LIGO/Virgo S200302c

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-Kislovodsk robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the LIGO/Virgo S200302c errorbox  2 sec after notice time and 208 sec after trigger time at 2020-03-02 02:01:39 UT, with upper limit up to  17.5 mag. The observations began at zenith distance = 71 deg. The sun  altitude  is -19.7 deg. 

The galactic latitude b = -3 deg., longitude l = 317 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/ligo_1.php?id=11407

We obtain a following upper limits.  

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

     228 | 2020-03-02 02:01:39 |   MASTER-Kislovodsk | (22h 50m 53.42s , +46d 08m 51.7s) |   C |    40 | 17.5 |        
Filter C is a clear (unfiltred) band. 


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

The LIGO Scientific Collaboration and the Virgo Collaboration report:

We identified the compact binary merger candidate S200302c during
real-time processing of data from LIGO Hanford Observatory
(H1) and Virgo Observatory (V1) at 2020-03-02 01:58:11.519 UTC (GPS
time: 1267149509.519). The candidate was found by the GstLAL [1]
analysis pipeline.

S200302c is an event of interest because its false alarm rate, as
estimated by the online analysis, is 9.3e-09 Hz, or about one in 3
years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S200302c

The classification of the GW signal, in order of descending
probability, is BBH (89%), Terrestrial (11%), BNS (<1%), MassGap
(<1%), or NSBH (<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
[2], distributed via GCN notice about a minute after the candidate
event time.
 * bayestar.fits.gz,1, distributed via GCN notice about 7 minutes after
the candidate event time.  (This is identical to bayestar.fits.gz,0 )

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 6704 deg2.
Marginalized over the whole sky, the a posteriori luminosity distance
estimate is 1737 +/- 500 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)

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
S200302c
in a time range of 1000 seconds [3] centered on the alert event time
(2020-03-02 01:49:51.519 UTC to 2020-03-02 02:06:31.519 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
S200302c calculated from the map circulated in the 2-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 S200302c ranges from 0.029 to 0.954 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)

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

We examined MAXI/GSC all-sky X-ray images (2-20 keV)
after the LVC trigger S200302c at 2020-03-02 01:58:11.519 UTC (GCN 27278
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 ).

At the trigger time of S200302c, the high-voltage of MAXI/GSC was off,
and it was turned on at T0+557 sec (+9.3 min).
The first one-orbit (92 min) scan observation with GSC after the event
covered 57%
of the 90% credible region of the bayestar skymap from 02:07:28 to
03:24:53 UTC (T0+557 to T0+5202 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.

M. Pilia (INAF/OA-Cagliari), F. Longo (Univ. Trieste, and INFN Trieste), M.
Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, C. Casentini,
G. Piano, A. Ursi (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia
(SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani
(INAF/OAS-Bologna), report on behalf of the AGILE Team:

In response to the LIGO/Virgo GW event S200302c at T0 = 2020-03-02
01:58:11.519 (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 65% of the S200302c 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 S200302c localization
region, from a minimum of 1.3E-06 erg cm^-2 to a maximum of 7.1E-06 erg
cm^-2 (assuming as spectral model a single power-law with photon index 1.5).

An independent procedure based on photon counting statistics provides UL
fluences in the range 0.4-1 MeV, for a 300 us integration time, from a
minimum of 1.0E-08 erg cm^-2 to a maximum of 4.4E-08 erg cm^-2.

The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the
energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.

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 S200302c event using the 90% contour of the Initial GW_SKYMAP probability
map provided by the GW interferometers (GCN#27278
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 ). 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/S200302c_Initial.png <http://antares.in2p3.fr/GW/S200302c_Initial.png>.
Considering the location probability provided by the LIGO/Virgo collaborations, there is a
49.5% 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 2020-03-02 01:58:11 and in the 90% contour of the S200302c
event. The expected number of atmospheric background events in the region visible by ANTARES is
2.84e-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 2.05e-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.

Alexis Coleiro (APC, France), Maeve Doyle (UCD, Ireland),
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

Using combination of INTEGRAL all-sky detectors (following [1]):
SPI/ACS, IBIS/Veto, and IBIS we have performed a search for a prompt
gamma-ray counterpart of S200302c (GCN 27278
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 ).

At the time of the event (2020-03-02 01:58:11 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 42 deg with respect to the
spacecraft pointing axis. This orientation implies strongly suppressed
(19% of optimal) response of ISGRI, strongly suppressed (39% of
optimal) response of IBIS/Veto, and near-optimal (78% of optimal)
response of SPI-ACS. 6.6% of the gravitational-wave localization was 
within the IBIS field-of-view at the trigger time.

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]), IBIS, and IBIS/Veto data.

We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 3.2e-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 (1.8e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.
For the mean reported distance of 1737.0 Mpc, this corresponds to a
limit on the total isotropic equivalent energy in 1 s of 1.2e+50 erg
for the short GRB spectrum and for a long GRB spectrum isotropic
equivalent luminosity in 1 s (8 s) of 2e+49 erg/s (6.7e+48 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+50 erg/s) | FAP
-31.9 | 8.75 | 3.5 | 5.86 +/- 2.59 +/- 5.07 | 0.0264

5 likely background excesses:

T-T0 | scale | S/N | luminosity ( x 1e+50 erg/s) | FAP
9.25 | 0.8 | 3.4 | 20.7 +/- 8.6 +/- 17.9 | 0.0935
-170 | 1.4 | 4.8 | 22 +/- 6.5 +/- 19 | 0.21
220 | 0.9 | 4.1 | 23.5 +/- 8.11 +/- 20.3 | 0.707
120 | 0.55 | 3.9 | 2.84 +/- 1.04 +/- 2.46 | 0.833
-73 | 0.55 | 3.5 | 2.61 +/- 1.04 +/- 2.26 | 0.86

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

For S200302c and using the initial bayestar.fits.gz skymap, Fermi-GBM was observing 71.1% 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 S200302c (GCN 27278
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 ). 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=288.0, Dec=1.6 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
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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: 3.9        6.1      12
1.024 s: 1.4        2.0      3.7
8.192 s: 0.40       0.73     1.8

Assuming the median luminosity distance of 1737.4 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
------------------------------------
0.128 s:   2.2      3.1     10
1.024 s:   0.79     1.0     3.1
8.192 s:   0.23     0.37    1.5

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

The HAWC Collaboration performed a follow-up of the gravitational wave
trigger S200302c (GCN #27278
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 ). At the time of the trigger the HAWC
local zenith was oriented towards (RA, Dec) = (92.3 deg, 19.0 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.

T. Sakamoto (AGU), S. D. Barthelmy (NASA/GSFC),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL)
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 S200302c (LIGO/VIRGO Collaboration GCN Circ. 27278
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 ),
where T0 is the LVC trigger time (2020-03-02T01:58:11.519 UTC).

The center of the BAT field of view (FOV) at T0 is
RA = 10.655 deg,
DEC = 41.334 deg,
and the roll angle is 223.231 deg.
The BAT FOV (>10% partial coding) covers 24.48% of the integrated
LVC localization probability, and 24.02% 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 astrophysical 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. The ~5.9 sigma detection
seen at ~T-17.8 s in the 64 ms light curve is likely due to cosmic ray
shower.

Assuming a short GRB with a typical spectrum in the BAT energy range
(i.e., a simple power-law model with a power-law index of -1.32,
Lien & Sakamoto et al. 2016), the 5-sigma upper limit in the 1-s binned
light curve corresponds to a flux upper limit (15-350 keV)
of ~ 6.99 x 10^-8 erg/s/cm^2 for the 100% coded region
(i.e., for a burst with 0 deg from BAT boresight) and ~ 1.47 x 10^-6
erg/s/cm2 for the 10% coded region (~56 deg from BAT boresight).
Assuming a luminosity of ~ 2 x 10^47 erg/s (similar to GW170817)
and an average Epeak of ~ 400 keV for short GRBs (Bhat et al. 2016),
these flux upper limits corresponds to a distance of ~ 85.94 Mpc (100%
coded)and ~ 18.73 Mpc (10% coded).

Event data are available from T0-45.142 s to T0+44.9692 s via the GUANO
system (Tohuvavohu et al. 2020, in prep). No significant detections
(above our typical image threshold of ~ 6.5 to 7 sigma) are found in the
15-350 keV images created using intervals of the whole event data range.

BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 52.88% 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/S200302c/web/source_public.html

Keto D. Zhang, Shaunak Modak, Sergiy Vasylyev, Benjamin E. Stahl,
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 S200302c (GCN 27278
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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 101 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 03:39:07, Mar.
02nd UT, about 1.7 hours after the trigger, and the last image at
06:25:13 UT. Our typical limiting mag is 18.5. No viable counterparts
were identified and the analysis is ongoing. A full list of galaxies
observed by KAIT is given below.

GladeID   UT(Mar02)  RA_J2000   Dec_J2000
-----------------------------------------------
G0977981  03:39:07  08:46:23.2178  -15:45:38.7936
G0628480  03:40:16  08:46:48.5376  -14:47:52.8288
G0756544  03:41:28  08:47:08.1554  -12:29:37.7124
G1109681  03:42:39  08:52:48.8414  -23:15:28.962
G0729469  03:43:48  08:54:05.9693  -19:17:53.2536
G0758017  03:44:58  08:54:20.951   -16:14:14.406
G0610914  03:46:09  09:01:41.6309  -23:55:46.3476
G0648481  03:47:20  09:02:49.2847  -15:38:00.6468
G0769731  03:48:32  09:03:42.583   -21:53:39.8328
G0756540  03:49:43  09:04:48.4387  -17:00:48.402
G1264339  03:50:53  09:07:44.6374  -22:32:42.2412
G0490601  04:15:53  07:41:32.1624  +51:41:17.952
G1052741  04:17:27  07:45:28.4546  -21:59:55.4136
G1161155  04:18:36  07:49:28.493   -16:55:01.974
G1210259  04:19:46  07:51:22.1887  -19:17:28.266
G0574475  04:20:59  07:53:14.4965  -03:35:56.958
G0790912  04:22:08  07:54:16.573   -03:54:54.2916
G1202125  04:23:22  07:54:22.6044  -21:33:18
G0799865  04:24:35  07:54:48.415   -04:27:08.0424
G1344201  04:25:46  07:56:44.4067  -10:46:32.502
G1114070  04:27:00  07:56:44.7912  -16:23:08.3616
G1023494  04:28:10  07:57:02.1624  -11:59:53.4228
G0829552  04:29:20  07:57:13.0114  -11:09:51.7428
G1441820  04:30:31  07:57:13.4179  -05:20:47.0904
G1390582  04:31:40  07:57:13.927   -08:55:08.7456
G1313908  04:32:52  07:58:00.6317  -14:14:11.2452
G1378903  04:33:59  07:58:02.9059  -14:47:50.244
G0592514  04:35:11  07:58:41.801   -06:03:36.1764
G1299638  04:36:20  07:59:07.4158  -10:21:53.3088
G1379691  04:37:29  07:59:15.3698  -12:04:31.5768
G1293714  04:38:38  07:59:20.6287  -10:26:41.352
G0727439  04:39:48  08:00:07.5055  -07:39:54.2052
G1399423  04:40:59  08:00:13.9068  -12:22:42.5064
G0985954  04:42:09  08:00:25.4407  -13:56:12.5556
G0953501  04:43:20  08:00:34.2662  -08:56:27.924
G1309230  04:44:29  08:01:02.4922  -12:47:27.5028
G0648186  04:45:41  08:01:20.1746  -02:21:50.13
G0636265  04:46:52  08:01:22.2821  -09:11:00.7476
G1296421  04:48:00  08:01:34.8816  -10:10:59.3436
G1147199  04:49:09  08:01:35.9875  -12:57:11.7792
G1231402  04:50:19  08:01:41.1199  -09:56:08.3652
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N. Di Lalla (Stanford Univ.), F. Longo (University and INFN, Trieste),
D. Kocevski (NASA/MSFC),
N. Omodei (Stanford Univ.), M. Arimoto (Kanazawa Univ.), A. Berretta
(University & INFN Perugia),
M. Crnogorcevic (Univ. of Maryland & NASA/GSFC), M. Axelsson (KTH &
Stockholm Univ) and
E. Bissaldi (Politecnico & INFN Bari) report on behalf of the
Fermi-LAT Collaboration:

We have searched data collected by the Fermi Large Area Telescope (LAT) on
March 2, 2020, for possible high-energy (E > 100 MeV) gamma-ray emission in
spatial/temporal coincidence with the LIGO/Virgo trigger S200302c (GCN 27278
Loading...
 
 ).

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 ~23% of the LIGO probability at the time
of the trigger
(T0 = 2020-03-02 01:58:11.519 UTC), and reached 100% cumulative coverage
after ~5 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.

A marginally significant excess (with a  soft spectrum) was found at
the location
RA, Dec  63.3, Dec = 18.8 (degrees, J2000)
with an error radius of 1.0 deg (90% containment, statistical error only).

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 1.1e-10 and 1.1e-09 [erg/cm^2/s].

The Fermi-LAT point of contact for this event is
Makoto Arimoto (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.

The LIGO Scientific Collaboration and the Virgo Collaboration report:

We have conducted further analysis of the LIGO Hanford Observatory
(H1) and Virgo Observatory (V1) data around the time of the compact
binary merger (CBC) candidate S200302c (GCN Circular 27278
Loading...
 
 ). Parameter
estimation has been performed using LALInference [1] and a new sky
map, LALInference.fits.gz,0, distributed via GCN Notice, is available
for retrieval from the GraceDB event page:

https://gracedb.ligo.org/superevents/S200302c

The preferred sky map at this time is LALInference.fits.gz,0. For the
LALInference.fits.gz,0 sky map, the 90% credible region is 5656 deg2.
Marginalized over the whole sky, the a posteriori luminosity distance
estimate is 1820 +/- 536 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)

S. Nakahira (RIKEN), A. Yoshida, T. Sakamoto, V. Pal'shin,
S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), 
Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, 
T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), 
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:


The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger 
time of S200302c T0 = 2020-03-02 01:58:11.519 UT (The LIGO Scientific 
Collaboration and Virgo Collaboration, GCN Circ. 27278
Loading...
 
 ).

No CGBM on-board trigger occurred around the event time.  Based on the
LVC high probability localization region, the summed LIGO probabilities
inside the CGBM HXM (7 - 3000 keV) and SGM (40 keV - 28 MeV) fields
of view are 23 % and 54 %, respectively (and 81 % credible region of the
updated localization map was above the horizon).  The HXM and SGM fields
of view were centered at RA = 243.2 deg, Dec = +61.5 deg and 
RA = 245.4 deg, Dec = +51.6 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 high energy trigger
mode at the trigger time of S200302c. Using the CAL data, we have
searched for gamma-ray events in the 10-100 GeV band from -60 sec
to +60 sec from the GW trigger time and found no candidates. There 
was no significant overlap with the LVC high probability localization 
region at T0+-60 sec. The CAL FOV was centered at RA = 245.4 deg,
Dec = +51.6 deg at T0.

Q. Luo, Y. G. Zheng, C. Cai, S. Xiao, Q. B. Yi, 
Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, 
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team:

Insight-HXMT was taking data normally around the reported LIGO/Virgo 
S200302c event (GCN #27278
Loading...
 
 ). At the GW trigger time 
2020-03-02T01:58:21.38 UTC (denoted as T0), about 55.0% of the 
GW localization region was covered by the Insight-HXMT without 
occultation by the Earth.

Within T0 +/- 100 s, no significant excess events (SNR > 3 sigma) are 
found in a search of the Insight-HXMT/HE raw light curves.

Assuming the GW counterpart GRB with three typical GRB Band spectral 
models, two typical duration timescales (1 s, 10 s) from the center 
of the LIGO-Virgo location probability map (RA=40.1 deg, DEC=70.0 deg) 
without occultation by the Earth, 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-07 erg cm^-2
10 s:  1.4e-06 erg cm^-2

Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1 s:   4.5e-07 erg cm^-2
10 s:  1.6e-06 erg cm^-2

Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1 s:   4.6e-07 erg cm^-2
10 s:  1.7e-06 erg cm^-2

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (deposited energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the spacecraft.

V. Shenoy (IITB), Aarthy E. (PRL), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

We have carried a search for X-ray candidates in Astrosat CZTI data in a 100 sec window around the trigger time of the BBH Merger event S200302c (UTC 2020-03-02 01:58:11, GraceDB event). We use the LALInference.fits.gz,0 map (https://gracedb.ligo.org/api/superevents/S200302c/files/LALInference.fits.gz,0) for our analysis. CZTI is a coded aperture mask instrument that has considerable effective area for about 29% of the entire sky, but is also sensitive to brighter transients from the entire sky. At the time of the merger, Astrosat's nominal pointing is RA,DEC = 17:29:19.1, -36:43:40.5 (262.3296,-36.7279), which is ~29 deg away from the maximum probability location. At the time of the merger event, the Earth-satellite-transient angle corresponding to maximum probability location is ~74 deg and hence is not occulted by Earth in satellite's frame. In a time interval of 100 sec around the event, the region of the localisation map which is not occulted by Earth in the satellite's frame has a cumulative probability of 0.79 (79%).

CZTI data were de-trended to remove orbit-wise background variation. We then searched data from the four independent, identical quadrants to look for coincident spikes in the count rates. Searches were undertaken by binning the data in 0.1s, 1s, and 10s respectively. Statistical fluctuations in background count rates were estimated by using data from 10 (+-5) neighbouring orbits. We selected confidence levels such that the probability of a false trigger in a 1000 sec window is 10^-4. We do not find any evidence for any hard X-ray transient in this window, in the CZTI energy range of 20-200 keV.

We use a detailed mass model of the satellite to calculate the direction-dependent instrument response for points in the visible sky. We then assume the source is modelled as a power law with photon index alpha = -1, and convert our count rate upper limits to direction-dependent flux limits. We obtain the following upper limits for source flux in the 20-200 keV band by taking a probability weighted mean over the visible sky:

0.1 s: flux limit= 2.19e-05 ergs/cm^2/s; fluence limit = 2.19e-06 ergs/cm^2
1.0 s: flux limit= 6.45e-06 ergs/cm^2/s; fluence limit = 6.45e-06 ergs/cm^2
10.0 s: flux limit= 1.16e-06 ergs/cm^2/s; fluence limit = 1.16e-05 ergs/cm^2

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.

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

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

We performed tiled observations of LIGO/Virgo S200302c event with the 
FRAM-Auger, TAROT-Calern (TCA), TAROT-Reunion (TRE) telescopes.

FRAM-Auger is located at Pierre Auger Observatory. TCA is located at 
Calern site at the Cote d'Azur observatory. TRE is located at Les 
Makes astronomical observatory. 

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

+-------------+---------+----------+-----------+------------+
| Telescope   | Delay   | Filter   | f.o.v.    | Limiting   |
|             | [min]   |          | [deg]     | Mag.       |
|-------------+---------+----------+-----------+------------|
| FRAM-Auger  | 60      | R        | 1.0 x 1.0 | 18.0 (60s) |
| TCA         | 1051    | Clear    | 1.9 x 1.9 | 18.0 (60s) |
| TRE         | 1016    | Clear    | 4.2 x 4.2 | 17.0 (60s) |
+-------------+---------+----------+-----------+------------+

We performed the following joint tiled observations [1] :

+-------------+------------+------------+---------+---------+---------+
| Telescope   | TStart     | TEnd       | RA      | DEC     | Proba   |
|             | [UTC]      | [UTC]      | [deg]   | [deg]   | [%]     |
|-------------+------------+------------+---------+---------+---------|
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 225.799 | -62.757 | <0.1    |
|             | 02:57:54   | 03:02:21   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 226.286 | -61.784 | <0.1    |
|             | 03:02:55   | 03:07:22   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 244.873 | -57.892 | <0.1    |
|             | 03:08:01   | 03:12:28   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 236.685 | -60.811 | <0.1    |
|             | 03:13:04   | 03:17:31   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 230.718 | -60.811 | <0.1    |
|             | 03:18:07   | 03:22:34   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 232.707 | -60.811 | <0.1    |
|             | 03:23:09   | 03:27:36   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 230.400 | -61.784 | <0.1    |
|             | 03:28:10   | 03:32:37   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 227.929 | -62.757 | <0.1    |
|             | 03:33:11   | 03:37:38   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 218.057 | -61.784 | <0.1    |
|             | 03:38:15   | 03:42:42   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 222.171 | -61.784 | <0.1    |
|             | 03:43:17   | 03:47:44   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 223.669 | -62.757 | <0.1    |
|             | 03:48:18   | 03:52:45   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 232.457 | -61.784 | <0.1    |
|             | 03:53:21   | 03:57:48   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 216.000 | -61.784 | <0.1    |
|             | 03:58:25   | 04:02:52   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 228.343 | -61.784 | <0.1    |
|             | 04:03:30   | 04:07:57   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 220.114 | -61.784 | <0.1    |
|             | 04:08:33   | 04:13:00   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 221.538 | -62.757 | <0.1    |
|             | 04:13:35   | 04:18:02   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 224.229 | -61.784 | <0.1    |
|             | 04:18:38   | 04:23:05   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 210.829 | -60.811 | <0.1    |
|             | 04:23:41   | 04:28:08   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 214.807 | -60.811 | <0.1    |
|             | 04:42:19   | 04:46:46   |         |         |         |
| FRAM-Auger  | 2020-03-02 | 2020-03-02 | 226.740 | -60.811 | <0.1    |
|             | 04:47:23   | 04:51:50   |         |         |         |
| -----       | -----      | -----      | -----   | -----   | -----   |
| TCA         | 2020-03-02 | 2020-03-03 | 53.891  | 70.538  | 0.2     |
|             | 19:28:46   | 01:40:32   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-05 | 39.869  | 68.682  | 0.3     |
|             | 19:35:33   | 01:33:59   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-02 | 64.193  | 68.682  | 0.2     |
|             | 19:42:18   | 23:22:54   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-05 | 25.274  | 68.682  | 0.3     |
|             | 19:54:40   | 02:19:03   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-03 | 59.185  | 70.538  | 0.2     |
|             | 20:01:28   | 01:07:47   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-03 | 59.328  | 68.682  | 0.2     |
|             | 20:08:12   | 01:14:32   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-03 | 72.950  | 64.971  | 0.2     |
|             | 20:20:40   | 01:26:58   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-05 | 35.004  | 68.682  | 0.3     |
|             | 20:27:28   | 01:46:16   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-02 | 64.748  | 66.826  | 0.2     |
|             | 20:53:25   | 23:29:41   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-02 | 69.304  | 66.826  | 0.2     |
|             | 21:00:07   | 23:36:25   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-05 | 69.058  | 68.682  | 0.3     |
|             | 21:12:31   | 00:42:01   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-05 | 19.178  | 66.826  | 0.2     |
|             | 21:19:19   | 01:08:00   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-05 | 30.139  | 68.682  | 0.3     |
|             | 21:58:44   | 01:59:53   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-04 | 48.597  | 70.538  | 0.3     |
|             | 22:05:33   | 19:36:42   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-05 | 54.464  | 68.682  | 0.3     |
|             | 22:12:17   | 02:12:11   |         |         |         |
| TCA         | 2020-03-02 | 2020-03-04 | 44.734  | 68.682  | 0.3     |
|             | 22:31:28   | 18:18:55   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-05 | 38.009  | 70.538  | 0.3     |
|             | 02:01:10   | 02:25:45   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-04 | 43.303  | 70.538  | 0.3     |
|             | 02:27:02   | 18:44:56   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-04 | 73.923  | 68.682  | 0.3     |
|             | 02:53:00   | 20:02:39   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-04 | 82.975  | 66.826  | 0.3     |
|             | 02:59:43   | 22:18:50   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-05 | 78.418  | 66.826  | 0.3     |
|             | 03:25:45   | 00:54:22   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-04 | 91.939  | 63.115  | 0.2     |
|             | 03:44:54   | 03:37:08   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-05 | 23.735  | 66.826  | 0.2     |
|             | 03:57:27   | 01:27:10   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-05 | 85.656  | 64.971  | 0.3     |
|             | 05:15:18   | 00:35:18   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-05 | 49.599  | 68.682  | 0.3     |
|             | 18:39:13   | 01:53:08   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-05 | 14.621  | 66.826  | 0.2     |
|             | 20:22:59   | 01:20:18   |         |         |         |
| TCA         | 2020-03-03 | 2020-03-05 | 32.715  | 70.538  | 0.3     |
|             | 20:48:51   | 01:01:11   |         |         |         |
| -----       | -----      | -----      | -----   | -----   | -----   |
| TRE         | 2020-03-02 | 2020-03-02 | 226.452 | -45.000 | 0.3     |
|             | 18:54:05   | 19:00:22   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-03 | 230.000 | -65.455 | 0.4     |
|             | 19:13:14   | 00:19:30   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-03 | 226.286 | -36.818 | 0.5     |
|             | 19:51:28   | 20:44:29   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-03 | 220.645 | -45.000 | 0.3     |
|             | 20:04:43   | 01:10:37   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-03 | 231.429 | -61.364 | 1.4     |
|             | 21:59:10   | 18:05:12   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-02 | 214.286 | -61.364 | 1.2     |
|             | 22:12:21   | 22:18:44   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-02 | 205.714 | -61.364 | 0.7     |
|             | 22:31:04   | 22:37:21   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-02 | 256.154 | -53.182 | 0.7     |
|             | 22:44:19   | 22:50:42   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-02 | 237.447 | -57.273 | 1.0     |
|             | 22:56:37   | 23:02:55   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-02 | 249.231 | -53.182 | 0.8     |
|             | 23:09:53   | 23:16:10   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-02 | 223.636 | -40.909 | 0.4     |
|             | 23:22:10   | 23:28:27   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-02 | 234.545 | -40.909 | 0.4     |
|             | 23:35:23   | 23:41:46   |         |         |         |
| TRE         | 2020-03-02 | 2020-03-02 | 238.065 | -45.000 | 0.3     |
|             | 23:47:39   | 23:53:57   |         |         |         |
| TRE         | 2020-03-03 | 2020-03-03 | 218.182 | -40.909 | 0.3     |
|             | 00:00:52   | 00:07:15   |         |         |         |
| TRE         | 2020-03-03 | 2020-03-03 | 231.429 | -36.818 | 0.4     |
|             | 00:26:27   | 00:32:50   |         |         |         |
| TRE         | 2020-03-03 | 2020-03-03 | 245.455 | -40.909 | 0.3     |
|             | 00:38:43   | 00:45:00   |         |         |         |
| TRE         | 2020-03-03 | 2020-03-03 | 257.143 | -61.364 | 0.4     |
|             | 20:51:24   | 20:53:24   |         |         |         |
| TRE         | 2020-03-03 | 2020-03-03 | 267.273 | -40.909 | 0.5     |
|             | 22:58:53   | 23:05:16   |         |         |         |
| TRE         | 2020-03-03 | 2020-03-03 | 214.468 | -57.273 | 0.5     |
|             | 23:22:03   | 23:24:03   |         |         |         |
| TRE         | 2020-03-03 | 2020-03-03 | 233.766 | -28.636 | 0.5     |
|             | 23:30:59   | 23:37:22   |         |         |         |
+-------------+------------+------------+---------+---------+---------+

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 18.1% of the cumulative probability of 
the LALinference skymap created on 2020-03-02 19:23:46 (UTC).


The coverage map is available at: 
https://grandma-
owncloud.lal.in2p3.fr/index.php/s/XgtMhPRxcyL09gR/download?path=%2F&files=GRANDMA_S200302c_1583492088.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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Y.-L. Mong (1); K. Ackley (1); D. K. Galloway (1); D. Steeghs (2); V.
Dhillon (3); P. O'Brien (4); G. Ramsay (5); D. Pollacco (2); E. Thrane (1);
S. Poshyachinda (6); R. Kotak (7); L. Nuttall (8); E. Pall\'e (9); K.
Ulaczyk (2); J. Lyman (2); R. Cutter (2); A. Levan (2); T. Marsh (2); R.
West (2); E. Stanway (2); B. Gompertz (2); K. Wiersema (2); T. Killestein
(2); A. Casey (1); M. Brown (1); B. Muller (1); M. Dyer (3); J. Mullaney
(3); E. Daw (3); S. Littlefair (3); J. Maund (3); L. Makrygianni (3); U.
Burhanudin (3); R. Starling (4); R. Eyles (4); S. Tooke (4); S.
Aukkaravittayapun (6); U. Sawangwit (6); S. Awiphan (6); D. Mkrtichian (6);
P. Irawati (6); S. Mattila (7); T. Heikkil\"a (7); E. Rol (1)

We report on optical observations with the Gravitational-wave Optical
Transient Observer prototype in response to S200302c (GCN #27278
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 ).
Targeted observations started shortly after the preliminary event
notification was received. These spanned 102 unique tile pointings
containing 30.8% of the source location probability (based on the initial
BAYESTAR skymap) and were acquired between 20:15 UT Mar 02 2020 and
20:35 UT Mar 04 2020 (starting 18.3 hours after the event trigger time
01:58 UT Mar 02 2020). No new transients that could be credibly
associated with S200302c were detected.

Each pointing spans 4.9x3.7 square degrees and consisted of 3x60s
exposures in our L-band filter (400-700nm passband similar to g+r)
with a median 5-sigma photometric depth equivalent to g=19.1 for an
individual pointing. Limits are based on a photometric calibration
against PS1 sources. Most pointings were observed multiple times,
typically 2-3 times.

Images are processed immediately after acquisition using the GOTOphoto
pipeline. Difference imaging was performed on the median of each triplet
of exposures using recent survey observations of the same pointings.
Source candidates were initially filtered using a classifier and
cross-matched against a variety of catalogs, including the MPC and PS1.
Human candidate vetting was performed following data acquisition and
automated classifier cuts.

GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT), The University of Portsmouth,
the University of Turku and the Instituto de Astrofisica de Canarias
(IAC) (https://goto-observatory.org/)

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 S200302c (2020-03-02 01:58:11.519 UTC, hereafter T0;
LIGO/Virgo Collaboration GCN Circ. 27278
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 ).

No triggered KW GRBs happened between ~18 hours before and ~1 day
after T0. Using waiting-mode data within the interval T0 +/- 100 s,
we found no significant (> 5 sigma) excess over the background
in both KW detectors on temporal scales from 2.944 s to 100 s.

We estimate an upper limit (90% conf.) on the 20 - 1500 keV fluence
to 8.5x10^-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 2.5x10^-7 erg/cm^2/s (20 - 1500 keV, 2.944 s scale).

All the quoted values are preliminary.