LIGO/Virgo S190718y
GCN Circular 25229
Subject
LIGO/Virgo S190718y: AstroSat CZTI upper limits
Date
2019-07-31T06:50:57Z (6 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
A. Anumarlapudi (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 S190718y (UTC 2019-07-18 14:35:12.000, GraceDB event). 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 merger, Astrosat's nominal pointing is (RA=16: 0:59.8 (240.249), DEC=31: 9:42.8 (31.162)), which is 56.49 deg away from the maximum probability location. At the time of merger event, the Earth-satellite-transient angle corresponding to maximum probability location is ~ 38.26 deg and hence is occulted by Earth in satellite's frame. In a time interval of 100 sec around the event, 57.81 % of sky locations in the 90% probability region for the event is visible in the satellite's frame and the rest of 42.19 % is occulted by earth.
CZTI data were de-trended to remove orbit-wise background variation. We then searched data from three of 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 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 convert our count rates into flux by assuming that the source spectrum is a power law with alpha = -1.0. We use a detailed mass model of the satellite to calculate the instrument response for every htm grid point that fall in 90% LIGO localization region and calculate flux limit in that direction. We get the following upper limits for source flux in the 20-200 keV band by taking a probability weighted mean of flux limit and are reported here :
0.1 s: flux limit= 4.71e-06 ergs/cm^2/s
1.0 s: flux limit= 1.48e-05 ergs/cm^2/s
10.0 s: flux limit= 1.72e-05 ergs/cm^2/s
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 25153
Subject
LIGO/Virgo S190718y: Classification of AT 2019lqm / Gaia19dcs as a Type Ia Supernova
Date
2019-07-26T07:19:57Z (6 years ago)
From
Peter Jonker at SRON/RU <p.jonker@sron.nl>
Kate Maguire (TCD), Mark Magee (TCD), Manuel Torres (IAC), Peter Jonker (SRON/Radboud
University), Morgan Fraser (UCD) report on behalf of the GW@WHT collaboration:
We obtained an optical spectrum of the transient AT2019lqm / Gaia19dcs
(discovered by Gaia within the probability map of S190718y; LIGO/Virgo
Collaboration GCN 25087, Kostrzewa-Rutkowska et al. GCN 25145) on 2019 July 25, 04:18
UT using the ACAM instrument mounted on the William Herschel Telescope located on the
Roque de Los Muchachos Observatory, La Palma, Spain. The exposure time was 1500 seconds.
Using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) we find a good fit to normal
Type Ia supernovae at a redshift of z=0.066, about 1 week after peak.
GCN Circular 25152
Subject
LIGO/Virgo S190718y: Classification of AT 2019lqn / Gaia19dct as a Type Ia Supernova
Date
2019-07-25T17:14:27Z (6 years ago)
From
Iair Arcavi at Tel Aviv University <arcavi@tauex.tau.ac.il>
Iair Arcavi (Tel Aviv University), Daichi Hiramatsu (Las Cumbres / UCSB), D. Andrew Howell (Las Cumbres / UCSB), Curtis McCully (Las Cumbres), Jamison Burke (Las Cumbres / UCSB), Craig Pellegrino (Las Cumbres / UCSB), on behalf of the Las Cumbres GW Follow-up Collaboration
We obtained an optical spectrum of the transient AT 2019lqn / Gaia19dct (discovered by Gaia within the probability map of S190718y; LIGO/Virgo Collaboration GCN 25087, Kostrzewa-Rutkowska et al. GCN 25145) on 2019 July 24.8 UT with the robotic FLOYDS instrument mounted on the Las Cumbres Observatory 2-meter telescope in Siding Spring, Australia.
Using Superfit (Howell et al. 2005, ApJ, 634, 1190) and SNID (Blondin & Tonry 2007, ApJ, 666, 1024) we find good fits to normal Type Ia supernovae at a redshift of z=0.076, and a phase of 9 days after peak. The spectrum is available on the <a href="http://wis-tns.weizmann.ac.il/object/2019lqn">Transient Name Server</a>.
GCN Circular 25151
Subject
LIGO/Virgo S190718y: Swift XRT observations, 45 X-ray sources
Date
2019-07-25T13:36:34Z (6 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
P.A. Evans (U. Leicester), J.A. Kennea (PSU), N.J. Klingler (PSU), A.
Tohuvavohu (PSU), S.D. Barthelmy (NASA/GSFC), A.P. Beardmore (U.
Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL), D.N.
Burrows (PSU), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC), G.
Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB),
V. D'Elia(ASDC), S.W.K. Emery (UCL-MSSL), P. Giommi (ASI), C. Gronwall
(PSU), D. Hartmann (U. Clemson), H.A. Krimm (CRESST/GSFC/USRA), N.P.M.
Kuin (UCL-MSSL), A.Y. Lien (GSFC/UMBC), F.E. Marshall (NASA/GSFC), A.
Melandri (INAF-OAB), J.A. Nousek (PSU), S.R. Oates (U. Warwick), P.T.
O'Brien (U. Leicester), J.P. Osborne (U. Leicester), C. Pagani (U.
Leicester), K.L. Page (U.Leicester), D.M. Palmer (LANL), M. Perri
(ASDC), J.L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M.H.
Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift team:
Swift has carried out 462 observations of the LVC error region for the
GW trigger S190718y convolved with the 2MPZ catalogue (Bilicki et al.
2014, ApJS, 210, 9), using the 'bayestar' GW localisation map. As this
is a 3D skymap, galaxy distances were taken into account in selecting
which ones to observe. The observations currently span from 13 ks to
365 ks after the LVC trigger, and the XRT has covered 30.9 sq degrees
on the sky (corrected for overlaps). This covers 17% of the probability
in the 'bayestar' skymap, and 22% after convolving with the 2MPZ galaxy
catalogue, as described by Evans et al. (2016, MNRAS, 462, 1591).
We have detected 45 X-ray sources. Each source is assigned a rank of
1-4 which describes how likely it is to be related to the GW trigger,
with 1 being the most likely and 4 being the least likely. The ranks
are described at https://www.swift.ac.uk/ranks.php.
We have found:
* 0 sources of rank 1
* 0 sources of rank 2
* 27 sources of rank 3
* 18 sources of rank 4
For all flux conversions and comparisons with catalogues and upper
limits from other missions, we assumed a power-law spectrum with
NH=3x10^20 cm^-2, and photon index (Gamma)=1.7
The results of the XRT automated analysis are online at
https://www.swift.ac.uk/LVC/S190718y
This circular is an official product of the Swift XRT team.
GCN Circular 25145
Subject
LIGO/Virgo S190718y: Gaia Photometric Alerts transient candidates
Date
2019-07-24T12:08:47Z (6 years ago)
From
Deepak Eappachen at SRON Netherlands <d.eappachen@sron.nl>
Z. Kostrzewa-Rutkowska, D. Eappachen (SRON/RU), S. Hodgkin, A. Delgado,
D.L. Harrison, M.van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), P.G. Jonker
(SRON/RU) on behalf of Gaia Alerts team report the discovery of a transient
candidates within the probability skymap of S190718y (LIGO/VIRGO
Collaboration GCN 25087):
---------------------------------------------------------------------------
Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL
----------------------------------------------------------------------------
Gaia19dbi AT2019lmu 2019-07-19T00:25:08 171.84914 -9.65161 17.52
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dbi/
Gaia19dcs AT2019lqm 2019-07-20T21:35:41 347.69159 9.81984. 18.78
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dcs/
Gaia19dct AT2019lqn 2019-07-20T12:06:12 348.79552 -33.33181 18.76
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dct/
---------------------------------------------------------------------------
Notes: Gaia19dbi - candidate SN near galaxy SDSS J112723.74-093904.1
Gaia19dcs - SN candidate near faint SDSS galaxy
Gaia19dct - blue transient 10 arcsec from galaxy 2MASX J23151011-3319533
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, DE, and PGJ
acknowledge support from the European Research Council under ERC
Consolidator Grant agreement no 647208.
GCN Circular 25117
Subject
LIGO/Virgo S190718y: No counterpart candidates in CNEOST
Date
2019-07-20T05:11:09Z (6 years ago)
From
Bin Li at PMO <binli@pmo.ac.cn>
Bin Li, Hai-bin Zhao (PMO),Dong Xu, Zi-pei Zhu, Bang-Yao Yu,Tian-meng Zhang, Xu Zhou,Chen-zhou Cui, Hui-juan Wang(NAOC), Xue-feng Wu, Zhi-ping Jin, Tian-rui Sun, Hao Lu, Ge-tu Zhaori, Ren-quan Hong, Long-fei Hu (PMO), Xiao-feng Wang, Wen-xiong Li (THU),Li-fan Wang (PMO/TAMU), Jin-zhong Liu (XAO), Ji-rong Mao, Jin-ming Bai (YNAO), report on behalf of the CNEOST collaboration.
We conducted optical imaging observations for gravitational wave alert with Chinese Near Earth Object Survey Telescope (CNEOST) at Xuyi astronomical station in Jiangsu Province, China (32.75N, 118.47E). The information of observations and preliminary results are listed below.
Alert: LIGO/Virgo S190718y (GCN 25087)
StartTime (UT): 2019-07-19T12:41:19.523
EndTime (UT): 2019-07-19T18:19:52.108
Skycover (Square Degree): 639.0
Telescope FoV (Square Degree):9.0
#id CentRA(D) CentDEC(D) LimiteMag3_sig 5_sig 10_sig Filter
1 208.869080 -6.786121 20.178 19.181 18.177 SR
2 207.332977 -1.223906 20.265 19.261 18.376 SR
3 210.666458 -4.041420 20.254 19.265 18.329 SR
4 216.043030 -9.596825 20.185 19.217 18.256 SR
5 217.903732 -15.211738 19.997 18.994 17.997 SR
6 215.287582 -12.401288 19.966 19.002 18.058 SR
7 210.364441 -9.628950 20.049 19.056 18.076 SR
8 207.832382 -4.038251 20.262 19.259 18.324 SR
9 210.156891 -1.234565 20.318 19.323 18.407 SR
10 211.684143 -6.830252 20.100 19.149 18.213 SR
11 220.779205 -15.240459 19.922 18.975 18.015 SR
12 208.869080 -6.786121 20.178 19.181 18.177 SR
13 210.156891 -1.234565 20.318 19.323 18.407 SR
14 211.684143 -6.830252 20.100 19.149 18.213 SR
15 216.043030 -9.596825 20.185 19.217 18.256 SR
16 220.779205 -15.240459 19.922 18.975 18.015 SR
17 215.287582 -12.401288 19.966 19.002 18.058 SR
18 306.185486 23.842829 19.291 18.356 17.303 SR
19 305.508270 29.443697 19.330 18.419 17.469 SR
20 307.824493 35.063766 19.557 18.656 17.621 SR
21 312.000488 37.857952 19.497 18.596 17.475 SR
22 314.533600 32.205532 19.391 18.475 17.317 SR
23 308.675293 29.416243 19.335 18.435 17.488 SR
24 305.508270 29.443697 19.330 18.419 17.469 SR
25 307.824493 35.063766 19.557 18.656 17.621 SR
26 312.000488 37.857952 19.497 18.596 17.475 SR
27 314.533600 32.205532 19.391 18.475 17.317 SR
28 307.880554 32.229843 19.462 18.527 17.523 SR
29 307.028320 26.640734 19.367 18.468 17.454 SR
30 304.380890 35.047928 19.489 18.588 17.431 SR
31 309.932098 40.646816 19.639 18.729 17.591 SR
32 311.208282 35.018509 19.474 18.566 17.400 SR
33 314.533600 32.205532 19.391 18.475 17.317 SR
34 307.880554 32.229843 19.462 18.527 17.523 SR
35 308.223480 1.420728 18.660 17.754 16.915 SR
36 309.839081 9.804000 18.793 17.888 16.974 SR
37 312.659424 9.800121 18.743 17.836 16.908 SR
38 309.607025 18.222225 18.980 18.071 17.074 SR
39 306.655151 18.243509 19.021 18.088 17.056 SR
40 312.075226 21.049301 19.014 18.083 17.079 SR
41 318.466370 18.222324 18.949 18.017 16.982 SR
42 313.774658 15.433895 19.007 18.055 17.062 SR
43 322.525757 15.434681 18.984 18.004 16.987 SR
44 315.705475 12.637063 18.935 18.010 17.033 SR
45 321.214417 9.811152 18.731 17.783 16.832 SR
46 316.081055 7.014183 18.795 17.842 16.921 SR
47 311.754395 4.228014 18.686 17.775 16.887 SR
48 313.776703 -1.401701 18.251 17.366 16.533 SR
49 308.223480 1.420728 18.660 17.754 16.915 SR
50 309.839081 9.804000 18.793 17.888 16.974 SR
51 310.891296 15.423524 18.974 18.075 17.106 SR
52 306.073547 21.013973 19.140 18.213 17.172 SR
53 315.045715 21.008123 18.907 17.995 17.038 SR
54 315.521973 18.200771 18.994 18.056 17.059 SR
55 316.691681 15.434895 18.960 18.034 17.055 SR
56 322.525757 15.434681 18.984 18.004 16.987 SR
57 318.607544 12.637962 18.854 17.920 16.948 SR
58 318.352875 9.810987 18.740 17.819 16.888 SR
59 318.875336 7.004980 18.767 17.841 16.919 SR
60 314.550995 4.224255 18.699 17.756 16.866 SR
61 313.830048 1.406936 18.628 17.684 16.804 SR
62 308.185730 -1.344688 18.493 17.572 16.766 SR
63 310.401428 7.007415 18.797 17.879 16.966 SR
64 312.835144 12.623907 18.896 17.977 17.014 SR
65 309.607025 18.222225 18.980 18.071 17.074 SR
66 306.073547 21.013973 19.140 18.213 17.172 SR
67 318.466370 18.222324 18.949 18.017 16.982 SR
68 313.774658 15.433895 19.007 18.055 17.062 SR
69 319.574982 15.416553 18.978 18.053 17.063 SR
70 321.712860 7.031455 18.669 17.751 16.811 SR
71 325.777649 26.589394 15.121 14.167 13.528 SR
Detailed data analysis is still in progress and any interesting transients will be reported later.
The new resulte will available at http://www.cneost.org/opem/list.php?gdate=2019-07-19 <http://www.cneost.org/opem/list.php?gdate=2019-07-19>
We aslo detect the source ��� MASTER OT J203053.79+384020.1 / AT2019lly (Lipunov et al., GCN #25105) in our survey, which are labeled OPEM-19vs ( http://www.cneost.org/opem/findname.php?opemname=OPEM-19vs <http://www.cneost.org/opem/findname.php?opemname=OPEM-19vs> ). And, a point source (r=16.32 +- 0.04 ,observed 2017-11-03) is present in the archive catalog of CNEOST at the location of AT2019lly.
GCN Circular 25109
Subject
LIGO/Virgo S190718y: No counterpart candidates in KAIT observations
Date
2019-07-19T22:22:54Z (6 years ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
Nachiket Girish, Sergiy Vasylyev, Keto Zhang, WeiKang Zheng,
Andrew Hoffman, Benjamin Stahl, and Alexei V. Filippenko (UC Berkeley)
report on behalf of the Lick/KAIT GW follow-up team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, observed the 90% region of the gravitational-wavei
event S190718y (GCN 25087; GCN 25107) detected by LIGO/Virgo. More
than one thousand galaxies were selected from the Glade catalog V1.0
(Dalya et al., 2018, MNRAS, 479, 2374; http://aquarius.elte.hu/glade/)
according to their priority score. KAIT observed 209 of them based on
their priority scores and elevation visibility, with each clear-filter
exposure time being 60 s. The first image was taken at 04:56:24, July
19th UT, about 14.4 hours after the trigger, and the last image at
11:34:24 UT. Our typical limiting mag is 19.0. No viable counterparts
were identified and the analysis is ongoing. A full list of galaxies
observed by KAIT is given below.
GladeID UT(July19) RA_J2000 Dec_J2000
-----------------------------------------------
G0623381 04:56:24 19:20:57.4073 +43:07:57.2052
G0655708 04:57:39 19:36:18.7061 +37:48:07.0164
G1132664 04:58:57 20:11:08.335 +45:15:15.8904
G0172766 05:00:14 20:15:02.6366 +31:40:50.8296
G0419718 05:01:32 20:16:30.2345 +44:21:15.2244
G0673986 05:02:51 20:16:34.5043 +26:58:34.4244
G1298003 05:04:11 20:17:45.769 +45:50:47.634
G0287573 05:05:30 20:19:38.1226 +27:00:10.9368
G0998960 05:06:52 20:19:51.2474 +48:16:20.5572
G1457918 05:08:15 20:20:02.3364 +25:08:48.0444
G1243102 05:09:25 20:21:42.3341 +26:55:00.642
G0289368 05:10:46 20:24:08.1226 +46:28:07.7484
G0002313 05:12:08 20:24:20.2296 +27:03:49.9032
G0418118 05:13:27 20:24:50.8008 +43:02:35.0304
G0639498 05:14:46 20:28:28.8427 +25:43:24.1932
G0563453 05:15:55 20:28:35.0611 +25:44:00.1788
G0041653 05:17:15 20:28:44.9779 +45:41:01.1724
G0721807 05:18:37 20:29:05.9693 +24:42:22.5576
G0428552 05:19:50 20:29:39.463 +32:37:34.4892
G0312245 05:20:59 20:30:29.1065 +33:36:02.8224
G0645883 05:22:11 20:30:29.5531 +27:40:42.906
G0414637 05:23:22 20:30:43.7182 +33:00:07.9092
G1207128 05:24:33 20:37:17.7101 +25:31:37.7652
G1439906 05:25:45 20:38:34.4604 +34:03:23.3172
G0452646 05:26:56 20:38:46.6332 +28:18:13.9572
G1405973 05:28:06 20:39:22.0385 +27:42:40.7952
G1467496 05:29:15 20:39:22.8662 +29:33:27.792
G0217063 05:30:26 20:40:35.5738 +37:40:18.282
G1429059 05:31:37 20:40:46.6478 +30:07:10.6356
G0171171 05:32:49 20:42:15.6372 +37:40:31.4544
G0628332 05:52:51 20:44:09.7999 +33:59:41.5968
G0776012 05:54:03 20:45:56.9458 +28:31:56.0208
G0057545 05:55:14 20:46:38.9942 +36:31:22.7424
G1172157 05:56:23 20:49:25.6788 +33:20:57.714
G1117494 05:57:33 20:53:42.81 +37:56:12.0336
G0142750 05:58:48 20:57:57.7296 +41:06:53.3484
G1069636 05:59:57 21:00:42.2242 +39:53:22.6644
G0862987 06:01:07 21:05:12.3926 +40:46:35.4036
G1444432 06:02:16 21:06:54.9828 +39:55:27.264
G0233317 06:03:25 21:07:28.6963 +40:01:22.026
G1449915 06:04:35 21:08:52.7638 +42:14:50.964
G0175642 06:05:54 21:13:55.752 +51:17:37.68
G0416212 06:07:10 21:14:41.0669 +44:06:32.5836
G1086036 06:08:19 21:14:47.4756 +42:31:12.7308
G1474801 06:09:28 21:16:49.9291 +41:36:48.4164
G1054563 06:10:38 21:18:05.1929 +43:57:30.7512
G0959572 06:11:47 21:18:57.8978 +40:50:12.012
G0778794 06:13:03 21:20:30.066 +37:35:00.2292
G0002434 06:14:14 21:20:42.4805 +44:23:59.0712
G0705251 06:15:23 21:21:39.0454 +44:03:49.9572
G0003499 06:16:35 21:35:32.688 +35:23:54.168
G0636708 06:17:44 21:36:39.353 +35:41:40.8444
G0811558 06:49:28 19:21:10.0488 +43:56:44.3184
G0800990 06:50:37 19:21:31.9044 +43:59:43.4508
G0789501 06:51:47 19:22:31.9922 +44:03:38.5884
G0746609 06:52:56 19:29:59.7144 +43:28:28.8948
G1418181 06:54:18 20:02:49.8852 +49:19:11.2296
G0383988 06:55:29 20:19:01.4722 +44:31:54.642
G0210012 06:56:38 20:21:56.1694 +46:35:14.4024
G0348545 06:57:48 20:23:03.2959 +45:55:17.3208
G0446797 06:59:02 21:09:03.8964 +42:36:11.4624
G0415024 07:00:26 21:11:57.0557 +54:14:51.6228
G1149403 07:01:47 21:13:38.5253 +42:10:46.2972
G1060955 07:02:57 21:17:24.7558 +43:07:26.7312
G0044507 07:04:16 21:18:24.9902 +51:23:57.7104
G1111208 07:05:36 21:18:33.6475 +40:59:52.5696
G1116069 07:06:45 21:19:05.2882 +42:27:31.122
G1367883 07:07:54 21:20:58.5499 +38:03:24.3324
G0305271 07:09:06 21:23:06.7896 +43:29:21.3684
G0540762 07:10:15 21:25:36.1303 +47:42:24.3792
G1394842 07:11:26 21:26:50.0244 +38:12:04.698
G1407104 07:12:36 21:31:30.7764 +38:56:38.1552
G1112914 07:13:47 21:42:08.5913 +33:56:54.2364
G1243714 07:14:56 21:45:18.7279 +34:27:32.22
G0275039 07:16:06 21:49:28.3226 +36:06:06.0228
G0553168 07:18:56 21:53:38.8622 +32:47:28.77
G1460879 07:21:45 21:54:08.7305 +32:54:24.876
G0692325 07:51:02 22:01:07.3901 +16:33:50.1228
G0643019 07:52:24 22:04:40.1441 -16:57:46.3788
G0651982 07:53:46 22:05:40.8912 +16:47:06.72
G0717972 07:54:55 22:09:01.5161 +17:49:17.3136
G0663093 07:56:04 22:09:02.5634 +17:50:19.3164
G0695974 07:57:16 22:11:35.376 +25:51:51.7752
G0798670 07:58:29 22:21:47.6148 +25:19:13.008
G0687421 08:01:18 22:26:54.3677 +19:32:53.6532
G0693516 08:02:28 22:33:50.4785 +20:48:18.9972
G0684178 08:03:37 22:36:28.0298 +21:37:18.6276
G0644132 08:04:53 23:05:27.3706 +21:09:43.272
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G0211687 11:34:24 23:59:59.4727 +65:09:27.9648
GCN Circular 25108
Subject
LIGO/Virgo S190718y: ZTF pre-detection of MASTER candidate AT2019lly
Date
2019-07-19T17:14:50Z (6 years ago)
From
Igor Andreoni at Caltech <igor.andreoni@gmail.com>
Igor Andreoni (Caltech) reports on behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations
We searched for Zwicky Transient Facility (ZTF) detections associated with MASTER OT J203053.79+384020.1 / AT2019lly (Lipunov et al., GCN #25105) in the archive of ZTF alerts. A point source (g=19.85 +- 0.03) is present in the ZTF reference image at the location of AT2019lly and an outburst was detected on 2019-07-15 08:00:18 UT at magnitude g=14.240 +- 0.027.
The ZTF detection occurred 3 days before the gravitational wave candidate S190718y (LIGO and Virgo Collaboration, GCN #25087, GCN #25107), excluding an association between MASTER OT J203053.79+384020.1 / AT2019lly and S190718y. Our conclusion is in agreement with the Cataclysmic Variable scenario suggested by Lipunov et al. (GCN #25105).
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 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).
GCN Circular 25107
Subject
LIGO/Virgo S190718y: Analysis update
Date
2019-07-19T16:31:52Z (6 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
The LIGO Scientific Collaboration and the Virgo Collaboration report:
We performed a preliminary follow-up investigation of the compact
binary merger candidate S190718y reported in GCN 25087. We removed
glitches reported therein, using the PyCBC [1] gating method and
reanalyzed the data with PyCBC / Bayestar [2], and also using the same
template as the gstlal event. The analysis yields no evidence for
retracting this event. There are no updates to the p_astro or
significance of this event at this time.
The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S190718y
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] Singer & Price PRD 93, 024013 (2016)
GCN Circular 25105
Subject
MASTER OT detection inside LIGO/Virgo S190718y error box
Date
2019-07-19T15:15:45Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, N.Tyurina , P.Balanutsa, F.Balakin,
V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov, A.Kuznetsov,
I.Gorbunov, A. Chasovnikov, V.Grinshpun, T.Pogrosheva (Lomonosov
Moscow State University, SAI, Physics Department),
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The
Instituto de Astrofisica de Canarias),
R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico
Felix Aguilar OAFA, San Juan National University),
D. Buckley (South African Astronomical Observatory),
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
H.Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE,SJNU)
O. Gress, N.M. Budnev, O.Ershova
(Applied Physics Institute, Irkutsk Stat University),
V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev
(Blagoveschensk Education State University),
MASTER OT J203053.79+384020.1 / AT2019lly discovery
MASTER-IAC auto-detection system discovered OT source at
(RA, Dec) = 20h 30m 53.79s +38d 40m 20.1s on 2019-07-18.92684 UT.
The OT unfiltered magnitude is 14.9m (limit 19.4m).
The OT is seen in 2 images. There is no minor planet at this place.
We have reference image without OT on 2019-07-09.14716 UT with unfiltered
magnitude limit 19.7m.
The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/203053.79384020.1.png
There is a DSS source inside 2" with mag = 20.0m.
This flash is registered in the error box GW S190718y,but is probably
unrelated to the GW event (Cataclysmic Variable)
MASTER cover map of Ligo/Virgo S190718y error-field inspection will be
available on-line at:
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10491
This message may be cited.
GCN Circular 25103
Subject
LIGO/Virgo S190718y: Upper limits from Insight-HXMT/HE observations
Date
2019-07-19T13:31:26Z (6 years ago)
From
Qi Luo at IHEP <luoqi@ihep.ac.cn>
Q. Luo, C. Cai, S. Xiao, Q. B. Yi, Y. G. Zheng, Y. Huang,
C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang,
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:
Insight-HXMT was taking data normally around the reported LIGO/Virgo
S190718y event (GCN #25087), trigger time 2019-07-18T14:35:12.000 UTC.
At T0, about 91% of the 90% credible region and all of the 50% credible
region of the bayestar sky map were 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=305 deg, DEC=32 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: 3.2e-08 erg cm^-2
10 s: 1.5e-07 erg cm^-2
Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1 s: 5.7e-08 erg cm^-2
10 s: 2.8e-07 erg cm^-2
Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1 s: 1.8e-07 erg cm^-2
10 s: 9.4e-07 erg cm^-2
All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (deposited energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the spacecraft.
Insight-HXMT is the first Chinese space X-ray telescope, which was
funded jointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information could be found at: http://www.hxmt.org.
GCN Circular 25102
Subject
LIGO/Virgo S190718y: No counterpart candidates in Fermi-LAT observations
Date
2019-07-19T08:35:27Z (6 years ago)
From
Magnus Axelsson at Stockholm U. <magaxe@kth.se>
M. Axelsson (KTH and Stockholm Univ.), E. Bissaldi (Politecnico and INFN Bari), F.Longo (University and INFN, Trieste) and M. Palatiello (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 July 18, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S190718y (GCN 25087).
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 a time, and "cumulative coverage" as the integral of the instantaneous coverage over time. Fermi-LAT had instantaneous coverage of ~30% of the LIGO probability region at the time of the trigger (T0 = 2019-07-18 14:35:12.068 UTC), and reached ~98% coverage at T0+4 ks. The remaining area was not observed within 10 ks of the trigger.
We performed a search for a transient counterpart within the observed region of the 90% contour of the LIGO map in a fixed time window from T0 to T0+10 ks. No significant sources were found. We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky, and no additional excesses were found.
Energy flux upper bounds for the fixed time interval between 100 MeV and 1 GeV for this search vary between 9.8e-11 and 1.1e-07 [erg/cm^2/s].
The Fermi-LAT point of contact for this event is Michele Palatiello (michele.palatiello@gmail.com<mailto:michele.palatiello@gmail.com>).
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 25100
Subject
LIGO/Virgo S190718y: Coverage and upper limits from MAXI/GSC observations
Date
2019-07-19T05:28:53Z (6 years ago)
From
Motoko Serino at RIKEN/MAXI <motoko@crab.riken.jp>
M. Sugizaki, N. Kawai (Tokyo Tech), H. Negoro (Nihon U.),
S. Sugita, M. Serino (AGU),
M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.),
S. Nakahira, 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. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, 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 S190718y at 2019-07-18 14:35:12.067 UTC (GCN 25087).
At the trigger time of S190718y, 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 95%
of the 90% credible region of the bayestar skymap from 14:35:12 to 16:07:8 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 25099
Subject
LIGO/Virgo S190718y: Upper limits from CALET observations
Date
2019-07-19T04:01:41Z (6 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
V. Pal'shin, A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu,
T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger
time of S190718y T0 = 2019-07-18 14:35:12.068 UT (The LIGO
Scientific Collaboration and Virgo Collaboration, GCN Circ. 25087).
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 9 % and 17 %, respectively (and 22 % credible region of the
initial localization map was above the horizon). The HXM and SGM fields
of view were centered at RA = 203.3 deg, Dec = -18.0 deg and
RA = 195.8 deg, Dec = -11.1 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 (signal-to-noise ratio >= 7) 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 S190718y. 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.
The 90% upper limit of CAL is 1.7x10^-6 erg/cm^2/s (1-10 GeV) when
the summed LIGO-Virgo probability reaches 5%.
The CAL FOV was centered at RA = 195.8 deg, DEC = -11.1 deg at T0.
GCN Circular 25096
Subject
LIGO/Virgo S190718y: No counterpart candidates in the Swift/BAT Observations
Date
2019-07-19T00:27:17Z (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. A. Breeveld (MSSL-UCL), A. P. Beardmore (U. Leicester),
D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC),
G. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA),
P. D'Avanzo (INAF-OAB), V. D'Elia (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 (PSU),
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 S190718y (LIGO/VIRGO Collaboration GCN Circ. 25087),
where T0 is the LVC trigger time (2019-07-18T14:35:12.067 UTC).
The center of the BAT FOV at T0 is
RA = 357.719 deg,
DEC = -45.287 deg,
and the ROLL angle is 94.804 deg.
The BAT Field of View (>10% partial coding) covers 6.27% of the integrated
LVC localization probability, and 11.94% of the galaxy convolved
probability (Evans et al. 2016).
Swift/BAT was in SAA during this time. Within T0 +/- 100 s, no significant
detections are found in the BAT raw light curves with time bins of 64 ms,
1 s, and 1.6 s. The flux upper limit estimation is unavailable due
to the rapid increase of background during the SAA.
BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 23.33% 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/S190718y/web/source.html
GCN Circular 25095
Subject
LIGO/Virgo S190718y: Upper limits from Fermi-GBM Observations
Date
2019-07-19T00:24:34Z (6 years ago)
From
Bagrat Mailyan at UAH <bm0054@uah.edu>
B. Mailyan (UAH), R. Hamburg (UAH) and A. Goldstein (USRA) report
on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group:
For the LIGO/Virgo detection of GW trigger S190718y (GCN 25087) and using
the initial BAYESTAR skymap, Fermi-GBM was observing 24.0% of the
localization probability at event time.
There was no Fermi-GBM onboard trigger around the event time of S190718y.
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 = 15.0 and Dec = 11.4 with a radius of 67.3 degrees.
We therefore set upper limits on impulsive gamma-ray emission. Using the
representative soft, normal, and
hard GRB-like templates described in arXiv:1612.02395, we set the following
3 sigma flux upper limits over 10-1000 keV, weighted by GW localization
probability, (in units of 10^-8 erg/s/cm^2):
Timescale soft norm hard
--------------------------------------
0.128 s: 7.2 16. 47.
1.024 s: 3.6 7.2 18.
8.192 s: 1.1 2.0 5.4
Assuming the median luminosity distance of 227 Mpc (z=0.051) from the GW
detection, we estimate the following intrinsic luminosity upper limits over
the 1 keV-10 MeV energy range (in units of 10^47 erg/s):
Timescale soft norm hard
--------------------------------------
0.128 s: 6.84 14.2 68.4
1.024 s: 3.42 6.37 26.2
8.192 s: 1.04 1.77 7.86
GCN Circular 25092
Subject
LIGO/Virgo S190718y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
Date
2019-07-18T16:53:50Z (6 years ago)
From
Maeve Doyle at U College Dublin, Ireland <maeve.doyle.1@ucdconnect.ie>
Maeve Doyle (UCD, Ireland), Alexander Lutovinov (IKI, Russia)
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 <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 S190718y (GCN 25087).
At the time of the event (2019-07-18 14:35:12 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 30 deg with respect to the
spacecraft pointing axis. This orientation implies strongly suppressed
(19% of optimal) response of ISGRI, strongly suppressed (29% of
optimal) response of IBIS/Veto, and somewhat suppressed (55% o f
optimal) response of SPI-ACS.
The background within +/-300 seconds around the event was rather
stable (excess variance 1.2).
We have performed a search for any impulsive events in INTEGRAL SPI-
ACS (as described in [2]) data.
We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 2.8e-07 erg/cm^2 (within the
50% probability containement 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 ~2.5e-07 (9.4e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.
For the mean reported distance 227.0 Mpc this corresponds to the limit
on the total isotropic equivalent energy in 1 s of 1.7e+48 erg for the
short GRB spectrum and for a long GRB spectrum isotropic equivalent
luminosity in 1 s (8 s) of 1.5e+48 erg/s (5.8e+47 erg/s)
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 25091
Subject
LIGO/Virgo S190718y : no neutrino counterpart candidate in ANTARES search
Date
2019-07-18T16:37:37Z (6 years ago)
From
Damien Dornic at CPPM,France <dornic@cppm.in2p3.fr>
M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (APC/Universite de Paris), M. Colomer
(APC/Universite de Paris), D. Dornic (CPPM/CNRS), A. Kouchner (APC/Universite de Paris),
T. Pradier (IPHC/Universite de Strasbourg) report on behalf of the ANTARES Collaboration:
Using on-line data from the ANTARES detector, we have performed a follow-up analysis of the
recently reported LIGO/Virgo S190718y event using the 90% contour of the bayestar probability
map provided by the GW interferometers (GCN#25087). 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/S190718y.png <http://antares.in2p3.fr/GW/S190718y.png>. Considering the location probability provided by the
LIGO/Virgo collaborations, there is a 77.5% 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 2019-07-18 14:35:12 and in the 90% contour of the S190718y
event. The expected number of atmospheric background events in the region visible by ANTARES is
1.88e-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 1.36e-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 25088
Subject
LIGO/Virgo S190718y Global MASTER-Net observations report
Date
2019-07-18T16:16:57Z (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 S190718y errorbox 1850 sec after trigger time at 2019-07-18 15:06:02 UT, with upper limit up to 18.4 mag. The observations began at zenit distance = 23 deg. The sun altitude is -18.6 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=10491
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
1880 | 2019-07-18 15:06:02 | MASTER-Amur | ( 20h 34m 43.42s , +32d 26m 26.69s) | C | 60 | 18.4 |
1968 | 2019-07-18 15:07:30 | MASTER-Amur | ( 20h 30m 10.98s , +32d 38m 06.07s) | C | 60 | 18.4 |
2057 | 2019-07-18 15:08:58 | MASTER-Amur | ( 20h 34m 43.58s , +32d 26m 25.35s) | C | 60 | 18.4 |
2145 | 2019-07-18 15:10:27 | MASTER-Amur | ( 20h 30m 11.11s , +32d 38m 07.77s) | C | 60 | 18.4 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 25087
Subject
LIGO/Virgo S190718y: Identification of a GW compact binary merger candidate
Date
2019-07-18T16:07:48Z (6 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
The LIGO Scientific Collaboration and the Virgo Collaboration report:
We identified the compact binary merger candidate S190718y during
real-time processing of data from LIGO Hanford Observatory (H1), LIGO
Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-07-18
14:35:12.068 UTC (GPS time: 1247495730.068). The candidate was found
by the GstLAL [1] analysis pipeline.
S190718y 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/S190718y
There were glitches in the interferometers tens of seconds before
merger which may affect the sky maps. Further analysis is underway.
The classification of the GW signal, in order of descending
probability, is Terrestrial (98%), BNS (2%), NSBH (<1%), BBH (<1%), or
MassGap (<1%).
Assuming the candidate is astrophysical in origin, there is strong
evidence for the lighter compact object having a mass < 3 solar masses
(HasNS: >99%). Using the masses and spins inferred from the signal,
there is strong evidence 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 27 minutes after the candidate
For the bayestar.fits.gz sky map, the 90% credible region is 7246
deg2. Marginalized over the whole sky, the a posteriori luminosity
distance estimate is 227 +/- 165 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)
GCN Circular 25086
Subject
LIGO/Virgo S190718y: Upper limits from IceCube neutrino searches
Date
2019-07-18T15:51:47Z (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
S190718y
in a time range of 1000 seconds [3] centered on the alert event time
(2019-07-18 14:26:52.068 UTC to 2019-07-18 14:43:32.068 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 S190718y 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 S190718y 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)