LIGO/Virgo S190910h
GCN Circular 25780
Subject
LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
Date
2019-09-19T13:10:38Z (6 years ago)
From
Kateryna Barynova at Kiev Uni., GRANDMA <katiaffoni@gmail.com>
K. Barynova (Kyiv Uni), H. Crisp (OzGrav-UWA), K. Noysena (Artemis,
IRAP), C. Stachie (Artemis), M. Boer (Artemis), N. Christensen
(Artemis), L. Eymar (Artemis), A. Klotz (IRAP), S. Antier (APC), S.
Basa (LAM), D. Corre (LAL), M. Coughlin (Caltech), D. Coward (OzGrav-
UWA), J.G. Ducoin (LAL), B. Gendre (OzGrav-UWA), P. Hello (LAL), C.
Lachaud (APC), N. Leroy (LAL), D. Turpin (NAOC)
Report on behalf of the TAROT network and GRANDMA collaborations.
We performed tiled observations of LIGO/Virgo S190910h event with the
TAROT-Calern (TCA) and TAROT-Chili (TCH) telescopes operating in the
visible located respectively at Calern site at the Cote d'Azur
observatory and La Silla ESO observatory (LaS/ESO).
The observation started for TCA on 09/10/19 19:01:32 UTC which
corresponds approximately to 632 minutes after the GW trigger time,
for TCH on 09/11/19 09:31:19 UTC which corresponds approximately to
1502 minutes after the GW trigger time.
We performed the following tiled observations :
+-------+------------+------------+---------+---------+---------+
| Tele | TStart | TEnd | RA | DEC | Proba |
| scope | [UTC] | [UTC] | [deg] | [deg] | [%] |
|-------|------------+------------+---------+---------+---------|
| TCA | 2019-09-10 | 2019-09-15 | 5.307 | 39.422 | <1 |
| | 19:01:32 | 23:50:08 | | | |
| TCA | 2019-09-10 | 2019-09-14 | 44.517 | 37.136 | <1 |
| | 19:33:51 | 03:16:20 | | | |
| TCA | 2019-09-10 | 2019-09-15 | 5.236 | 31.569 | <1 |
| | 20:03:41 | 21:33:08 | | | |
| TCA | 2019-09-10 | 2019-09-15 | 8.398 | 42.703 | <1 |
| | 21:01:16 | 23:56:53 | | | |
| TCA | 2019-09-10 | 2019-09-15 | 20.706 | 33.424 | <1 |
| | 21:29:10 | 18:36:50 | | | |
| TCA | 2019-09-10 | 2019-09-16 | 16.832 | 46.414 | <1 |
| | 21:59:00 | 02:39:48 | | | |
| TCA | 2019-09-11 | 2019-09-16 | 10.881 | 41.753 | <1 |
| | 00:28:59 | 00:35:58 | | | |
| TCA | 2019-09-11 | 2019-09-16 | 24.773 | 46.414 | <1 |
| | 00:35:49 | 03:11:38 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 33.445 | 37.136 | <1 |
| | 00:42:39 | 22:18:28 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 41.749 | 37.136 | <1 |
| | 01:07:55 | 20:14:06 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 13.71 | 46.414 | <1 |
| | 01:14:46 | 20:20:54 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 10.122 | 37.136 | <1 |
| | 01:21:37 | 20:27:39 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 38.981 | 37.136 | <1 |
| | 02:07:32 | 23:43:19 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 31.207 | 33.424 | <1 |
| | 02:46:06 | 19:22:19 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 30.068 | 46.414 | <1 |
| | 02:52:57 | 19:29:03 | | | |
| TCA | 2019-09-11 | 2019-09-16 | 27.782 | 34.805 | <1 |
| | 19:03:47 | 04:10:20 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 22.835 | 34.33 | <1 |
| | 21:01:16 | 00:07:36 | | | |
| TCA | 2019-09-11 | 2019-09-15 | 15.847 | 42.703 | <1 |
| | 23:57:48 | 23:03:35 | | | |
| TCA | 2019-09-13 | 2019-09-16 | 36.213 | 37.136 | <1 |
| | 20:18:41 | 03:25:16 | | | |
| TCA | 2019-09-13 | 2019-09-15 | 38.267 | 33.424 | <1 |
| | 20:25:28 | 22:31:55 | | | |
|-------|------------+------------+---------+---------+---------|
| TCH | 2019-09-11 | 2019-09-13 | 44.649 | 29.05 | <1 |
| | 09:31:19 | 06:37:59 | | | |
| TCH | 2019-09-11 | 2019-09-16 | 220.434 | -28.657 | <1 |
| | 23:25:37 | 01:01:25 | | | |
| TCH | 2019-09-11 | 2019-09-16 | 218.309 | -36.323 | <1 |
| | 23:32:25 | 01:08:13 | | | |
| TCH | 2019-09-11 | 2019-09-16 | 212.727 | -38.616 | <1 |
| | 23:44:21 | 01:21:49 | | | |
| TCH | 2019-09-11 | 2019-09-14 | 208.557 | -38.616 | <1 |
| | 23:51:09 | 01:55:45 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 223.201 | -36.323 | <1 |
| | 00:37:06 | 02:13:53 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 227.454 | -30.868 | <1 |
| | 00:43:54 | 02:20:41 | | | |
| TCH | 2019-09-12 | 2019-09-15 | 206.262 | -49.05 | <1 |
| | 00:50:43 | 23:57:21 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 226.017 | -32.686 | <1 |
| | 01:03:06 | 02:40:00 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 223.918 | -38.616 | <1 |
| | 01:09:54 | 02:46:48 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 220.402 | -41.777 | <1 |
| | 01:16:42 | 00:23:11 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 209.252 | -36.323 | <1 |
| | 01:35:48 | 00:42:17 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 215.47 | -41.777 | <1 |
| | 01:42:36 | 00:49:05 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 215.525 | -38.616 | <1 |
| | 02:08:35 | 01:15:01 | | | |
| TCH | 2019-09-12 | 2019-09-16 | 225.94 | -36.323 | <1 |
| | 23:27:18 | 02:33:12 | | | |
| TCH | 2019-09-12 | 2019-09-14 | 224.619 | -30.868 | <1 |
| | 23:53:08 | 23:29:18 | | | |
| TCH | 2019-09-13 | 2019-09-15 | 218.323 | -38.616 | <1 |
| | 00:19:08 | 02:25:31 | | | |
| TCH | 2019-09-13 | 2019-09-15 | 206.988 | -36.323 | <1 |
| | 01:03:49 | 00:40:55 | | | |
| TCH | 2019-09-13 | 2019-09-16 | 211.311 | -32.686 | <1 |
| | 23:28:00 | 01:33:52 | | | |
| TCH | 2019-09-14 | 2019-09-15 | 221.12 | -38.616 | <1 |
| | 23:29:36 | 02:05:32 | | | |
+-------+------------+------------+---------+---------+---------+
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. Each tile is 1.9x1.9 degrees. These
observations cover about 1.1% of the cumulative probability of the skymap.
The typical limiting magnitude is 18.0 for a 60.0 s exposure.
The coverage map is available at:
https://grandma-owncloud.lal.in2p3.fr/index.php/s/fJdB1OS0Fj3Pg3t
No significant transient candidates were found during our
low latency analysis.
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 (https://grandma.lal.in2p3.fr/).
Details on the TCA telescope are available on the GRANDMA web pages
or on http://tarot.obs-hp.fr/.
This circular is citable.
GCN Circular 25778
Subject
LIGO/Virgo S190910h: Updated Sky Localization
Date
2019-09-18T19:25:13Z (6 years ago)
From
Francesca Badaracco at GSSI, Ligo/VIRGO <francesca.badaracco@gssi.it>
The LIGO Scientific Collaboration and the Virgo Collaboration report:
We have conducted further analysis of the LIGO Livingston Observatory
(L1) data around the time of the compact binary merger (CBC) candidate
S190910h (GCN Circular 25707).
Parameter estimation has been performed using LALInference [1] and a new
sky map, LALInference.fits.gz, distributed via GCN Notice, is available
for retrieval from the GraceDB event page:
https://gracedb.ligo.org/superevents/S190910h
For the LALInference.fits.gz sky map, the 90% credible region is 24264
deg2. Marginalized over the whole sky, the a posteriori luminosity
distance estimate is 230 +/- 88 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 25744
Subject
LIGO/Virgo S190910h: WHT spectroscopy of Gaia19ebl, Gaia19eba, Gaia19eaz
Date
2019-09-14T06:01:07Z (6 years ago)
From
Giacomo Cannizzaro at SRON <g.cannizzaro@sron.nl>
I. Pastor-Marazuela (API/ASTRON), G. Cannizzaro (SRON/Radboud Univ), P. Jonker (SRON/Radboud Univ), K. Maguire (TCD), M. Fraser (UCD) and M. Perez Torres (IAC) report on behalf of the GW@WHT collaboration:
We obtained optical spectroscopy of Gaia19ebl/AT2019qba, Gaia19eba/AT2019qam and Gaia19eaz/AT2019qal (GCN 25740), three optical transients within the sky localisation of the gravitational wave trigger S190910h (GCN 25707) with the ACAM instrument mounted on the William Herschel Telescope located at the Roque de Los Muchachos Observatory, La Palma, Spain. We cross-correlate the transient spectra with a library of supernova template spectra using the code SNID (Blondin and Tonry, 2007).
Gaia19ebl: the spectrum is dominated by the host-galaxy light and shows a strong Halpha emission line, from which we derive a redshift of z=0.02, corresponding to a distance of around 97 Mpc. This puts the galaxy outside the distance region (241+-89 Mpc) reported for S20190910h. No match with any template is found.
Gaia19eba: SNID gives a good match with a type Ia supernova at redshift z=0.06 (253 Mpc).
Gaia19eaz: SNID gives a good match with a type Ia supernova at redshift z=0.03 (127 Mpc).
We therefore consider that these three transients are unrelated to the gravitational wave trigger S20190910h.
GCN Circular 25742
Subject
LIGO/Virgo S190910h: No counterpart candidates in Fermi-LAT observations
Date
2019-09-13T16:07:53Z (6 years ago)
From
Magnus Axelsson at Stockholm U. <magaxe@kth.se>
M. Axelsson (KTH and Stockholm Univ.), D. Kocevski (NASA/MSFC), N. Omodei (Stanford Univ.), L. Scotton (University and INFN, Torino), E. Bissaldi (Politecnico and INFN Bari), F. Longo (Univ. and INFN Trieste) and M. Arimoto (Kanazawa Univ.) report on behalf of the Fermi-LAT Collaboration:
We have searched data collected by the Fermi Large Area Telescope (LAT) on Sep 10, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S190910h (GCN 25707).
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 instantaneous coverage of 25% of the LIGO probability region at the time of the trigger (T0 = 2019-09-10 08:29:58.544 UTC), and reached 100% cumulative coverage after ~9 ks.
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. One significant excess (with TS>25) was found at R.A., Dec. = 57.0, -27.9, but it is associated with the known and flaring source PKS 0346-27 (lies within the 90% uncertainty region).
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 7.6E-09 [erg/cm^2/s].
The Fermi-LAT point of contact for this event is Makoto Arimoto (arimoto@se.kanazawa-u.ac.jp<mailto:arimoto@se.kanazawa-u.ac.jp>).
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 25740
Subject
LIGO/Virgo S190910h: Gaia Photometric Alerts transient candidates
Date
2019-09-13T11:46:53Z (6 years ago)
From
Zuzanna Kostrzewa-Rutkowska at SRON <z.p.kostrzewa@sron.nl>
Z. Kostrzewa-Rutkowska (Leiden Observatory), S. Hodgkin, A. Delgado, D.L. Harrison, M. van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), D. Eappachen, P.G. Jonker (SRON/RU) on behalf of Gaia Alerts team report the discovery of transient candidates within the probability skymap of S190910h (The LIGO Scientific Collaboration and the Virgo Collaboration GCN 25707)
---------------------------------------------------------------------------
Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL
---------------------------------------------------------------------------
Gaia19ebl AT2019qba 2019-09-11T15:52:20 234.43626 22.42680 18.96 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19ebl/
Gaia19ebk AT2019qaz 2019-09-11T16:27:37 291.30830 -35.00503 18.76 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19ebk/
Gaia19eba AT2019qam 2019-09-11T07:02:41 52.99630 -26.07598 18.14 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19eba/
Gaia19eaz AT2019qal 2019-09-10T14:52:32 282.64281 -23.91376 18.22 http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19eaz/
Acknowledgements: This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. ZKR acknowledges funding from the Netherlands Research School for Astronomy (NOVA). DE and PGJ acknowledge support from the European Research Council under ERC Consolidator Grant agreement no 647208.
GCN Circular 25735
Subject
LIGO/Virgo S190910h: Upper limits from CALET observations.
Date
2019-09-13T03:38:21Z (6 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, V. Pal'shin,
S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U),
S. Nakahira (RIKEN), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu,
T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
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 S190910h T0 = 2019-09-10 08:29:58.544 UT (The LIGO Scientific
Collaboration and Virgo Collaboration, GCN Circ. 25707).
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 16 % and 50 %, respectively (and 75 % credible region
of the initial localization map was above the horizon). The HXM and
SGM fields of view were centered at RA = 286.6 deg, Dec = 0.3 deg
and RA = 294.8 deg, Dec = -5.4 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 low energy trigger
mode at the trigger time of S190910h. Using the CAL data, we have
searched for gamma-ray events in the 1-10 GeV band from -60 sec
to +60 sec from the GW trigger time and found no candidates
in the overlap region with the LIGO-Virgo high probability localization
region. The 90% upper limit of CAL is 9.4x10^-6 erg/cm^2/s (1-10 GeV)
when the summed LIGO-Virgo probability reaches 10%. The CAL FOV
was centered at RA= 294.8 deg, DEC= -5.5 deg at T0.
GCN Circular 25733
Subject
LIGO/Virgo S190910h: WHT spectroscopy of AT2019pyz/PS19fbi
Date
2019-09-12T11:27:30Z (6 years ago)
From
Kate Maguire at Trinity College Dublin <kate.maguire@tcd.ie>
K. Maguire (TCD), S. Smartt (QUB), P. Jonker (SRON/Radboud Univ.), G. Cannizzaro (SRON/Radboud Univ.), I. Pastor-Marazuela (API/ASTRON), M. Fraser (UCD), A. Levan (Radboud Univ.), M. Perez-Torres (IAC), S. Srivastav (QUB) report on behalf of the GW@WHT collaboration:
We obtained an optical spectrum of AT2019pyz/PS19fbi (TNS Astronote 2019-92) an optical transient within the sky localisation of the gravitational wave trigger S190910h (GCN 25707) with the ACAM instrument mounted on the William Herschel Telescope located at the Roque de Los Muchachos Observatory, La Palma, Spain on 20190912 02:35 UT.
Using the supernova template matching code SNID (Blondin and Tonry, 2007), we find a good match with the Type Iax SN 2005hk at -4 days from peak at the redshift of the host galaxy of 0.038.
We conclude that AT2019pyz is unrelated to the GW event S190910h.
GCN Circular 25732
Subject
LIGO/Virgo S190910h and S190910d: WHT photometry of ZTF candidates
Date
2019-09-12T06:26:28Z (6 years ago)
From
Giacomo Cannizzaro at SRON <g.cannizzaro@sron.nl>
G. Cannizzaro (SRON/Radboud Univ), I. Pastor-Marazuela (API/ASTRON), P. Jonker (SRON/Radboud Univ), K. Maguire (TCD), M. Fraser (UCD), S. Brennan (UCD) and M Perez Torres (IAC) report on behalf of the GW@WHT collaboration:
We performed optical photometry on the optical transients reported by the Zwicky Transient Facility (GCN 25722 and 25727) localised within the sky error region of the gravitational wave trigger S190910h (GCN 25707) with the ACAM instrument mounted on the William Herschel Telescope located at the Roque de Los Muchachos Observatory, La Palma, Spain.
We obtained the following magnitudes:
Name rMag rMagErr gMag gMagErr
-------------------------------------------------------
ZTF19abyheza 18.78 0.04 19.68 0.06
ZTF19abyiwiw 24.1 (L)
ZTF19abyhhml 19.57 0.04
ZTF19abygvmp 18.81 0.05 19.045 0.06
ZTF19abymhyi 24.1 (L) 24.3 (L)
ZTF19abyjcom 22.8 (L)
ZTF19abyjcoo 21.4 (L) 22.5 (L)
ZTF19abyjfiw 21.33 0.07 21.40 0.09
The photometry was obtained without performing image subtraction. With (L) we indicate 3-sigma limiting magnitudes. We note that ZTF19abyheza and ZTF19abyiwiw are within the sky localisation of gravitational wave trigger S190910d (GCN 25695).
GCN Circular 25731
Subject
LIGO/Virgo S190910h: AT2019pxi, AT2019pxj and AT2019pxn 10.4m GTC spectroscopy
Date
2019-09-12T04:21:13Z (6 years ago)
From
Alberto J. Castro-Tirado at IAA-CSIC <ajct@iaa.es>
A. F. Valeev (SAO-RAS), Y.-D. Hu, A. J. Castro-Tirado and E.
Fernandez-Garcia (IAA-CSIC), V. Sokolov (SAO-RAS), I. Carrasco and A.
Castellon (UMA) and R. Scarpa (GRANTECAN, IAC, ULL), on behalf of a
larger collaboration, report:
Following the detection of AT2019pxi/ZTF19abyheza,
AT2019pxj/ZTF19abyhhml and AT2019pxn/ZTF19abyjfiw (Stein et al., GCN
25727) within the error area of the GW event S190910h (LVC, GCNC 25707),
we obtained imaging and optical spectra covering the range 3700-7500 A
with the 10.4m GTC telescope equipped with OSIRIS in La Palma (Spain)
starting on Sep 11, 22:30 UT.
For AT2019pxi/ZTF19abyheza a magnitude r = 18.74+/-0.05 on Sep 11, 22:34
UT is derived, significantly brighter than the one given in the
PanSTARRS DR2 catalog (r = 22.26+/-0.01). The spectrum shows H-alpha in
emission and H-beta in absorption, at redshift z = 0.
For AT2019pxj/ZTF19abyhhml a magnitude r = 19.26+/-0.04 on Sep 11, 22:52
UT is derived, compared to r = 20.67 +/- 0.01 (PanSTARRS DR2). The
spectrum shows emissions lines of He II 4686, several He I and a
double-peaked component H-alpha line, consistent with the cataclismic
variable in our Galaxy.
For AT2019pxn/ZTF19abyjfiw a magnitude r = 21.36+/-0.07 on Sep 12, 00:32
UT is derived. The spectrum shows a featureless blue continuum.
Therefore we consider that two of the reported optical transients
(AT2019pxi and AT2019pxj) lie in the Milky Way and therefore are
unrelated to the GW event S190910h. No conclusion can be given for
AT2019pxn.
GCN Circular 25730
Subject
LIGO/Virgo S190910h: WHT spectroscopy of ZTF19abygvmp/AT2019pzg
Date
2019-09-12T02:05:38Z (6 years ago)
From
Giacomo Cannizzaro at SRON <g.cannizzaro@sron.nl>
p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica}
p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica; min-height: 14.0px}
G. Cannizzaro (SRON/Radboud Univ), I. Pastor-Marazuela (API/ASTRON), P. Jonker (SRON/Radboud Univ), K. Maguire (TCD), M. Fraser (UCD) report on behalf of the GW@WHT collaboration:
We obtained optical spectroscopy of ZTF19abygvmp/AT2019pzg (GCN 25727) an optical transient within the sky localisation of the gravitational wave trigger S190910h (GCN 25707) with the ACAM instrument mounted on the William Herschel Telescope located at the Roque de Los Muchachos Observatory, La Palma, Spain.
The spectrum is dominated by the host galaxy light and shows a strong emission line compatible with Halpha at redshift z=0.049 (219 Mpc), confirming its location spectroscopically within the most up-to-date distance range based on the GW signal of S190910h of 241 +- 89 Mpc.
GCN Circular 25727
Subject
LIGO/Virgo S190910h: Four additional candidates from the Zwicky Transient Facility
Date
2019-09-11T16:11:01Z (6 years ago)
From
Robert Stein at DESY <robert.stein@desy.de>
Robert Stein (DESY), Igor Andreoni (Caltech), Michael Coughlin (Caltech), Harsh Kumar (IITB), Varun Bhalerao (IITB), Shreya Anand (Caltech), Maitreya Khandagale (IITB), Kunal Deshmukh (IITB), Pradip Gatkine (UMD), Viraj Karambelkar (Caltech), Yashvi Sharma (Caltech), Mansi Kasliwal (Caltech), Tomas Ahumada (UMD), Leo P. Singer (NASA GSFC), Eric Bellm (UW):
On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations:
We have continued serendipitous observations of the localization region of the gravitational wave trigger S190910h (LVC et al. GCN 25707) with the Palomar 48-inch telescope equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). These observations began at UT 2019-09-04 10:18 UT (GCN 25722). Each exposure was 30s, with a typical median depth of 20.6 mag. Since merger, we now have covered 40.4% of the enclosed probability at least twice. This estimate does not account for chip gaps.
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. We rejected stellar sources (Tachibana and Miller 2018) and moving objects, applied machine learning algorithms (Mahabal et al. 2019), and removed candidates with history of variability prior to the merger time. Four additional candidates were found by our pipeline, lying within the 95% probability region.
+------------------------------------------------------------------------------+
| ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr |
+------------------------------------------------------------------------------+
| ZTF19abygvmp | AT2019pzg | 28.9759767 | +41.0910268| g | 19.97 | 0.21 |
| ZTF19abyiwiw | AT2019pzi | 340.5214408| +55.2202438| g | 20.03 | 0.20 |
| ZTF19abylleu | AT2019pyu | 355.3382246| -23.4507064| g | 18.80 | 0.18 |
| ZTF19abymhyi | AT2019pzh | 340.8557195| +34.1863443| g | 20.47 | 0.21 |
+------------------------------------------------------------------------------+
ZTF19abygvmp was first detected approximately 1 hour after merger, and has now been detected a second time, with a small offset from its host. Since the last non-detection, it has risen at least 0.5 mag in g. ZTF19abyiwiw was also first detected approximately 1 hour after merger. We note that ZTF19abyiwiw object is additionally spatially and temporally coincident with the updated localisation of gravitational wave trigger S190910d (LVC et al. GCN 25695, GCN 25723), and is thus a potential counterpart to that event too. ZTF19abylleu, already reported to the TNS as AT2019pyu, is a bright transient that was not detected to a depth of 20.4 mag in observations 4 days ago. It was first detected approximately 23 hours after merger. ZTF19abymhyi is faint, apparently hostless, and was first detected approximately 2 hours after merger.
We encourage spectroscopic and photometric observations to discern the nature of these candidates.
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 25722
Subject
LIGO/Virgo S190910h: Candidates from the Zwicky Transient Facility
Date
2019-09-10T23:58:06Z (6 years ago)
From
Robert Stein at DESY <robert.stein@desy.de>
Robert Stein (DESY), Michael Coughlin (Caltech), Harsh Kumar (IITB), Varun Bhalerao (IITB), Shreya Anand (Caltech), Igor Andreoni (Caltech), Maitreya Khandagale (IITB), Kunal Deshmukh (IITB), Pradip Gatkine (UMD), Viraj Karambelkar (Caltech), Yashvi Sharma (Caltech), Mansi Kasliwal (Caltech), Tomas Ahumada (UMD), Leo P. Singer (NASA GSFC), Eric Bellm (UW):
On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations:
We serendipitously observed the localization region of the gravitational wave trigger S190910h (LVC et al. GCN 25707) with the Palomar 48-inch telescope equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). These observations began in the g-band and r-band beginning at UT 2019-09-04 10:18 UT. Each exposure was 30s, with a typical median depth of 20.6 mag. Since merger, we have covered 28.2% of the enclosed probability at least twice. This estimate does not account for chip gaps.
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. We rejected stellar sources (Tachibana and Miller 2018) and moving objects, applied machine learning algorithms (Mahabal et al. 2019), and removed candidates with history of variability prior to the merger time. Seven candidates were found by our pipeline, lying within the 95% probability region.
------------------------------------------------------------------------
ZTF Name | RA (deg) | DEC (deg) | Filter | Mag | Magerr
------------------------------------------------------------------------
ZTF19abyheza | 332.91339 | +60.39576 | g | 19.92 | 0.18
ZTF19abyhhml | 339.69149 | +55.93658 | g | 19.92 | 0.21
ZTF19abyirjl | 30.471176 | +30.733550 | r | 20.10 | 0.15
ZTF19abyjcom | 32.936353 | +12.033344 | g | 20.47 | 0.21
ZTF19abyjcon | 33.252469 | +12.472604 | g | 20.37 | 0.21
ZTF19abyjcoo | 33.089712 | +12.297698 | g | 20.43 | 0.21
ZTF19abyjfiw | 39.186807 | +34.647299 | r | 20.34 | 0.19
------------------------------------------------------------------------
Based on machine learning using PanStarrs photometry to flag sources with stellar counterparts, we find that ZTF19abyheza is likely non-stellar, while ZTF19abyhhml is ambiguous. We note that both of these objects are additionally spatially and temporally coincident with gravitational wave trigger S190910d (LVC et al. GCN 25695), and are thus potential counterparts to that event too.
ZTF19abyirjl, reported to the TNS as AT2019pxe, is a transient with estimated host redshift of 0.1 +/- 0.017, consistent with the reported merger event. ZTF19abyjcom, ZTF19abyjcon, ZTF19abyjcoo and ZTF19abyjfiw are all hostless. We caution that ZTF19abyjcom, ZTF19abyjcon, and ZTF19abyjcoo are all from the same exposure, though see no other reason to rule them out as candidates.
We encourage spectroscopic and photometric observations to discern the nature of these candidates.
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 25718
Subject
LIGO/Virgo S190910h: no counterpart candidates in the Swift/BAT observations
Date
2019-09-10T16:23:00Z (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), 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 S190910h (LIGO/VIRGO Collaboration GCN Circ. 25707),
where T0 is the LVC trigger time (2019-09-10T08:29:58.544 UTC).
The center of the BAT field of view (FOV) at T0 is
RA = 272.039 deg,
DEC = 13.253 deg,
and the roll angle is 278.260 deg.
The BAT FOV (>10% partial coding) covers 9.60% of the integrated
LVC localization probability, and 7.16% 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 an on-axis (100% coded) short GRB with a typical
spectrum in the BAT energy range (i.e., a simple power-law model with a
power-law index of -1.32, Lien & Sakamoto et al. 2016), the 5-sigma upper
limit in the 1-s binned light curve corresponds to a flux upper
limit (15-350 keV) of ~ 7.77 x 10^-8 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 ~ 81.51 Mpc.
No event data are available within T0 +/- 100 s.
BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 52.67% 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/S190910h/web/source_public.html
GCN Circular 25715
Subject
LIGO/Virgo S190910h: No counterpart candidates in HAWC observations
Date
2019-09-10T12:50:00Z (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 S190910h (GCN #25707). At the time of the trigger the HAWC
local zenith was oriented towards (RA, Dec) = (19.0 deg, 18.9 deg).
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 1.2e-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 25714
Subject
LIGO/Virgo S190910h: Upper limits from Fermi-GBM Observations
Date
2019-09-10T12:40:57Z (6 years ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
C. Fletcher (USRA) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group
For S190910h and using the initial bayestar skymap, Fermi-GBM was observing 59.9% 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 S190910h (GCN 25707). 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=357.1, Dec=16.0 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 norm hard
--------------------------------------
0.128 s: 3.3 5.7 12
1.024 s: 0.99 1.5 3.2
8.192 s: 0.32 0.53 0.93
Assuming the median luminosity distance of 242 Mpc from the GW detection, we estimate the following intrinsic luminosity upper limits over the 1 keV-10 MeV energy range (in units of 10^48 erg/s):
Timescale Soft Normal Hard
------------------------------------
0.128 s: 3.5 5.7 19.7
1.024 s: 1.1 1.5 5.2
8.192 s: 0.34 0.53 1.5
GCN Circular 25713
Subject
LIGO/Virgo S190910h: No counterpart candidates in AGILE-MCAL observations
Date
2019-09-10T12:37:27Z (6 years ago)
From
Giovanni Piano at INAF-IAPS <giovanni.piano@inaf.it>
G. Piano, C. Casentini (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M.
Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, A. Ursi
(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 S190910h at T0 = 2019-09-10 08:29:58
(UT), a preliminary analysis of the AGILE minicalorimeter (MCAL) triggered
data found no event candidates within a time interval covering -/+ 15 sec
from the LIGO/Virgo T0.
At the T0, about 60% of the S190910h 90 c.l. localization region 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 S190910h localization region, from a minimum of 1.33E-06 erg
cm^-2 to a maximum of 7.35E-06 erg cm^-2 (assuming as spectral model a
single power law with photon index 1.5).
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 25712
Subject
LIGO/Virgo S190910h Global MASTER-Net observations report
Date
2019-09-10T11:37:19Z (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 S190910h errorbox 9379 sec after trigger time at 2019-09-10 11:06:17 UT, with upper limit up to 18.5 mag. Observations started at twilight. The observations began at zenit distance = 58 deg. The sun altitude is -11.4 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=10792
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
9469 | 2019-09-10 11:06:17 | MASTER-Amur | (00h 35m 19.061s , +39d 43m 52.06s) | C | 180 | 18.3 |
9681 | 2019-09-10 11:09:48 | MASTER-Amur | (00h 58m 02.961s , +41d 43m 35.15s) | C | 180 | 18.3 |
9893 | 2019-09-10 11:13:21 | MASTER-Amur | (01h 22m 21.252s , +43d 43m 36.45s) | C | 180 | 18.4 |
10105 | 2019-09-10 11:16:52 | MASTER-Amur | (00h 35m 19.334s , +39d 43m 46.44s) | C | 180 | 18.5 |
10315 | 2019-09-10 11:20:22 | MASTER-Amur | (00h 45m 45.264s , +39d 43m 37.68s) | C | 180 | 18.5 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 25711
Subject
LIGO/Virgo S190910h : no neutrino counterpart candidate in ANTARES search
Date
2019-09-10T11:25:51Z (6 years ago)
From
Thierry Pradier at ANTARES/IPHC/U of Strasbourg <tpradier@km3net.de>
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 S190910h event using the 90% contour of the Initial bayestar probability
map provided by the GW interferometers (GCN#25707 <https://gcn.gsfc.nasa.gov/gcn3/25707.gcn3>). 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/S190910h_Initial.png <http://antares.in2p3.fr/GW/S190910h_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 2019-09-10 08:29:58 and in the 90% contour of the S190910h
event. The expected number of atmospheric background events in the region visible by ANTARES is
5.82e-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 4.19e-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 25710
Subject
LIGO/Virgo S190910h: Coverage and upper limits from MAXI/GSC observations
Date
2019-09-10T11:10:34Z (6 years ago)
From
Motoko Serino at RIKEN/MAXI <motoko@crab.riken.jp>
S. Sugita, M. Serino (AGU), H. Negoro (Nihon U.),
N. Kawai, M. Sugizaki (Tokyo Tech),
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)
report on behalf of the MAXI team:
We examined MAXI/GSC all-sky X-ray images (2-20 keV)
after the LVC trigger S190910h at 2019-09-10 08:29:58.544 UTC (GCN 25707).
At the trigger time of S190910h, 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 80%
of the 90% credible region of the bayestar skymap from 08:29:58 to 10:01:57 UTC (T0+0 to T0+5519 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 25709
Subject
LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
Date
2019-09-10T09:47:10Z (6 years ago)
From
Alexis Coleiro at APC/U. Paris Diderot <coleiro@apc.in2p3.fr>
A. Coleiro (APC, France),
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
J. Rodi (IAPS-Roma, Italy)
S. Mereghetti (INAF IASF-Milano, Italy)
on behalf of the INTEGRAL multi-messenger collaboration:
https://www.astro.unige.ch/cdci/integral-multimessenger-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 S190910h (GCN 25707).
At the time of the event (2019-09-10 08:29:58 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 129 deg with respect to
the spacecraft pointing axis. This orientation implies strongly
suppressed (4% of optimal) response of ISGRI, somewhat suppressed (57%
of optimal) response of IBIS/Veto, and strongly suppressed (30% o f
optimal) response of SPI-ACS.
The background within +/-300 seconds around the event was very stable
(excess variance 1.1).
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 3.1e-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 ~2.8e-07 (5.2e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.
For the mean reported distance 241.0 Mpc this corresponds to the limit
on the total isotropic equivalent energy in 1 s of 2.2e+48 erg for
the short GRB spectrum and for a long GRB spectrum isotropic
equivalent luminosity in 1 s (8 s) of 1.2e+48 erg/s (3.7e+47 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
0.3 | 1.48 | 3.1 | 7.71 +/- 3.62 +/- 7.58 | 0.082
1.95 | -27.4 | 3.5 | 3.25 +/- 1.41 +/- 3.19 | 0.105
0.95 | 107 | 3.6 | 4.79 +/- 2.03 +/- 4.71 | 0.69
1.5 | -85.7 | 3.2 | 3.24 +/- 1.61 +/- 3.18 | 0.773
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. In addition we note that the most likely excess in the search region, despite
high FAP, occurred at the time delay previously found in BNS GRB association.
The FAP is computed with respect to the GW T0 and not to the likely GRB offset (1.7s).
Using GW T0 + 1.7s as the reference for the FAP would slightly improve the
association significance, but not enough to claim significant association.
Furthermore changing the reference for FAP would not be compliant with the
predefined procedure.
All results quoted are preliminary.
This circular is an official product of the IN TEGRAL Multi-Messenger
team.
[1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A
541A, 122S
GCN Circular 25708
Subject
LIGO/Virgo S190910h: Upper limits from IceCube neutrino searches
Date
2019-09-10T09:44:09Z (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
S190910h
in a time range of 1000 seconds [3] centered on the alert event time
(2019-09-10 08:21:38.544 UTC to 2019-09-10 08:38:18.544 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 S190910h calculated from the map
circulated in the 1-Preliminary 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 S190910h 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 25707
Subject
LIGO/Virgo S190910h: Identification of a GW compact binary merger candidate
Date
2019-09-10T09:23:20Z (6 years ago)
From
Francesca Badaracco at GSSI, Ligo/VIRGO <francesca.badaracco@gssi.it>
The LIGO Scientific Collaboration and the Virgo Collaboration report:
We identified the compact binary merger candidate S190910h during
real-time processing of data from LIGO Livingston Observatory (L1) at
2019-09-10 08:29:58.544 UTC (GPS time: 1252139416.544). The candidate
was found by the GstLAL [1] analysis pipeline.
S190910h is an event of interest because its false alarm rate, as
estimated by the online analysis, is 3.6e-08 Hz, or about one in 10
months. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S190910h
The classification of the GW signal, in order of descending
probability, is BNS (61%), Terrestrial (39%), BBH (<1%), MassGap
(<1%), or NSBH (<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 for matter outside the final compact object
(HasRemnant: >99%).
One sky map is available at this time and can be retrieved from the
GraceDB event page:
* bayestar.fits.gz, an updated localization generated by BAYESTAR
[2], distributed via GCN notice about 6 minutes after the candidate
For the bayestar.fits.gz sky map, the 90% credible region is 24226
deg2. Marginalized over the whole sky, the a posteriori luminosity
distance estimate is 241 +/- 89 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] Singer & Price PRD 93, 024013 (2016)