LIGO/Virgo S190718y

IceCube Collaboration (http://icecube.wisc.edu/) reports:

Searches [1,2] for track-like muon neutrino events detected by IceCube
consistent with the sky localization of gravitational-wave candidate
S190718y
 in a time range of 1000 seconds [3] centered on the alert event time
(2019-07-18 14:26:52.068 UTC to 2019-07-18 14:43:32.068 UTC) have been
performed.  During this time
period IceCube was collecting good quality data.  No significant track-like
events are found in spatial coincidence of S190718y calculated from the map
circulated in the 3-Initial notice.

IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino
point sources within the locations spanned by the 90% spatial  containment
of S190718y ranges from  0.029 to 1.150 GeV cm^-2 in a 1000 second
time window.

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


[1] Bartos et al. arXiv:1810.11467
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  (2018) and Countryman et
al.arXiv:1901.05486
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  (2019)
[2] 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 compact binary merger candidate S190718y during
real-time processing of data from LIGO Hanford Observatory (H1), LIGO
Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-07-18
14:35:12.068 UTC (GPS time: 1247495730.068). The candidate was found
by the GstLAL [1] analysis pipeline.

S190718y is an event of interest because its false alarm rate, as
estimated by the online analysis, is 3.6e-08 Hz, or about one in 10
months. The event's properties can be found at this URL:

https://gracedb.ligo.org/superevents/S190718y

There were glitches in the interferometers tens of seconds before 
merger which may affect the sky maps. Further analysis is underway.

The classification of the GW signal, in order of descending
probability, is Terrestrial (98%), BNS (2%), NSBH (<1%), BBH (<1%), or
MassGap (<1%).

Assuming the candidate is astrophysical in origin, there is strong
evidence for the lighter compact object having a mass < 3 solar masses
(HasNS: >99%). Using the masses and spins inferred from the signal,
there is strong evidence for matter outside the final compact object
(HasRemnant: >99%).

One sky map is available at this time and can be retrieved from the
GraceDB event page:
 * bayestar.fits.gz, an updated localization generated by BAYESTAR
[2], distributed via GCN notice about 27 minutes after the candidate

For the bayestar.fits.gz sky map, the 90% credible region is 7246
deg2. Marginalized over the whole sky, the a posteriori luminosity
distance estimate is 227 +/- 165 Mpc (a posteriori mean +/- standard
deviation).

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

 [1] Messick et al. PRD 95, 042001 (2017)
 [2] Singer & Price PRD 93, 024013 (2016)

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

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

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

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

D. Buckley 
(South African Astronomical Observatory),

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

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

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




MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the LIGO/Virgo S190718y errorbox  1850 sec after trigger time at 2019-07-18 15:06:02 UT, with upper limit up to  18.4 mag. The observations began at zenit distance = 23 deg. The sun  altitude  is -18.6 deg. 

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


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10491

We obtain a following upper limits.  

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

    1880 | 2019-07-18 15:06:02 |         MASTER-Amur | ( 20h 34m 43.42s , +32d 26m 26.69s) |   C |    60 | 18.4 |        
    1968 | 2019-07-18 15:07:30 |         MASTER-Amur | ( 20h 30m 10.98s , +32d 38m 06.07s) |   C |    60 | 18.4 |        
    2057 | 2019-07-18 15:08:58 |         MASTER-Amur | ( 20h 34m 43.58s , +32d 26m 25.35s) |   C |    60 | 18.4 |        
    2145 | 2019-07-18 15:10:27 |         MASTER-Amur | ( 20h 30m 11.11s , +32d 38m 07.77s) |   C |    60 | 18.4 |        
Filter C is a clear (unfiltred) band. 


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

M. Ageron (CPPM/CNRS), B. Baret (APC/CNRS), A. Coleiro (APC/Universite de Paris), M. Colomer 
(APC/Universite de Paris), D. Dornic (CPPM/CNRS), A. Kouchner (APC/Universite de Paris), 
T. Pradier (IPHC/Universite de Strasbourg) report on behalf of the ANTARES Collaboration:

Using on-line data from the ANTARES detector, we have performed a follow-up analysis of the
recently reported LIGO/Virgo S190718y event using the 90% contour of the bayestar probability
map provided by the GW interferometers (GCN#25087
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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/S190718y.png <http://antares.in2p3.fr/GW/S190718y.png>. Considering the location probability provided by the 
LIGO/Virgo collaborations, there is a 77.5% chance that the GW emitter was in the ANTARES **upgoing** 
field of view at the time of the alert.

No up-going muon neutrino candidate events were recorded in the ANTARES sky during a
+/-500s time-window centered on the time 2019-07-18 14:35:12 and in the 90% contour of the S190718y
event. The expected number of atmospheric background events in the region visible by ANTARES is
1.88e-03 in the +/- 500s time window. An extended search during +/- 1 hour gives no
up-going muon neutrino coincidence. The expected number of atmospheric background events in the
region visible by ANTARES is 1.36e-02 in this larger time window.

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

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

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

Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed
a search for a prompt gamma-ray counterpart of S190718y (GCN 25087
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 ).

At the time of the event (2019-07-18 14:35:12 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 30 deg with respect to the
spacecraft pointing axis. This orientation implies strongly suppressed
(19% of optimal) response of ISGRI, strongly suppressed (29% of
optimal) response of IBIS/Veto, and somewhat suppressed (55% o f
optimal) response of SPI-ACS.

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

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

We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 2.8e-07 erg/cm^2 (within the
50% probability containement region of the source localization) for a
burst lasting less than 1 s with a characteristic short GRB spectrum
(an exponentially cut off power law with alpha=-0.5 and Ep=600 keV)
occurring at any time in the interval within 300 s around T0. For a
typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and
Ep=300 keV), the derived peak flux upper limit is ~2.5e-07 (9.4e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.

For the mean reported distance 227.0 Mpc this corresponds to the limit
on the total isotropic equivalent energy in 1 s of 1.7e+48 erg for the
short GRB spectrum and for a long GRB spectrum isotropic equivalent
luminosity in 1 s (8 s) of 1.5e+48 erg/s (5.8e+47 erg/s)


All results quoted are preliminary.

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

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

B. Mailyan (UAH), R. Hamburg (UAH) and A. Goldstein (USRA) report
on behalf of the Fermi-GBM Team and the GBM-LIGO/Virgo group:

For the LIGO/Virgo detection of GW trigger S190718y (GCN 25087
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 ) and using
the initial BAYESTAR skymap, Fermi-GBM was observing 24.0% of the
localization probability at event time.

There was no Fermi-GBM onboard trigger around the event time of S190718y.
An automated, blind search for short gamma-ray bursts below the onboard
triggering threshold in Fermi-GBM also identified no counterpart
candidates. The GBM
targeted search, the most sensitive, coherent search for GRB-like signals,
was run
from +/- 30 s around merger time, and also identified no counterpart
candidates.

Part of the LVC localization region is behind the Earth for Fermi, located
at RA = 15.0 and Dec = 11.4  with a radius of 67.3 degrees.
We therefore set upper limits on impulsive gamma-ray emission. Using the
representative soft, normal, and
hard GRB-like templates described in arXiv:1612.02395
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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^-8 erg/s/cm^2):

Timescale  soft     norm     hard
--------------------------------------
0.128 s:   7.2        16.       47.
1.024 s:   3.6        7.2       18.
8.192 s:   1.1        2.0       5.4

Assuming the median luminosity distance of 227 Mpc (z=0.051) from the GW
detection, we estimate the following intrinsic luminosity upper limits over
the 1 keV-10 MeV energy range (in units of 10^47 erg/s):

Timescale  soft     norm     hard
--------------------------------------
0.128 s:   6.84    14.2     68.4
1.024 s:   3.42    6.37     26.2
8.192 s:   1.04    1.77     7.86

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

We report the search results in the BAT data within T0 +/- 100 s of the
LVC event S190718y (LIGO/VIRGO Collaboration GCN Circ. 25087
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 ),
where T0 is the LVC trigger time (2019-07-18T14:35:12.067 UTC).

The center of the BAT FOV at T0 is
RA = 357.719 deg,
DEC = -45.287 deg,
and the ROLL angle is 94.804 deg.
The BAT Field of View (>10% partial coding) covers 6.27% of the integrated
LVC localization probability, and 11.94% of the galaxy convolved
probability (Evans et al. 2016).

Swift/BAT was in SAA during this time. Within T0 +/- 100 s, no significant
detections are found in the BAT raw light curves with time bins of 64 ms,
1 s, and 1.6 s. The flux upper limit estimation is unavailable due
to the rapid increase of background during the SAA.

BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 23.33% of the integrated LVC
localization probability was outside of the BAT FOV but above the
Earth's limb from Swift's location, and the corresponding flux upper limits
for this region are within roughly an order of magnitude higher than those
within the FOV.

The results of the BAT analysis are available at
https://swift.gsfc.nasa.gov/results/BATbursts/team_web/S190718y/web/source.html

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

The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger 
time of S190718y T0 = 2019-07-18 14:35:12.068 UT (The LIGO
Scientific Collaboration and Virgo Collaboration, GCN Circ. 25087
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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 9 % and 17 %, respectively (and 22 % credible region of the 
initial localization map was above the horizon).  The HXM and SGM fields
of view were centered at RA = 203.3 deg, Dec = -18.0 deg and 
RA = 195.8 deg, Dec = -11.1 deg at T0, respectively.

Based on the analysis of the light curve data with 0.125 sec
time resolution from T0-60 sec to T0+60 sec, we found no
significant excess (signal-to-noise ratio >= 7) around the trigger
time in either the HXM or the SGM data.

The CALET Calorimeter (CAL) was operating in the low energy
trigger mode at the trigger time of S190718y. Using the CAL data,
we have searched for gamma-ray events in the 1-10 GeV
band from -60 sec to +60 sec from the GW trigger time and
found no candidates.
The 90% upper limit of CAL is 1.7x10^-6 erg/cm^2/s (1-10 GeV) when
the summed LIGO-Virgo probability reaches 5%.
The CAL FOV was centered at RA = 195.8 deg, DEC = -11.1 deg at T0.

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

We examined MAXI/GSC all-sky X-ray images (2-20 keV) 
after the LVC trigger S190718y at 2019-07-18 14:35:12.067 UTC (GCN 25087
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 ).

At the trigger time of S190718y, the high-voltage of MAXI/GSC was on.
The instantaneous field of view of GSC at the GW trigger time covered 1% of the 90% credible region 
of the bayestar sky map, in which we found no significant new X-ray source.
The first one-orbit (92 min) scan observation with GSC after the event covered 95% 
of the 90% credible region of the bayestar skymap from 14:35:12 to 16:07:8 UTC (T0+0 to T0+5516 sec).

No significant new source was found in the region in the one-orbit scan observation.
A typical 1-sigma averaged upper limit obtained in one scan observation
is 20 mCrab at 2-20 keV.

If you require information about X-ray flux by MAXI/GSC at specific coordinates,
please contact the submitter of this circular by email.

M. Axelsson (KTH and Stockholm Univ.), E. Bissaldi (Politecnico and INFN Bari), F.Longo (University and INFN, Trieste) and M. Palatiello (University and INFN, Trieste) report on behalf of the Fermi-LAT Collaboration:

We have searched data collected by the Fermi Large Area Telescope (LAT) on July 18, 2019, for possible high-energy (E > 100 MeV) gamma-ray emission in spatial/temporal coincidence with the LIGO/Virgo trigger S190718y (GCN 25087
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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 a time, and "cumulative coverage" as the integral of the instantaneous coverage over time. Fermi-LAT had instantaneous coverage of ~30% of the LIGO probability region at the time of the trigger (T0 = 2019-07-18 14:35:12.068 UTC), and reached ~98% coverage at T0+4 ks. The remaining area was not observed within 10 ks of the trigger.

We performed a search for a transient counterpart within the observed region of the 90% contour of the LIGO map in a fixed time window from T0 to T0+10 ks. No significant sources were found. We also performed a search which adapted the time interval of the analysis to the exposure of each region of the sky, and no additional excesses were found.

Energy flux upper bounds for the fixed time interval between 100 MeV and 1 GeV for this search vary between 9.8e-11 and 1.1e-07 [erg/cm^2/s].

The Fermi-LAT point of contact for this event is Michele Palatiello (michele.palatiello@gmail.com<mailto:michele.palatiello@gmail.com>).

The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.

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

Insight-HXMT was taking data normally around the reported LIGO/Virgo 
S190718y event (GCN #25087
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 ), trigger time 2019-07-18T14:35:12.000 UTC. 
At T0, about 91% of the 90% credible region and all of the 50% credible 
region of the bayestar sky map were covered by the Insight-HXMT 
without occultation by the Earth.

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

Assuming the GW counterpart GRB with three typical GRB Band spectral 
models, two typical duration timescales (1 s, 10 s) from the center 
of the LIGO-Virgo location probability map (RA=305 deg, DEC=32 deg), 
the 5-sigma upper-limits fluence (0.2 - 5 MeV, incident energy) are 
reported below:

Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV):
1 s:   3.2e-08 erg cm^-2
10 s:  1.5e-07 erg cm^-2

Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1 s:   5.7e-08 erg cm^-2
10 s:  2.8e-07 erg cm^-2

Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1 s:   1.8e-07 erg cm^-2
10 s:  9.4e-07 erg cm^-2

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

Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.

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

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The 
Instituto de Astrofisica de Canarias),

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico 
Felix Aguilar OAFA, San Juan National University),

D. Buckley (South African Astronomical Observatory),

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

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

O. Gress, N.M. Budnev, O.Ershova
(Applied Physics Institute, Irkutsk Stat University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev
(Blagoveschensk   Education State University),

MASTER OT J203053.79+384020.1 / AT2019lly
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  discovery

MASTER-IAC auto-detection system discovered OT source at
(RA, Dec) = 20h 30m 53.79s +38d 40m 20.1s on 2019-07-18.92684 UT.

The OT unfiltered magnitude is 14.9m (limit 19.4m).

The OT is seen in 2 images. There is no minor planet at this place.
We have reference image without OT on 2019-07-09.14716 UT with unfiltered
magnitude limit 19.7m.

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/203053.79384020.1.png

There is a DSS  source inside 2" with mag = 20.0m.
This flash is registered in the error box GW S190718y,but is probably 
unrelated to the GW event (Cataclysmic Variable)

MASTER cover map of Ligo/Virgo S190718y error-field inspection  will be
available on-line at:
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10491

This message may be cited.

The LIGO Scientific Collaboration and the Virgo Collaboration report:

We performed a preliminary follow-up investigation of the compact
binary merger candidate S190718y reported in GCN 25087
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 . We removed
glitches reported therein, using the PyCBC [1] gating method and
reanalyzed the data with PyCBC / Bayestar [2], and also using the same
template as the gstlal event. The analysis yields no evidence for
retracting this event. There are no updates to the p_astro or
significance of this event at this time.

The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S190718y

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

[1] Nitz et al. PRD 98, 024050 (2018)
[2] Singer & Price PRD 93, 024013 (2016)

Igor Andreoni (Caltech) reports on behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations


We searched for Zwicky Transient Facility (ZTF) detections associated with MASTER OT J203053.79+384020.1 / AT2019lly
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  (Lipunov et al., GCN #25105
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 ) in the archive of ZTF alerts.  A point source (g=19.85 +- 0.03) is present in the ZTF reference image at the location of AT2019lly
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  and an outburst was detected on 2019-07-15 08:00:18 UT at magnitude g=14.240 +- 0.027.

The ZTF detection occurred 3 days before the gravitational wave candidate S190718y (LIGO and Virgo Collaboration, GCN #25087
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 , GCN #25107
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 ), excluding an association between MASTER OT J203053.79+384020.1 / AT2019lly
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  and S190718y.  Our conclusion is in agreement with the Cataclysmic Variable scenario suggested by Lipunov et al. (GCN #25105
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 ). 


ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IIT-B, India; IIA, India; LJMU, UK; TTU USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019).

Nachiket Girish, Sergiy Vasylyev, Keto Zhang, WeiKang Zheng,
Andrew Hoffman, Benjamin Stahl, and Alexei V. Filippenko (UC Berkeley)
report on behalf of the Lick/KAIT GW follow-up team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, observed the 90% region of the gravitational-wavei
event S190718y (GCN 25087
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 ; GCN 25107
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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 209 of them based on
their priority scores and elevation visibility, with each clear-filter
exposure time being 60 s. The first image was taken at 04:56:24, July
19th UT, about 14.4 hours after the trigger, and the last image at
11:34:24 UT. Our typical limiting mag is 19.0. No viable counterparts
were identified and the analysis is ongoing. A full list of galaxies
observed by KAIT is given below.

GladeID   UT(July19)  RA_J2000   Dec_J2000
-----------------------------------------------
G0623381  04:56:24  19:20:57.4073  +43:07:57.2052
G0655708  04:57:39  19:36:18.7061  +37:48:07.0164
G1132664  04:58:57  20:11:08.335   +45:15:15.8904
G0172766  05:00:14  20:15:02.6366  +31:40:50.8296
G0419718  05:01:32  20:16:30.2345  +44:21:15.2244
G0673986  05:02:51  20:16:34.5043  +26:58:34.4244
G1298003  05:04:11  20:17:45.769   +45:50:47.634
G0287573  05:05:30  20:19:38.1226  +27:00:10.9368
G0998960  05:06:52  20:19:51.2474  +48:16:20.5572
G1457918  05:08:15  20:20:02.3364  +25:08:48.0444
G1243102  05:09:25  20:21:42.3341  +26:55:00.642
G0289368  05:10:46  20:24:08.1226  +46:28:07.7484
G0002313  05:12:08  20:24:20.2296  +27:03:49.9032
G0418118  05:13:27  20:24:50.8008  +43:02:35.0304
G0639498  05:14:46  20:28:28.8427  +25:43:24.1932
G0563453  05:15:55  20:28:35.0611  +25:44:00.1788
G0041653  05:17:15  20:28:44.9779  +45:41:01.1724
G0721807  05:18:37  20:29:05.9693  +24:42:22.5576
G0428552  05:19:50  20:29:39.463   +32:37:34.4892
G0312245  05:20:59  20:30:29.1065  +33:36:02.8224
G0645883  05:22:11  20:30:29.5531  +27:40:42.906
G0414637  05:23:22  20:30:43.7182  +33:00:07.9092
G1207128  05:24:33  20:37:17.7101  +25:31:37.7652
G1439906  05:25:45  20:38:34.4604  +34:03:23.3172
G0452646  05:26:56  20:38:46.6332  +28:18:13.9572
G1405973  05:28:06  20:39:22.0385  +27:42:40.7952
G1467496  05:29:15  20:39:22.8662  +29:33:27.792
G0217063  05:30:26  20:40:35.5738  +37:40:18.282
G1429059  05:31:37  20:40:46.6478  +30:07:10.6356
G0171171  05:32:49  20:42:15.6372  +37:40:31.4544
G0628332  05:52:51  20:44:09.7999  +33:59:41.5968
G0776012  05:54:03  20:45:56.9458  +28:31:56.0208
G0057545  05:55:14  20:46:38.9942  +36:31:22.7424
G1172157  05:56:23  20:49:25.6788  +33:20:57.714
G1117494  05:57:33  20:53:42.81    +37:56:12.0336
G0142750  05:58:48  20:57:57.7296  +41:06:53.3484
G1069636  05:59:57  21:00:42.2242  +39:53:22.6644
G0862987  06:01:07  21:05:12.3926  +40:46:35.4036
G1444432  06:02:16  21:06:54.9828  +39:55:27.264
G0233317  06:03:25  21:07:28.6963  +40:01:22.026
G1449915  06:04:35  21:08:52.7638  +42:14:50.964
G0175642  06:05:54  21:13:55.752   +51:17:37.68
G0416212  06:07:10  21:14:41.0669  +44:06:32.5836
G1086036  06:08:19  21:14:47.4756  +42:31:12.7308
G1474801  06:09:28  21:16:49.9291  +41:36:48.4164
G1054563  06:10:38  21:18:05.1929  +43:57:30.7512
G0959572  06:11:47  21:18:57.8978  +40:50:12.012
G0778794  06:13:03  21:20:30.066   +37:35:00.2292
G0002434  06:14:14  21:20:42.4805  +44:23:59.0712
G0705251  06:15:23  21:21:39.0454  +44:03:49.9572
G0003499  06:16:35  21:35:32.688   +35:23:54.168
G0636708  06:17:44  21:36:39.353   +35:41:40.8444
G0811558  06:49:28  19:21:10.0488  +43:56:44.3184
G0800990  06:50:37  19:21:31.9044  +43:59:43.4508
G0789501  06:51:47  19:22:31.9922  +44:03:38.5884
G0746609  06:52:56  19:29:59.7144  +43:28:28.8948
G1418181  06:54:18  20:02:49.8852  +49:19:11.2296
G0383988  06:55:29  20:19:01.4722  +44:31:54.642
G0210012  06:56:38  20:21:56.1694  +46:35:14.4024
G0348545  06:57:48  20:23:03.2959  +45:55:17.3208
G0446797  06:59:02  21:09:03.8964  +42:36:11.4624
G0415024  07:00:26  21:11:57.0557  +54:14:51.6228
G1149403  07:01:47  21:13:38.5253  +42:10:46.2972
G1060955  07:02:57  21:17:24.7558  +43:07:26.7312
G0044507  07:04:16  21:18:24.9902  +51:23:57.7104
G1111208  07:05:36  21:18:33.6475  +40:59:52.5696
G1116069  07:06:45  21:19:05.2882  +42:27:31.122
G1367883  07:07:54  21:20:58.5499  +38:03:24.3324
G0305271  07:09:06  21:23:06.7896  +43:29:21.3684
G0540762  07:10:15  21:25:36.1303  +47:42:24.3792
G1394842  07:11:26  21:26:50.0244  +38:12:04.698
G1407104  07:12:36  21:31:30.7764  +38:56:38.1552
G1112914  07:13:47  21:42:08.5913  +33:56:54.2364
G1243714  07:14:56  21:45:18.7279  +34:27:32.22
G0275039  07:16:06  21:49:28.3226  +36:06:06.0228
G0553168  07:18:56  21:53:38.8622  +32:47:28.77
G1460879  07:21:45  21:54:08.7305  +32:54:24.876
G0692325  07:51:02  22:01:07.3901  +16:33:50.1228
G0643019  07:52:24  22:04:40.1441  -16:57:46.3788
G0651982  07:53:46  22:05:40.8912  +16:47:06.72
G0717972  07:54:55  22:09:01.5161  +17:49:17.3136
G0663093  07:56:04  22:09:02.5634  +17:50:19.3164
G0695974  07:57:16  22:11:35.376   +25:51:51.7752
G0798670  07:58:29  22:21:47.6148  +25:19:13.008
G0687421  08:01:18  22:26:54.3677  +19:32:53.6532
G0693516  08:02:28  22:33:50.4785  +20:48:18.9972
G0684178  08:03:37  22:36:28.0298  +21:37:18.6276
G0644132  08:04:53  23:05:27.3706  +21:09:43.272
G0270067  08:06:04  23:18:43.3301  +22:52:26.8752
G0565999  08:07:13  23:20:05.669   +24:13:16.0356
G0657290  08:08:23  23:22:47.5416  +22:56:12.2064
G1269436  08:09:32  23:25:44.8169  +21:04:07.3704
G0873371  08:10:41  23:27:02.6806  +20:15:39.9024
G1089235  08:11:51  23:31:24.8071  +22:48:24.3108
G1453130  08:13:00  23:31:47.5416  +21:31:20.4528
G0635673  08:14:13  23:31:50.2368  +25:32:40.0164
G1460379  08:15:29  23:31:59.2382  +12:58:57.7092
G0507421  08:16:44  23:32:58.1762  +25:57:39.672
G0604275  08:17:54  23:34:05.4785  +22:59:00.0024
G1851005  08:19:03  23:34:49.2     +26:18:39.636
G0801572  08:20:19  23:34:55.2612  +14:17:31.074
G0940627  08:21:30  23:35:13.9452  +22:56:18.8592
G1428518  08:22:40  23:35:35.7934  +20:41:59.5356
G0616925  08:23:49  23:35:39.192   +21:04:39.5544
G0795523  08:24:58  23:36:38.9575  +20:48:06.1992
G0695340  08:26:08  23:36:39.7193  +21:06:07.2036
G1217882  08:47:45  23:36:56.9386  +23:11:07.2348
G0742036  08:49:01  23:37:05.3614  +15:55:58.242
G0717159  08:50:10  23:37:09.3163  +15:55:00.2604
G1458621  08:51:24  23:37:26.316   +09:07:37.1856
G0950103  08:52:39  23:38:00.6151  +20:57:22.05
G0251333  08:53:53  23:38:02.9371  +12:52:12.252
G0771275  08:55:06  23:38:26.9897  +04:48:05.0724
G0614282  08:56:22  23:38:42.2242  +21:30:03.8664
G0772475  08:57:33  23:38:50.603   +27:16:03.9072
G1135364  08:58:45  23:38:55.3418  +22:17:03.8904
G0588368  08:59:54  23:39:19.2408  +21:26:28.1832
G0988727  09:01:01  23:39:21.9653  +20:39:46.1808
G0821402  09:02:13  23:39:27.2167  +14:53:34.8
G0611611  09:03:24  23:39:32.3438  +21:25:59.1744
G1438609  09:04:34  23:39:41.7115  +20:11:58.992
G0744617  09:05:47  23:40:56.521   +14:15:57.5352
G0677365  09:08:12  23:41:08.6134  +24:46:49.4652
G1036668  09:09:21  23:41:13.4179  +22:11:59.028
G0126643  09:10:30  23:41:16.0913  +25:33:04.482
G0000538  09:11:48  23:41:19.4897  +04:01:02.82
G1459451  09:13:04  23:41:21.3574  +20:22:31.044
G1411478  09:14:18  23:41:32.2778  +09:04:31.8504
G1008913  09:15:29  23:41:33.2006  +19:57:11.0304
G0550014  09:16:41  23:41:37.5221  +15:05:06.2772
G0610839  09:17:56  23:41:49.1822  +27:42:09.2232
G1299685  09:19:05  23:41:56.1254  +26:16:02.2584
G1852081  09:20:15  23:41:59.52    +26:48:33.336
G1044821  09:21:24  23:42:03.6401  +27:33:56.412
G1080511  09:22:42  23:42:08.4595  +08:54:03.9456
G0952404  09:34:26  23:42:34.5118  +25:15:00.7776
G1185636  09:35:37  23:42:42.8393  +19:31:38.5392
G0710272  09:36:51  23:42:46.7506  +15:06:53.082
G1078365  09:38:00  23:42:53.2032  +11:46:11.4348
G0105565  09:39:45  23:42:59.2968  +66:09:59.2488
G0480035  09:41:27  23:43:24.4483  +28:30:17.6256
G0785556  09:42:43  23:43:42.019   +17:38:48.444
G0629698  09:43:54  23:43:49.6363  +28:20:21.0768
G0960135  09:45:08  23:44:31.56    +12:42:03.8268
G1108394  09:46:19  23:44:35.4931  +17:56:58.7112
G1894341  09:47:30  23:44:37.2     +27:48:33.264
G1358952  09:48:42  23:44:55.7592  +19:19:27.2568
G1168733  09:49:53  23:45:04.0063  +27:44:10.3092
G0940408  09:51:09  23:45:22.6246  +09:48:22.5612
G1006318  09:52:18  23:45:45.7836  +12:33:35.2728
G1338962  09:53:33  23:46:03.8525  +26:32:00.1212
G0802908  09:54:49  23:46:29.7216  +14:53:11.5584
G0839063  09:55:58  23:46:35.1708  +12:46:25.5612
G1058560  09:57:12  23:46:41.1401  +27:24:08.3196
G1410635  09:58:23  23:46:45.5786  +17:19:05.5704
G0888210  09:59:32  23:47:18.3766  +19:29:38.2056
G0715005  10:00:44  23:47:24.4409  +28:23:36.9132
G0858934  10:01:53  23:47:43.169   +25:33:55.0188
G0630787  10:03:03  23:47:43.1909  +27:25:38.0172
G0471437  10:04:18  23:47:46.2965  +33:26:36.672
G0990722  10:05:29  23:49:01.626   +27:56:58.6104
G0894456  10:06:41  23:49:07.9176  +34:00:26.0784
G0895955  10:07:50  23:49:31.465   +33:35:03.8148
G1437133  10:08:59  23:49:42.0924  +29:05:49.1712
G0685988  10:10:50  23:49:47.0434  +72:38:39.3792
G1080152  10:31:41  23:49:59.0551  +31:07:11.8596
G1308734  10:33:27  23:50:14.3921  +67:57:12.402
G0935229  10:35:19  23:50:18.684   +28:05:21.948
G1085319  10:36:29  23:50:19.2115  +32:33:31.9536
G0714419  10:37:38  23:50:33.9331  +28:59:53.6748
G0585103  10:39:33  23:51:21.4452  +71:31:51.348
G1010191  10:41:28  23:51:26.6676  +30:09:48.51
G0282338  10:42:37  23:51:31.3915  +30:51:19.4868
G1097041  10:43:52  23:51:58.8502  +19:13:49.818
G0149051  10:45:45  23:51:59.5459  +65:53:27.294
G0505505  10:47:35  23:52:09.8731  +31:16:35.6772
G0800525  10:48:45  23:52:26.0083  +33:25:06.006
G0946134  10:50:00  23:52:37.2583  +21:30:54.36
G0368788  10:51:51  23:52:44.0112  +64:53:44.1024
G0678233  10:53:41  23:52:44.773   +33:19:47.4312
G1024148  10:54:56  23:52:51.5844  +18:33:58.3812
G0923373  10:56:10  23:52:59.7655  +33:35:19.5252
G0966996  10:57:23  23:53:02.849   +18:35:50.4708
G0558238  10:58:32  23:53:13.4033  +10:53:41.3124
G0068137  10:59:48  23:53:44.0258  +31:55:51.456
G0797580  11:00:57  23:54:44.1797  +34:20:46.4388
G0347029  11:02:53  23:54:44.3335  +67:47:57.5664
G1329374  11:04:48  23:55:03.0835  +35:48:50.5764
G0133534  11:06:03  23:55:38.8769  +21:49:20.4456
G1422410  11:07:17  23:55:46.6406  +37:13:23.8152
G1215170  11:08:28  23:56:38.1811  +26:34:10.578
G1107920  11:09:37  23:56:50.2001  +19:18:57.4272
G1473772  11:10:51  23:57:00.8935  +33:44:57.5268
G1212312  11:12:02  23:57:03.0103  +25:06:39.4488
G1205490  11:13:11  23:57:17.5416  +26:37:02.5212
G0737131  11:18:18  23:58:03.5815  +16:30:05.1516
G0896765  11:19:27  23:58:05.581   +19:27:57.762
G1053887  11:20:38  23:58:29.3042  +34:11:27.7296
G1120484  11:21:48  23:58:30.0586  +33:56:33.7308
G0959684  11:22:57  23:58:31.7945  +32:22:22.7352
G0992266  11:24:08  23:59:08.1739  +24:51:37.3212
G1324056  11:25:20  23:59:26.9093  +31:23:13.4448
G1247305  11:26:29  23:59:36.0278  +33:28:36.5448
G1031217  11:27:45  23:59:37.6978  +20:06:50.0364
G0425462  11:28:54  23:59:41.4185  +21:13:17.0436
G1454476  11:30:05  23:59:44.3774  +32:22:22.5984
G0060927  11:31:15  23:59:47.1094  +36:58:15.6144
G1189490  11:32:24  23:59:56.7847  +32:54:26.6184
G0211687  11:34:24  23:59:59.4727  +65:09:27.9648

Bin Li, Hai-bin Zhao (PMO),Dong Xu, Zi-pei Zhu, Bang-Yao Yu,Tian-meng Zhang, Xu Zhou,Chen-zhou Cui, Hui-juan Wang(NAOC), Xue-feng Wu, Zhi-ping Jin, Tian-rui Sun, Hao Lu, Ge-tu Zhaori, Ren-quan Hong, Long-fei Hu (PMO), Xiao-feng Wang, Wen-xiong Li (THU),Li-fan Wang (PMO/TAMU), Jin-zhong Liu (XAO), Ji-rong Mao, Jin-ming Bai (YNAO),  report on behalf of the CNEOST collaboration.

 We conducted optical imaging observations for gravitational wave alert with Chinese Near Earth Object Survey Telescope (CNEOST) at Xuyi astronomical station in Jiangsu Province, China (32.75N, 118.47E). The information of observations and preliminary results are listed below.

Alert: LIGO/Virgo S190718y (GCN 25087
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 )
StartTime (UT):               2019-07-19T12:41:19.523       
EndTime (UT):                 2019-07-19T18:19:52.108       
Skycover (Square Degree):     639.0   
Telescope FoV (Square Degree):9.0     
#id CentRA(D) CentDEC(D) LimiteMag3_sig 5_sig 10_sig Filter 
  1 208.869080  -6.786121   20.178   19.181   18.177   SR
  2 207.332977  -1.223906   20.265   19.261   18.376   SR
  3 210.666458  -4.041420   20.254   19.265   18.329   SR
  4 216.043030  -9.596825   20.185   19.217   18.256   SR
  5 217.903732 -15.211738   19.997   18.994   17.997   SR
  6 215.287582 -12.401288   19.966   19.002   18.058   SR
  7 210.364441  -9.628950   20.049   19.056   18.076   SR
  8 207.832382  -4.038251   20.262   19.259   18.324   SR
  9 210.156891  -1.234565   20.318   19.323   18.407   SR
 10 211.684143  -6.830252   20.100   19.149   18.213   SR
 11 220.779205 -15.240459   19.922   18.975   18.015   SR
 12 208.869080  -6.786121   20.178   19.181   18.177   SR
 13 210.156891  -1.234565   20.318   19.323   18.407   SR
 14 211.684143  -6.830252   20.100   19.149   18.213   SR
 15 216.043030  -9.596825   20.185   19.217   18.256   SR
 16 220.779205 -15.240459   19.922   18.975   18.015   SR
 17 215.287582 -12.401288   19.966   19.002   18.058   SR
 18 306.185486  23.842829   19.291   18.356   17.303   SR
 19 305.508270  29.443697   19.330   18.419   17.469   SR
 20 307.824493  35.063766   19.557   18.656   17.621   SR
 21 312.000488  37.857952   19.497   18.596   17.475   SR
 22 314.533600  32.205532   19.391   18.475   17.317   SR
 23 308.675293  29.416243   19.335   18.435   17.488   SR
 24 305.508270  29.443697   19.330   18.419   17.469   SR
 25 307.824493  35.063766   19.557   18.656   17.621   SR
 26 312.000488  37.857952   19.497   18.596   17.475   SR
 27 314.533600  32.205532   19.391   18.475   17.317   SR
 28 307.880554  32.229843   19.462   18.527   17.523   SR
 29 307.028320  26.640734   19.367   18.468   17.454   SR
 30 304.380890  35.047928   19.489   18.588   17.431   SR
 31 309.932098  40.646816   19.639   18.729   17.591   SR
 32 311.208282  35.018509   19.474   18.566   17.400   SR
 33 314.533600  32.205532   19.391   18.475   17.317   SR
 34 307.880554  32.229843   19.462   18.527   17.523   SR
 35 308.223480   1.420728   18.660   17.754   16.915   SR
 36 309.839081   9.804000   18.793   17.888   16.974   SR
 37 312.659424   9.800121   18.743   17.836   16.908   SR
 38 309.607025  18.222225   18.980   18.071   17.074   SR
 39 306.655151  18.243509   19.021   18.088   17.056   SR
 40 312.075226  21.049301   19.014   18.083   17.079   SR
 41 318.466370  18.222324   18.949   18.017   16.982   SR
 42 313.774658  15.433895   19.007   18.055   17.062   SR
 43 322.525757  15.434681   18.984   18.004   16.987   SR
 44 315.705475  12.637063   18.935   18.010   17.033   SR
 45 321.214417   9.811152   18.731   17.783   16.832   SR
 46 316.081055   7.014183   18.795   17.842   16.921   SR
 47 311.754395   4.228014   18.686   17.775   16.887   SR
 48 313.776703  -1.401701   18.251   17.366   16.533   SR
 49 308.223480   1.420728   18.660   17.754   16.915   SR
 50 309.839081   9.804000   18.793   17.888   16.974   SR
 51 310.891296  15.423524   18.974   18.075   17.106   SR
 52 306.073547  21.013973   19.140   18.213   17.172   SR
 53 315.045715  21.008123   18.907   17.995   17.038   SR
 54 315.521973  18.200771   18.994   18.056   17.059   SR
 55 316.691681  15.434895   18.960   18.034   17.055   SR
 56 322.525757  15.434681   18.984   18.004   16.987   SR
 57 318.607544  12.637962   18.854   17.920   16.948   SR
 58 318.352875   9.810987   18.740   17.819   16.888   SR
 59 318.875336   7.004980   18.767   17.841   16.919   SR
 60 314.550995   4.224255   18.699   17.756   16.866   SR
 61 313.830048   1.406936   18.628   17.684   16.804   SR
 62 308.185730  -1.344688   18.493   17.572   16.766   SR
 63 310.401428   7.007415   18.797   17.879   16.966   SR
 64 312.835144  12.623907   18.896   17.977   17.014   SR
 65 309.607025  18.222225   18.980   18.071   17.074   SR
 66 306.073547  21.013973   19.140   18.213   17.172   SR
 67 318.466370  18.222324   18.949   18.017   16.982   SR
 68 313.774658  15.433895   19.007   18.055   17.062   SR
 69 319.574982  15.416553   18.978   18.053   17.063   SR
 70 321.712860   7.031455   18.669   17.751   16.811   SR
 71 325.777649  26.589394   15.121   14.167   13.528   SR

Detailed data analysis is still in progress and any interesting transients will be reported later.
The new resulte will available at http://www.cneost.org/opem/list.php?gdate=2019-07-19 <http://www.cneost.org/opem/list.php?gdate=2019-07-19>

We aslo detect the  source ��� MASTER OT J203053.79+384020.1 / AT2019lly
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  (Lipunov et al., GCN #25105
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 ) in our survey, which are labeled OPEM-19vs ( http://www.cneost.org/opem/findname.php?opemname=OPEM-19vs <http://www.cneost.org/opem/findname.php?opemname=OPEM-19vs> ). And, a point source (r=16.32 +- 0.04 ,observed 2017-11-03) is present in the archive  catalog  of CNEOST at the location of AT2019lly
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 .

Z. Kostrzewa-Rutkowska, D. Eappachen (SRON/RU), S. Hodgkin, A. Delgado, 
D.L. Harrison, M.van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), P.G. Jonker
(SRON/RU) on behalf of Gaia Alerts team report the discovery of a transient
candidates within the probability skymap of S190718y (LIGO/VIRGO
Collaboration GCN 25087
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 ):

---------------------------------------------------------------------------
Name      	TNSid    	 Date [TCB]       		RaDeg     DecDeg    AlertMag URL
----------------------------------------------------------------------------

Gaia19dbi  AT2019lmu
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   2019-07-19T00:25:08	171.84914   -9.65161  17.52
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dbi/

Gaia19dcs AT2019lqm
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   2019-07-20T21:35:41	347.69159   9.81984.  18.78
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dcs/

Gaia19dct  AT2019lqn
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    2019-07-20T12:06:12       348.79552   -33.33181 18.76
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19dct/

---------------------------------------------------------------------------

Notes:	 Gaia19dbi - candidate SN near galaxy SDSS J112723.74-093904.1
		 Gaia19dcs - SN candidate near faint SDSS galaxy
		 Gaia19dct - blue transient 10 arcsec from galaxy 2MASX J23151011-3319533

Acknowledgements: This work has made use of data from the European Space
Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by
the Gaia Data Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC
has been provided by national institutions, in particular the institutions
participating in the Gaia Multilateral Agreement. ZKR, DE, and PGJ
acknowledge support from the European Research Council under ERC
Consolidator Grant agreement no 647208.

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

Swift has carried out 462 observations of the LVC error region for the
GW trigger S190718y convolved with the 2MPZ catalogue (Bilicki et al.
2014, ApJS, 210, 9), using the 'bayestar' GW localisation map. As this
is a 3D skymap, galaxy distances were taken into account in selecting
which ones to observe. The observations currently span from 13 ks to
365 ks after the LVC trigger, and the XRT has covered 30.9 sq degrees
on the sky (corrected for overlaps). This covers 17% of the probability
in the 'bayestar' skymap, and 22% after convolving with the 2MPZ galaxy
catalogue, as described by Evans et al. (2016, MNRAS,  462, 1591).

We have detected 45 X-ray sources. Each source is assigned a rank of
1-4 which describes how likely it is to be related to the GW trigger,
with 1 being the most likely and 4 being the least likely. The ranks
are described at https://www.swift.ac.uk/ranks.php.

We have found:

  * 0 sources of rank 1
  * 0 sources of rank 2
  * 27 sources of rank 3
  * 18 sources of rank 4

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

The results of the XRT automated analysis are online at
https://www.swift.ac.uk/LVC/S190718y

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

Iair Arcavi (Tel Aviv University), Daichi Hiramatsu (Las Cumbres / UCSB), D. Andrew Howell (Las Cumbres / UCSB), Curtis McCully (Las Cumbres), Jamison Burke (Las Cumbres / UCSB), Craig Pellegrino (Las Cumbres / UCSB), on behalf of the Las Cumbres GW Follow-up Collaboration

We obtained an optical spectrum of the transient AT 2019lqn
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  / Gaia19dct (discovered by Gaia within the probability map of S190718y; LIGO/Virgo Collaboration GCN 25087
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 , Kostrzewa-Rutkowska et al. GCN 25145
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 ) on 2019 July 24.8 UT with the robotic FLOYDS instrument mounted on the Las Cumbres Observatory 2-meter telescope in Siding Spring, Australia.

Using Superfit (Howell et al. 2005, ApJ, 634, 1190) and SNID (Blondin & Tonry 2007, ApJ, 666, 1024) we find good fits to normal Type Ia supernovae at a redshift of z=0.076, and a phase of 9 days after peak. The spectrum is available on the <a href="http://wis-tns.weizmann.ac.il/object/2019lqn">Transient Name Server</a>.

Kate Maguire (TCD), Mark Magee (TCD), Manuel Torres (IAC), Peter Jonker (SRON/Radboud
University), Morgan Fraser (UCD) report on behalf of the GW@WHT collaboration:

We obtained an optical spectrum of the transient AT2019lqm
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  / Gaia19dcs
(discovered by Gaia within the probability map of S190718y; LIGO/Virgo
Collaboration GCN 25087
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 , Kostrzewa-Rutkowska et al. GCN 25145
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 ) on 2019 July 25, 04:18
UT using the ACAM instrument mounted on the William Herschel Telescope located on the
Roque de Los Muchachos Observatory, La Palma, Spain. The exposure time was 1500 seconds.

Using SNID (Blondin & Tonry 2007, ApJ, 666, 1024) we find a good fit to normal
Type Ia supernovae at a redshift of z=0.066, about 1 week after peak.

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

We have carried a search for X-ray candidates in Astrosat CZTI data in a 100 sec window around the trigger time of the BBH merger event S190718y (UTC 2019-07-18 14:35:12.000, GraceDB event). CZTI is a coded aperture mask instrument that has considerable effective area for about 29% of the entire sky, but is also sensitive to brighter transients from the entire sky. At the time of merger, Astrosat's nominal pointing is (RA=16: 0:59.8 (240.249), DEC=31: 9:42.8 (31.162)), which is 56.49 deg away from the maximum probability location. At the time of merger event, the Earth-satellite-transient angle corresponding to maximum probability location is ~ 38.26 deg and hence is occulted by Earth in satellite's frame. In a time interval of 100 sec around the event, 57.81 % of sky locations in the 90% probability region for the event is visible in the satellite's frame and the rest of 42.19 % is occulted by earth.

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

We convert our count rates into flux by assuming that the source spectrum is a power law with alpha = -1.0. We use a detailed mass model of the satellite to calculate the instrument response for every htm grid point that fall in 90% LIGO localization region and calculate flux limit in that direction. We get the following upper limits for source flux in the 20-200 keV band by taking a probability weighted mean of flux limit and are reported here :
  
0.1 s: flux limit= 4.71e-06 ergs/cm^2/s 
1.0 s: flux limit= 1.48e-05 ergs/cm^2/s 
10.0 s: flux limit= 1.72e-05 ergs/cm^2/s

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