gmail.com>
J. Alvarez-Muniz, F. Pedreira, E. Zas (IGFAE & University of Santiago de
Compostela, Spain),
K. H. Kampert & M. Schimp (University of Wuppertal, Germany)
on behalf of the Pierre Auger Collaboration.
In response to:
LIGO/Virgo GW trigger S190930t
T0=2019-09-30 14:34:07 UTC
We searched for Ultra-High-Energy (UHE) neutrinos
in the data collected with the Surface Detector (SD)
of the Pierre Auger Observatory in a [-500,500] second interval
about the LIGO-Virgo trigger S190930t as well as in a 24 hr time
interval following the event. The Observatory is mostly sensitive
to neutrinos above ~ 1e17 eV.
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 PARTIALLY COINCIDENT (35.7%) with
the LIGO/Virgo 90% localization region (bayestar.fits.gz,0)
at the time T0 of the merger alert, achieving a MAXIMUM OVERLAP (36.1%)
at approximately T0+17.5 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
https://arxiv.org/abs/1906.07422
GCN Circular 25928
Subject
LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO optical photometry
Date
2019-10-02T19:14:59Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), V. Rumyantsev (CrAO), A. Pozanenko (IKI), A.
Volnova (IKI), S. Belkin (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the ZTF19acbpqlh (AT2019rpn) reported by Stein et al. (GCN
25899) and the ATLAS19wyn (AT2019rpj) optical transients with ZTSh 2.6m
telescope of CrAO observatory starting on Oct. 01 (UT) 19:30:53. We took
several images in B,R filters under good conditions and mean seeing of
1.5 arcsec. Both optical transients are clearly visible in separate images.
Preliminary photometry of the optical transients is following
Name, UT start T_mid Filter Exp. OT err
(MJD) (s)
AT2019rpj 2019-10-01 20:16:16 58757.84880 R 11*60 19.37 0.04
AT2019rpj 2019-10-01 20:28:33 58757.85886 B 15*60 19.86 0.04
AT2019rpn 2019-10-01 19:30:53 58757.81861 R 12*60 19.26 0.11
AT2019rpn 2019-10-01 19:47:03 58757.83270 B 11*60 20.17 0.07
The photometry for AT2019rpj is based on the stars:
SDSS-DR12_id RA Dec R(Lupton) err B(Lupton) err
J223926.51+313057.4 339.860475 +31.515949 17.94 0.02
19.23 0.02
J223929.26+313022.7 339.871951 +31.506316 16.89 0.02
18.52 0.01
J223919.69+312904.5 339.832062 +31.484605 18.69 0.02
19.83 0.02
J223916.31+313047.2 339.817967 +31.513116 18.71 0.02
19.97 0.02
The photometry for AT2019rpn is based on the stars:
Pan-STARRS_id RA Dec R(Lupton) err B(Lupton) err
153053199373132992 319,937282460 +37,543645500 15.64 0.01
16.79 0.01
153013199432441728 319,943228690 +37,509269790 17.25 0.01
18.50 0.01
153013199414348544 319,941391010 +37,514951160 17.04 0.01
18.44 0.01
153003199240135584 319,924010430 +37,504130480 16.52 0.01
17.89 0.01
153043199658230976 319,965800600 +37,533607760 16.10 0.01
17.57 0.01
GCN Circular 25931
Subject
LIGO/Virgo S190930t: Palomar 200-in DBSP spectroscopy of ZTF19acbwaah
Date
2019-10-03T00:36:54Z (6 years ago)
From
Kishalay De at Caltech, GROWTH <kde@astro.caltech.edu>
V. Karambelkar, K. De, J. Van Roestel, M. M. Kasliwal (Caltech)
On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of
Observatories Watching Transients Happen (GROWTH) collaborations
On 2019 Oct 2 UT, we obtained a spectrum of ZTF19acbwaah/AT2019rpp
(Stein et al. GCN 25899) with the Double Beam Spectrograph on the
Palomar 200-in telescope. The spectrum is consistent with a type Ia
supernova at redshift ~0.03 a few weeks after peak.
GCN Circular 25934
Subject
LIGO/Virgo S190930t: Upper limits from Insight-HXMT/HE observations
Date
2019-10-03T09:27:19Z (6 years ago)
From
Qi Luo at IHEP <luoqi@ihep.ac.cn>
Q. Luo, Q. B. Yi, S. Xiao, C. Cai, Y. G. Zheng, Y. Huang,
C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang,
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
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 reported LIGO/Virgo
S190930t event (GCN #25876), trigger time 2019-09-30T14:34:07 UTC.
At T0, about 77% of the LIGO localization region was covered by
Insight-HXMT without occultation by the Earth.
Within T0 +/- 100 s, no significant excess events (SNR > 3 sigma) are
found in a search of the Insight-HXMT/HE raw light curves.
Assuming the GW counterpart GRB with three typical GRB Band spectral
models, two typical duration timescales (1 s, 10 s) from the center
of the LIGO-Virgo location probability map (RA=136 deg, DEC=31 deg),
the 5-sigma upper-limits fluence (0.2 - 5 MeV, incident energy) are
reported below:
Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV):
1 s: 7.0e-08 erg cm^-2
10 s: 3.2e-07 erg cm^-2
Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1 s: 1.1e-07 erg cm^-2
10 s: 5.1e-07 erg cm^-2
Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1 s: 3.2e-07 erg cm^-2
10 s: 1.4e-06 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 (deposited 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 spacecraft.
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 could be found at: http://www.hxmt.org.
GCN Circular 25939
Subject
LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
Date
2019-10-03T18:11:57Z (6 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
S. R. Oates (Uni. of Warwick), N. P. M. Kuin (UCL-MSSL), A. A. Breeveld
(MSSL-UCL),
F. E. Marshall (NASA/GSFC), P. Brown (TAMU), C. Gronwall (PSU),
M. J. Page (UCL-MSSL), M. De Pasquale (Istanbul U.), M. H. Siegel (PSU),
A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), S. D. Barthelmy (NASA/GSFC),
A. P. Beardmore (U. Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB),
S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), V. D'Elia(ASDC),
P. A. Evans (U. Leicester), P. Giommi (ASI), D. Hartmann (Clemson U.),
J. A. Kennea (PSU), N. J. Klingler (PSU), H. A. Krimm (NSF), A. Y. Lien
(GSFC/UMBC),
D. B. Malesani (DTU Space), A. Melandri (INAF-OAB), J. A. Nousek (PSU),
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), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU),
G. Tagliaferri (INAF-OAB), A. Tohuvavohu (U Toronto), and
E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:
Swift UVOT reobserved the field of Swift J221951-484240 (Oates et al., GCN
Circ.
25901), a candidate transient found in the UVOT search results of the LVC
event
S190930t (LIGO/VIRGO Collaboration GCN Circ. 25876).
A search of this source in various catalogs shows only a weak IR source,
however
Swift observed a blue source which maintained its brightness in the second
observation
suggesting that this is not a flaring M-dwarf.
The second tranche of observations began at 2019-10-02 16:14:34 UT 179ks
after
the LVC trigger.
Preliminary detections using the UVOT photometric system (Breeveld et
al. 2011, AIP Conf. Proc. 1358, 373) are:
Filter Exp(s) Mag
v 79 > 18.7
b 79 19.68+\-0.36
u 79 18.57+\-0.21
w1 157 17.95+\-0.16
m2 249 17.91+\-0.15
w2 315 18.11+\-0.13
In the combined 1.1 ks of data collected so far, no X-ray source is
detected to a 3-sigma upper limit of 9.9e-3 count s^-1 (equivalent to an
observed flux ~4e-13 erg cm^-2 s^-1, assuming a typical power-law
spectrum).
This new blue transient requires spectroscopy for further identification,
and we
encourage spectroscopic followup of this transient.
This circular is an official product of the Swift team.
GCN Circular 25941
Subject
LIGO/Virgo S190930t: J-GEM follow-up observation for Swift J221951-484240
Date
2019-10-03T19:52:55Z (6 years ago)
From
Katsuhiro L. Murata at Nagoya U <murata@u.phys.nagoya-u.ac.jp>
Kamei, Y.; Abe, F.; Tristram, P. J. (Nagoya U.); Murata, K. L. (Tokyo Institute of Technology); Onozato, H. (U. Hyogo); Utsumi, Y. (Stanford/SLAC) on behalf of J-GEM collaboration
We report an optical follow-up observation for the electromagnetic counterpart candidate of the gravitational wave event S190930t (The LIGO Scientific Collaboration and the Virgo Collaboration, GCN Circ. 25876) reported by Stein et al. (Oates et al., GCN Circ. 25901, 25939).
We observed one of the EM counterpart candidates of neutron star and black hole merger, Swift J221951-484240, using 61 cm Boller & Chivens telescope at Mt. John Observatory in New Zealand (B&C) and a three color imager Tripole5 (g, r, i). The brightness of the candidate on 2019-10-02 23:00:37 UTC (MJD 58758.490340) is
g~19.6
r~19.3
i~19.3
in AB magnitude system compared with nearby stars with UCAC4 catalog (Zacharias et al. 2012).
We would like to thank observers for helping the observations.
GCN Circular 25943
Subject
LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
Date
2019-10-04T16:31:19Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), S. Belkin
(IKI), A. Volnova (IKI) report on behalf of larger GRB follow-up
collaboration:
We observed the ZTF19acbpqlh (AT2019rpn) reported by Stein et al. (GCN
25899) and the ATLAS19wyn (AT2019rpj) optical transients with ZTSh 2.6m
telescope of CrAO observatory on Oct. 02 and Oct. 3.
Preliminary photometry of the optical transients is following
(we repeat our photometry previously published in GCN 25928 in the table
below for convenience)
Name, UT start T_mid Filter Exp. OT err
(MJD) (s)
AT2019rpj 2019-10-01 20:16:16 58757.84880 R 11*60 19.37 0.04
AT2019rpj 2019-10-01 20:28:33 58757.85886 B 15*60 19.86 0.04
AT2019rpj 2019-10-02 19:44:58 58758.82668 R 10*60 19.31 0.05
AT2019rpj 2019-10-02 20:28:33 58758.83825 B 20*60 19.83 0.03
AT2019rpj 2019-10-03 17:56:18 58759.75245 R 12*60 19.33 0.06
AT2019rpj 2019-10-03 18:11:03 58759.76604 B 22*60 19.91 0.06
AT2019rpn 2019-10-01 19:30:53 58757.81861 R 12*60 19.26 0.11
AT2019rpn 2019-10-01 19:47:03 58757.83270 B 11*60 20.17 0.07
AT2019rpn 2019-10-02 19:01:22 58758.79640 R 10*60 19.34 0.12
AT2019rpn 2019-10-02 19:12:33 58758.80874 B 22*60 20.20 0.04
AT2019rpn 2019-10-03 17:13:26 58759.72220 R 10*60 19.26 0.12
AT2019rpn 2019-10-03 17:26:42 58759.73485 B 21*60 20.18 0.05
The photometry is based on the same stars reported by Mazaeva et al.
(GCN 25928).
The color of AT2019rpj (B-R) = 0.5 is not resemble of any object which
can be related to LVC OT counterpart, and the detection the AT2019rpj
before S190930t (Smartt et al. GCN 25922), exclude it from candidates.
Based on the photometry, it can be seen that AT2019rpn does not rise for
three epochs (which is previously reported by Tan et al. (GCN 25916)) or
is near a maximum.
GCN Circular 25962
Subject
LIGO/Virgo S190930t: SALT optical spectroscopy of Swift J221951-484240
Date
2019-10-06T16:30:30Z (6 years ago)
From
Marina Orio at INAF-Padova and U of Wisconsin <orio@astro.wisc.edu>
David Buckley (South African Astronomical Observatory), Subo Dong (Kavli Institute of Astronomy and Astrophysics of Peking University), Stefano Ciroi (Padova University), Mariusz Gromadzski (Warsaw University Observatory), Marina Orio (Istituto Nazionale di Astrofisica, Padova and University of Wisconsin), Jirong Mao (Yunnan Observatories, Chinese Academy of Sciences), Dong Xu (National Astronomical Observatory, Chinese Academy of Sciences) and Rajeev Manick (South African Astronomical Observatory and Southern African Large Telescope) report:
On 2019/10/04 at UT 22:39:21 we obtained a 1800 sec exposure SALT spectrum of the blue transient source, Swift J221951-484240, discovered by the Neil Gehrels Swift Observatory in the field of the gravitational wave event S190930t (GCN 25901, 25939). We used the Robert Stobie spectrograph with the PG 300 grating and a 1.5 arsec slit, covering 3300-9800 Angstroms with a resolving power of 370. The spectrum is characterized by a steeply rising blue continuum, consistent with the earlier report (GCN 25939). The spectrum is essentially featureless, except for a possible weak double-peaked emission line at 4250A, although its reality needs further confirmation. Thus there is still no indication as to whether this transient is Galactic or it is instead a hostless extragalactic object.
GCN Circular 25963
Subject
LIGO/Virgo S190930t: Swift J221951-484240 optical photometry of Chilescope observatory
Date
2019-10-06T18:27:57Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), M. Krugov (AFIF), E. Mazaeva (IKI),
A. Volnova (IKI) report on behalf of IKI-FuN follow-up collaboration:
We observed the Swift J221951-484240 blue Optical Transient (Oates et
al., GCN 25901; Oates et al., GCN 25939) in the field of the
LIGO/Virgo S190930t (LIGO Scientific Collaboration and the Virgo
Collaboration, GCN 25876). Several images were obtained in r' -filter
of RC-1000 telescope. The OT was also previously observed by Kamei et
al. (GCN 25941) and Buckley et al. (GCN 25962). Preliminary photometry
of the Swift J221951-484240 OT is following.
Date UT start MJD Filter Exp. OT Err. UL
(mid, days) (s)
2019-10-05 04:22:44 58761.19808 r' 2700 19.35 0.06 22.7
The photometry is based on the USNO-B1.0 stars (reverse Lupton's
transformation VRI -> r)
USNO-B1.0_id r_Sloan(Lupton)
0412-0779298 16.866
0412-0779234 17.469
0413-0785834 16.580
0413-0785834 17.565
0413-0785847 16.517
GCN Circular 25964
Subject
LIGO/Virgo S190930t: Swift discovery of Swift J224718-581442 (AT2019sbk): a fading UV transient with an X-ray counterpart
Date
2019-10-07T00:23:29Z (6 years ago)
From
Aaron Tohuvavohu at U Toronto <aaron.kholodenko@gmail.com>
A . Tohuvavohu (U. Toronto), N. P. M. Kuin (UCL-MSSL), S. R. Oates
(Uni. of Warwick), A. A. Breeveld (MSSL-UCL),
F. E. Marshall (NASA/GSFC), P. Brown (TAMU),C. Gronwall (PSU),
M. J. Page (UCL-MSSL), M. De Pasquale (Istanbul U.),
M. H. Siegel (PSU), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB),
S. D. Barthelmy (NASA/GSFC), A. P. Beardmore (U. Leicester), D. N.
Burrows (PSU),
S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA),
V. D'Elia(ASDC), P. A. Evans (U. Leicester), P. Giommi (ASI),
D. Hartmann (Clemson U.), J. A. Kennea (PSU), N. J. Klingler (PSU),
H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), D. B. Malesani (DTU Space),
A. Melandri (INAF-OAB), J. A. Nousek (PSU), 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),
T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), G. Tagliaferri (INAF-OAB),
and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:
We report the discovery of Swift J224718-581442 a transient found
in the UVOT and XRT search results of the LVC event
S190930t (LIGO/Virgo Collaboration GCN Circ. 25876).
On 2019-10-01 07:19:41 (GW T0+17 hours) UT Swift UVOT took
a 75 s exposure in the u band with observation ID 07021863001.
An uncatalogued source was found.
The new source is not listed in the USNO-B1, Gaia DR1, GSC2.3 or 2MASS
catalogues and is not listed as a minor planet.
The UVOT position is
RA (J2000) 22:47:18.100= 341.825417
Dec (J2000) -58:14:50.80 = -58.247444
The magnitude using the UVOT photometric system (Breeveld et al. 2011, AIP
Conf. Proc. 1358, 373) was u = 18.76 +/- 0.21 mag (Vega).
On 2019-10-04 05:01:0 UT Swift UVOT took another 78 s exposure in the u band
with observation ID 07400055001. The source is found to have faded by
> 1 mag, to u = 19.84 (Vega).
A faint uncatalogued X-ray source is found by XRT 1.9 arcseconds away,
consistent with the location of the UVOT source.
The X-ray source is located at RA, Dec 341.82803, -58.2451 which
is equivalent to:
RA(J2000) = 22h 47m 18.73s
Dec(J2000) = -58d 14��� 42.3���
The count rate of this source is measured in XRT at 0.013 (��0.004) ct s-1.
This source is located on the outskirts of the galaxy 2MASX J22471856-5814422,
with a redshift of z=0.054 (D~240 Mpc), ~ 4 sigma above the mean GW
distance along this line of sight (mean = 94 Mpc, sigma = 34 Mpc).
We encourage spectroscopic followup of this transient.
Further Swift UVOT and XRT observations are planned.
This transient has been reported to the TNS as AT2019sbk.
This circular is an official product of the Swift team.
GCN Circular 25966
Subject
LIGO/Virgo S190930t: Swift XRT observations, no secure afterglow found
Date
2019-10-07T07:20:45Z (6 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester), K.L. Page (U.Leicester), J.A. Kennea (PSU),
A. Tohuvavohu (U. Toronto), S.D. Barthelmy (NASA/GSFC), A.P. Beardmore
(U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL),
P. Brown (TAMU), 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), D. Hartmann (U. Clemson), H.A. Krimm
(CRESST/GSFC/USRA), N.J. Klingler (PSU), 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),
M.J.Page (UCL-MSSL), 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 carried out 649 observations of the LVC error region for the
GW trigger S190930t convolved with the 2MPZ catalogue (Bilicki et al.
2014, ApJS, 210, 9), using the 'bayestar' GW localisation map. As this
is a 3D skymap, galaxy distances were taken into account in selecting
which ones to observe. The observations currently span from 7.6 ks to
345 ks after the LVC trigger, and the XRT has covered 71.6 deg^2 on the
sky (corrected for overlaps). This covers 0.5% of the probability in
the 'bayestar' skymap, and 2.5% after convolving with the 2MPZ galaxy
catalogue, as described by Evans et al. (2016, MNRAS, 462, 1591). Our
pointings have been uploaded to the "Treasure Map" web service:
http://treasuremap.space/alerts?graceids=S190930t.
We have detected 14 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 https://www.swift.ac.uk/ranks.php.
One rank 3 source, "source 12", is of potential interest as it appears
to be fading. This source is at RA,Dec = 07h 47m 58.93s +43d 18' 20.1",
which is equivalent to:
RA(J2000.0) = 116.99554
Dec(J2000) = +43.3056
with an uncertainty of 8 arcsec (radius, 90% confidence). There is no
galaxy in 2MPZ near this location at a position consistent with the LVC
distance along this line of sight (105 Mpc), however, 2MPZ is only 75%
complete to this distance.
In total, we have found:
* 0 sources of rank 1
* 0 sources of rank 2
* 5 sources of rank 3
* 9 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=3x10^20 cm^-2, and photon index (Gamma)=1.7
The results of the XRT automated analysis are online at
https://www.swift.ac.uk/LVC/S190930t
This circular is an official product of the Swift XRT team.
GCN Circular 25967
Subject
LIGO/Virgo S190930t: Magellan/IMACS imaging of Swift J224718-581442 (AT2019sbk)
Date
2019-10-07T08:01:49Z (6 years ago)
From
Subo Dong at KIAA-PKU <dongsubo@pku.edu.cn>
Ping Chen (KIAA, Peking University), Joshua D. Simon (Carnegie Observatories), and Subo Dong (KIAA, Peking University) report:
We observed the transient Swift J224718-581442 (AT2019sbk) (Tohuvavohu et al., GCN Circ. 25964), which was discovered in the UVOT and XRT search for the electromagnetic counterpart of LIGO/Virgo S190930t (LIGO/Virgo Collaboration GCN Circ. 25876).
On 2019-Oct-07.14 UTC (JD = 2458763.64), we obtained g���-band (90s exposure) and i���-band (60s exposure) images with IMACS mounted on the 6.5 meter Magellan telescope at Las Campanas Observatory. We do not detect the source at the reported position (RA = 22:47:18.1 Dec = -58:14:50.80) in these images with approximate 3-sigma upper limits of ~22.4 mag in g���-band and ~22.9 mag in i���-band, respectively.
GCN Circular 25984
Subject
LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
Date
2019-10-08T16:54:30Z (6 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (Uni. of Warwick), N. P. M. Kuin (UCL-MSSL), A. A. Breeveld (MSSL-UCL),
A. Tohuvavohu (U. Toronto), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),
P. Brown (TAMU), C. Gronwall (PSU), M. J. Page (UCL-MSSL),
M. De Pasquale (Istanbul U.), M. H. Siegel (PSU), A. D'Ai (INAF-IASFPA),
P. D'Avanzo (INAF-OAB), S. D. Barthelmy (NASA/GSFC), A. P. Beardmore (U. Leicester),
D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC),
G. Cusumano (INAF-IASF PA), V. D'Elia(ASDC), P. A. Evans (U. Leicester),
P. Giommi (ASI), D. Hartmann (Clemson U.), N. J. Klingler (PSU),
H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), D. B. Malesani (DTU Space),
A. Melandri (INAF-OAB), J. A. Nousek (PSU), 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),
T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), G. Tagliaferri (INAF-OAB),
and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:
Starting 2019-10-07 at 15:58:58 UT (GW T0+169 hours) Swift/UVOT reobserved
the field of AT2019sbk (Tohuvavohu et al., GCN Circ. 25964), a candidate
transient found in the UVOT search results of the LVC event S190930t
(LIGO/VIRGO Collaboration GCN Circ. 25876).
In total 2.7 ks were observed with the u band (observation ID 07021863003). The
transient reported in Tohuvavohu et al. (GCN Circ. 25964) can no longer be discerned
from the underlying host galaxy.
We also have an improvement on the position of the XRT source reported
in Tohuvavohu et al. (GCN Circ. 25964). The new UVOT enhanced XRT position is:
RA(J2000) = 22:47:18.46 = 341.82692 deg
Dec(J2000) = -58:14:41.9 = -58.24498 deg
with an error radius 2.0" (90% confidence). This refined position is ~9 arcsecond
away from the UVOT position of AT2019sbk and is instead consistent with
the centre of the galaxy 2MASX J22471856-5814422. We therefore retract its association
with AT2019sbk.
This circular is an official product of the Swift team.