LIGO/Virgo S200128d

A. Ridnaia, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline,
on behalf of the Konus-Wind team, report:

Konus-Wind (KW) was observing the whole sky at the time of the
LIGO/Virgo event S200128d (2020-01-28 02:20:11.903 UTC, hereafter T0;
LIGO/Virgo Collaboration GCN Circ. 26906
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 ).

No triggered KW GRBs happened between ~2 days before and ~2 days
after T0. The closest waiting-mode GRB was observed ~2.5 hours before T0.
Using waiting-mode data within the interval T0 +/- 100 s,
we found no significant (> 5 sigma) excess over the background
in both KW detectors on temporal scales from 2.944 s to 100 s.

We estimate an upper limit (90% conf.) on the 20 - 1500 keV fluence
to 8.0x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having a
typical KW short GRB spectrum (an exponentially cut off power law with
alpha =-0.5 and Ep=500 keV). For a typical long GRB spectrum (the Band
function with alpha=-1, beta=-2.5, and Ep=300 keV), the corresponding
limiting peak flux is 2.4x10^-7 erg/cm^2/s (20 - 1500 keV, 2.944 s scale).

All the quoted values are preliminary

L. P. Xin (NAOC), D. Turpin (CEA/AIM), X. H. Han (NAOC), 
P. Maggi (CNRS/ObAS), G. W. Li (NAOC)

report on behalf of the SVOM Multi Messenger Astronomy and GWAC teams
(http://www.svom.fr/en/svom-mma-and-gwac-team):

We observed 24 (~3600 square deg) sky regions to cover the skymap of the
advanced LIGO/Virgo trigger S200128d  (GCN # 26906), with SVOM/GWAC,
at Xinglong Observatory. SVOM/GWAC is equipped with two sets of
wide angle cameras:
- FFOV cameras (FOV~900 square degrees/camera, aperture = 3.5 cm),
- JFOV cameras (FOV~150 square degrees/camera, aperture = 18 cm).

SVOM/GWAC currently comprises 4 FFOV cameras and 16 JFOV cameras,
working in the unfiltered band. The observations are operated in
time-series mode, taking one exposure every 25 seconds
(20s exposure + 5s readout). The observed and processed regions enclosed
an estimated 41.5% of the probability of the advanced LIGO/Virgo skymap.
Images were taken between ~ 1 day 8 hours and ~ 1 day 19 hours 
after the GW trigger time. The coordinates of the 24 sky regions 
observed and their observation times and covered probability are 
listed below:

Id Ra           Dec         start (UTC)       end (UTC)         Proba. Cam.
1  07:26:22.5  52:57:12 2020-01-29 10:55:07 2020-01-29 11:22:13 0.026 JFOV
2  05:56:38.9  65:08:37 2020-01-29 11:06:26 2020-01-29 11:18:58 0.004 JFOV
3  06:12:15.3  53:15:18 2020-01-29 11:09:16 2020-01-29 11:22:12 0.057 JFOV
4  07:44:20.8  51:50:32 2020-01-29 11:25:03 2020-01-29 11:51:47 0.017 JFOV
5  09:06:04.5  52:07:04 2020-01-29 11:31:07 2020-01-29 11:45:42 0.010 JFOV
6  11:13:44.4  53:09:28 2020-01-29 13:20:41 2020-01-29 13:48:54 0.006 JFOV
7  09:59:12.0  53:29:36 2020-01-29 13:20:41 2020-01-29 13:48:53 0.011 JFOV
8  11:02:15.3  52:27:35 2020-01-29 13:59:08 2020-01-29 14:29:24 0.007 JFOV
9  13:30:27.8  02:35:47 2020-01-29 18:03:07 2020-01-29 18:31:15 0.012 JFOV
10 14:14:55.2  02:19:21 2020-01-29 18:03:07 2020-01-29 18:31:16 0.016 JFOV
11 13:29:46.0  14:38:49 2020-01-29 18:10:38 2020-01-29 18:31:15 0.007 JFOV
12 14:43:27.3 -14:26:44 2020-01-29 19:41:57 2020-01-29 21:15:50 0.039 JFOV
13 14:42:23.5 -2:16:58  2020-01-29 19:51:29 2020-01-29 21:15:59 0.006 JFOV
14 01:16:21.5 -15:28:16 2020-01-29 11:55:59 2020-01-29 12:18:06 0.003 JFOV
15 02:08:49.9 -15:25:18 2020-01-29 11:55:59 2020-01-29 12:18:55 0.006 JFOV
16 02:42:44.0  02:33:55 2020-01-29 10:29:21 2020-01-29 10:50:23 0.032 JFOV
17 02:41:52.7  14:37:03 2020-01-29 10:29:46 2020-01-29 10:50:23 0.033 JFOV
18 03:27:08.5  02:20:08 2020-01-29 10:37:52 2020-01-29 10:50:24 0.004 JFOV
19 03:28:18.0  18:21:27 2020-01-29 10:51:19 2020-01-29 11:19:23 0.058 JFOV
20 02:36:11.9  18:14:12 2020-01-29 10:52:39 2020-01-29 11:19:23 0.015 JFOV
21 04:10:49.1  36:06:55 2020-01-29 11:56:45 2020-01-29 12:10:03 0.082 JFOV
22 04:02:39.9  31:31:29 2020-01-29 11:38:13 2020-01-29 11:50:46 0.079 JFOV
23 04:26:07.4  35:11:34 2020-01-29 10:20:42 2020-01-29 10:49:06 0.073 JFOV
24 05:27:37.7  35:23:43 2020-01-29 10:23:32 2020-01-29 10:42:37 0.004 JFOV

The sky coverage map is available at:
http://cmm.svom.cn/gwpub/O3/S200128d/S200128d.png
(user:svomo3 pwd:gwo3).

Weather conditions were clear during the observations. An average 3-sigma
limiting magnitude of 16 mag in the R band was obtained in the single
frames. No credible new source was detected by our online pipeline during
follow-up observations. A more detailed image analysis including
co-addition is ongoing with our offline pipeline to search for transient
candidates.

C. Stachie (Artemis), S. Beradze (Iliauni), D. A. Kann (HETH/IAA-CSIC), 
Z. Vidadi (SHAO), S. Karpov (FZU), M. Masek (FZU), 
M. Prouza (FZU), M. Boer (Artemis), N. Christensen (Artemis), 
L. Eymar (Artemis), A. Klotz (IRAP), K. Noysena (Artemis, IRAP), 
S. Antier (APC), A. Coleiro (APC), D. Corre (IJCLab), 
M. Coughlin (UMN), D. Coward (OzGrav-UWA), J.G. Ducoin (IJCLab), 
B. Gendre (OzGrav-UWA), P. Hello (IJCLab), N. Kochiashvili (Iliauni), 
C. Lachaud (APC), N. Leroy (IJCLab), C. Thoene (HETH/IAA-CSIC), 
D. Turpin (AIM-CEA), X. Wang (THU) 

report on behalf of the FRAM, TAROT and GRANDMA collaborations. 

We performed tiled observations of LIGO/Virgo S200128d event with the 
FRAM-Auger, FRAM-CTA-N, TAROT-Calern (TCA), TAROT-Chili (TCH) 
telescopes. 

FRAM-Auger is located at Pierre Auger Observatory. FRAM-CTA-N is 
located at Observatorio del Roque de los Muchachos. TCA is located at 
Calern site at the Cote d'Azur observatory. TCH is located at La Silla 
ESO observatory (LaS/ESO). 

The following table shows for each telescope: the delay in minutes 
from the trigger, which filter is used, the field of view of the 
telescope in degrees and the typical limiting magnitude (AB mag) for a 
given exposure in seconds (s). 

+-------------+---------+----------+-------------+------------+ 
| Telescope | Delay | Filter | f.o.v. | Limiting | 
| | [min] | | [deg] | Mag. | 
|-------------+---------+----------+-------------+------------| 
| FRAM-Auger | 27 | R | 1.0 x 1.0 | 18.0 (60s) | 
| FRAM-CTA-N | 24 | R | 0.45 x 0.45 | 17.0 (90s) | 
| TCA | 1148 | Clear | 1.9 x 1.9 | 18.0 (60s) | 
| TCH | 155 | Clear | 1.9 x 1.9 | 18.0 (60s) | 
+-------------+---------+----------+-------------+------------+ 

We performed the following joint tiled observations [1] : 

+-------------+------------+------------+---------+---------+---------+ 
| Telescope | TStart | TEnd | RA | DEC | Proba | 
| | [UTC] | [UTC] | [deg] | [deg] | [%] | 
|-------------+------------+------------+---------+---------+---------| 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 60.583 | 33.568 | 0.1 | 
| | 02:46:24 | 02:50:51 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 59.240 | 31.622 | 0.1 | 
| | 02:51:26 | 02:55:53 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 233.660 | -44.270 | 0.1 | 
| | 04:14:01 | 04:18:28 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 230.504 | -41.351 | 0.1 | 
| | 04:19:04 | 04:23:31 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 226.623 | -34.541 | 0.1 | 
| | 05:17:46 | 05:22:12 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 228.980 | -37.459 | 0.1 | 
| | 05:22:47 | 05:27:14 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 229.655 | -38.432 | 0.1 | 
| | 05:27:48 | 05:32:15 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 227.755 | -37.459 | 0.1 | 
| | 05:32:50 | 05:37:17 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 230.350 | -39.405 | 0.1 | 
| | 05:37:53 | 05:42:20 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 231.064 | -40.378 | 0.1 | 
| | 05:42:54 | 05:47:21 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 236.250 | -46.216 | 0.1 | 
| | 06:31:19 | 06:35:46 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 227.803 | -34.541 | 0.1 | 
| | 06:36:24 | 06:40:51 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 234.483 | -45.243 | 0.1 | 
| | 06:41:27 | 06:45:54 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 237.143 | -47.189 | 0.1 | 
| | 06:46:29 | 06:50:56 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 230.204 | -37.459 | 0.1 | 
| | 06:51:33 | 08:00:09 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 224.430 | -31.622 | 0.1 | 
| | 08:00:46 | 08:05:13 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 228.414 | -38.432 | 0.1 | 
| | 08:05:48 | 08:10:15 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 233.333 | -43.297 | 0.1 | 
| | 08:10:52 | 08:15:18 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 235.862 | -45.243 | 0.1 | 
| | 08:15:54 | 08:20:21 | | | | 
| FRAM-Auger | 2020-01-28 | 2020-01-28 | 234.667 | -43.297 | 0.1 | 
| | 08:20:55 | 08:25:22 | | | | 
| ----- | ----- | ----- | ----- | ----- | ----- | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 71.752 | 42.604 | <0.1 | 
| | 02:44:06 | 03:07:01 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 65.302 | 38.672 | <0.1 | 
| | 02:48:28 | 03:11:23 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 67.761 | 40.419 | <0.1 | 
| | 02:52:54 | 03:15:44 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 63.885 | 37.136 | <0.1 | 
| | 03:16:00 | 03:20:06 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 66.531 | 38.672 | <0.1 | 
| | 03:20:26 | 03:24:32 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 65.125 | 37.897 | <0.1 | 
| | 03:24:45 | 03:28:51 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 64.770 | 37.361 | <0.1 | 
| | 03:29:10 | 03:33:16 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 67.760 | 38.672 | <0.1 | 
| | 03:33:33 | 03:37:39 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 65.980 | 39.645 | <0.1 | 
| | 03:37:54 | 03:42:00 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 228.239 | -37.348 | <0.1 | 
| | 07:00:51 | 07:04:57 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 228.425 | -36.812 | <0.1 | 
| | 07:05:11 | 07:09:16 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 229.117 | -37.348 | <0.1 | 
| | 07:09:29 | 07:13:35 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 230.179 | -38.334 | <0.1 | 
| | 07:13:49 | 07:17:55 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 227.368 | -35.163 | <0.1 | 
| | 07:18:28 | 07:22:34 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 227.361 | -37.348 | <0.1 | 
| | 07:22:48 | 07:26:54 | | | | 
| FRAM-CTA-N | 2020-01-28 | 2020-01-28 | 230.005 | -37.348 | <0.1 | 
| | 07:27:08 | 07:29:08 | | | | 
| ----- | ----- | ----- | ----- | ----- | ----- | 
| TCA | 2020-01-28 | 2020-01-29 | 61.323 | 34.805 | 0.4 | 
| | 21:27:35 | 00:33:56 | | | | 
| TCA | 2020-01-28 | 2020-01-29 | 66.832 | 38.991 | 0.3 | 
| | 21:34:18 | 00:40:37 | | | | 
| TCA | 2020-01-28 | 2020-01-28 | 70.467 | 42.703 | 0.3 | 
| | 21:46:45 | 22:53:03 | | | | 
| TCA | 2020-01-28 | 2020-01-28 | 63.559 | 35.280 | 0.3 | 
| | 21:53:29 | 22:59:48 | | | | 
| TCA | 2020-01-28 | 2020-01-28 | 57.317 | 29.713 | 0.3 | 
| | 22:00:14 | 23:06:33 | | | | 
| TCA | 2020-01-28 | 2020-01-28 | 65.154 | 37.136 | 0.3 | 
| | 23:21:05 | 23:23:05 | | | | 
| ----- | ----- | ----- | ----- | ----- | ----- | 
| TCH | 2020-01-28 | 2020-01-30 | 236.439 | -47.232 | 0.4 | 
| | 04:55:03 | 09:27:07 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 232.208 | -39.959 | 0.4 | 
| | 05:16:40 | 07:23:02 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 227.365 | -36.323 | 0.4 | 
| | 05:23:26 | 07:29:47 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 232.731 | -41.777 | 0.4 | 
| | 05:30:10 | 07:36:31 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 223.609 | -29.050 | 0.4 | 
| | 05:42:41 | 07:48:57 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 237.200 | -49.050 | 0.4 | 
| | 05:51:36 | 07:55:42 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 224.144 | -30.868 | 0.4 | 
| | 05:56:12 | 08:02:14 | | | | 
| TCH | 2020-01-28 | 2020-01-28 | 241.967 | -52.686 | 0.3 | 
| | 06:12:54 | 08:42:48 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 240.950 | -50.868 | 0.3 | 
| | 06:19:40 | 08:21:39 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 246.260 | -54.505 | 0.3 | 
| | 06:24:14 | 08:28:21 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 230.265 | -41.777 | 0.3 | 
| | 06:34:31 | 08:41:03 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 231.654 | -43.595 | 0.3 | 
| | 06:41:17 | 08:47:37 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 225.394 | -34.505 | 0.3 | 
| | 06:48:00 | 08:54:21 | | | | 
| TCH | 2020-01-28 | 2020-01-28 | 229.824 | -39.959 | 0.4 | 
| | 07:27:31 | 07:33:50 | | | | 
| TCH | 2020-01-28 | 2020-01-30 | 240.012 | -49.050 | 0.4 | 
| | 07:34:15 | 07:10:36 | | | | 
| TCH | 2020-01-29 | 2020-01-29 | 227.617 | -34.505 | 0.3 | 
| | 05:00:12 | 05:02:12 | | | | 
| TCH | 2020-01-29 | 2020-01-30 | 249.525 | -56.323 | 0.3 | 
| | 05:23:56 | 06:30:48 | | | | 
| TCH | 2020-01-30 | 2020-01-30 | 234.189 | -43.595 | 0.4 | 
| | 05:06:42 | 05:13:01 | | | | 
| TCH | 2020-01-30 | 2020-01-30 | 235.733 | -45.414 | 0.4 | 
| | 05:36:58 | 08:08:55 | | | | 
+-------------+------------+------------+---------+---------+---------+ 

TStart and TEnd refers respectively to the time of the first and last 
exposure for a given tile. Observations are not necessarily continuous 
in this interval. 
The Probability refers to the 2D spatial probability of the GW skymap 
enclosed in a given tile. 

These observations cover about 9.7% of the cumulative probability of 
the BAYESTAR skymap created on 2020-01-28 02:22:21 (UTC). 


The coverage map is available at: 
https://grandma-owncloud.lal.in2p3.fr/index.php/s/XgtMhPRxcyL09gR/download?path=%2F&files=GRANDMA_S200128d_1580458038.svg 

No significant transient candidates were found during our low latency 
analysis [2,3]. 

GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger 
Addicts) is a network of robotic telescopes connected all over the 
world with both photometry and spectrometry capabilities for Time- 
domain Astronomy [2](https://grandma.lal.in2p3.fr/). 

Details on the different telescopes are available on the GRANDMA web 
pages. 

[1] M. W Coughlin et al., MNRAS 2019, https://doi.org/10.1093/mnras/stz2485
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[2] S. Antier et al., MNRAS 2019, https://doi.org/10.1093/mnras/stz3142
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[3] K. Noysena et al., ApJ 2019, arXiv:1910.02770
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F. Verrecchia (SSDC, and INAF/OAR), A. Ursi (INAF/IAPS), C. Pittori (SSDC,
and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M.
Cardillo, C. Casentini, G. Piano (INAF/IAPS), F. Lucarelli, 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 S200128d at T0 = 2020-01-28
02:20:11.903 UTC a preliminary analysis of the AGILE data shows that no
AGILE/MCAL and AGILE/GRID data were available at T0 due to a telemetry gap.

We performed an analysis of the GRID data in the energy range 50 MeV -
10 GeV over time intervals before and after T0, where good exposure of the
S200128d 90% c.l. LR was available.

No candidate gamma-ray transient was detected.

The following preliminary GRID value of 3-sigma upper limit (UL) is
obtained:

from 3.6e-08 to 3.4e-06 erg cm^-2 s^-1, with exposure of about 44% of the
LR over the time interval ( T0 + 200 s ; T0 + 300 s );

These measurements were obtained with AGILE observing a large portion of
the sky in spinning mode. Additional analysis of AGILE data is in progress.

M. Axelsson (KTH & Stockholm Univ.), F. Longo (University and INFN, Trieste), M. Kovacevic (INFN Perugia), E. Bissaldi (Politecnico & INFN Bari), D. Kocevski (NASA/MSFC), N. Omodei (Stanford Univ.) and M. Arimoto (Kanazawa University) report on behalf of the Fermi-LAT Collaboration:

We have searched data collected by the Fermi Large Area Telescope (LAT) on January 28, 2020, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S200128d (GCN 26906
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 ).

We define "instantaneous coverage" as the integral over the region of the LIGO probability map that is within the LAT field of view at a given time, and ���cumulative coverage" as the integral of the instantaneous coverage over time. Fermi-LAT had an instantaneous coverage of ~35% of the LIGO probability at the time of the trigger (T0 = 2020-01-28 02:20:11.903 UTC), and reached 100% cumulative coverage after ~4.2 ks.

We performed a search for a transient counterpart within the observed region of the 90% contour of LIGO map in  a fixed time window from T0 to T0 + 10 ks. No significant new sources are found.

We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky, and no additional excesses were found.

Energy flux upper bounds for the fixed time interval between 100 MeV and 1 GeV for this search vary between 1.4e-10 and 3.0e-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.

N. Cannady (GSFC/UMBC),  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), 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 S200128d T0 = 2020-01-28 02:20:11.903 UT (The LIGO Scientific
Collaboration and Virgo Collaboration, GCN Circ.26906
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 ).

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 26 % and 49 %, respectively (and 65 % credible region of the
initial sky map was above the horizon).  The HXM and SGM fields of
view were centered at RA = 134.1 deg, Dec = +30.5 deg and RA = 126.1 
deg, Dec = +23.4 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 high energy trigger
mode at the trigger time of S200128d. Using the CAL data, we have
searched for gamma-ray events in the 10-100 GeV band from -60 sec 
to +60 sec from the GW trigger time and found no candidates in the
overwrap region with the LIGO-Virgo high probability localization
region. 

The 90% upper limit of CAL is 4.6 x 10^-6 erg/cm^2/s (10-100 GeV) 
when the summed LIGO-Virgo probability reaches 10%.
The CAL FOV was centered at RA = 126.1 deg, DEC = +23.4 deg at
T0.

Shaunak Modak, Andrew Hoffman, Nachiket Girish, Yukei Murakami,
WeiKang Zheng, 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-wave
event S200128d (GCN 26906
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 ) 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 100 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 02:32:19, Jan.
28th UT, about 12.0 minutes after the trigger, and the last image at
10:19:35 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(Jan28)  RA_J2000   Dec_J2000
-----------------------------------------------
G0696216  02:32:19  01:17:45.1378  -25:50:21.1524
G0795121  02:33:30  01:37:49.0049  -23:38:01.3056
G0882384  02:34:39  01:44:47.0527  -23:23:18.2724
G1619053  02:35:52  01:45:50.352   -09:18:49.428
G0665450  02:37:06  01:47:45.3487  -21:50:00.51
G0824841  02:38:15  01:48:39.0418  -18:43:43.212
G0784259  02:39:27  01:49:47.124   -21:54:26.9496
G0710198  02:40:37  01:52:03.413   -20:09:58.4748
G0571685  02:41:46  01:56:32.7274  -20:02:54.114
G0747645  02:42:58  01:57:01.9176  -17:01:23.4948
G0648368  02:44:07  01:59:04.5048  -19:30:01.4292
G0565331  02:45:16  02:01:06.5748  -18:53:47.8644
G0814247  02:46:25  02:01:28.493   -18:04:01.8768
G0817926  02:47:35  02:01:46.837   -16:24:20.934
G1614837  02:48:46  02:03:34.632   -09:25:40.188
G0816503  02:49:57  02:04:09.7622  -15:58:48.4284
G0786849  02:51:07  02:04:59.6902  -16:08:05.1684
G0750785  02:52:16  02:05:29.7775  -18:02:35.2572
G0656369  02:53:25  02:10:30.553   -13:29:37.0176
G0081229  02:54:35  02:11:53.1912  -12:06:25.776
G0731349  02:55:46  02:25:23.2416  -07:50:24.2664
G0594730  02:56:55  02:26:58.9747  -04:35:26.9484
G0633562  02:58:05  02:27:09.342   -02:52:19.956
G0001576  02:59:14  02:30:42.8393  -02:56:20.4144
G0653886  03:00:23  02:36:56.6858  -02:11:59.1648
G1139246  03:01:35  02:47:12.2479  +05:39:53.6004
G0756115  03:02:46  02:57:53.0868  +13:01:50.8656
G0641223  03:03:55  02:58:57.8184  +13:34:58.332
G0576258  03:05:14  03:41:17.3546  +26:40:14.7324
G0582436  03:06:25  03:54:09.8887  +34:07:08.4396
G0731349  03:50:59  02:25:23.2416  -07:50:24.2664
G0594730  03:52:09  02:26:58.9747  -04:35:26.9484
G0001576  03:54:27  02:30:42.8393  -02:56:20.4144
G0653886  03:55:37  02:36:56.6858  -02:11:59.1648
G1139246  03:56:48  02:47:12.2479  +05:39:53.6004
G0756115  03:57:59  02:57:53.0868  +13:01:50.8656
G0641223  03:59:09  02:58:57.8184  +13:34:58.332
G0576258  04:00:25  03:41:17.3546  +26:40:14.7324
G0582436  04:01:37  03:54:09.8887  +34:07:08.4396
G0770459  04:52:59  04:09:18.3919  +33:53:23.9172
G0796246  04:54:16  04:11:56.4852  +39:30:13.32
G0565674  04:55:26  04:17:34.9824  +36:08:05.1144
G1167642  04:56:35  04:21:29.436   +36:56:57.2568
G0650034  04:57:44  04:22:59.9047  +43:06:38.844
G0609806  04:58:56  04:28:28.9546  +38:21:29.9592
G0487836  05:00:05  04:30:09.049   +42:44:48.8076
G0649095  05:01:14  04:38:28.3392  +44:02:13.6752
G0736266  05:02:26  04:38:58.2751  +39:16:50.6856
G0567652  05:03:35  04:41:00.9706  +37:10:40.3248
G0734583  05:04:44  04:43:34.3745  +38:12:34.4592
G0791297  05:05:56  04:49:09.0638  +45:00:39.3984
G0726428  05:07:05  04:49:37.8058  +43:47:43.5876
G0651979  05:08:15  04:50:06.6852  +45:03:05.7384
G1509641  05:09:47  05:42:36.336   +49:51:07.38
G0225879  05:11:12  05:53:42.9274  +53:37:11.3232
G0630005  05:12:25  06:02:29.2512  +50:43:10.2864
G0599403  05:13:53  06:59:38.13    +54:11:47.3424
G1418861  05:15:02  07:04:52.1942  +55:35:28.3812
G0646693  05:16:13  07:20:26.6839  +56:23:27.1968
G0476768  05:17:32  08:00:08.5181  +56:21:56.232
G0671466  05:18:41  08:01:45.9026  +56:33:12.0564
G0615908  05:19:57  08:58:36.4855  +54:19:02.676
G0701014  05:21:06  09:01:30.0953  +55:39:16.6356
G0706321  05:22:17  09:35:58.8941  +54:36:39.0384
G0761971  05:23:29  09:46:53.3424  +54:26:45.2544
G0575796  07:34:10  10:32:38.4924  +53:09:24.0516
G0631724  07:35:17  10:33:47.8418  +52:22:16.4748
G0776673  07:36:35  10:37:12.2278  +50:07:14.3184
G0784581  07:37:48  10:38:51.8261  +53:58:18.9264
G0273464  07:38:59  10:48:09.3127  +48:19:53.2668
G0600260  07:40:09  10:51:31.6625  +49:30:08.6652
G0899439  07:41:19  11:04:22.3205  +48:38:11.3352
G0576057  07:42:28  11:06:10.4479  +48:16:03.6804
G0234381  07:43:39  11:21:35.8886  +48:02:52.2924
G0726921  07:44:49  11:24:06.4819  +48:41:46.518
G0609396  07:45:58  11:24:27.323   +48:52:45.8076
G0827094  07:47:10  11:43:39.5911  +46:21:20.2932
G0732456  07:48:21  12:04:57.9053  +43:08:59.0316
G0639300  07:49:31  12:06:13.4436  +45:20:01.176
G0769163  07:50:40  12:12:16.9848  +45:30:49.7556
G1437067  07:51:49  12:15:59.4799  +41:22:29.478
G1836334  07:52:58  12:16:07.92    +40:36:49.32
G0668285  07:54:08  12:16:46.5235  +44:40:15.8124
G0810953  07:55:17  12:21:13.147   +41:52:13.9476
G1699892  07:56:26  12:26:42.24    +43:47:04.056
G0787284  07:57:36  12:27:55.0891  +45:26:58.452
G1817097  07:58:45  12:28:48.72    +44:52:08.58
G0783585  07:59:55  12:30:34.9877  +42:11:29.9544
G0613621  08:01:04  12:31:54.6314  +40:34:25.2084
G0356212  08:02:14  12:34:18.4534  +40:49:34.7808
G0881944  08:03:23  12:35:09.3823  +39:27:05.634
G0571256  08:04:33  12:38:43.5792  +41:33:07.7148
G0761416  08:05:42  12:42:10.2612  +42:02:21.1884
G0782000  10:10:14  13:06:56.737   +18:53:53.6892
G1143431  10:12:33  13:07:18.8268  +17:41:53.7972
G0750196  10:13:42  13:07:34.0577  +16:21:22.8204
G1143718  10:14:52  13:08:22.0642  +15:42:20.9808
G1435594  10:16:03  13:08:45.3038  +18:46:13.1016
G0743613  10:18:26  13:11:03.534   +19:01:12.8244
G0595223  10:19:35  13:12:38.1151  +15:38:21.0408

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-ASDC), S. Emery (UCL-MSSL),
P. A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU),
D. Hartmann (Clemson U.), J. A. Kennea (PSU),
N. Klingler (PSU), H. A. Krimm (NSF),
N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),
A. Melandri (INAF-OAB), J. A. Nousek (PSU),
S. R. Oates (U. of Birmingham), P. T. O'Brien (U. Leicester),
J. P. Osborne (U. Leicester), C. Pagani (U. Leicester),
K. L. Page (U.Leicester), M. J. Page (UCL-MSSL), M. Perri (ASDC),
J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU),
M. H. Siegel (PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (U. Toronto),
E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:

We report the search results in the BAT data within T0 +/- 100 s of the
LVC event S200128d (LIGO/VIRGO Collaboration GCN Circ. 26906
Loading...
 
 ),
where T0 is the LVC trigger time (2020-01-28T02:20:11.903 UTC).

The center of the BAT field of view (FOV) at T0 is
RA = 40.666 deg,
DEC = 0.035 deg,
and the roll angle is 242.886 deg.
The BAT FOV (>10% partial coding) covers 24.07% of the integrated
LVC localization probability, and 23.84% 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 ~ 1.01 x 10^-7 erg/s/cm^2.
Assuming a luminosity of ~ 2 x 10^47 erg/s (similar to GW170817)
and an average Epeak of ~ 400 keV for short GRBs (Bhat et al. 2016),
this flux upper limit corresponds to a distance of ~ 71.59 Mpc.

Event data are available from T0-45.29 s to T0+44.84 s. No significant
detections (above our typical image threshold of ~ 6.5 to 7 sigma) are
found in the 15-350 keV images created using intervals of T0-0.1 to T0+0.1
s,
T0-2 s to T0+8 s, and the whole event data range.

BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 25.22% 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/S200128d/web/source_public.html

J. Wood (NASA/MSFC) reports on behalf of the Fermi-GBM Team and the
GBM-LIGO/Virgo group

For S200128d and using the bayestar.fits.gz,1 skymap, Fermi-GBM was observing
48.7% 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 S200128d (GCN 26906
Loading...
 
 ). 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=266.6, Dec=-24.9 with a radius of 67.5 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
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 , we set the following
3 sigma flux upper limits over 10-1000 keV, weighted by GW localization
probability (in units of 10^-7 erg/s/cm^2):

Timescale   Soft   Normal   Hard
------------------------------------
0.128 s:    2.5    3.2      8.3
1.024 s:    0.8    1.3      2.7
8.192 s:    0.2    0.4      1.0

Assuming the median luminosity distance of 4031 Mpc from the GW detection,
we estimate the following intrinsic luminosity upper limits over the 1
keV-10 MeV energy range (in units of 10^50 erg/s):

Timescale   Soft   Normal   Hard
------------------------------------
0.128s:     7.8    8.5      37.
1.024s:     2.4    3.4      12.
8.192s:     0.7    1.0      4.5

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 S200128d event using the 90% contour of the Initial GW_SKYMAP probability
map provided by the GW interferometers (GCN#26906
Loading...
 
  <https://gcn.gsfc.nasa.gov/gcn3/26906.gcn3
Loading...
 
 >). 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/S200128d_Initial.png <http://antares.in2p3.fr/GW/S200128d_Initial.png>.
Considering the location probability provided by the LIGO/Virgo collaborations, there is a
50.1% chance that the GW emitter was in the ANTARES **upgoing** field of view at the time of
the alert.

No up-going muon neutrino candidate events were recorded in the ANTARES sky during a
+/-500s time-window centered on the time 2020-01-28 02:20:11 and in the 90% contour of the S200128d
event. The expected number of atmospheric background events in the region visible by ANTARES is
6.46e-04 in the +/- 500s time window. An extended search during +/- 1 hour gives no
up-going muon neutrino coincidence. The expected number of atmospheric background events in the
region visible by ANTARES is 4.65e-03 in this larger time window.

ANTARES is the largest undersea neutrino detector, installed in the Mediterranean Sea, and it is
primarily sensitive to neutrinos in the TeV-PeV  energy range. At 10 TeV, the median angular
resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a
competitive sensitivity to this position in the sky.

S. Sugita, M. Serino (AGU), N. Kawai (Tokyo Tech), H. Negoro (Nihon U.),
M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi, R. Takagi (Nihon U.),
T. Mihara, C. Guo, Y. Zhou, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, H. Nishida, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.),
M. Shidatsu (Ehime U.), M. Oeda, K. Shiraishi (Tokyo Tech),
S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, R.
Shimomukai, M. Tominaga (JAXA),
Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake
(Kyoto U.),
H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.),
M. Yamauchi, S. Iwahori, Y. Kurihara, K. Kurogi, K. Miike (Miyazaki U.),
T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M.
Sugizaki (NAOC)
report on behalf of the MAXI team:

We examined MAXI/GSC all-sky X-ray images (2-20 keV)
after the LVC trigger S200128d at 2020-01-28 02:20:11.903 UTC (GCN 26906
Loading...
 
 ).

At the trigger time of S200128d, 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 92%
of the 90% credible region of the bayestar skymap from 02:20:11 to
03:52:09 UTC (T0+0 to T0+5518 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.

LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS
prompt observation

Francesca Onori (IAPS, Italy), Alexis Coleiro
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
J. Rodi (IAPS-Roma, Italy)
A. Coleiro (APC, France)
S. Mereghetti (INAF IASF-Milano, Italy)

on behalf of the INTEGRAL multi-messenger collaboration:
https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration

Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed
a search for a prompt gamma-ray counterpart of S200128d (GCN 26906
Loading...
 
 ).

At the time of the event (2020-01-28 02:20:11 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 135 deg with respect to
the spacecraft pointing axis. This orientation implies strongly
suppressed (3.4% of optimal) response of ISGRI, somewhat suppressed
(42% of optimal) response of IBIS/Veto, and somewhat suppressed (43 %
of 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 2.6e-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 ~2.3e-07 (5.4e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.

For the mean reported distance 4031.0 Mpc this corresponds to the
limit on the total i sotropic equivalent energy in 1 s of 5e+50 erg
for the short GRB spectrum and for a long GRB spectrum isotropic
equivalent luminosity in 1 s (8 s) of 3.2e+50 erg/s (1e+50 erg/s)

We report for completeness and in order of FAP, all excesses
identified in the search region. We find: 1 possibly associated
excess:

T-T0 | scale | S/N | luminosity ( x 1e+51 erg/s) | FAP
4.73 | 0.5 | 4.1 | 16.5 +/- 5.64 +/- 14.1 | 0.0284

9 likely background excesses:

T-T0 | scale | S/N | luminosity ( x 1e+51 erg/s) | FAP
-201 | 5 | 4.3 | 5.28 +/- 1.77 +/- 4.5 | 0.0959
-128 | 1.5 | 5 | 11.3 +/- 3.25 +/- 9.64 | 0.128
6.65 | 0.75 | 3.1 | 9.85 +/- 4.59 +/- 8.38 | 0.175
-53.1 | 0.65 | 4 | 14.3 +/- 4.94 +/- 12.2 | 0.257
9.78 | 0.2 | 3.5 | 22.4 +/- 8.95 +/- 19 | 0.316
72.2 | 0.7 | 3.8 | 12.9 +/- 4.76 +/- 11 | 0.44
-9.6 | 0.15 | 3.4 | 2.48 +/- 1.03 +/- 2.11 | 0.566
271 | 3.3 | 3.5 | 5.06 +/- 2.18 +/- 4.31 | 0.577
45.6 | 1.15 | 3.1 | 8.14 +/- 3.7 +/- 6.93 | 0.646

Note that FAP estimates (especially at timescales above 2s) may be
possibly further affected by enhanced non-stationary local background
noise. This list excludes any excesses for which FAP is close to
unity.



All results quoted are preliminary.

This circular is an official product of the INTEGRAL Multi-Messenger
team.

[1] Savchenko et al. 2017, A&A 603, A46 [2] Savchenko et al. 2012, A&A
541A, 122S


-- 
Dr. Francesca Onori
Postdoctoral Researcher
IAPS, via Fosso del Cavaliere, 100, 00133 - Rome, Italy
e-mail: francesca.onori@inaf.it
Tel: +39 06 45488128

The HAWC Collaboration (https://www.hawc-observatory.org) reports:

The HAWC Collaboration performed a follow-up of the gravitational wave
trigger S200128d. At the time of the trigger the HAWC
local zenith was oriented towards (RA, Dec) = (64.3 deg, 18.9deg).
38% 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 5deg to 45deg 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
(6.7e-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.

The LIGO Scientific Collaboration and the Virgo Collaboration report:

We identified the compact binary merger candidate S200128d during
real-time processing of data from LIGO Hanford Observatory (H1) and
LIGO Livingston Observatory (L1) at 2020-01-28 02:20:11.903 UTC (GPS
time: 1264213229.903). The candidate was found by the PyCBC Live [1],
CWB [2], MBTAOnline [3], and GstLAL [4] analysis pipelines.

S200128d is an event of interest because its false alarm rate, as
estimated by the online analysis, is 1.6e-08 Hz, or about one in 1
year, 11 months. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S200128d

The classification of the GW signal, in order of descending
probability, is BBH (97%), Terrestrial (3%), BNS (<1%), NSBH (<1%), or
MassGap (<1%).

Assuming the candidate is astrophysical in origin, the probability
that the lighter compact object has a mass < 3 solar masses (HasNS) is
<1%. Using the masses and spins inferred from the signal, the
probability of matter outside the final compact object (HasRemnant) is
<1%.

Two sky maps are available at this time and can be retrieved from the
GraceDB event page:
 ��* bayestar.fits.gz,0, an initial localization generated by BAYESTAR
[5], distributed via GCN notice about 3 minutes after the candidate
event time.
 ��* bayestar.fits.gz,1, an initial localization generated by BAYESTAR
[5], distributed via GCN notice about 9 minutes after the candidate
event time.

The preferred sky map at this time is bayestar.fits.gz,1. For the
bayestar.fits.gz,1 sky map, the 90% credible region is 2521 deg2.
Marginalized over the whole sky, the a posteriori luminosity distance
estimate is 4031 +/- 1241 Mpc (a posteriori mean +/- standard
deviation).

For further information about analysis methodology and the contents of
this alert, refer to the LIGO/Virgo Public Alerts User Guide
<https://emfollow.docs.ligo.org/userguide/>.

[1] Nitz et al. PRD 98, 024050 (2018)
[2] Klimenko et al. PRD 93, 042004 (2016)
[3] Adams et al. CQG 33, 175012 (2016)
[4] Messick et al. PRD 95, 042001 (2017)
[5] Singer & Price PRD 93, 024013 (2016)

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
S200128d
 in a time range of 1000 seconds [3] centered on the alert event time
(2020-01-28 02:11:51.903 UTC to 2020-01-28 02:28:31.903 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
S200128d 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 S200128d ranges from 0.029 to 0.966 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
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  (2018) and Countryman et
al.arXiv:1901.05486
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  (2019)
[2] PoS(ICRC2019)918 and Braun et al., Astroparticle Physics 29, 299 (2008)
[3] Baret et al., Astroparticle Physics 35, 1 (2011)

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, 
V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,
D.Kuvshinov,  D. Cheryasov
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

H.Levato 
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev, O.Ershova 
(Irkutsk State University, API),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich, Yu. Sergienko 
(Blagoveschensk Educational State University)




MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the LIGO/Virgo S200128d errorbox  37 sec after notice time and 322 sec after trigger time at 2020-01-28 02:25:33 UT, with upper limit up to  18.4 mag. The observations began at zenith distance = 41 deg. The sun  altitude  is -18.1 deg. 

MASTER-IAC robotic telescope  located in Spain (IAC Teide Observatory) started inspect of the LIGO/Virgo S200128d errorbox  71 sec after notice time and 356 sec after trigger time at 2020-01-28 02:26:07 UT, with upper limit up to  18.1 mag. The observations began at zenith distance = 68 deg. The sun  altitude  is -71.2 deg. 

The galactic latitude b = 11 deg., longitude l = 332 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/ligo_1.php?id=11283

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     353 | 2020-01-28 02:25:33 |         MASTER-SAAO | (15h 32m 49.48s , -42d 18m 49.4s) |   C |    60 | 18.4 |        
     392 | 2020-01-28 02:26:07 |          MASTER-IAC | (04h 23m 02.77s , +35d 36m 33.1s) |  P| |    70 | 18.1 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.