LIGO/Virgo S191110af

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

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

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

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

D. Buckley
(South African Astronomical Observatory),

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

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

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




MASTER-Tavrida robotic telescope  (Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L)  located in Russia (Lomonosov MSU, SAI Crimea astronomical 
station) started inspect of the LIGO/Virgo S191110af errorbox  41 sec 
after trigger time at 2019-11-10 23:07:25 UT, with upper limit up to  16.5 
mag. The observations began at zenith distance = 78 deg. The sun  altitude 
is -55.8 deg.

MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, 
Kislovodsk Solar Station of Pulkovo observatory) started inspect of the 
LIGO/Virgo S191110af errorbox  240 sec after trigger time at 2019-11-10 
23:10:44 UT, with upper limit up to  16.9 mag. The observations began at 
zenith distance = 79 deg. The sun  altitude  is -51.3 deg.

The galactic latitude b = -60 deg., longitude l = 98 deg.


Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10908

We obtain a following upper limits.

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

       71 | 2019-11-10 23:07:25 |      MASTER-Tavrida | (16h 07m 26.66s , +57d 55m 00.4s) |   C |    60 | 16.1 |
      188 | 2019-11-10 23:09:22 |      MASTER-Tavrida | (17h 02m 30.68s , +59d 58m 16.8s) |   C |    60 | 16.5 |
      270 | 2019-11-10 23:10:44 |   MASTER-Kislovodsk | (15h 36m 28.22s , +55d 56m 45.4s) |   C |    60 | 16.9 |
      270 | 2019-11-10 23:10:44 |   MASTER-Kislovodsk | (15h 50m 47.97s , +55d 29m 20.1s) |   C |    60 | 16.9 |
      304 | 2019-11-10 23:11:17 |      MASTER-Tavrida | (17h 05m 18.61s , +59d 53m 22.1s) |   C |    60 | 16.0 |
      419 | 2019-11-10 23:13:13 |      MASTER-Tavrida | (16h 49m 58.92s , +58d 01m 16.2s) |   C |    60 | 15.0 |
Filter C is a clear (unfiltred) band.


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

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
S191110af
 in a time range of 1000 seconds [3] centered on the alert event time
(2019-11-10 22:58:24.183 UTC to 2019-11-10 23:15:04.183 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
S191110af calculated from the map circulated in the 2-Initial notice.

IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino
point sources within the locations spanned by the 90% spatial containment
of S191110af ranges from 0.029 to 1.067 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)

The LIGO Scientific Collaboration and the Virgo Collaboration report:


We identified the unmodeled transient candidate S191110af during real-
time processing of data from LIGO Hanford Observatory (H1), LIGO
Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-11-10
23:06:44.183 UTC (GPS time: 1257462422.183). The candidate was found
by the CWB [1] analysis pipeline.

S191110af is an event of interest because its false alarm rate, as
estimated by the online analysis, is 2.5e-09 Hz, or about one in 12
years. The event's properties can be found at this URL:

https://gracedb.ligo.org/superevents/S191110af


One sky map is available at this time and can be retrieved from the
GraceDB event page:
 * cWB.fits.gz,1 an initial localization generated by CWB [1],
    distributed via GCN notice about 10 minutes after the
    candidate event time.

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] Klimenko et al. PRD 93, 042004 (2016)

S. Sugita, M. Serino (AGU),
N. Kawai (Tokyo Tech), H. Negoro (Nihon U.),
M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.),
T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, H. Nishida, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.),
M. Shidatsu (Ehime U.), M. Oeda, K. Shiraishi (Tokyo Tech),
S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, N. Isobe,
R. Shimomukai, M. Tominaga (JAXA),
Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake
(Kyoto U.),
H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.),
M. Yamauchi, S. Iwahori, Y. Kurihara, K. Kurogi, K. Miike (Miyazaki U.),
T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), 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 S191110af at 2019-11-10 23:06:44.183 UTC (GCN 26222
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 ).

At the trigger time of S191110af, the high-voltage of MAXI/GSC was off,
and it was turned on at T0+768 sec (+12.8 min).
The first one-orbit (92 min) scan observation with GSC after the event
covered 70%
of the 90% credible region of the cWB skymap from 23:19:33 to 00:34:28
UTC (T0+769 to T0+5264 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.

C.A. Wilson-Hodge (NASA/MSFC) reports on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group

For S191110af and using the initial cWB.fits.gz skymap, Fermi-GBM was observing 90.5% 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 S191110af (GCN 26222
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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=315.2, Dec=9.0 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     norm     hard
--------------------------------------
0.128 s:   7.4      12.      20.
1.024 s:   2.2      3.4      5.6
8.192 s:   0.8      1.1      2.3

Sergey Molkov (IKI, Russia), Maeve Doyle (UCD, Ireland),
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
J. Rodi (IAPS-Roma, Italy)
A. Coleiro (APC, France)
S. Mereghetti (INAF IASF-Milano, Italy)

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

Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed
a search for a prompt gamma-ray counterpart of S191110af (GCN 26222
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 ).

At the time of the event (2019-11-10 23:06:44 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 105 deg with respect to
the spacecraft pointing axis. This orientation implies strongly
suppressed (6.1% of optimal) response of ISGRI, strongly suppressed
(22% of optimal) response of IBIS/Veto, and somewhat suppressed (59%
of optimal) respo nse 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 2.8e-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 ~2.4e-07 (8e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.

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

scale | T | S/N | flux ( x 1e-06 erg/cm2/s) | FAP
0.1 | 0.877 | 3.6 | 1.14 +/- 0.312 +/- 0.357 | 0.0497

3 likely background excesses:

scale | T | S/N | flux ( x 1e-06 erg/cm2/s) | FAP
0.2 | -31 | 3.7 | 0.832 +/- 0.22 +/- 0.261 | 0.735
0.95 | 185 | 3.8 | 0.385 +/- 0.1 +/- 0.121 | 0.853
0.65 | 63.2 | 3.4 | 0.413 +/- 0.121 +/- 0.13 | 0.953

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


All results quoted are preliminary.

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

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

[GCN OPS NOTE(12nov19):  Per author's request, the "unknown" in the Subject-line
was replavced with "S191110af".]

Hank Corbett (University of North Carolina), Kendall Ackley (Monash), Nicholas Law,
Ramses Gonzalez Chavez, Alan Vasquez, Jeffrey Ratzloff (UNC), Stephen S. Eikenberry (University of Florida),
Ward Howard, Amy Glazier, Nathan Galliher, Dan Reichart,
Josh Haislip, and Vladimir Kouprianov (UNC), Robert Quimby (San Diego State University)

The contact person for this circular is Hank Corbett (htc@unc.edu).

Evryscope-South, located at Cerro Tololo Inter-American Observatory, (Ratzloff et al. 2019, Law et al. 2015)
began observing the error region of LIGO/Virgo S191110af at 2019-11-11 01:00:05 UT during regular
science operations.  Evryscope-South has an instantaneous field of view of 8520 sq. degrees and observes
at a continuous 2-minute cadence in Sloan g'.

Evryscope-North, located at Mount Laguna Observatory, California, began observing the error region
of LIGO/Virgo S191110af at 2019-11-11 01:35:30 UT during regular science operations. Evryscope-North
has an instantaneous field of view of 7409 sq. degrees and observes at a continuous 2-minute cadence in Sloan g'.

Under current full-moon conditions, single-exposure limiting magnitudes ranged from 12.5 to 14.5 as
a function of moon elongation and airmass, averaging 13.7, calibrated to the ATLAS All-Sky Stellar
Reference Catalog (Tonry 2018).

We performed an automated search for optical transients over all Evryscope-South images within
5 hours of the alert, selecting candidates that appeared in multiple frames and were not associated
with previously-detected variable sources. During this interval, Evryscope-South observed 93% of the
LIGO/Virgo skymap and Evryscope-North observed 2% of the skymap. We found no candidates
within the visible 90% probability containment region for S191110af. Evryscope-North data analysis is ongoing.

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

In response to the LIGO/Virgo GW event S191110af at T0 = 2019-11-10 
23:06:44 (UT), analysis of AGILE data shows that the satellite at T0 was 
in the South Atlantic Anomaly (SAA). Scientific telemetry was inhibited 
during the time interval (T0 -700 s; T0 + 200 s).

At T0+200s we obtained a MCAL preliminary 3-sigma fluence upper limits 
(UL) for a 1 s integration time t different celestial positions within 
the accessible S191110af localization region, from a minimum of 1.46E-06 
erg cm^-2 to a maximum of 6.76E-06 erg cm^-2 (assuming as spectral model 
a single power law with photon index 1.5).

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

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


We have searched data collected by the Fermi Large Area Telescope (LAT)
on Nov 10, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission
in spatial/temporal coincidence with the LIGO/Virgo trigger S191110af
(GCN 26222
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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 ~18% of the LIGO probability region
at the time of the trigger (T0 = 2019-11-10 23:06:44.183 UTC)
and reached 100% cumulative coverage at approximately T0 + 5 ks.

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

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

Energy flux upper bounds between 100 MeV and 1 GeV
for the fixed time interval of this search vary
between 2.3e-10 and 1.3e-7 [erg/cm^2/s].

The Fermi-LAT point of contact for this event
is Michael Moss (michaelmoss@gwmail.gwu.edu).

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.

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 S191110af event using the 90% contour of the Initial CWB probability map provided by the GW interferometers (GCN#26222
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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 gw191110af_preliminary.png <https://www.cppm.in2p3.fr/~dornic/gw191110af_preliminary.png>. Considering the location probability provided by the LIGO/Virgo collaborations, there is a 56.0% chance that the GW emitter was in the ANTARES **upgoing** field of view at the time of the alert. No up-going muon neutrino candidate events were recorded in the ANTARES sky during a ��500s time-window centered on the time 2019-11-10 23:06:44 and in the 90% contour of the S191110af event. The expected number of atmospheric background events in the region visible by ANTARES is 4.5e-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 3.3e-03 in this larger time window.

Moreover, no increase of the event rate compatible with an excess of MeV neutrinos from a Galactic core-collapse supernova was detected within +/-1h from the GW trigger time.

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.

Sergey Molkov (IKI, Russia), Maeve Doyle (UCD, Ireland),
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
J. Rodi (IAPS-Roma, Italy)
A. Coleiro (APC, France)
S. Mereghetti (INAF IASF-Milano, Italy)

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

The GCN should be regarded as a substitute for 26225, which was not
processed correctly due to a technical issue.

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 S191110af (GCN 26222
Loading...
 
 ).

At the time of the event (2019-11-10 23:06:44 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 178 deg with respect to
the spacecraft pointing axis. This orientation implies strongly
suppressed (4.1% of optimal) response of ISGRI, near-optimal
(86% of optimal) response of IBIS/Veto, and strongly suppressed
(34% of optimal) response of SPI-ACS.

The background within +/-300 seconds around the event was very
stable (excess variance 1.2).

We have performed a search for any impulsive events in INTEGRAL
SPI-ACS (as described in [2]), IBIS, and IBIS/Veto data.

We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 5e-07 erg/cm^2 (within the
50% probability containment region of the source localization) for a
burst lasting less than 1s 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 300s 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 ~5.2e-07 (7.7e-08) erg/cm^2/s at 1s (8s) time scale
in 75-2000 keV energy range.

We report for completeness and in order of FAP, all excesses
identified in the search region. We find 1 possibly associated
excess:
scale | T�������� | S/N | flux ( x 1e-05 erg/cm2/s)�� | FAP
0.1���� | 0.877 | 3.6 | 2.07 +/- 0.739�� +/- 1.46���� | 0.0497

3 likely background excesses:
scale | T�������� | S/N | flux ( x 1e-05 erg/cm2/s)�� | FAP
0.2���� | -31���� | 3.7 | 1.51 +/- 0.52���� +/- 1.07���� | 0.735
0.95�� | 185���� | 3.8 | 0.701 +/- 0.237 +/- 0.495�� | 0.853
0.65�� | 63.2�� | 3.4 | 0.752 +/- 0.287 +/- 0.531�� | 0.953

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

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 (Uni. of Warwick), P. T. O'Brien (U. Leicester),
J. P. Osborne (U. Leicester), C. Pagani (U. Leicester),
K. L. Page (U.Leicester), M. J. Page (UCL-MSSL), M. Perri (ASDC),
J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU),
M. H. Siegel (PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (Toronto),
E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:

We report the search results in the BAT data within T0 +/- 100 s of the
LVC event S191110af (LIGO/VIRGO Collaboration GCN Circ. 26222
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 ),
where T0 is the LVC trigger time (2019-11-10T23:06:44.183 UTC).

The center of the BAT field of view (FOV) at T0 is
RA = 133.684 deg,
DEC = 20.134 deg,
and the roll angle is 98.137 deg.
The BAT FOV (>10% partial coding) covers 0.58% of the integrated
LVC localization probability, and 4.37% 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 ~ 8.26 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 ~ 25.00 Mpc.

No event data are available at this time.

BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 13.34% 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/S191110af/web/source_public.html

The IceCube Collaboration (http://icecube.wisc.edu/) has investigated the possibility that gravitational wave candidate S191110af is a burst 
event consistent with a core-collapse supernova in the Milky Way.  

IceCube can detect the O(10 MeV) neutrinos from a core-collapse supernova by searching for correlated increases in the hit rates of 
photosensors in the detector during the 10-second duration of the associated neutrino burst [1,2]. IceCube is primarily sensitive to 
inverse beta decay events produced by electron antineutrinos from the accretion phase of the supernova, and can observe a core-collapse 
event at any location in the Milky Way independent of the mass of the stellar progenitor [2].  

Two triggers in the IceCube MeV neutrino detection system bracket the time of the gravitational wave alert: one at 2019-11-10 16:21:11 and 
one at 2019-11-11 00:20:47. Both triggers are consistent with background fluctuations which occur at a false alarm rate of about 5/day.

Using the non-detection of a correlated increase in the hit rates in IceCube, we estimate the total energy emitted into neutrinos from the gravitational 
wave candidate to be

E < 6.5e50 erg * (d / 10 kpc)**2 * (15 MeV / E_avg)**2,

at 90% confidence, with d giving the distance to the burst and E_avg the average energy of emitted neutrinos.

The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole in Antarctica. 
The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu.

[1] R. Abbasi et al., Astronomy and Astrophysics 535, A109 (2011).
[2] R. Cross, A. Fritz, S. Griswold, PoS(ICRC2019) 889, arXiv:1908.07249
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  (2019).

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

At the trigger time of the compact binary merger candidate 
S191110af, T0 = 2019-11-10 23:06:44.183 UT (The LIGO 
Scientific Collaboration and Virgo Collaboration, GCN 
Circ. 26222
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 ), the CALET Gamma-ray Burst Monitor (CGBM)
high voltages were off (from T0-1 min to T0+31 min).

The CALET Calorimeter (CAL) was operating in the high 
energy trigger mode at the trigger time of S191110af. 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 8.4x10^-6 erg/cm^2/s (10-100 GeV) when the
summed LIGO-Virgo probability reaches 40%. The CAL FOV
was centered at RA= 218.6 deg, DEC= -42.7 deg at T0.

P.A. Evans (U. Leicester), K.L. Page (U.Leicester), J.A. Kennea (PSU),
A. Tohuvavohu (U. Toronto), S.D. Barthelmy (NASA/GSFC), A.P. Beardmore
(U. Leicester), M.G. Bernardini (INAF-OAB), A.A. Breeveld (UCL-MSSL),
P. Brown (TAMU), D.N. Burrows (PSU), S. Campana (INAF-OAB), S.B. Cenko
(NASA/GSFC), G. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P.
D'Avanzo (INAF-OAB), V. D'Elia(ASDC), S.W.K. Emery (UCL-MSSL), P.
Giommi (ASI), C. Gronwall (PSU), D. Hartmann (U. Clemson), H.A. Krimm
(CRESST/GSFC/USRA), N.J. Klingler (PSU), N.P.M. Kuin (UCL-MSSL), A.Y.
Lien (GSFC/UMBC), F.E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB),
J.A. Nousek (PSU), S.R. Oates (U. Warwick), P.T. O'Brien (U.
Leicester), J.P. Osborne (U. Leicester), C. Pagani (U. Leicester),
M.J.Page (UCL-MSSL), D.M. Palmer (LANL), M. Perri (ASDC), J.L. Racusin
(NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU), M.H. Siegel (PSU), G.
Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/UMCP) report on behalf of
the Swift team:

Swift has carried out 449 observations of the LVC error region for the
GW trigger S191110af, using the 'cWB' GW localisation map. Because this
was a 'burst' pipeline trigger with a high frequency, observations were
weighted towards the Galactic plane.The observations currently span
from 10 ks to 88 ks after the LVC trigger, and the XRT has covered 53.5
degrees^2 on the sky (corrected for overlaps). This covers 0.441% of
the probability in the 'cWB' skymap, and 16% after weighting towards
the Galactic plane is accounted for.

We have detected 11 X-ray sources. Each source is assigned a rank of
1-4 which describes how likely it is to be related to the GW trigger,
with 1 being the most likely and 4 being the least likely. The ranks
are described at https://www.swift.ac.uk/ranks.php.

We note that a number of GCN/COUNTERPART notices were issued with ranks
1 or 2; these also all had the WARN_FLAG field set to 1. These were
spurious sources caused by stray light from a bright X-ray source
outside of the nominal field of view. Counterpart notices are
automatically produced before any human vetting of the sources has been
carried out.

After vetting, we have found:

  * 0 sources of rank 1
  * 0 sources of rank 2
  * 5 sources of rank 3
  * 6 sources of rank 4

For all flux conversions and comparisons with catalogues and upper
limits from other missions, we assumed a power-law spectrum with
NH=3x10^20 cm^-2, and photon index (Gamma)=1.7

The results of the XRT automated analysis are online at
https://www.swift.ac.uk/LVC/S191110af

This circular is an official product of the Swift XRT team.

David Kaplan and John Friedman (University of Wisconsin-Milwaukee),
and Jocelyn Read (CSU Fullerton, Caltech) report on behalf of the
GROWTH collaboration:

The unmodelled GW burst S191110af (LVC, GCN 26222
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 ) consisted of a
narrow-band signal near 1781.72 Hz with duration 0.1 s.  This
frequency is consistent with the frequency of the fundamental
quadrupole mode of a star with mass in the range of 1.2 to 1.45 Msun
and radii within current estimates. We use Andersson & Kokkotas (1998,
MNRAS, 299, 10591068) Eqs. (1), (5) and (8) for the frequency, damping
time, and effective amplitude of the quadrupole f mode.  In
particular, for a neutron star with mass 1.25 Msun, a frequency of
1782 Hz corresponds to radius 13.3 km, and the damping time is then
0.2 s, consistent with observations.  Similarly, the range of EOS
considered in Chirenti et al. (2015, Phys. Rev. D 91, 044034) generate
f-modes along a band in frequency and decay time that seems compatible
with this candidate.

While we do not know the strain amplitude associated with this burst,
we can estimate a minimum detectable strain based on the observed
frequency, duration, and the LIGO noise properties.  At the observed
frequency we estimate a noise level of 1.5e-23 Hz**-0.5
(https://www.gw-openscience.org/detector_status/day/20191110/).
Following Eqs. (3) and (4) of Kokkotas et al. (2001, MNRAS, 320, 307)
we estimate that a signal with f=1782Hz and duration 0.15s will have
amplitude 5e-22, and SNR~10 in a detector with noise 1.5e-23 Hz**-0.5,
for a source at 1kpc emitting 2.5e-9 Msun c**2 of energy in
gravitational waves. Comparably, in a physical model where similar
oscillations come from a pulsar triggered by a significant glitch,
Keer & Jones (2015, MNRAS, 446, 865) estimate a stain of 3e-22 at a
distance of 1 kpc.

Motivated by this, we searched for potential counterparts among known
pulsars (note that if such a signal originates with a neutron star it
need not be visible as a pulsar). Based on the amplitude estimates
referenced above, we restrict our search to Galactic pulsars and do
not consider significantly more distant objects.

We looked at the latest version (1.61) of the ATNF pulsar catalog
(Manchester et al. 2005, AJ, 129, 1993;
http://www.atnf.csiro.au/research/pulsar/psrcat) and computed the
probability of the GW sky map at the position of each pulsar.  The top
3 pulsars ranked by probability are:

PSR J0045-7042 1.6e-3
PSR J0101-6422 2.4e-4
PSR B2045-16   4.9e-5

All other pulsars have probabilities <3e-5, and do not stand out from
the rest of the population, with 394 other sources at probabilities
>1e-6.

For these three pulsars:

PSR J0045-7042 is a slow (0.6s period) pulsar in the Small Magellanic
Cloud, and would not appear to be sufficiently energetic or close
enough to give rise to a significant GW signal.

PSR J0101-6422 is a nearby (~1 kpc), energetic (rotational energy loss
1.2e34 erg/s) millisecond pulsar in a 1.8d orbit, which is also a
Fermi gamma-ray source (Kerr et al. 2012, ApJ, 748, 2; Nolan et
al. 2012, ApJS, 199, 31).

PSR J2045-16 is a nearby (~0.8 kpc) slow (2.0s period) pulsar, which
does not appear otherwise notable.

Unfortunately, PSRs J0045-7042 and B2045-16 do not have sufficient
timing data to search for a recent glitch.  PSR J0101-6422 is timed
regularly with the Fermi Large Area Telescope, but detecting a
putative glitch will take weeks to months, depending on the magnitude
of the glitch (M. Kerr and P.S. Ray, private communication).  As
mentioned above, any or none of these sources could be the origin of
the possible gravitational wave emission, or the candidate could be
terrestrial in origin.  It also may be worth searching for short GW
bursts associated with known glitches, especially those from the Vela
pulsar (as in Abadie et al. 2011, PRD 83, 042001).

We thank Joe Swiggum, Sinead Walsh, Nils Andersson, and Cecilia
Chirenti for helpful conversations.  GROWTH is a worldwide
collaboration comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC,
Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan;
UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IIT-B, India; IIA,
India; LJMU, UK; TTU USA and USyd, Australia. GROWTH acknowledges
generous support of the NSF under PIRE Grant No 1545949.

D. Svinkin, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, 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 S191110af (2019-11-10 23:06:44.183 UTC, hereafter T0;
LIGO/Virgo Collaboration GCN Circ. 26222
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 ).

No triggered KW GRBs happened between ~5 days before and ~14 hours
after T0. The closest waiting-mode GRB was observed ~9 hours 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 9.6x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having a
typical KW short GRB spectrum (an exponentially cut off power law with
alpha =-0.5 and Ep=500 keV). For a typical long GRB spectrum (the Band
function with alpha=-1, beta=-2.5, and Ep=300 keV), the corresponding
limiting peak flux is 2.6x10^-7 erg/cm^2/s (20 - 1500 keV, 2.944 s scale).

All the quoted values are preliminary.

M. Colomer (APC, Universite de Paris), M. Lincetto (Aix Marseille Univ, CNRS/IN2P3, CPPM), A. Coleiro (APC, Universite de Paris), D. Dornic (Aix Marseille Univ, CNRS/IN2P3, CPPM), V. Kulikovskiy (INFN - Sezione di Genova), report on behalf of the KM3NeT Collaboration.

Using online data from the KM3NeT detector, we have performed a follow-up analysis of the recently reported gravitational-wave (GW) burst candidate S191110af (GCN #26222
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 ) to investigate the possibility that this burst was emitted by a core-collapse supernova (CCSN) event.

KM3NeT can detect ~10 MeV neutrinos from a Galactic CCSN through a collective rise of the photomultiplier (PMT) detection rates on top of the noise due to the Cherenkov light produced by the interaction of electron antineutrinos through inverse beta decay. This is expected  mostly during the CCSN accretion phase (lasting a few hundred ms) where most of the electron antineutrinos are supposed to be emitted [1].

No CCSN trigger in the KM3NeT/ORCA online infrastructure was detected during a 400 ms time-window, starting at the time of the GW trigger, while 0.8 events are expected on average from the background at trigger time. 

Using Feldman and Cousins approach, a preliminary 90% confidence level upper limit on the number of signal events is estimated. Assuming two progenitor models from the Garching group [2] with masses of 27 Msun and 11.2 Msun, we derive an upper limit on the distance of the potential source of 11.4 kpc and 5.7 kpc respectively.

Moreover, assuming a quasi-thermal neutrino spectrum as in [2] with a spectral pinching parameter value of 3 and a mean neutrino energy of 15 MeV and assuming that 70% of the energy is released in the 400 ms, the total energy emitted into neutrinos from this GW burst candidate is determined to be E < 2.8e53 erg at 10 kpc.

KM3NeT detectors are currently under construction in the Mediterranean Sea. The ORCA detector is nowadays composed of an array of 4 instrumented lines, each containing 18 digital optical modules hosting 31 directional PMTs. It is equivalent to a 3 kton CCSN neutrino detector. With the current configuration, ORCA detector can detect a CCSN at 5 sigma up to 3.5 and 7.5 kpc respectively for the low and high-mass progenitor considered in the CCSN neutrino flux models of the Garching group.

[1] M. Colomer, M. Lincetto et al. (on behalf of the KM3NeT collaboration), PoS(ICRC2019)857.
[2] I. Tamborra et al., Phys. Rev. D, 90 (2014).

The LIGO Scientific Collaboration and the Virgo Collaboration report:

The trigger S191110af (GCN Circular 26222
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 ) is no longer considered to
be a candidate of interest. Further analysis by the cWB [1] pipeline
and investigations of the data quality at LIGO Hanford identified a
short period with an elevated rate of instrumental artifacts in the
frequency range of the trigger.

[1] Klimenko et al. PRD 93, 042004 (2016)