LIGO/Virgo S200225q
GCN Circular 27526
Subject
LIGO/Virgo S200225q: Swift XRT observations, 1 X-ray sources
Date
2020-04-10T13:16:29Z (6 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
P.A. Evans (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. Birmingham), 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), 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 70 observations of the LVC error region for the
GW trigger S200225q convolved with the 2MPZ catalogue (Bilicki et al.
2014, ApJS, 210, 9), using the 'LALInference' (version 1) 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 172 ks to 224 ks after the LVC trigger, and the XRT
has covered 3.8 deg^2 on the sky (corrected for overlaps). This covers
51% of the probability in the 'LALInference' (version 1) skymap, and
51% after convolving with the 2MPZ galaxy catalogue, as described by
Evans et al. (2016, MNRAS, 462, 1591). These pointings and associated
metadata have been reported to the Treasure Map (Wyatt et al., arXiv
2001.00588; http://treasuremap.space/alerts?graceids=S200225q).
We have detected 1 X-ray source. 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.
We have found:
* 0 sources of rank 1
* 0 sources of rank 2
* 0 sources of rank 3
* 1 source of rank 4
RANK 4 sources
==============
These are catalogued X-ray sources, showing no signs of outburst
compared to previous observations, so they are not likely to be related
to the GW trigger.
| Source ID | RA | Dec | Err90 |
| S200225q_X1 | 06h 42m 40.91s | +88d 04' 42.7" | 9.0" |
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, including details of the
sources listed above, are online at
https://www.swift.ac.uk/LVC/S200225q
This circular is an official product of the Swift XRT team.
GCN Circular 27485
Subject
LIGO/Virgo S200225q: Upper limits from Konus-Wind observations
Date
2020-04-03T22:15:39Z (6 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A. Ridnaia, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline,
on behalf of the Konus-Wind team, report:
Konus-Wind (KW) was observing the whole sky at the time of the
LIGO/Virgo event S200225q (2020-02-25 06:04:21.397 UTC, hereafter T0;
LIGO/Virgo Collaboration GCN Circ. 27193).
No triggered KW GRBs happened between ~1 day before and ~2 days
after T0. Using waiting-mode data within the interval T0 +/- 100 s,
we found no significant (> 5 sigma) excess over the background
in both KW detectors on temporal scales from 2.944 s to 100 s.
We estimate an upper limit (90% conf.) on the 20 - 1500 keV fluence
to 5.6x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having a
typical KW short GRB spectrum (an exponentially cut off power law with
alpha =-0.5 and Ep=500 keV). For a typical long GRB spectrum (the Band
function with alpha=-1, beta=-2.5, and Ep=300 keV), the corresponding
limiting peak flux is 1.6x10^-7 erg/cm^2/s (20 - 1500 keV, 2.944 s scale).
All the quoted values are preliminary.
GCN Circular 27317
Subject
LIGO/Virgo S200225q: No notable candidates in GOTO imaging
Date
2020-03-05T13:57:38Z (6 years ago)
From
Ben Gompertz at U of Warwick <b.gompertz@warwick.ac.uk>
K. Ackley (1); Y.-L. Mong (1); D. K. Galloway (1); D. Steeghs (2); V.
Dhillon (3); P. O'Brien (4); G. Ramsay (5); D. Pollacco (2); E. Thrane
(1); S. Poshyachinda (6); R. Kotak (7); L. Nuttall (8); E. Pall\'e (9);
K. Ulaczyk (2); J. Lyman (2); R. Cutter (2); A. Levan (2); T. Marsh (2);
R. West (2); E. Stanway (2); B. Gompertz (2); K. Wiersema (2); T.
Killestein (2); A. Casey (1); M. Brown (1); B. Muller (1); M. Dyer (3);
J. Mullaney (3); E. Daw (3); S. Littlefair (3); J. Maund (3); L.
Makrygianni (3); U. Burhanudin (3); R. Starling (4); R. Eyles (4); S.
Tooke (4); S. Aukkaravittayapun (6); U. Sawangwit (6); S. Awiphan (6);
D. Mkrtichian (6); P. Irawati (6); S. Mattila (7); T. Heikkil\"a (7); E.
Rol (1)
((1) Monash University, (2) Warwick University, (3) University of
Sheffield, (4) University of Leicester, (5) Armagh Observatory &
Planetarium, (6) National Astronomical Research Institute of Thailand,
(7) University of Turku, (8) University of Portsmouth, (9) Instituto de
Astrofisica de Canarias)
report on behalf of the GOTO collaboration:
We report on optical observations with the Gravitational-wave Optical
Transient Observer prototype in response to S200225q (GCN #27193).
Targeted observations started shortly after the preliminary event
notification was received. These spanned 64 unique tile pointings, with
image subtraction, containing 81.6% of the source location probability
(based on the initial BAYESTAR skymap) and were acquired between 21:46
UT Feb 25 2020 and 00:30 UT Feb 26 2020 (starting 15.6 hours after the
event trigger). No new transients that could be credibly associated with
S200225q were detected.
Each pointing spans 4.9x3.7 square degrees and consisted of 3x60s
exposures in our L-band filter (400-700nm passband similar to g+r) with
a median 5-sigma photometric depth equivalent to g=19.3 for an
individual pointing. Limits are based on a photometric calibration
against PS1 sources. Most pointings were observed multiple times,
typically 2-3 times.
Images are processed immediately after acquisition using the GOTOphoto
pipeline. Difference imaging was performed on the median of each triplet
of exposures using recent survey observations of the same pointings.
Source candidates were initially filtered using a classifier and
cross-matched against a variety of catalogs, including the MPC and PS1.
Human candidate vetting was performed following data acquisition and
automated classifier cuts.
GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT), The University of Portsmouth,
the University of Turku and the Instituto de Astrofisica de Canarias
(IAC) (https://goto-observatory.org/)
GCN Circular 27282
Subject
LIGO/Virgo S200225q: AstroSat CZTI upper limits
Date
2020-03-02T06:37:57Z (6 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
V. Shenoy (IITB), Aarthy E. (PRL), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
We have carried a search for X-ray candidates in Astrosat CZTI data in a 100 sec window around the trigger time of the BBH Merger event S200225q (UTC 2020-02-25 06:04:21, GraceDB event). We use the LALInference.fits.gz,1 map (https://gracedb.ligo.org/api/superevents/S200225q/files/LALInference.fits.gz,1) for our analysis. CZTI is a coded aperture mask instrument that has considerable effective area for about 29% of the entire sky, but is also sensitive to brighter transients from the entire sky. At the time of the merger, Astrosat's nominal pointing is RA,DEC = 04:56:04.7, -71:22:15.0 (74.0196,-71.3708), which is ~160 deg away from the maximum probability location. At the time of the merger event, the Earth-satellite-transient angle corresponding to maximum probability location is ~83 deg and hence is not occulted by Earth in satellite's frame. In a time interval of 100 sec around the event, the region of the localisation map which is not occulted by Earth in the satellite's frame has a cumulative probability of 0.99 (99%).
CZTI data were de-trended to remove orbit-wise background variation. We then searched data from the four independent, identical quadrants to look for coincident spikes in the count rates. Searches were undertaken by binning the data in 0.1s, 1s, and 10s respectively. Statistical fluctuations in background count rates were estimated by using data from 10 (+-5) neighbouring orbits. We selected confidence levels such that the probability of a false trigger in a 1000 sec window is 10^-4. We do not find any evidence for any hard X-ray transient in this window, in the CZTI energy range of 20-200 keV.
We use a detailed mass model of the satellite to calculate the direction-dependent instrument response for points in the visible sky. We then assume the source is modelled as a power law with photon index alpha = -1, and convert our count rate upper limits to direction-dependent flux limits. We obtain the following upper limits for source flux in the 20-200 keV band by taking a probability weighted mean over the visible sky:
0.1 s: flux limit= 1.84e-05 ergs/cm^2/s; fluence limit = 1.84e-06 ergs/cm^2
1.0 s: flux limit= 5.36e-06 ergs/cm^2/s; fluence limit = 5.36e-06 ergs/cm^2
10.0 s: flux limit= 6.73e-07 ergs/cm^2/s; fluence limit = 6.73e-06 ergs/cm^2
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
GCN Circular 27275
Subject
LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
Date
2020-03-01T14:12:31Z (6 years ago)
From
Jean-Gregoire Ducoin at LAL <ducoin@lal.in2p3.fr>
J.-G. Ducoin (IJCLab), H. Crisp (OzGrav-UWA), P. Hello (IJCLab), T.
Sadibekova (AIM-CEA), Z. Vidadi (SHAO), M. Prouza (FZU), M. Boer
(Artemis), N. Christensen (Artemis), L. Eymar (Artemis), S. Karpov
(FZU), A. Klotz (IRAP), M. Masek (FZU), K. Noysena (Artemis, IRAP),
S. Antier (APC), A. Coleiro (APC), D. Corre (IJCLab), M. Coughlin
(UMN), D. Coward (OzGrav-UWA), B. Gendre (OzGrav-UWA), D. A. Kann
(HETH/IAA-CSIC), N. Kochiashvili (Iliauni), C. Lachaud (APC),
N. Leroy (IJCLab), C. Thoene (HETH/IAA-CSIC), D. Turpin (AIM-CEA),
X. Wang (THU)
Report on behalf of the FRAM, TAROT and GRANDMA collaborations.
We performed tiled observations of LIGO/Virgo S200225q event with the
FRAM-Auger, FRAM-CTA-N, TAROT-Calern (TCA), TAROT-Chili (TCH), TAROT-
Reunion (TRE) telescopes.
FRAM-Auger is located at Pierre Auger Observatory. FRAM-CTA-N is
located at Observatorio del Roque de los Muchachos. TCA is located at
Calern site at the Cote d'Azur observatory. TCH is located at La Silla
ESO observatory (LaS/ESO). TRE is located at Les Makes astronomical
observatory.
The following table shows for each telescope: the delay in minutes
from the trigger, which filter is used, the field of view of the
telescope in degrees and the typical limiting magnitude (AB mag) for a
given exposure in seconds (s).
+-------------+---------+----------+-------------+------------+
| Telescope | Delay | Filter | f.o.v. | Limiting |
| | [min] | | [deg] | Mag. |
|-------------+---------+----------+-------------+------------|
| FRAM-Auger | 1084 | R | 1.0 x 1.0 | 18.0 (60s) |
| FRAM-CTA-N | 826 | R | 0.45 x 0.45 | 17.0 (90s) |
| TCA | 718 | Clear | 1.9 x 1.9 | 18.0 (60s) |
| TCH | 1102 | Clear | 1.9 x 1.9 | 18.0 (60s) |
| TRE | 712 | Clear | 4.2 x 4.2 | 17.0 (60s) |
+-------------+---------+----------+-------------+------------+
We performed the following joint tiled observations [1] :
+-------------+------------+------------+---------+---------+---------+
| Telescope | TStart | TEnd | RA | DEC | Proba |
| | [UTC] | [UTC] | [deg] | [deg] | [%] |
|-------------+------------+------------+---------+---------+---------|
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 103.893 | 36.486 | <0.1 |
| | 00:08:04 | 00:12:30 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 104.082 | 37.459 | <0.1 |
| | 00:13:05 | 00:17:32 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 105.306 | 37.459 | <0.1 |
| | 00:18:07 | 00:22:34 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 103.709 | 35.514 | <0.1 |
| | 00:23:09 | 00:27:36 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 103.869 | 34.541 | <0.1 |
| | 00:28:10 | 00:32:37 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 102.524 | 33.568 | <0.1 |
| | 00:33:12 | 00:37:39 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 102.689 | 34.541 | <0.1 |
| | 00:38:13 | 00:42:40 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 105.101 | 36.486 | <0.1 |
| | 00:43:32 | 00:47:58 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 102.532 | 31.622 | <0.1 |
| | 00:48:34 | 00:53:01 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 102.692 | 32.595 | <0.1 |
| | 00:53:37 | 00:58:03 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 103.689 | 33.568 | <0.1 |
| | 00:58:38 | 01:03:05 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 101.392 | 31.622 | <0.1 |
| | 01:10:24 | 01:14:51 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 101.567 | 30.649 | <0.1 |
| | 02:23:25 | 02:27:52 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 104.901 | 35.514 | <0.1 |
| | 02:28:28 | 02:32:55 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 102.517 | 35.514 | <0.1 |
| | 02:33:30 | 03:28:23 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 101.739 | 29.676 | <0.1 |
| | 03:29:00 | 03:33:27 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 102.685 | 36.486 | <0.1 |
| | 03:34:04 | 03:38:31 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 101.538 | 32.595 | <0.1 |
| | 03:39:06 | 03:43:33 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 100.800 | 28.703 | <0.1 |
| | 03:44:09 | 03:48:36 | | | |
| FRAM-Auger | 2020-02-26 | 2020-02-26 | 100.621 | 29.676 | <0.1 |
| | 03:49:10 | 03:53:37 | | | |
| ----- | ----- | ----- | ----- | ----- | ----- |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 110.284 | 52.215 | <0.1 |
| | 19:50:06 | 19:54:12 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 107.353 | 45.662 | <0.1 |
| | 19:54:33 | 19:58:39 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 107.901 | 47.846 | <0.1 |
| | 19:58:54 | 20:03:00 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 110.326 | 53.089 | <0.1 |
| | 20:03:16 | 20:07:22 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 109.574 | 52.215 | <0.1 |
| | 20:07:36 | 20:11:42 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 108.549 | 47.846 | <0.1 |
| | 20:12:04 | 20:16:10 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 106.534 | 43.914 | <0.1 |
| | 20:16:28 | 20:20:34 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 108.357 | 48.720 | <0.1 |
| | 20:20:50 | 20:24:56 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 109.548 | 51.342 | <0.1 |
| | 20:25:12 | 20:29:18 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 108.828 | 49.594 | <0.1 |
| | 20:29:32 | 20:33:38 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 105.732 | 41.293 | <0.1 |
| | 20:34:00 | 20:38:06 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 106.937 | 44.788 | <0.1 |
| | 20:38:28 | 20:42:34 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 110.414 | 54.612 | <0.1 |
| | 20:42:51 | 20:46:57 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 106.038 | 42.604 | <0.1 |
| | 20:47:15 | 20:51:21 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 107.906 | 46.973 | <0.1 |
| | 20:51:37 | 20:55:43 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 110.369 | 53.963 | <0.1 |
| | 20:55:59 | 21:00:05 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 109.523 | 50.468 | <0.1 |
| | 21:00:21 | 21:04:26 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 108.840 | 50.468 | <0.1 |
| | 21:04:40 | 21:08:46 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 109.016 | 48.720 | <0.1 |
| | 21:09:07 | 21:13:13 | | | |
| FRAM-CTA-N | 2020-02-25 | 2020-02-25 | 105.178 | 39.545 | <0.1 |
| | 21:13:30 | 21:17:36 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 139.091 | 86.942 | 0.8 |
| | 23:03:21 | 23:07:26 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 147.273 | 86.942 | 0.6 |
| | 23:07:41 | 23:11:47 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 151.200 | 86.505 | 0.6 |
| | 23:12:01 | 23:16:06 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 144.000 | 86.505 | 0.5 |
| | 23:16:20 | 23:20:26 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 130.909 | 86.942 | 0.5 |
| | 23:20:53 | 23:24:58 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 122.400 | 86.505 | 0.5 |
| | 23:25:13 | 23:29:19 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 115.200 | 86.505 | 0.4 |
| | 23:29:33 | 23:33:39 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 115.714 | 86.068 | 0.4 |
| | 23:33:52 | 23:37:57 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 116.129 | 85.631 | 0.4 |
| | 23:38:10 | 23:42:16 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 129.600 | 86.505 | 0.4 |
| | 23:42:32 | 23:46:38 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 122.143 | 86.068 | 0.4 |
| | 23:46:52 | 23:50:58 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 121.936 | 85.631 | 0.4 |
| | 23:51:10 | 23:55:17 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-26 | 136.800 | 86.505 | 0.4 |
| | 23:55:32 | 23:59:38 | | | |
| FRAM-CTA-N | 2020-02-26 | 2020-02-27 | 110.323 | 85.631 | 0.4 |
| | 23:59:54 | 00:04:00 | | | |
| FRAM-CTA-N | 2020-02-27 | 2020-02-27 | 128.571 | 86.068 | 0.4 |
| | 00:04:17 | 00:08:23 | | | |
| FRAM-CTA-N | 2020-02-27 | 2020-02-27 | 158.400 | 86.505 | 0.4 |
| | 00:08:49 | 00:12:54 | | | |
| FRAM-CTA-N | 2020-02-27 | 2020-02-27 | 114.783 | 85.194 | 0.4 |
| | 00:13:19 | 00:17:25 | | | |
| FRAM-CTA-N | 2020-02-27 | 2020-02-27 | 155.455 | 86.942 | 0.4 |
| | 00:17:49 | 00:21:55 | | | |
| FRAM-CTA-N | 2020-02-27 | 2020-02-27 | 109.286 | 86.068 | 0.3 |
| | 00:22:20 | 00:26:26 | | | |
| FRAM-CTA-N | 2020-02-27 | 2020-02-27 | 127.742 | 85.631 | 0.3 |
| | 00:26:42 | 00:30:48 | | | |
| ----- | ----- | ----- | ----- | ----- | ----- |
| TCA | 2020-02-25 | 2020-02-27 | 110.041 | 48.270 | <0.1 |
| | 18:01:40 | 02:54:13 | | | |
| TCA | 2020-02-25 | 2020-02-27 | 113.891 | 59.404 | <0.1 |
| | 18:08:28 | 01:16:38 | | | |
| TCA | 2020-02-25 | 2020-02-27 | 110.130 | 51.981 | <0.1 |
| | 18:34:56 | 00:12:04 | | | |
| TCA | 2020-02-25 | 2020-02-26 | 115.303 | 64.971 | <0.1 |
| | 18:41:42 | 21:18:35 | | | |
| TCA | 2020-02-25 | 2020-02-27 | 111.978 | 57.548 | <0.1 |
| | 18:48:26 | 03:24:10 | | | |
| TCA | 2020-02-25 | 2020-02-28 | 110.236 | 55.692 | <0.1 |
| | 18:55:11 | 02:53:28 | | | |
| TCA | 2020-02-25 | 2020-02-28 | 107.314 | 48.270 | <0.1 |
| | 19:07:22 | 03:39:23 | | | |
| TCA | 2020-02-25 | 2020-02-26 | 111.719 | 53.837 | <0.1 |
| | 19:14:07 | 20:12:25 | | | |
| TCA | 2020-02-25 | 2020-02-27 | 108.666 | 50.125 | <0.1 |
| | 19:20:51 | 00:18:48 | | | |
| TCA | 2020-02-25 | 2020-02-28 | 113.450 | 61.259 | <0.1 |
| | 19:27:37 | 02:46:42 | | | |
| TCA | 2020-02-25 | 2020-02-28 | 104.843 | 40.847 | <0.1 |
| | 19:39:46 | 03:51:29 | | | |
| TCA | 2020-02-25 | 2020-02-28 | 107.709 | 42.703 | <0.1 |
| | 19:46:32 | 03:00:27 | | | |
| TCA | 2020-02-25 | 2020-02-27 | 108.642 | 53.837 | <0.1 |
| | 20:18:57 | 02:24:59 | | | |
| TCA | 2020-02-25 | 2020-02-28 | 114.874 | 66.826 | <0.1 |
| | 20:25:42 | 04:05:02 | | | |
| TCA | 2020-02-25 | 2020-02-26 | 110.362 | 59.404 | <0.1 |
| | 20:38:08 | 00:05:35 | | | |
| TCA | 2020-02-25 | 2020-02-28 | 106.832 | 46.414 | <0.1 |
| | 21:31:26 | 03:19:10 | | | |
| TCA | 2020-02-25 | 2020-02-26 | 108.184 | 44.558 | <0.1 |
| | 21:50:37 | 22:56:56 | | | |
| TCA | 2020-02-26 | 2020-02-26 | 109.479 | 46.414 | <0.1 |
| | 18:34:49 | 20:51:36 | | | |
| TCA | 2020-02-26 | 2020-02-28 | 104.479 | 38.991 | <0.1 |
| | 19:01:05 | 03:32:38 | | | |
| TCA | 2020-02-26 | 2020-02-28 | 107.259 | 40.847 | <0.1 |
| | 19:26:42 | 03:58:18 | | | |
| TCA | 2020-02-26 | 2020-02-27 | 105.226 | 42.703 | <0.1 |
| | 19:40:14 | 02:15:31 | | | |
| TCA | 2020-02-26 | 2020-02-28 | 104.528 | 37.136 | <0.1 |
| | 21:04:30 | 03:25:53 | | | |
| TCA | 2020-02-27 | 2020-02-27 | 105.631 | 44.558 | <0.1 |
| | 02:32:11 | 02:38:30 | | | |
| ----- | ----- | ----- | ----- | ----- | ----- |
| TCH | 2020-02-26 | 2020-02-28 | 84.550 | -3.202 | <0.1 |
| | 00:25:44 | 02:17:30 | | | |
| TCH | 2020-02-26 | 2020-02-28 | 75.781 | -9.050 | <0.1 |
| | 00:34:09 | 02:25:55 | | | |
| TCH | 2020-02-26 | 2020-02-28 | 81.356 | -7.232 | <0.1 |
| | 00:39:14 | 02:30:07 | | | |
| TCH | 2020-02-26 | 2020-02-28 | 73.125 | -15.930 | <0.1 |
| | 01:44:04 | 01:22:20 | | | |
| TCH | 2020-02-26 | 2020-02-28 | 99.300 | 13.161 | <0.1 |
| | 02:19:26 | 04:06:51 | | | |
| TCH | 2020-02-26 | 2020-02-28 | 66.756 | -19.959 | <0.1 |
| | 03:36:13 | 03:12:28 | | | |
| TCH | 2020-02-26 | 2020-02-28 | 67.617 | -18.141 | <0.1 |
| | 03:44:38 | 03:25:56 | | | |
| TCH | 2020-02-26 | 2020-02-27 | 69.160 | -16.323 | <0.1 |
| | 03:55:09 | 03:41:49 | | | |
| TCH | 2020-02-27 | 2020-02-28 | 72.371 | -12.686 | <0.1 |
| | 00:51:09 | 02:54:56 | | | |
| TCH | 2020-02-27 | 2020-02-27 | 106.127 | 29.525 | <0.1 |
| | 01:01:40 | 01:07:52 | | | |
| TCH | 2020-02-27 | 2020-02-28 | 83.216 | 3.202 | <0.1 |
| | 01:36:43 | 01:31:15 | | | |
| TCH | 2020-02-27 | 2020-02-28 | 95.985 | 9.050 | <0.1 |
| | 01:45:09 | 03:51:37 | | | |
| TCH | 2020-02-27 | 2020-02-27 | 78.489 | -11.343 | <0.1 |
| | 01:53:34 | 01:57:40 | | | |
| TCH | 2020-02-27 | 2020-02-27 | 78.657 | -5.414 | <0.1 |
| | 02:15:49 | 04:33:44 | | | |
| TCH | 2020-02-27 | 2020-02-28 | 71.055 | -16.323 | <0.1 |
| | 02:48:25 | 02:48:37 | | | |
| TCH | 2020-02-27 | 2020-02-27 | 101.371 | 17.273 | <0.1 |
| | 04:01:10 | 04:07:23 | | | |
| TCH | 2020-02-27 | 2020-02-28 | 75.801 | -7.232 | <0.1 |
| | 04:20:40 | 04:11:03 | | | |
| TCH | 2020-02-27 | 2020-02-27 | 72.200 | -14.505 | <0.1 |
| | 04:51:37 | 05:04:24 | | | |
| TCH | 2020-02-27 | 2020-02-28 | 94.148 | 9.132 | <0.1 |
| | 05:05:35 | 02:50:44 | | | |
| TCH | 2020-02-28 | 2020-02-28 | 69.521 | -18.141 | <0.1 |
| | 00:50:14 | 03:06:09 | | | |
| TCH | 2020-02-28 | 2020-02-28 | 78.648 | -3.595 | <0.1 |
| | 01:42:13 | 01:50:32 | | | |
| ----- | ----- | ----- | ----- | ----- | ----- |
| TRE | 2020-02-25 | 2020-02-26 | 98.571 | 16.364 | <0.1 |
| | 17:56:09 | 20:08:55 | | | |
| TRE | 2020-02-25 | 2020-02-26 | 96.279 | 12.273 | <0.1 |
| | 18:07:07 | 17:33:36 | | | |
| TRE | 2020-02-26 | 2020-02-26 | 98.182 | 28.636 | <0.1 |
| | 18:50:22 | 18:52:22 | | | |
| TRE | 2020-02-26 | 2020-02-26 | 107.027 | 32.727 | <0.1 |
| | 19:22:28 | 19:28:50 | | | |
| TRE | 2020-02-26 | 2020-02-26 | 78.621 | -8.182 | <0.1 |
| | 20:20:08 | 20:26:30 | | | |
| TRE | 2020-02-26 | 2020-02-26 | 81.818 | 0.000 | <0.1 |
| | 20:32:34 | 20:38:50 | | | |
+-------------+------------+------------+---------+---------+---------+
TStart and TEnd refers respectively to the time of the first and last
exposure for a given tile. Observations are not necessarily continuous
in this interval.
The Probability refers to the 2D spatial probability of the GW skymap
enclosed in a given tile.
These observations cover about 9.2% of the cumulative probability of
the LALInference skymap created on 2020-02-26 16:55:29 (UTC).
The coverage map is available at:
https://grandma-
owncloud.lal.in2p3.fr/index.php/s/XgtMhPRxcyL09gR/download?path=%2F&files=GRANDMA_S200225q_1583068540.svg
No significant transient candidates were found during our low latency
analysis [2,3].
GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger
Addicts) is a network of robotic telescopes connected all over the
world with both photometry and spectrometry capabilities for Time-
domain Astronomy [2](https://grandma.lal.in2p3.fr/).
Details on the different telescopes are available on the GRANDMA web
pages.
[1] M. W Coughlin et al., MNRAS 2019, https://doi.org/10.1093/mnras/stz2485
[2] S. Antier et al., MNRAS 2019, https://doi.org/10.1093/mnras/stz3142
[3] K. Noysena et al., ApJ 2019, arXiv:1910.02770
GCN Circular 27232
Subject
LIGO/Virgo S200225q: Not observable by CALET
Date
2020-02-27T06:00:18Z (6 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto,
V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU),
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:
At the trigger time of the compact binary merger candidate S200225q,
T0 = 2020-02-25 06:04:21.397 UT (The LIGO Scientific Collaboration
and Virgo Collaboration, GCN Circ. 27193), the CALET Gamma-ray
Burst Monitor (CGBM) high voltages were off (from T0-23 min to
T0+10 min).
The CALET Calorimeter (CAL) was operating in the high energy trigger
mode at the trigger time of S200225q. 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. There
was no significant overlap with the LVC high probability localization
region at T0+-60 sec. The CAL FOV was centered at RA = 157.8 deg,
Dec= -32.7 deg at T0.
GCN Circular 27229
Subject
LIGO/Virgo S200225q: Updated Sky Localization
Date
2020-02-26T20:40:15Z (6 years ago)
From
Leo Singer at GSFC <leo.p.singer@nasa.gov>
The LIGO Scientific Collaboration and the Virgo Collaboration report:
We have conducted further analysis of the LIGO Hanford Observatory
(H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data
around the time of the compact binary merger (CBC) candidate S200225q
(GCN Circular 27193). Parameter estimation has been performed using
LALInference [1] and a new sky map, LALInference.fits.gz,1, distributed
via GCN Notice, is available for retrieval from the GraceDB event page:
https://gracedb.ligo.org/superevents/S200225q
The original localization in GCN 27193 only used data from H1 and L1.
This updated localization uses data from H1, L1, and V1.
The preferred sky map at this time is LALInference.fits.gz,1. For the
LALInference.fits.gz,1 sky map, the 90% credible region is well fit by
an ellipse with an area of 27 deg2 described by the following DS9
region (right ascension, declination, semi-major axis, semi-minor
axis, position angle of the semi-minor axis):
icrs; ellipse(08h28m26s, +87d45m51s, 3.38d, 2.54d, 104.41d)
Marginalized over the whole sky, the a posteriori luminosity distance
estimate is 995 +/- 188 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] Veitch et al. PRD 91, 042003 (2015)
GCN Circular 27221
Subject
LIGO/Virgo S200225q: no counterpart candidate in SVOM/GWAC observations
Date
2020-02-26T09:41:33Z (6 years ago)
From
Jirong Mao at Yunnan Obs <jirongmao_obs@ynao.ac.cn>
J. Mao (YNAO), N. Leroy (IJCLab), X. G. Wang (GXU), D. Corre (IJCLab),
J. Y. Wei (NAOC)
report on behalf of the SVOM Multi Messenger Astronomy and GWAC teams
(http://www.svom.fr/en/svom-mma-and-gwac-team):
We observed 6 (~900 square deg) sky regions to cover the skymap of the
advanced LIGO/Virgo trigger S200225q (GCN # 27193), with SVOM/GWAC,
at Xinglong Observatory. SVOM/GWAC is equipped with two sets of
wide angle cameras:
- FFOV cameras (FOV~900 square degrees/camera, aperture = 3.5 cm),
- JFOV cameras (FOV~150 square degrees/camera, aperture = 18 cm).
SVOM/GWAC currently comprises 4 FFOV cameras and 16 JFOV cameras,
working in the unfiltered band. The observations are operated in
time-series mode, taking one exposure every 25 seconds
(20s exposure + 5s readout). The observed and processed regions enclosed
an estimated 56.5% of the probability of the advanced LIGO/Virgo skymap.
Images were taken between ~5.5 hours and ~6.5 hours
after the GW trigger time. The coordinates of the 6 sky regions
observed and their observation times and covered probability are
listed below:
Id Ra Dec start (UTC) end (UTC) Proba. Cam.
1 05:56:47.7 65:08:15 2020-02-25 11:42:19 2020-02-25 12:33:05 0.001 JFOV
2 07:26:34.3 52:57:54 2020-02-25 11:34:41 2020-02-25 12:02:57 0.197 JFOV
3 06:34:13.4 31:32:25 2020-02-25 11:03:34 2020-02-25 11:31:49 0.142 JFOV
4 06:19:52.5 30:20:19 2020-02-25 11:03:45 2020-02-25 11:31:57 0.085 JFOV
5 07:28:23.2 63:59:54 2020-02-25 12:36:01 2020-02-25 12:36:25 0.165 JFOV
6 07:04:46.5 36:07:24 2020-02-25 11:48:36 2020-02-25 12:32:32 0.170 JFOV
The sky coverage map is available at:
http://cmm.svom.cn/gwpub/O3/S200225q/S200225q.png
(user:svomo3 pwd:gwo3).
Weather conditions were hazy during the observations. An average 3-sigma
limiting magnitude of 16 mag in the R band was obtained in the single
frames. No credible new source was detected by our online pipeline during
follow-up observations. A more detailed image analysis including
co-addition is ongoing with our offline pipeline to search for transient
candidates.
GCN Circular 27220
Subject
LIGO/Virgo S200225q: Upper limits from Insight-HXMT/HE observations
Date
2020-02-26T08:51:45Z (6 years ago)
From
Qi Luo at IHEP <luoqi@ihep.ac.cn>
Q. Luo, Y. G. Zheng, C. Cai, S. Xiao, Q. B. Yi,
Y. Huang, C. K. Li, G. Li, X. B. 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
S200225q event (GCN #27193). At the GW trigger time
2020-02-25T06:04:21.397 UTC (denoted as T0), all of the
GW localization region was covered by the 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=108.7 deg, DEC=48.8 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: 1.7e-07 erg cm^-2
10 s: 8.6e-07 erg cm^-2
Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1 s: 2.3e-07 erg cm^-2
10 s: 1.3e-06 erg cm^-2
Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1 s: 4.0e-07 erg cm^-2
10 s: 2.2e-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.
GCN Circular 27217
Subject
LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
Date
2020-02-26T01:35:34Z (6 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (NASA/GSFC),
A. Y. Lien (GSFC/UMBC), 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-ASDC), 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 (U. of Birmingham), 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 (U. 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 S200225q (LIGO/VIRGO Collaboration GCN Circ. 27193),
where T0 is the LVC trigger time (2020-02-25T06:04:21.396 UTC).
The center of the BAT field of view (FOV) at T0 is
RA = 132.968 deg,
DEC = -43.114 deg,
and the roll angle is 209.672 deg.
The BAT FOV (>10% partial coding) covers 0.26% of the integrated
LVC localization probability, and 0.40% 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) are found in the BAT raw light curves with time bins of 64 ms,
1 s, and 1.6 s. Assuming a short GRB with a typical
spectrum in the BAT energy range (i.e., a simple power-law model with a
power-law index of -1.32, Lien & Sakamoto et al. 2016), the 5-sigma upper
limit in the 1-s binned light curve corresponds to a flux upper
limit (15-350 keV) of ~ 7.90 x 10^-8 erg/s/cm^2 for the 100% coded region
(i.e., for a burst with 0 deg from BAT boresight) and ~ 1.66 x 10^-6
erg/s/cm2
for the 10% coded region (~56 deg from BAT boresight).
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),
these flux upper limits corresponds to a distance of ~ 80.82 Mpc (100%
coded)
and ~ 17.61 Mpc (10% coded).
Event data are available from T0-44.978 s to T0+45.130 s via the GUANO
system
(Tohuvavohu et al. 2020, in prep). No significant detections (above our
typical
image threshold of ~ 6.5 to 7 sigma) are found in the 15-350 keV images
created using intervals of T0-0.1 to T0+0.1 s, T0-2 s to T0+8 s, and
the whole event data range.
BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 96.26% 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/S200225q/web/source_public.html
GCN Circular 27209
Subject
LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
Date
2020-02-25T16:45:33Z (6 years ago)
From
Adam Goldstein at Fermi-GBM, USRA <adam.michael.goldstein@gmail.com>
A. Goldstein (USRA) reports on behalf of the Fermi-GBM Team and the
GBM-LIGO/Virgo group
For S200225q and using the latest BAYESTAR skymap, Fermi-GBM was observing
88.6% 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 S200225q (GCN Circ. 27193). 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.
Part of the LVC localization region is behind the Earth for Fermi, located
at RA=224.3, Dec=24.7 with a radius of 67.2 degrees. We therefore set upper
limits on impulsive gamma-ray emission for the LVC localization region
visible to Fermi at merger time. 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: 10. 13. 23.
1.024 s: 3.7 3.8 6.6
8.192 s: 0.9 1.0 2.0
Assuming the median luminosity distance of 1234 Mpc from the GW detection,
we estimate the following intrinsic luminosity upper limits over the 1
keV-10 MeV energy range (in units of 10^50 erg/s):
Timescale Soft Normal Hard
------------------------------------
0.128s: 2.8 3.3 9.8
1.024s: 1.0 1.0 2.8
8.192s: 0.2 0.2 0.8
GCN Circular 27207
Subject
LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
Date
2020-02-25T16:26:40Z (6 years ago)
From
Milena Crnogorcevic at U.of Maryland/NASA-GSFC <milenaGCN@gmail.com>
L. Scotton (CNRS/IN2P3/LUPM), M. Crnogorcevic (Univ. of Maryland & NASA/GSFC), N. Di Lalla (Stanford University), M. Axelsson (KTH & Stockholm Univ), E. Bissaldi (Politecnico & INFN Bari), D. Kocevski (NASA/MSFC), N. Omodei (Stanford Univ.) and F. Longo (University and INFN, Trieste) report on behalf of the Fermi-LAT Collaboration:
We have searched data collected by the Fermi Large Area Telescope (LAT) on
February 25, 2020, for possible high-energy (E > 100 MeV) gamma-ray emission in
spatial/temporal coincidence with the LIGO/Virgo trigger S200225q (GCN 27193).
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 ~3% of the LIGO probability at the time of the trigger
(T0 = 2020-02-25 06:04:21.397 UTC), and reached 100% cumulative coverage
after ~5.3 ks.
We performed a search for a transient counterpart within the observed region of
the 90% contour of LIGO map in a fixed time window from T0 to T0 + 10 ks.
No significant new sources are found.
We also performed a search which adapted the time interval of the analysis to the
exposure of each region of the sky, and no additional excesses were found.
Energy flux upper bounds for the fixed time interval between 100 MeV and 1 GeV
for this search vary between 1.8e-10 and 8.1e-7 [erg/cm^2/s].
The Fermi-LAT point of contact for this event is
Lorenzo Scotton (lorenzo.scotton@lupm.in2p3.fr).
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 27206
Subject
LIGO/Virgo S200225q: upper limits from AGILE/GRID observations
Date
2020-02-25T16:23:18Z (6 years ago)
From
Francesco Verrecchia at SSDC,INAF-OAR <francesco.verrecchia@ssdc.asi.it>
F. Verrecchia (SSDC, and INAF/OAR), A. Ursi (INAF/IAPS), M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini, G. Piano
(INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V.
Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F.
Longo (Univ. Trieste, and INFN Trieste), report on behalf of the AGILE Team:
In response to the LIGO-Virgo GW event S200225q at T0 = 2020-02-25
06:04:21.396 UTC a preliminary analysis of the AGILE exposure at T0 shows
that the Gamma-Ray Imaging Detector (GRID) exposure covered the 40% of the
90% c.l. localization region (LR; 39% of the LR is occulted by Earth).
We performed an analysis of the GRID data in the energy range 50 MeV - 10
GeV on T0, where good exposure of the S200225q 90% c.l. LR was available.
No candidate gamma-ray transient was detected.
The following preliminary GRID values of 3-sigma upper limit (UL) are
obtained:
from 9.8e-07 to 3.9e-06 erg cm^-2 s^-1, with exposure of about 40% of the
LR over the time interval (T0 - 2 s ; T0 + 2 s );
from 3.6e-07 to 1.1e-06 erg cm^-2 s^-1, with exposure of about 40% of the
LR over the time interval (T0 s ; T0 + 10 s);
from 3.0e-08 to 1.2e-07 erg cm^-2 s^-1, with exposure of about 40% of the
LR over the time interval (T0 s ; T0 + 100 s );
These measurements were obtained with AGILE observing a large portion of
the sky in spinning mode. Additional analysis of AGILE data is in progress.
GCN Circular 27204
Subject
LIGO/Virgo S200225q: upper limits from AGILE/MCAL observations
Date
2020-02-25T15:07:02Z (6 years ago)
From
Alessandro Ursi at INAF/IAPS <alessandro.ursi@gmail.com>
A. Ursi (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini, G.
Piano (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A.
Bulgarelli, V. Fioretti, N. Parmiggiani (INAF/OAS-Bologna), M. Pilia
(INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), report on
behalf of the AGILE Team:
In response to the LIGO/Virgo GW event S200225q at T0 = 2020-02-25
06:04:21.397 (UT), a preliminary analysis of the AGILE minicalorimeter
(MCAL) triggered data found no significant event candidates within a time
interval covering -/+ 15 sec from the LIGO/Virgo T0.
At the T0, about 45% of the S200225q 90% c.l. localization region (LR) was
accessible to the AGILE/MCAL.
Three-sigma upper limits (ULs) are obtained for a 1 s integration time at
different celestial positions within the accessible S200225q LR, from a
minimum of 1.7E-06 erg cm^-2 to a maximum of 8.0E-06 erg cm^-2 (assuming as
spectral model a single power-law with photon index 1.5).
An independent procedure based on photon counting statistics provides UL
fluences in the range 0.4-1 MeV, for a 300 us integration time, from a
minimum of 1.1E-08 erg cm^-2 to a maximum of 4.4E-08 erg cm^-2.
The AGILE/MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the
energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.
GCN Circular 27203
Subject
LIGO/Virgo S200225q: Upper limits from IceCube neutrino searches
Date
2020-02-25T13:39:45Z (6 years ago)
From
Alex Pizzuto at ICECUBE/U of Wisconsin <pizzuto@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 S200225q
in a time range of 1000 seconds [3] centered on the alert event time
(2020-02-25 05:56:01.397 UTC to 2020-02-25 06:12:41.397 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
S200225q calculated from the map circulated in the 3-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 S200225q ranges from 0.029 to 0.358 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<mailto:roc@icecube.wisc.edu>
[1] Bartos et al. arXiv:1810.11467 (2018) and Countryman et al.arXiv:1901.05486 (2019)
[2] PoS(ICRC2019)918 and Braun et al., Astroparticle Physics 29, 299 (2008)
[3] Baret et al., Astroparticle Physics 35, 1 (2011)
GCN Circular 27202
Subject
LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
Date
2020-02-25T11:58:50Z (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 S200225q (GCN #27193). At the time of the trigger the HAWC
local zenith was oriented towards (RA, Dec) = (148.1 deg, 19.1 deg).
32% 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 37 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 1.6e-5 erg/cm^2 to 1.1e-4 erg/cm^2
(7.7e-5 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 27201
Subject
LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
Date
2020-02-25T11:46:40Z (6 years ago)
From
Antoine Kouchner at ANTARES Collaboration <kouchner@apc.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 S200225q event using the 90% contour of the Preliminary GW_SKYMAP probability
map provided by the GW interferometers (GCN#27193). 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/S200225q_Preliminary.png <http://antares.in2p3.fr/GW/S200225q_Preliminary.png>.
Considering the location probability provided by the LIGO/Virgo collaborations, there is a
42.4% 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 2020-02-25 06:04:21 and in the 90% contour of the S200225q
event. The expected number of atmospheric background events in the region visible by ANTARES is
4.03e-04 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 2.90e-03 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 27200
Subject
LIGO/Virgo S200225q: Global MASTER-Net observations report
Date
2020-02-25T10:36:10Z (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, D. Cheryasov
(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 S200225q errorbox 15719 sec after trigger time at 2020-02-25 10:26:20 UT, with upper limit up to 18.4 mag. Observations started at twilight. The observations began at zenith distance = 19 deg. The sun altitude is -13.9 deg.
The galactic latitude b = 25 deg., longitude l = 169 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/ligo_1.php?id=11369
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
15810 | 2020-02-25 10:26:20 | MASTER-Amur | (07h 15m 42.44s , +52d 07m 18.8s) | C | 180 | 18.4 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 27198
Subject
LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
Date
2020-02-25T09:35:05Z (6 years ago)
From
Maeve Doyle at U College Dublin, Ireland <maeve.doyle.1@ucdconnect.ie>
M. Doyle (UCD, Ireland)
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 combination of INTEGRAL all-sky detectors (following [1]):
SPI/ACS, IBIS/Veto, and IBIS we have performed a search for a prompt
gamma-ray counterpart of S200225q (GCN 27193).
At the time of the event (2020-02-25 06:04:21 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 62 deg with respect to the
spacecraft pointing axis. This orientation implies strongly suppressed
(24% of optimal) response of ISGRI, somewhat suppressed (46% of
optimal) response of IBIS/Veto, and near-optimal (85% of optimal)
response of SPI-ACS.
The background within +/-300 seconds around the event was very stable
(excess variance 1.2).
We have performed a search for any impulsive events in INTEGRAL SPI-
ACS (as described in [2]), IBIS, and IBIS/Veto data.
We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 2.1e-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 ~1.8e-07 (6.1e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.
For the mean reported distance 1234.0 Mpc this corresponds to the
limit on the total isotropic equivalent energy in 1 s of 3.8e+49 erg
for the short GRB spectrum and for a long GRB spectrum isotropic
equivalent luminosity in 1 s (8 s) of 3.1e+49 erg/s (1.1e+49 erg/s)
We report for completeness and in order of FAP, all excesses
identified in the search region. We find 1 tentatively associated
excess:
T-T0 | scale | S/N | luminosity ( x 1e+49 erg/s) | FAP
-2.77 | 2.55 | 3.6 | 31 +/- 8.7 +/- 11.1 | 0.00657
5 likely background excesses:
T-T0 | scale | S/N | luminosity ( x 1e+49 erg/s) | FAP
-251 | 2.9 | 3.6 | 29.1 +/- 8.16 +/- 10.4 | 0.555
186 | 1 | 4 | 5.5 +/- 1.39 +/- 1.97 | 0.569
48.4 | 1.15 | 3.1 | 3.97 +/- 1.3 +/- 1.42 | 0.701
-135 | 2 | 3.3 | 31.2 +/- 9.83 +/- 11.2 | 0.742
7.18 | 0.05 | 3.4 | 20.8 +/- 6.34 +/- 7.47 | 0.924
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 27197
Subject
LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
Date
2020-02-25T08:46:12Z (6 years ago)
From
Satoshi Sugita at Aoyama Gakuin U. <sugita@phys.aoyama.ac.jp>
H. Negoro (Nihon U.), N. Kawai (Tokyo Tech),
S. Sugita, M. Serino (AGU),
M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi, R. Takagi (Nihon U.),
T. Mihara, C. Guo, Y. Zhou, 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, 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 S200225q at 2020-02-25 06:04:21.397 UTC (GCN 27193).
At the trigger time of S200225q, the high-voltage of MAXI/GSC was on.
The instantaneous field of view of GSC at the GW trigger time covered
1% 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 27%
of the 90% credible region of the bayestar skymap from 06:04:21 to
07:36:17 UTC (T0+0 to T0+5516 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 27193
Subject
LIGO/Virgo S200225q: Identification of a GW compact binary merger candidate The LIGO Scientific Collaboration and the Virgo Collaboration
Date
2020-02-25T06:38:12Z (6 years ago)
From
Vinaya Valsan at U. of Wisconsin Milwaukee <vvalsan@uwm.edu>
We identified the compact binary merger candidate S200225q during
real-time processing of data from LIGO Hanford Observatory (H1) and LIGO
Livingston Observatory (L1) at 2020-02-25 06:04:21.397 UTC (GPS time:
1266645879.397). The candidate was found by the PyCBC Live [1],
CWB [2], MBTAOnline [3], GstLAL [4], and SPIIR [5] analysis pipelines.
S200225q is an event of interest because its false alarm rate, as
estimated by the online analysis, is 9.2e-09 Hz, or about one in 3
years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S200225q
The classification of the GW signal, in order of descending
probability, is BBH (96%), Terrestrial (4%), BNS (<1%), NSBH
(<1%), or MassGap (<1%).
Assuming the candidate is astrophysical in origin, the probability
that the lighter compact object has a mass < 3 solar masses (HasNS) is
<1%. Using the masses and spins inferred from the signal, the
probability of matter outside the final compact object (HasRemnant) is
<1%.
Two sky maps are available at this time and can be retrieved from the
GraceDB event page:
* bayestar.fits.gz,0, an initial localization generated by BAYESTAR
[6], distributed via GCN notice about 3 minutes after the candidate
event time.
* bayestar.fits.gz,1, an initial localization generated by BAYESTAR
[6], distributed via GCN notice about 11 minutes after the candidate
event time.
The preferred sky map at this time is bayestar.fits.gz,1. For the
bayestar.fits.gz,1 sky map, the 90% credible region is 668 deg2.
Marginalized over the whole sky, the a posteriori luminosity distance
estimate is 1234 +/- 341 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] Nitz et al. PRD 98, 024050 (2018)
[2] Klimenko et al. PRD 93, 042004 (2016)
[3] Adams et al. CQG 33, 175012 (2016)
[4] Messick et al. PRD 95, 042001 (2017)
[5] Qi Chu, PhD Thesis, The University of Western Australia (2017)
[6] Singer & Price PRD 93, 024013 (2016)