LIGO/Virgo S190425z
GCN Circular 24767
Subject
LIGO/Virgo S190425z: Swift UVOT - no new sources identified, and a summary of the Swift UVOT processing of GW triggers.
Date
2019-06-06T22:47:28Z (6 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL), A. A. Breeveld (MSSL-UCL), C. Gronwall (PSU),
F. E. Marshall (NASA/GSFC), S. R. Oates (Uni. of Warwick), M.J. Page
(UCL-MSSL),
M. de Pasquale (U Istambul), M. H. Siegel (PSU), A. D'Ai (INAF-IASFPA),
P. D'Avanzo (INAF-OAB), S. D. Barthelmy (NASA/GSFC), A. P. Beardmore (U.
Leicester),
D. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC),
G. Cusumano (INAF-IASF PA), V. D'Elia(ASDC), P. A. Evans (U. Leicester),
P. Giommi (ASI), D. Hartmann (Clemson U.), J. A. Kennea (PSU),
H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), D. B. Malesani (DARK/NBI),
A. Melandri (INAF-OAB), J. A. Nousek (PSU), 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), T. Sakamoto
(AGU),
B. Sbarufatti (INAF-OAB/PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu
(PSU),
and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:
The Neil Gehrels Swift Observatory UVOT and XRT instruments began pointed
galaxy-targeted followup of the LIGO/Virgo detected S190425z (LVC GCN.
24168)
at 2019-04-25 12:53 UT (T0+274 min), delayed due to a commanding gap.
The observations continued until 2019-04-26 20:15 UT, when they were aborted
to begin followup of S190426c (LVC GCN. 24237).
The UVOT points at the same sky area as the Swift XRT but with a slightly
smaller FOV (17'x17'). As announced in Tohuvavohu et al.
(GCN Circ. 24353 ), the Swift GW follow up can be seen at
http://www.swift.ac.uk/LVC/.
The Swift UVOT exposures of around 70s are usually in the u-band (central
wavelength 350nm) or a UV band when there are bright stars in the FOV. The
nominal exposure time varies depending on several factors like the slew
time.
The limiting magnitude can vary but typically is 18.6th magnitude.
Each field is automatically processed by detecting sources in the image,
matching them to several catalogs and screening the remaining sources to
remove artifacts. A check is made for any remaining candidates against the
Minor Planet Center list of solar system objects. Candidates are ranked for
further examination. In addition, for each galaxy detected in the UVOT image
which is in the GLADE catalog, a "postage stamp" image of a small region
around
the galaxy is produced as well as a comparison "postage stamp" from the
DSS to be used for manual inspection.
After the automated processing, potential candidates are all examined
manually.
This allows for the removal of image artifacts from our candidate lists
that
sometimes get flagged as potential sources. For S190425z the automated
processing
identified 21 source candidates which all, except for one, were either
image
artifacts or fast moving objects that passed the screening.
A further examination of the "postage stamps" with galaxies is then made as
effort allows. This is done mainly because the source-finding algorithm
has difficulty finding point sources in extended sources such as galaxies.
For the fields observed for S190425z, 2298 galaxy postage stamp images were
generated. No credible sources were found.
The candidate source reported in Breeveld et al. (GCN Circ. 24296) was
identified
initially by the automated processing, and is likely a very red flaring
object
(see also Lipunov et al. GCN Circ. 24326).
GCN Circular 24673
Subject
LIGO/Virgo S190425z: No counterpart candidate in Zadko-GRANDMA observations.
Date
2019-05-28T22:21:03Z (6 years ago)
From
Bruce Gendre at UVI <bruce.gendre@gmail.com>
B. Gendre (OzGrav-UWA), C. Lachaud (APC), V. Aivazyan (Iliauni), K.
Barynova (Kyiv Uni), A. Burrel (OzGrav-UWA), B. Chabert (OzGrav-UWA), H.
Crisp (OzGrav-UWA), D.Coward (OzGrav-UWA), E. Howell (OzGrav-UWA), A. N.
Klotz (UPS), J. Moore (OzGrav-UWA), S. Antier (APC), S. Basa (LAM), M.
Boer (Artemis), D. Corre (LAL), M. Coughlin (Caltech), J.G. Ducoin
(LAL), P. Hello (LAL), A. Klotz (IRAP), N. Leroy (LAL), D. Turpin
(NAOC), X. Wang (THU),
report on behalf of the Zadko Telescope team and GRANDMA collaboration;
We performed tiled observations of LIGO/Virgo BNS event S190425z with
the Zadko telescope, using a clear filter.
The observation started on 04/25/19 14:56:19 UTC which corresponds
approximately to 6.65 hours after the GW trigger time. However, due to
hardware issues, the first images of interest were obtained the next day
(04/26/19, 14:19:00 UTC)
We performed the following observations in galaxy targeting mode:
R.A. DEC.
16:57:53 -01:56:51
16:57:38 -01:48:37
16:57:07 -01:52:10
16:04:51 +24:03:15
16:04:32 +23:55:05
We have not found any credible counterpart candidate, down to R ~ 16.
The Zadko team acknowledges support from the OzGrav Centre of Excellence
of the Australian Research Council. 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
(https://grandma.lal.in2p3.fr/).
---
L'absence de virus dans ce courrier ��lectronique a ��t�� v��rifi��e par le logiciel antivirus Avast.
https://www.avast.com/antivirus
GCN Circular 24459
Subject
LIGO/Virgo S190425z: CAHA-GRANDMA Observation of the Swift UVOT Source
Date
2019-05-10T19:16:15Z (6 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), C. Thoene (HETH/IAA-CSIC), C. Stachie
(Artemis), X. Zhang (THU), Z. Vidadi (Shao), M. Blazek (HETH/IAA-CSIC),
K. Bensch (HETH/IAA-CSIC), L. Izzo (HETH/IAA-CSIC), A. de Ugarte Postigo
(HETH/IAA-CSIC, DARK/NBI), S. Antier (APC), S. Basa (LAM), M. Boer
(Artemis), D. Corre (LAL), M. Coughlin (Caltech), D. Coward
(OzGrav-UWA), J.G. Ducoin (LAL), B. Gendre (OzGrav-UWA), P. Hello (LAL),
A. Klotz (IRAP), C. Lachaud (APC), N. Leroy (LAL), D. Turpin (NAOC), and
X. Wang (THU)
report on behalf of the HETH group and GRANDMA collaboration:
We observed the location of the Swift UVOT transient (Breeveld et al.,
GCN #24296) discovered in the error region of the aLIGO/Virgo Binary
Neutron Star merger event S190425z (Ligo Scientific Collaboration and
VIRGO Collaboration, GCN #24168, #24228), with
the 2.2m CAHA telescope and CAFOS. We obtained 3 x 240 s each in U/B and
6 x 120 s in V/Rc/Ic. The observations were performed on 2019-04-28 from
02:11:50 to 03:52:47 UT.
At the position (Palmese et al., GCN #24312) of the likely counterpart
(thought to be an M2 dwarf that had a powerful flare which UVOT
detected, Lipunov et al., GCN #24326; Bloom et al., GCN #24337), we
detect a source in Rc and Ic and derive the following upper limits and
magnitudes:
U > 22.9 mag;
B > 23.5 mag;
V > 23.5 mag;
Rc = 22.51 +/- 0.15 mag (depth Rc > 23.8 mag);
Ic = 21.53 +/- 0.15 mag (depth Ic > 22.9 mag).
Magnitudes are given in the AB system and were obtained vs. a comparison
star from PanSTARRS and the transformations of Lupton (2005).
Our detections are in reasonable agreement with other reports (Palmese
et al., GCN #24312; Bloom et al., GCN #24337; Hu et al., GCN #24324) and
indicate the source was quiescent during our observations.
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 (https://grandma.lal.in2p3.fr/).
This message may be cited.
[GCN OPS NOTE(12jun19), The second reference in the first paragraph
was changed from "Breeveld et al., #24296" to
"Ligo Scientific Collaboration and VIRGO Collaboration, GCN #24168, #24228".]
GCN Circular 24417
Subject
LIGO/Virgo S190425z: Konus-Wind observations
Date
2019-05-07T11:24:07Z (6 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, 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 S190425z (2019-04-25 08:18:05.017 UTC, hereafter T0;
LIGO/Virgo Collaboration GCN Circ. 24168).
No triggered KW event happened from ~6 days before and ~2 days
after T0. The closest waiting-mode event was ~0.5 days before T0.
Using waiting-mode data within the interval T0 +/- 100 s,
we found no significant (> 5 sigma) excess over the background
in both KW detectors on temporal scales from 2.944 s to 100 s.
We estimate an upper limit (90% conf.) on the 20 ��� 1500 keV fluence
to 9.0x10^-7 erg/cm^2 for a burst lasting less than 2.944 s and having a
typical KW short GRB spectrum (an exponentially cut off power law with
alpha =-0.5 and Ep=500 keV). For a typical long GRB spectrum (the Band
function with alpha=-1, beta=-2.5, and Ep=300 keV), the corresponding
limiting peak flux is 2.7x10^-7 erg/cm^2/s (20 ��� 1500 keV, 2.944 s scale).
All the quoted values are preliminary.
GCN Circular 24369
Subject
LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
Date
2019-05-02T15:30:36Z (6 years ago)
From
Zhengwei Li at IHEP <lizw@ihep.ac.cn>
LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
J. Guan, Y. Nang, N. Sai, C, Wang, C. K. Li, J. Y. Liao, Y. Huang, Y. J. Yang, Z. W. Li, X. B. Li, G. Li, S. L. Xiong, L. Tao, C. Z.
+Liu, X. L. Cao, Y. Chen, A. M. Zhang, 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:
We performed small area scan survey of the LIGO localization region with Insight-HXMT after the LVC trigger S190425z (LVC et al. GCN
+24168). The observation started at 2019-4-25 16:28 UTC, about 8 hours after the trigger time. Four fields were visited, with
+overlaps, mapping 987.2 square degrees of the bayestar map 90% credible region and covering a sky region totalling of 20.4% of the
+LIGO localization likelihood. Each field was scanned twice and the total exposure time was 79.2 ks. No significant new source is
+found in the region in search of the Insight-HXMT raw light curves.
The survey also covered T2019ebq/PS19qp (Smith et al. GCN, 24210), a possible optical counterpart to S190425z, at 2019-04-26 02:12
+UTC (for 400s) and 2019-04-26 15:06 UTC (for 250s). We find no significant new X-ray sources in the data. The 5-sigma flux upper
+limits are obtained when fitting the light curves to the position of T2019ebq/PS19qp: 6.8 mCrab (HE���25-100 keV), 16.2 mCrab
+(ME���7-40 keV) and 5.2 mCrab (LE���1-6 keV). The flux upper limits for other positions in the scanned fields are about the same as
+quoted above.
Further analysis will be reported in the following circulars.
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.
List of observed fields:
Start (UTC) RA and Dec (J2000) radius(degree)
2019/4/25 16:28 245 20 10
2019/4/25 19:38 252 12 10
2019/4/25 22:49 235 30 10
2019/4/26 02:00 255 0 10
2019/4/26 05:11 245 20 10
2019/4/26 08:22 252 12 10
2019/4/26 11:33 235 30 10
2019/4/26 14:44 255 0 10
--
Sincerely Yours,
Zhengwei Li,
Key Laboratory of Particle Astrophysics,
Institute of High Energy Physics,
Chinese Academy of Sciences, Beijing China
TEL:15210983070 E-mail:lizw@ihep.ac.cn
GCN Circular 24367
Subject
LIGO/Virgo S190425z: Konkoly imaging of target galaxies
Date
2019-05-02T13:57:30Z (6 years ago)
From
Jozsef Vinko at Konkoly Observatory <vinko@konkoly.hu>
J. Vinko, A. Bodi, L. Kriskovics, K. Sarneczky and A. Pal (Konkoly Observatory) report additional CCD imaging of potential host galaxies of S190425z targeted by the Hobby-Eberly Telescope VIRUS spectrograph (GCN #24175). CCD frames were taken with the 0.6/0.9m Schmidt telescope (FoV 70x70 arcmin^2, unfiltered, limiting mag ~21.5) and the 0.8m RC telescope (FoV 18x18 arcmin^2, g- and r-band, limiting mag r~20.4) between 2019-04-25.9 and 2019-04-26.0 UT. The frames were centered at the following positions:
241.236267 +23.932871 = 16:04:56.7 +23:55:58:33
247.400574 +15.65844 = 16:29:36.1 +15:39:03.38
253.245255 +2.400985 = 16:52:58.8 +02:24:03.06
254.505371 -1.822693 = 16:58:01.2 -01:49:20.17
254.780334 -5.741986 = 16:59:07.2 -05:44:31.14
The deepest unfiltered frames were compared to PS1 templates applying image subtraction.
No new transient source has been found on either frames down to the limiting magnitude of ~ 21.5 listed above.
GCN Circular 24366
Subject
LIGO/Virgo S190425z: Gaia Photometric Alerts transient candidates
Date
2019-05-02T13:22:02Z (6 years ago)
From
Zuzanna Kostrzewa-Rutkowska at SRON <z.p.kostrzewa@sron.nl>
Z. Kostrzewa-Rutkowska (SRON/RU), S. Hodgkin, A. Delgado, D.L. Harrison, M.
van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), D. Eappachen, P.G. Jonker
(SRON/RU) on behalf of Gaia Alerts team report the discovery of transient
candidates within the probability skymap of S190425z (LIGO/VIRGO
Collaboration GCN 24168):
---------------------------------------------------------------------------
Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL
---------------------------------------------------------------------------
Gaia19bqf AT2019eiu 2019-05-01T09:54:18 50.39901 -52.89803 18.81
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bqf/
Gaia19bqe AT2019eit 2019-04-30T17:13:48 20.70267 -38.78741 18.76
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bqe/
Gaia19bqd AT2019eis 2019-04-30T15:41:20 32.80392 -48.59636 18.68
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bqd/
---------------------------------------------------------------------------
Acknowledgements: This work has made use of data from the European Space
Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by
the Gaia Data Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC
has been provided by national institutions, in particular the institutions
participating in the Gaia Multilateral Agreement. ZKR, DE, and PGJ
acknowledge support from the European Research Council under ERC
Consolidator Grant agreement no 647208.
GCN Circular 24362
Subject
LIGO/Virgo S190425z: Gaia Photometric Alerts transient candidate
Date
2019-05-01T13:54:04Z (6 years ago)
From
Zuzanna Kostrzewa-Rutkowska at SRON <z.p.kostrzewa@sron.nl>
Z. Kostrzewa-Rutkowska (SRON/RU), S. Hodgkin, A. Delgado, D.L. Harrison, M.
van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), D. Eappachen, P.G. Jonker
(SRON/RU) on behalf of Gaia Alerts team report the discovery of a transient
candidate within the probability skymap of S190425z (LIGO/VIRGO
Collaboration GCN 24168):
---------------------------------------------------------------------------
Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL
---------------------------------------------------------------------------
Gaia19bpw AT2019eig 2019-04-29T15:15:23 9.92876 -31.99236 18.54
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bpw/
---------------------------------------------------------------------------
Acknowledgements: This work has made use of data from the European Space
Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by
the Gaia Data Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC
has been provided by national institutions, in particular the institutions
participating in the Gaia Multilateral Agreement. ZKR, DE, and PGJ
acknowledge support from the European Research Council under ERC
Consolidator Grant agreement no 647208.
GCN Circular 24358
Subject
LIGO/Virgo S190425z: Keck/MOSFIRE NIR spectroscopy of PS19qp (= AT 2019ebq)
Date
2019-04-30T20:50:59Z (6 years ago)
From
Georgios Dimitriadis at UCSC <gdimitri@ucsc.edu>
G. Dimitriadis, D. O. Jones, M. R. Siebert, J. S. Brown (UCSC),
I. Arcavi (Tel Aviv University), J. S. Bloom (UC Berkeley),
K. A. Bostroem (UC Davis), D. A. Coulter (UCSC), M. R. Drout (University of Toronto),
H. Ebeling (IfA-Hawaii), A. V. Filippenko (UC Berkeley), R. J. Foley (UCSC),
D. A. Howell (LCO/UCSB), T. Hung (UCSC), S. W. Jha (Rutgers), D. Kasen (UC Berkeley),
C. D. Kilpatrick (UCSC), A. L. Piro (Carnegie Obs.), J. X. Prochaska (UCSC),
E. Quataert (UC Berkeley), E. Ramirez-Ruiz (UCSC), A. G. Riess (STSci),
C. Rojas-Bravo (UCSC), D. J. Sand (UA), D. M. Scolnic (Duke), K. Siellez (UCSC),
S. Valenti (UC Davis) and W. Zheng (UC Berkeley).
We obtained near-IR spectroscopy of PS19qp (= AT 2019ebq) (GCN #24210), a proposed
counterpart to the gravitational wave event S190425z (GCN #24168), with the
Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) on the Keck I telescope
on Mauna Kea, starting at UT 2019-04-26 14:32:11, aproximately 1.2 days after
the LIGO/Virgo alert.
Our spectrum covers the J-band (1.15-1.35 microns). Visual inspection of the spectrum
indicates it is consistent with Type Ic supernovae a few days prior to maximum light,
similar to previous spectroscopic classifications (GCN #24230, GCN #24233, GCN #24252).
We thank the staff of Keck observatory, especially Josh Walawender,
for facilitating this Target of Opportunity observation.
GCN Circular 24356
Subject
LIGO/Virgo S190425z: ZTF pre-detections of Gaia19bpt AT2019ehz
Date
2019-04-30T18:33:36Z (6 years ago)
From
Igor Andreoni at Caltech <igor.andreoni@gmail.com>
Igor Andreoni (Caltech), Eric Bellm (UW) report 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 Gaia19bpt AT2019ehz (Kostrzewa-Rutkowska et al., GCN 24354) in the archive of ZTF alerts. ��A source, dubbed ZTF19aarioci, was found varying at the location of Gaia19bpt.�� The source was first detected in ZTF data on 2019-04-21 (g ~ 19.8), with detections in the public surveys beginning on 2019-04-23.
The optical event was detected days before the gravitational wave trigger S190425z (LIGO and Virgo Collaboration, GCN 24168), therefore we exclude an association between Gaia19bpt AT2019ehz and S190425z.
ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IIT-B, India; IIA, India; LJMU, UK; TTU USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019).
GCN Circular 24354
Subject
LIGO/Virgo S190425z: Gaia Photometric Alerts transient candidates
Date
2019-04-30T15:16:32Z (6 years ago)
From
Zuzanna Kostrzewa-Rutkowska at SRON <z.p.kostrzewa@sron.nl>
Z. Kostrzewa-Rutkowska (SRON/RU), S. Hodgkin, A. Delgado, D.L. Harrison, M.
van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), D. Eappachen, P.G. Jonker
(SRON/RU) on behalf of Gaia Alerts team report the discovery of transient
candidates within the probability skymap of S190425z (LIGO/VIRGO
Collaboration GCN 24168):
---------------------------------------------------------------------------
Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL
---------------------------------------------------------------------------
Gaia19bpt AT2019ehz 2019-04-29T06:51:22 212.42448 55.49114 18.49
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bpt/
Gaia19bps <http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bpt/%0DGaia19bps>
AT2019ehy 2019-04-28T22:13:01 80.97925 -67.87885 15.78
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bps/
Gaia19bpr AT2019ehx 2019-04-29T04:14:24 83.92087 -66.86490 14.19
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bpr/
---------------------------------------------------------------------------
Notes:
Gaia19bpt - galaxy SDSS J140941.88+552928.1 brightens by 2 mag
Gaia19bps - blue source brightens by 0.4 mag
Gaia19bpr - HMXB RX J0535.6-6651 brightens by 1 mag
Acknowledgements: This work has made use of data from the European Space
Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by
the Gaia Data Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC
has been provided by national institutions, in particular the institutions
participating in the Gaia Multilateral Agreement. ZKR, DE, and PGJ
acknowledge support from the European Research Council under ERC
Consolidator Grant agreement no 647208.
GCN Circular 24348
Subject
LIGO/Virgo S190425z: 1.3-m optical imaging of UVOT transient field
Date
2019-04-29T23:24:43Z (6 years ago)
From
Marc A. Murison at U.S.Naval Obs,Flagstaff <marc.nofs@gmail.com>
Marc A. Murison, U.S. Naval Observatory--Flagstaff Station (NOFS)
We imaged the position of the reported Swift/UVOT transient (Breeveld
et al., GCN Circ. 24296), potentially corresponding to LIGO/Virgo trigger
S190425z (LIGO/Virgo Collaboration, GCN Circ. 24168), with the NOFS
1.3-meter telescope. Nine 900-second exposures were taken in SDSS r (5)
and g (4). Examination and comparison to PS1 reveals no new sources
brighter than apparent SDSS r magnitude 22.3. Exposure times were
2019-04-28 08:44 to 11:12 UTC. Stacking images did not produce benefit
due to variable and worsening seeing.
GCN Circular 24345
Subject
LIGO/Virgo S190425z: Gaia Photometric Alerts transient candidate
Date
2019-04-29T15:58:28Z (6 years ago)
From
Zuzanna Kostrzewa-Rutkowska at SRON <z.p.kostrzewa@sron.nl>
Z. Kostrzewa-Rutkowska (SRON/RU), S. Hodgkin, A. Delgado, D.L. Harrison, M.
van Leeuwen, G. Rixon, A. Yoldas (IoA Cambridge), D. Eappachen, P.G. Jonker
(SRON/RU) on behalf of Gaia Alerts team report the discovery of a transient
candidate within the probability skymap of S190425z (LIGO/VIRGO
Collaboration GCN Circ. 24168):
---------------------------------------------------------------------------
Name TNSid Date [TCB] RaDeg DecDeg AlertMag URL
---------------------------------------------------------------------------
Gaia19bpf AT2019egx 2019-04-28T17:04:25 8.95631 -35.89300 14.38
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia19bpf/
---------------------------------------------------------------------------
Note: outburst of candidate CV ASASSN-14da
Acknowledgements: This work has made use of data from the European Space
Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by
the Gaia Data Processing and Analysis Consortium (DPAC,
https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC
has been provided by national institutions, in particular the institutions
participating in the Gaia Multilateral Agreement. ZKR, DE, and PGJ
acknowledge support from the European Research Council under ERC
Consolidator Grant agreement no 647208.
GCN Circular 24343
Subject
LIGO/Virgo S190425z: KPED Follow-Up of ZTF transients
Date
2019-04-29T13:58:10Z (6 years ago)
From
Tomas Ahumada at U. of Maryland <tahumada@astro.umd.edu>
Tomas Ahumada (UMD), Michael W. Coughlin (Caltech), Kai Staats
(Northwestern), Kevin Burdge (Caltech), Richard G. Dekany (Caltech), Dmitry
A. Duev (Caltech), Michael Feeney (Caltech), S. R. Kulkarni (Caltech), Reed
Riddle (Caltech) on behalf of the KPED team and the Global Relay of
Observatories Watching Transients Happen (GROWTH) collaboration.
We used the Kitt Peak EMCCD Demonstrator (KPED) on the Kitt Peak 84-inch
telescope (Coughlin et al 2019b) to obtain 300 s r-band images for ZTF
optical transients listed in Kasliwal et al. (GCN 24191) and Anand et al.
(GCN 24311) starting at 3:56:56.876 UT on 2019-04-28.
The measurements of ZTF19aasckkq are consistent with Malesani et al. (GCN
24319) and Ahumada et al. (GCN 24320). The object ZTF19aasbphu shows a
slight decrease in the r magnitude (r~-0.3) with respect to Anand et al.
(GCN 24311)
We report upper limits for the rest of the transients. Magnitudes are
derived after calibrating against PS1:
ID JD RA DEC magnitude
ZTF19aasckkq 2458602.473900463 248.4131017 13.9101828 g = 20.7 +- 0.2
ZTF19aasckkq 2458601.7544584144 248.4131017 13.9101828 r = 20.2 +- 0.1
ZTF19aasckkq 2458602.474675926 248.4131017 13.9101828 r = 20.1 +- 0.1
ZTF19aasckkq 2458601.7452688077 248.4131017 13.9101828 I = 19.4 +- 0.3
ZTF19aasckkq 2458601.750166088 248.4131017 13.9101828 I = 19.4 +- 0.3
ZTF19aasbphu 2458601.7107427316 245.5831354 21.4081853 r = 19.47 +- 0.2
ZTF19aasejil 2458601.8664184026 261.9458106 1.6537207 r > 20.8
ZTF19aasbamy 2458601.664547176 231.2656676 24.9275799 r > 20.4
ZTF19aascxux 2458601.8588976967 258.2933102 17.2938689 r > 20.3
ZTF19aasfogv 2458601.8632696294 261.8430161 -11.3338523 r > 19.9
ZTF19aarycuy 2458602.4741666666 244.0832363 21.7409257 r > 19.9
More observations for this objects are scheduled.
The KPED team thanks the National Science Foundation, the Caltech Space
Innovation Council, the National Optical Astronomical Observatory and the
Murty family for support in the building and operation of KPED.
GCN Circular 24338
Subject
LIGO/Virgo S190425z: MASTER detection of the faint flare in SDSS Seyfert galaxy z = 0.09
Date
2019-04-29T07:37:07Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, N.Tyurina, E. Gorbovskoy, V.Kornilov, D.Vlasenko, V.Vladimirov,
D.Zimnukhov, A.Kuznetsov, P.Balanutsa, I.Gorbunov, A. Chasovnikov,
V.Grinshpun, F.Balakin, A.Chasovnikov (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),
H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio
ICATE,SJNU)
D. Buckley (South African Astronomical Observatory),
O. Gress, N.M. Budnev, O.Ershova (Applied Physics Institute, Irkutsk State
University),
V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk EducationState
University),
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Station
of the Pulkovo Observatory),
Global MASTER-Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in
Astronomy, vol. 2010, 30L) started inspect of the LIGO/Virgo S190425z
errorbox (Singer et al. GCN 24168) 3133 sec after trigger time at 2019-04-25
09:10:18 UT (Lipunov et al. GCN 24167).
After reviewing 25% of total probability, we found several possible
transients. The most interesting is the MASTER OT J155829.22+271714.6.
Most likely this flash is related to the activity of the galaxy nuclear.
Too large redshift s = 0.09 (distance ~380 Mpc) excludes OT from possible
candidates for a gravitational-wave event LIGO/Virgo S190425z.
MASTER OT J155829.22+271714.6 - Optical Flare in Active Seyfert Galaxy
MASTER-IAC (Teide Observatory, IAC, Tenerife, Spain) auto-detection system
discovered OT source at (RA, Dec) = 15h 58m 29.22s +27d 17m 14.63s
2019-04-25 23:42:39.4 UT.
The OT unfiltered magnitude is 18.4m (limit 19.7 m).
There is no minor planet at this place.
The discovery, referenceand differences images are available at
http://observ.pereplet.ru/images/MASTEROTJ155829.22+271714.6.jpg
The message may be cited.
GCN Circular 24337
Subject
LIGO/Virgo S190425z: DECam Observations of the UVOT Candidate Region
Date
2019-04-29T05:06:28Z (6 years ago)
From
Josh Bloom at UC Berkeley <jbloom@astron.berkeley.edu>
Joshua S. Bloom (UC Berkeley), Catherine Zucker (Harvard), Eddie Schlafly
(LBNL), Doug Finkbeiner (Harvard), Jorge Mart��nez-Palomera (UC Berkeley),
Daniel A. Goldstein (Caltech), and Igor Andreoni (Caltech) report:
"Starting at 2019-04-28 5:10 UTC, we observed the region of the UVOT
transient (Breeveld et al. GCN #24296) candidate counterpart of the
gravitational wave event S190425z (LIGO/VIRGO Collaboration, GCN #24168)
with the Victor M. Blanco 4m Telescope at Cerro Tololo Inter-American
Observatory, equipped with the Dark Energy Camera (DECam). We observed in
four bands (g for 6 minutes, r for 6 minutes, i for 8 minutes, z for 8
minutes).
Consistent with previous reports (Kong et al. GCN #24301, Arcavi et al. GCN
#24307, Im et al. GCN #24318, Shappee et al. GCN #24313, Hu et al. GCN
#24324, Chang et al. GCN #24325, Morihana et al. GCN #24328, Tanvir et al.
GCN #24334, Troja et al. GCN #24335), in 1.2 arcsec seeing, we find no
source at the reported position of the UVOT source, placing the following
upper limits, calibrated to PS1 photometry (Chambers et al. 2016,
arXiv:1612.05560C):
g > 24.0
r > 24.0
i > 23.7
z > 23.1
The nearby source noted in Palmese et al. (GCN #24312) at position
ra=17:02:19.19, dec=-12:29:07.3 is detected in r, i, z and not detected in
g. We report the following magnitudes for this source:
z = 21.50
i = 22.04
r = 23.03
g > 24.0
All detection magnitudes inhere a ~0.1 mag uncertainty currently. The
r-band detection is consistent with Palmese et al. (GCN #24312) and thus
does not appear to be variable between the two observations. We find no
evidence for any spatial extent beyond the stellar PSF. The photometric
measurements (albeit not corrected for the Galactic extinction along the
line of sight) suggest the source to be a M2-dwarf star (see West et al.,
2011).
The currently reported astrometric location of the bright UV transient is
not precisely consistent with the location of the source discussed above.
However, if they are indeed physically associated (through a refined
astrometric study, especially since the UVOT source appears trailed) a
consistent picture emerges: the UVOT detection was due to a flare from an
M2-dwarf star in our galaxy. We thus agree with the hypothesis advanced by
Lipunov et al. (GCN #24326) that the UVOT event is unrelated to GW
S190425z."
This message may be cited.
GCN Circular 24335
Subject
LIGO/Virgo S190425z: RATIR non-detection of the Swift/UVOT source
Date
2019-04-28T22:39:18Z (6 years ago)
From
Eleonora Troja at NASA/GSFC/UMD <eleonora@umd.edu>
Eleonora Troja (GSFC/UMD), Alan M. Watson (UNAM), Rosa L. Becerra (UNAM),
Nat Butler (ASU), Diego Gonzalez (UNAM), Alexander Kutyrev (GSFC/UMD),
William H. Lee (UNAM), Margarita Pereyra (UNAM), and
Tanner Wolfram (ASU) report:
We observed the location of the Swift/UVOT transient (Breeveld et al.,
GCN Circ. 24296) with the Reionization and Transients Infrared Camera
(RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
Astron��mico Nacional on Sierra San Pedro Martir from 2019/04 28.28 to
2019/04 28.49 UTC (approximately 3 d after the GW trigger), obtaining
a total of 1.92 hours exposure in the r and i bands and 1.21 hours
exposure in the Z, Y, J, and H bands.
For a source within the UVOT error circle, in comparison with the
USNO-B1 and 2MASS catalogs, we obtain the following upper limits (3-sigma):
g > 23.5
r > 23.4
i > 23.3
Z > 22.2
Y > 22.2
J > 21.8
H > 21.4
The nearby objected reported by Palmese et al. (GCN Circ. 24312) is
detected in our images at H~20.1 mag.
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astronomico Nacional in San Pedro
Martir
GCN Circular 24334
Subject
LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
Date
2019-04-28T21:30:26Z (6 years ago)
From
Nial Tanvir at U.Leicester <nrt3@star.le.ac.uk>
N. R. Tanvir (U. Leicester), C. Gonzalez-Fernandez (IoA, U. Cambridge),
A. J. Levan (Radbound U.), D. B. Malesani (DAWN/NBI and DARK/NBI),
P. A. Evans (U. Leicester) report on behalf of the VINROUGE collaboration:
The location of the variable source reported in Swift/UVOT
observations (Breeveld et al., GCN 24296) appears in a field
imaged by the 4m VISTA telescope as part of our follow-up of the
binary neutron star merger S190425z (LVC collaboration, GCN 24168).
The observations were obtained on 2019-04-28 07:55 UT in the 2.15 um
Ks-filter. We find no significant flux at the transient location,
corresponding to a 2-sigma limiting magnitude of K(AB)~20.6.
The absence of a detection in these observations suggests that
either it has rapidly faded and/or is not very red in UV-nIR colours.
The faint constant source, close to the UVOT position, noted by
Palmese et al. (GCN 24312), is marginally visible in our imaging,
at about the 2-sigma level.
GCN Circular 24328
Subject
LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometric follow-up observation of the Swift/UVOT Transient
Date
2019-04-28T13:15:44Z (6 years ago)
From
Kumiko Morihana at Nagoya University <morihana@u.phys.nagoya-u.ac.jp>
K. Morihana (Nagoya U.), M. Jian (U. of Tokyo), T. Nagayama (Kagoshima
U.) on behalf of J-GEM collaboration
We carried out NIR photometric follow-up observation of Swift/UVOT
transient (Breeveld et al.,GCN 24296) of the GW event S190425z (GCN
24168) with the near-infrared (J, H, Ks) simultaneous imaging camera
SIRIUS attached to the IRSF (InfraRed Survey Facility) 1.4 m telescope
in Sutherland Observatory, South Africa.
The observation started on 2019-04-28 00:44:28 UT. The exposure time
on the source is 40 min. A very faint source (possibly noise) is seen
at the position of Swift/UVOT transient in the J-band image. The
simple aperture photometry returns J=20.2 mag (Vega system), but it is
quite unsure. The conservative upper limit magnitudes for the
JHKs-band images are 18.8 mag, 18.4 mag, and 16.9 mag (Vega system),
respectively.
GCN Circular 24326
Subject
LIGO/Virgo S190425z: MASTER explanation of the nature of an optical flash detected by a Swift as a short flare on a fast-moving WISE brown
Date
2019-04-28T11:05:43Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, N.Tyurina, E. Gorbovskoy, V.Kornilov, D.Vlasenko,
V.Vladimirov, D.Zimnukhov, A.Kuznetsov, P.Balanutsa, I.Gorbunov, A.
Chasovnikov, V.Grinshpun, F.Balakin, A.Chasovnikov
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix
Aguilar OAFA, San Juan National University),
H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio
ICATE,SJNU)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto
de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O. Gress, N.M. Budnev, O.Ershova (Applied Physics Institute, Irkutsk State
University),
V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk EducationState
University),
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Station
of the Pulkovo Observatory),
Global MASTER-Net (http://observ.pereplet.ru, Lipunov et al., 2010,
Advances in Astronomy, vol. 2010, 30L) started inspect of the
LIGO/Virgo S190425z errorbox (Singer et al. GCN 24168) 3133 sec after
trigger time at 2019-04-25 09:10:18 UT (Lipunov et al. GCN 24167).
MASTER-IAC observed Swift OT (Breeveld et al., GCN 24296) at 2019-04-26
01:45:59 with mlim=20.0, and at 2019-04-26 01:57:23 with mlim=20.0
during automatic inspect of GW190425.
There is optical transient with m_OT ~ 19.0 detected at both
images.
MASTER-OAFA observed these coordinates at 2019-04-26 05:24:35 during
automatic GW190425 inspection with unfiltered mlim=19.0. There is no OT
detection.
MASTER-SAAO observed this area at 2019-04-27 21:15:24 and at 2019-04-27
21:26:02 with mlim=21.0 and at 2019-04-26 04:01:55 with mlim=19.3 during
automatic GW190425 inspection . There is no OT detection.
All instrumental unfiltered magnitude is W = 0.2B + 0.8R with respect to
USNO B reference stars.
The object detected by Swift possibly connected with the blue flare on
fast moving cool AllWISE star (RA,DEC) = 255.5777822 -12.4869992 (2" per
yr!).
So this OT not connected with Gravitational Waves Event.
You can find below the community observations of the Swift OT
region:
Telescope Apr Limit OT Filt GCN
Zwicky 25.4 20.5 - R 24302
Zwicky 25.4 20.5 - g 24302
ASAS-SN 25.4 18.7 - g 24313
Gattini 25.5 15.2 - J 24306
Zwicky 25.5 20.5 - R 24302
KMTNet SSO 25.6 21.5 - R 24318
MASTER-IAC 26.1 20.0 19.0 W This
MASTER-OAFA 26.2 19.0 19.0 W This
Zwicky 26.3 20.5 - g 24302
Gattini 26.4 15.2 - J 24306
Zwicky 26.5 20.4 - R 24302
ASAS-SN 26.5 18.7 - g 24313
Swift 26.8 ? 17.7 U 24296
ASAS-SN 27.3 18.4 - g 24313
MASTER-SAAO 27.88 21.0 - W This
LCO SAAO 27.9 21.5 - R 24307
Lulin 28.8 21.5 - R 24301
These data do not contradict the hypothesis of a short (10-15 minutes
flash) on a red-brown dwarf.
The message may be cited.
GCN Circular 24325
Subject
LIGO/Virgo S190425z: No i-band detection of the Swift/UVOT transient in SkyMapper observations
Date
2019-04-28T07:54:48Z (6 years ago)
From
Seo-Won Chang at SkyMapper <seowon.chang@anu.edu.au>
Seo-Won Chang (ANU/OzGrav), Christian Wolf (ANU/OzGrav), Christopher A. Onken (ANU), Lance Luvaul (ANU), Susan Scott (ANU/OzGrav) report on behalf of the SkyMapper Transient survey collaboration:
We checked the SkyMapper observations at the location of the Swift UVOT candidate (Breeveld et al. GCN 24296). These images were taken with the 1.35-m ANU SkyMapper telescope at Siding Spring Observatory about 6 hours after the GW detection in response to LIGO/Virgo GW trigger S190425z (LVC collaboration, GCN 24168). We do not see any transient down to an i-band (779/140 nm) magnitude of 20 (AB mag) at the two epochs: 2019-04-25 14:17:00 and 2019-04-25 14:25:53 UT. Our magnitude limits were obtained by calibrating with the zero-point from the SkyMapper Data Release 2 (Onken et al. 2019).
GCN Circular 24324
Subject
LIGO/Virgo S190425z: 1.5m OSN and 10.4m imaging of the UVOT source field
Date
2019-04-28T07:28:53Z (6 years ago)
From
Alberto J. Castro-Tirado at IAA-CSIC <ajct@iaa.es>
Y.-D. Hu, A. J. Castro-Tirado, X.-Y. Li, A. Ayala, E. Fernandez-Garcia
and F. J. Aceituno (IAA-CSIC), R. Sanchez-Ramirez (INAF-IAPS), M. D.
Caballero-Garcia (ASU-CAS) and N. Castro-Rodriguez (GRANTECAN, IAC,
ULL), on behalf of a larger collaboration, report:
Following the detection of Swift/UVOT of a transient (Breeveld et al.,
GCN 24296) within the error area of the GW event S190425z (LIGO
Scientific Collaboration and the Virgo Collaboration, GCN 24168), we
observed the target with the 1.5m telescope at the Observatorio de
Sierra Nevada (Spain) in the R-band, starting on Apr 27, 03:44 UT. The
co-add of 3 frames (600s each) revealed no object down to 22.3 mag at
the position of the UVOT source. Deeper images were taken at the 10.4m
GTC telescope equipped with OSIRIS in La Palma (Spain) starting on Apr
27, 05:11 UT. The potential host galaxy reported by Palmese et al., GCN
24312) is detected in our 60s frames with r = 22.8+-0.2.
We acknowledge the excellent support from the GTC staff.
GCN Circular 24321
Subject
LIGO/Virgo S190425z: Spectroscopic observations of two ZTF candidates with SOAR
Date
2019-04-28T06:17:29Z (6 years ago)
From
Matt Nicholl at Royal Astronomical Soc. <mrn@roe.ac.uk>
M. Nicholl (Edinburgh), R. Cartier (CTIO), I. Pelisoli (Potsdam), E. Berger, P. Blanchard, T. Eftekhari, S. Gomez, G. Hosseinzadeh, A. Villar, P. Williams (Harvard), P. Cowperthwaite (Carnegie), K. Alexander, D. Coppejans, W. Fong, R. Margutti, G. Terreran (Northwestern), R. Chornock (Ohio), J. Braga (INPE), L. Chomiuk, J. Strader (MSU), C. Clemens, D. Reichart (UNC), M. Drout (Toronto), D. Sand, N. Smith (Arizona), D. Kasen (Berkeley), B. Metzger (Columbia)
We report spectroscopic observations with the 4m SOAR telescope and Goodman spectrograph, of two potential electromagnetic counterparts to the gravitational wave trigger S190425z (GCN 24168): ZTF19aasckkq and ZTF19aasckwd, reported by ZTF/GROWTH (Anand et al, GCN 24311).
These candidates were deemed to be the most likely counterparts as they are offset from bright galaxies and have low spectroscopic or photometric redshifts. ZTF19aasckkq has been detected in follow-up photometry by Perley et al. (GCN 24314), Malesani et al. (GCN 24319) and Ahumada et al. (GCN 24320).
SOAR classifications:
ZTF19aasckwd is a young Type Ia SN at z~0.15, consistent with the photometric redshift of the nearby galaxy.
ZTF19aasckkq also shows clear SN features in the spectrum. Using the code SNID (Blondin & Tonry, 2007) we find good matches to Type IIb SNe at z~0.05, consistent with the galaxy redshift.
GCN Circular 24320
Subject
LIGO/Virgo S190425z: KPED Follow-Up of ZTF transients
Date
2019-04-28T05:08:34Z (6 years ago)
From
Tomas Ahumada at U. of Maryland <tahumada@astro.umd.edu>
Tomas Ahumada (UMD), Michael W. Coughlin (Caltech), Kai Staats
(Northwestern), Kevin Burdge (Caltech), Richard G. Dekany
<https://arxiv.org/search/astro-ph?searchtype=author&query=Dekany%2C+R+G>
(Caltech), Dmitry A. Duev
<https://arxiv.org/search/astro-ph?searchtype=author&query=Duev%2C+D+A>
(Caltech), Michael Feeney
<https://arxiv.org/search/astro-ph?searchtype=author&query=Feeney%2C+M>
(Caltech), S. R. Kulkarni
<https://arxiv.org/search/astro-ph?searchtype=author&query=Kulkarni%2C+S+R>
(Caltech), Reed Riddle
<https://arxiv.org/search/astro-ph?searchtype=author&query=Riddle%2C+R>
(Caltech) on behalf of the KPED team and the Global Relay of Observatories
Watching Transients Happen (GROWTH) collaboration.
We used the Kitt Peak EMCCD Demonstrator (KPED) on the Kitt Peak 84-inch
telescope (Coughlin et al 2019b) to obtain 300 s r-band images for ZTF
optical transients listed in Kasliwal et al. (GCN 24191) and Anand et al.
(GCN 24311) starting at 9:13:24 UT on 2019-04-27.
The measurement of ZTF19aasckkq is consistent with Perley et al. (GCN
24314) and we report upper limits for the rest of the transients.
Magnitudes are derived after calibrating against PS1:
ID JD RA DEC magnitude
ZTF19aasckkq 2458600.9291 248.413102 13.910183 r = 20.29 +- 0.18
ZTF19aaskbzh 2458600.9541 206.393046 69.329244 r > 19.65 +- 0.03
ZTF19aasejil 2458600.9837 261.945810 1.653720 r > 20.38 +- 0.34
ZTF19aasckkm 2458600.9248 247.302345 12.930679 r > 19.79 +- 0.18
More observations for this objects are scheduled.
The KPED team thanks the National Science Foundation, the National Optical
Astronomical Observatory and the Murty family for support in the building
and operation of KPED.
GCN Circular 24319
Subject
LIGO/Virgo S190425z: NOT photometry of ZTF19aasckkq
Date
2019-04-28T04:18:11Z (6 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
L. Izzo (HETH/IAA-CSIC), D. B. Malesani (DAWN/NBI and DARK/NBI), R.
Carini (INAF/OAR) report:
We observed the field of ZTF19aasckkq, reported by the Zwicky Transient
Facility (Anand et al., GCN 24311) to lie within the localization area
of the LIGO/Virgo trigger S190425z (GCN 24168). We used the Nordic
Optical Telescope (NOT) located in La Palma (Canary Islands, Spain) and
equipped with the AlFOSC camera.
We report the following magnitudes on the approximate date April 28.14
UT (2.8 days after the explosion of S190425z):
g = 20.63 +- 0.02
r = 20.33 +- 0.02
i = 20.29 +- 0.02
These magnitudes are calibrated against the Pan-STARRS survey; no
subtraction of the host galaxy was attempted, but the target is
relatively isolated and host contamination should not be a major
contribution. Our measurements are consistent with those reported by
Anand et al. (GCN 24311) on April 26 (unspecified time), as well as by
Perley et al. (GCN 24314) on April 27.14 UT.
The object seems therefore slowly variable, and less likely to be
associated with S190425z.
GCN Circular 24318
Subject
LIGO/Virgo S190425z: No source found at UVOT source location at 6 hrs after LVC report
Date
2019-04-28T03:51:56Z (6 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
Myungshin Im (SNU), Joonho Kim (SNU), Gregory S. H. Paek (SNU), Chung-Uk
Lee (KASI), Seung-Lee Kim (KASI), Hyung Mok Lee (KASI), on behalf of a
larger collaboration
We checked the KMTNet image at the location of the UVOT transient
(Breeveld et al., GCN Circ. 24296). The image was taken at 2019-04-25
14:05:29 (UT) at the KMTNet Siding Spring Observatory station, about 6
hours after the GW detection (LVC collaboration, GCN Circ. 24168) and 28
hours before the reported UVOT detection. We do not find any transient at
the UVOT location down to the preliminary magnitude limit of R<21.5
(3-sigma, point source). We do find the reported faint host galaxy
candidate in our KMTNet data (Palmese et al., GCN Circ. 24312)
We thank the KMTNet operators for performing the observation.
GCN Circular 24315
Subject
LIGO/Virgo S190425z: SVOM/GWAC-F60A observations
Date
2019-04-28T00:48:58Z (6 years ago)
Edited On
2024-11-16T16:15:13Z (a year ago)
From
Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
L.P. Xin (NAOC), X.H. Han (NAOC), J.Y. Wei (NAOC), C. Wu (NAOC),
D. Turpin (NAOC), J.G. Ducoin (CNRS/LAL), D. Corre (CNRS/LAL),
L. Huang (NAOC), Y. Xu (NAOC), H.B. Cai (NAOC), J. Wang (NAOC),
X.M. Lu (NAOC), Y.L. Qiu (NAOC), J.S. Deng (NAOC), L. Jia (NAOC),
S.C. Zou (NAOC), S.F. Liu (NAOC), Q.C. Feng (NAOC), H.L. Li (NAOC),
D.W. Xu (NAOC), Y.J. Xiao (NAOC), W.L. Dong (NAOC), Y.T. Zheng (NAOC),
P. P. Zhang (NAOC), R.S. Zhang (NAOC), E.W. Liang (GXU),
X.G. Wang (GXU), Z.G. Dai (NJU), X.Y. Wang (NJU), Y.G. Yang (HBNU),
J.R. Mao (YNAO), B. Cordier (CEA/AIM), S. Basa (CNRS/LAM),
J.L. Atteia (UPS/IRAP), D. Götz (CEA/AIM), A. Claret (CEA/AIM),
N. Leroy (CNRS/LAL), C. Lachaud (CNRS/APC), S. Antier (CNRS/APC/CNES),
S.N. Zhang (IHEP), B.B. Wu (IHEP), report on behalf of the SVOM Ground Follow-up Group:
We observed the LIGO/Virgo trigger S190425z with GWAC-F60A.
Two 60cm GWAC-F60(A/B) are operated by Guangxi University and NAOC,
CAS, at Xinglong Observatory. China. They are equipped with Standard
Johnson filters and 2Kx2K Andor CCD (FOV~18x18 arcmin). GWAC-F60(A/B)
are used for galaxy-targeted observations. The galaxies are selected
from the GLADE catalog (Version 2.3, Dalya et al. 2018) in the probability
skymap of GW event. All these galaxies were observed in clear band.
The weather was not good during the observations.
The first image was taken ~6 hours after the event trigger. No credible
new source was detected in our pipeline. A total number of
80 galaxies were observed. The coordinates (J2000) of galaxies,
the observation time, the limit magnitude (3sigma) and telescopes
are listed below:
# Ra Dec start-obs(UTC) Limit (R) Telescope
246.40900 16.45500 2019-04-25T14:07:30.157 16.86 F60A
235.47600 28.13410 2019-04-25T12:26:20.678 20.16 F60A
236.94100 28.64190 2019-04-25T13:38:20.485 18.81 F60A
186.25200 28.55850 2019-04-25T12:14:11.215 20.25 F60A
241.23600 23.93290 2019-04-25T13:09:22.662 16.66 F60A
243.74100 21.93830 2019-04-25T13:49:55.528 14.15 F60A
246.11400 19.48260 2019-04-25T13:44:10.488 16.35 F60A
247.40100 15.65840 2019-04-25T14:03:29.676 17.11 F60A
252.98900 4.38356 2019-04-26T15:14:39.330 20.03 F60A
253.53600 -7.63537 2019-04-26T15:41:09.103 19.00 F60A
248.25700 22.79720 2019-04-26T16:18:33.855 18.88 F60A
246.40900 16.45500 2019-04-26T13:39:32.350 19.24 F60A
242.31500 25.71250 2019-04-26T13:29:26.576 18.96 F60A
101.82200 33.56730 2019-04-26T13:03:41.172 18.12 F60A
213.21400 35.71070 2019-04-26T19:31:21.044 15.55 F60A
252.26500 -17.64590 2019-04-26T18:17:23.676 15.12 F60A
213.61300 36.40440 2019-04-26T19:12:15.038 16.48 F60A
252.69500 4.60474 2019-04-26T15:10:41.648 18.50 F60A
253.24500 2.40099 2019-04-26T15:06:31.427 18.98 F60A
252.92700 -2.61525 2019-04-26T15:30:55.776 18.12 F60A
251.59400 9.03763 2019-04-26T14:23:38.733 17.37 F60A
188.92200 26.52300 2019-04-26T12:50:39.801 19.69 F60A
236.90100 26.06370 2019-04-26T12:40:17.254 19.40 F60A
252.71300 8.78387 2019-04-26T15:57:48.620 18.05 F60A
216.14600 35.27980 2019-04-26T13:12:20.095 18.89 F60A
256.23700 -1.53050 2019-04-26T19:27:31.002 14.74 F60A
239.01600 24.44800 2019-04-26T18:58:18.867 16.39 F60A
240.75100 27.01030 2019-04-26T12:36:02.920 18.67 F60A
246.06300 20.18360 2019-04-26T14:06:52.457 18.67 F60A
256.68100 -4.93311 2019-04-26T19:42:41.710 14.82 F60A
236.97500 25.72940 2019-04-26T16:10:06.932 18.87 F60A
189.55500 28.93690 2019-04-26T12:03:09.117 18.55 F60A
203.60500 34.69040 2019-04-26T12:59:12.069 19.63 F60A
240.68800 25.25220 2019-04-26T14:45:39.591 19.17 F60A
251.85200 -20.14170 2019-04-26T18:25:26.961 13.73 F60A
252.33700 -17.64450 2019-04-26T16:46:18.132 14.91 F60A
254.52400 -21.27410 2019-04-26T18:29:34.531 13.66 F60A
265.63300 0.21675 2019-04-26T18:54:30.920 13.77 F60A
252.72300 -15.00400 2019-04-26T16:22:46.980 16.61 F60A
217.50600 36.36090 2019-04-26T19:08:30.994 16.65 F60A
242.40600 28.05180 2019-04-26T14:31:48.522 19.80 F60A
258.11900 -9.12416 2019-04-26T16:26:50.153 16.71 F60A
218.40500 35.96650 2019-04-26T14:11:05.568 19.82 F60A
200.21300 43.96540 2019-04-26T12:26:20.960 19.19 F60A
243.14800 29.48450 2019-04-26T19:16:03.251 16.82 F60A
208.41000 36.13420 2019-04-26T13:33:42.807 19.49 F60A
249.86000 11.21050 2019-04-26T14:27:45.663 19.03 F60A
216.08600 36.46140 2019-04-26T12:16:57.909 19.57 F60A
190.43600 35.06290 2019-04-26T13:08:04.914 19.41 F60A
212.69800 35.91340 2019-04-26T12:08:27.646 19.09 F60A
243.14800 29.48480 2019-04-26T18:42:22.185 16.77 F60A
251.94600 -7.21269 2019-04-26T16:30:59.956 16.95 F60A
203.64600 34.77790 2019-04-26T19:19:52.570 15.29 F60A
253.27000 -16.29090 2019-04-26T18:13:21.035 15.42 F60A
221.59100 32.78010 2019-04-26T13:20:54.590 20.53 F60A
182.57600 26.43080 2019-04-26T14:19:29.899 20.04 F60A
243.14700 29.36490 2019-04-26T19:35:09.298 15.77 F60A
252.07700 6.31221 2019-04-26T14:53:56.092 18.74 F60A
254.78000 -5.74199 2019-04-26T15:45:20.977 17.63 F60A
253.60000 -9.88924 2019-04-26T16:01:51.545 16.91 F60A
193.51000 29.60370 2019-04-26T13:25:15.579 19.72 F60A
194.91500 53.34130 2019-04-26T12:12:42.478 20.34 F60A
242.27700 24.87030 2019-04-26T18:46:29.445 15.58 F60A
260.77200 12.69540 2019-04-26T16:05:56.399 17.81 F60A
256.25200 -1.54133 2019-04-26T19:38:57.637 14.77 F60A
253.72400 -16.95200 2019-04-26T16:50:26.458 14.38 F60A
205.41500 55.67070 2019-04-26T16:14:20.651 19.45 F60A
252.09000 6.22276 2019-04-26T14:49:46.057 18.45 F60A
196.48300 53.65920 2019-04-26T16:35:23.719 18.93 F60A
240.66900 37.35940 2019-04-26T12:21:33.662 19.43 F60A
252.38800 6.01625 2019-04-26T14:57:55.285 18.43 F60A
253.03200 -17.05380 2019-04-26T18:21:23.262 14.86 F60A
254.50500 -1.82269 2019-04-26T15:26:51.357 17.91 F60A
240.36900 22.42770 2019-04-26T14:15:09.801 19.36 F60A
232.92900 40.86490 2019-04-26T13:16:36.533 20.10 F60A
243.89800 19.45340 2019-04-26T18:50:43.803 15.42 F60A
255.21800 2.10185 2019-04-26T15:18:42.705 18.77 F60A
197.38900 53.49420 2019-04-26T12:31:38.012 20.40 F60A
250.01400 15.88340 2019-04-26T14:02:46.419 19.04 F60A
245.79700 16.93260 2019-04-26T13:58:39.077 19.32 F60A
This circular is citable.
GCN Circular 24314
Subject
LIGO/Virgo S190425z: Liverpool Telescope imaging of ZTF19aasckkq
Date
2019-04-28T00:46:18Z (6 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>
D. A. Perley, C. M. Copperwheat, and K. L. Taggart (LJMU) report on
behalf of the Global Relay of Observatories Watching Transients Happen
(GROWTH) collaboration:
We acquired a series of 60-second exposures of ZTF19aasckkq (Anand et
al., GCN 24311), an optical transient in the error region of LIGO/Virgo
S190425z (GCN 24168), using the IO:O imager on the 2m Liverpool
Telescope in the u, g, r, i, and z filters between 03:17:56 and 03:30:00
UT on 2019-04-27.
The transient is detected with the following magnitudes (measured after
image subtraction and calibrated relative to PS1):
JD magnitude
2458600.6384 g = 20.66 +/- 0.18
2458600.6395 r = 20.37 +/- 0.17
2458600.6406 i = 20.28 +/- 0.23
2458600.6416 z = 20.09 +/- 0.38
It is not detected in u-band. These suggest a moderately but not
extremely red transient and show no obvious evolution relative to the
ZTF imaging on 2019-04-26 (g = 20.86 +/- 0.18).
DisclaimerNone
GCN Circular 24313
Subject
LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient in ASAS-SN observations hours before and after discovery
Date
2019-04-28T00:26:54Z (6 years ago)
From
Benjamin Shappee at U. of Hawaii <shappee@hawaii.edu>
B. J. Shappee (IfA-Hawaii), C. S. Kochanek (OSU), K. Z. Stanek (OSU), S.
Holmbo (Aarhus), A. Franckowiak (DESY), T. W.-S. Holoien (Carnegie
Observatories), J. L. Prieto (Diego Portales; MAS), Subo Dong (KIAA-PKU),
T. A. Thompson (OSU), J. F. Beacom (OSU)
Swift reported a possible counterpart (Breeveld et al., GCN #24296) to
LIGO/Virgo
Alert GCN #24168 of a BNS merger. The reported detection was acquired
on 2019-04-26.784282
UT Swift UVOT u=17.74 +/- 0.18 mag (Vega). ZTF (Andreoni et al., GCN #24302
) reported non-detections 9 hours before the reported Swift observations.
ASAS-SN observations cover both 7 hours before and 12 hours after the
reported Swift transient with 3-sigma g-band limits deeper than the
reported u-band detection:
2019-04-25.4180376 >18.755
2019-04-26.4875420 >18.749
2019-04-27.3040667 >18.421
The transient Swift observed must have evolved on a short timescale or have
been very blue (u-g)~-1.
We would like to thank Las Cumbres Observatory and its staff for their
continued support of ASAS-SN. ASAS-SN is funded in part by the Gordon and
Betty Moore Foundation through grant GBMF5490 to the Ohio State University,
NSF grant AST-1515927, the Mt. Cuba Astronomical Foundation, the Center for
Cosmology and AstroParticle Physics (CCAPP) at OSU, the Chinese Academy of
Sciences South America Center for Astronomy (CASSACA), and the Villum
Fonden (Denmark). For more information about the ASAS-SN project, see
http://www.astronomy.ohio-state.edu/asassn/index.shtml.
GCN Circular 24312
Subject
LIGO/Virgo S190425z: Potential host galaxy of UVOT candidate counterpart found in BLISS
Date
2019-04-28T00:13:42Z (6 years ago)
From
Antonella Palmese at Fermilab <palmese@fnal.gov>
A. Palmese (Fermilab), M. Soares-Santos (Brandeis U.), L. Santana-Silva (OV/UFRJ), A. Drlica-Wagner (Fermilab), K. Herner (Fermilab), R. Morgan (U Wisconsin-Madison)
We searched for previous observations at the position of the UVOT candidate (Breeveld et al. GCN Circ. 24296) in archival DECam data which we have compiled and processed as part of the Blanco Images of the Southern Sky (BLISS) project (PIs: Soares-Santos, Drlica-Wagner). The candidate was identified as part of the counterpart search for the LVC event S190425z (LIGO/VIRGO Collaboration GCN (Circ. 24168).
We find a faint object <1 arcsec away from the UVOT candidate. Visual inspection suggests it is a galaxy. Its AB magnitude is r=22.95+-0.096 (MAG_AUTO) at position (J2000):
RA 255.57996 deg
Dec -12.48536 deg
We suggest to observe this object in other bands or spectroscopically to assess its origin and redshift.
GCN Circular 24311
Subject
LIGO/Virgo S190425z: Additional Candidates from the Zwicky Transient Facility
Date
2019-04-28T00:01:16Z (6 years ago)
From
Shreya Anand at GROWTH Caltech <sanand@caltech.edu>
Shreya Anand (Caltech), Mansi M. Kasliwal (Caltech), Michael W. Coughlin (Caltech), Tomas Ahumada (UMD), Daniel A. Perley (LJMU), Varun Bhalerao (IITB), Danny Goldstein (Caltech), �Leo P. Singer (NASA GSFC), Igor Andreoni (Caltech), Dmitry Duev (Caltech), S. Bradley Cenko (NASA GSFC), Eric C. Bellm (UW), Kishalay De (Caltech), Anna Ho (Caltech), Harsh Kumar (IITB), Gaurav Waratkar (IITB), Chris Copperwheat (LJMU), Virginia Cunningham (UMD), Shaon Ghosh (UWM), Ariel Goobar (OKC), David Kaplan (UWM), Jesper Sollerman (OKC), Joshua S. Bloom (UCB), M. Bulla (OKC), Nobuyuki Kawai (Tokyo Tech), Yoichi Yatsu (Tokyo Tech), Katsuhiro Murata (Tokyo Tech), Hidekazu Hanayama (IAO), Takashi Horiuchi (IAO), G. C. Anupama (IIA), G. Helou (IPAC)
On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations
We continued observations of the gravitational wave trigger S190425z (LVC et al. GCN 24168) with ZTF on UT 2019-04-26. We covered a total of 4950 sq deg in g-band and r-band with over 50% of the enclosed probability targeted based on the original sky map and 24% actual probability enclosed based on the new sky map. Each exposure on the second night was 90s, with a typical depth of 21 mag. See details in Kasliwal et al. GCN 24191 for additional details on data processing.
Objects with a spectroscopic host galaxy redshift higher than 0.1 were excluded and photometric redshifts, where available are noted below. Additional candidates with no detections prior to merger, inside the 90% localization area of the LALInference sky map are:
------------------------------------------------------------------------------------------------------------------
ZTF Name | RA (deg) | DEC (deg) ��| Filter | Mag ��| Magerr �| Notes
------------------------------------------------------------------------------------------------------------------
ZTF19aasckwd | 253.1643781 | �10.6022943 | r | 20.15 | 0.13 |
ZTF19aasfogv | 261.8430161 | -11.3338523 | g � | 20.53 | 0.18 | [hostless] [lowb]
ZTF19aasejil | 261.9458106 | ��1.6537207 | g | 20.53 | 0.14 | z~0.199 +/- 0.035 [nuc]
ZTF19aaryxjf | 254.5952784 | �-3.9847379 | g | 19.95 | 0.08 | z~0.083 +/- 0.015 [nuc]
ZTF19aascxux | 258.2933102 | �17.2938689 | g | 20.56 | 0.13 �
ZTF19aasdajo | 254.3550291 | �11.9961079 | g | 20.70 | 0.20 | z~0.292 +/- 0.067
ZTF19aasbamy | 231.2656676 | �24.9275799 | g | 20.66 | 0.15 | z~0.201 +/- 0.047
ZTF19aasckkq | 248.4131017 | �13.9101828 | g | 20.86 | 0.18 | z=0.0528 [specz]
ZTF19aarycuy | 244.0832042 | �21.7409392 | r | 20.07 | 0.15 | z~0.127 +/- 0.011 [nuc]
ZTF19aasbphu | 245.5831354 | �21.4081853 | r | 19.71 | 0.13 | z~0.0971 +/- 0.0292
�ZTF19aasbaui | 235.2496342 | �24.0816102 | g | 20.49 | 0.14 | z~0.216 +/- 0.052
�ZTF19aarxxwb | 288.6933231 | �-3.0075058 | g | 18.89 | 0.07 | [hostless] [lowb]
�ZTF19aashlts | 253.1875476 | -19.0941338 | r � | 19.95 | 0.11 | [lowb]
------------------------------------------------------------------------------------------------------------------
Notes:
[specz] : Spectroscopic redshift.
[hostless] : No discernable host galaxy.
[nuc] : Close to the host nucleus
[lowb] : Galactic latitude less than 20 degrees
Our most promising event is ZTF19aasckkq as it is -16.3 absolute mag and we encourage follow-up. We also encourage due diligence follow-up of ZTF19aasckwd and ZTF19aascxux. We caution these targets are somewhat fainter and our upper limits relatively less constraining on age. We also caution that we cannot rule out the supernova hypothesis.
Additional follow-up and analysis is ongoing.
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). Alert filtering and follow-up co-ordination is being undertaken by the GROWTH marshal system (Kasliwal et al. 2019).
GCN Circular 24309
Subject
LIGO/Virgo S190425z: ASAS-SN observations
Date
2019-04-27T23:03:16Z (6 years ago)
From
Benjamin Shappee at U. of Hawaii <shappee@hawaii.edu>
B. J. Shappee (IfA-Hawaii), C. S. Kochanek (OSU), K. Z. Stanek (OSU),
S. Holmbo (Aarhus), A. Franckowiak (DESY), T. W.-S. Holoien (Carnegie
Observatories),
J. L. Prieto (Diego Portales; MAS), Subo Dong (KIAA-PKU), T. A. Thompson
(OSU), J. F. Beacom (OSU)
ASAS-SN covered 10% of the probability region in the 1 hour preceding the
LIGO/Virgo Alert GCN #24168 of a BNS merger through normal operations.
Following, the LIGO/VIRGO alert optical follow-up was triggered with the
All-Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014;
Kochanek et al. 2017). ASAS-SN covered 67% of the probability region in
the 24 hours after the LIGO/VIRGO alert through a combination of normal
operations and triggered observations. The majority of the remaining
probability region was Sun constrained. We obtained 6 epochs on the
highest probability regions during that time. Candidates were scanned in
near real time. No obvious candidates were discovered. Given the lunation,
our depth was typically between g~18-18.5 mag.
Our coverage is shown here:
http://www.astronomy.ohio-state.edu/~assassin/LIGO/S190425z_coverage.png
We would like to thank Las Cumbres Observatory and its staff for their
continued support of ASAS-SN. ASAS-SN is funded in part by the Gordon and
Betty Moore Foundation through grant GBMF5490 to the Ohio State University,
NSF grant AST-1515927, the Mt. Cuba Astronomical Foundation, the Center for
Cosmology and AstroParticle Physics (CCAPP) at OSU, the Chinese Academy of
Sciences South America Center for Astronomy (CASSACA), and the Villum
Fonden (Denmark). For more information about the ASAS-SN project, see
http://www.astronomy.ohio-state.edu/asassn/index.shtml
GCN Circular 24307
Subject
LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient with Las Cumbres Observatory
Date
2019-04-27T22:39:24Z (6 years ago)
From
Iair Arcavi at LCOGT <arcavi@gmail.com>
Iair Arcavi (Tel Aviv University), D. Andrew Howell (LCO/UCSB), Curtis
McCully (LCO), Daichi Hiramatsu (LCO/UCSB), Jamison Burke (LCO/UCSB), Craig
Pellegrino (LCO/UCSB) on behalf of the Las Cumbres GW Follow-up
Collaboration
We observed the field of the UVOT transient (Breeveld et al. GCN 24296)
with a Las Cumbres Observatory 1m telescope at the South African
Astronomical Observatory in the g and r bands starting at 2019-04-27 21:40
UT. We do not see the transient down to a g-band limiting magnitude of
roughly 21.8, and an r-band limiting magnitude of 21.5 (determined by
comparison to PS1 images).
GCN Circular 24306
Subject
LIGO/Virgo S190425z: Pre-discovery NIR limits of the UVOT transient candidate from Gattini-IR
Date
2019-04-27T22:02:39Z (6 years ago)
From
Kishalay De at Caltech, GROWTH <kde@astro.caltech.edu>
K. De (Caltech), M. Hankins (Caltech), S. M. Adams (Caltech), M. M.
Kasliwal (Caltech), M. Coughlin (Caltech), I. Andreoni (Caltech), S.
Anand (Caltech), L. Singer (NASA GSFC), T. Ahumada (UMD), A. Moore
(ANU), J. Soon (ANU), M. Ashley (UNSW), T. Travouillon (ANU)
report on behalf of the Palomar Gattini-IR team and the larger GROWTH
(Global Relay of Observatories Watching Transients Happen)
collaboration
The Palomar Gattini-IR survey (Moore and Kasliwal 2019) observed the
location of the Swift UVOT counterpart candidate (GCN #24296) for the
BNS gravitational wave event S190425z (GCN #24168) on UT 2019-04-26
09:59 and UT 2019-04-25 at 10:54. Forced photometry on the images show
no source at the reported location down to a limiting magnitude of
15.2 AB mag in J band. The non-detections rule out bright infrared
emission from the source prior to the Swift detection.
GCN Circular 24305
Subject
LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart
Date
2019-04-27T21:56:02Z (6 years ago)
From
Aaron Tohuvavohu at PSU/Swift <auc444@psu.edu>
Aaron Tohuvavohu (PSU), Phil Evans (U. Leicester), Mike Siegel (PSU),
Frank Marshall (NASA GSFC), Brad Cenko (NASA GSFC) and Jamie Kennea
(PSU) report on behalf of the Swift Gravitational Wave Galaxy Survey
(SGWGS) team
The position of the potential Swift/UVOT counterpart (Breeveld et
al. GCN. 24296) to the LIGO/Virgo S190425z trigger (LIGO/Virgo
Collaboration GCN. 24168) was imaged by the Neil Gehrels Swift
Observatory on 2018, October 21/22 UT with the Swift
Ultraviolet/Optical Telescope in the u and uvw1 filters for a total
1.2 ks of exposure as part of the Swift Gravitational Wave Galaxy
Survey (PI Tohuvavohu). Examining the image we do not detect any
source at the position of the counterpart candidate to a 5-sigma
limiting magnitude of ~21 mag in U-band, corresponding to ~ -14 mag
at the distance of the associated host galaxies (~100 Mpc). These
magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the event.
The Swift Gravitational Wave Galaxy Survey is a 5 Million second
pre-imaging survey of the ~14,000 most likely host galaxies for BNS
mergers within ~100 Mpc. It is performed in the u and uvw1 bands and
with XRT in the Photon Counting mode. It is currently ~43%
complete. When complete it will cover 41.2% of the integrated B-band
luminosity within 100 Mpc down to ~21 mag in u and uvw1 and
~5 �� 10 ���13 erg cm ���2 s ���1 in the X-rays (0.3 - 10 keV).
GCN Circular 24304
Subject
LIGO/Virgo S190425z: GROWTH-India observations of the Swift/UVOT transient
Date
2019-04-27T21:24:40Z (6 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
G. Waratkar, H. Kumar, V. Bhalerao (IITB), J. Stanzin, G. C. Anupama (IIA) report on behalf of the Global Relay of Observatories Watching Transients Happen (GROWTH) collaboration:
We imaged the location of the Swift/UVOT transient candidate (Breeveld et al., GCN 24296) for the counterpart of LIGO/Virgo S190425z with the 0.7m GROWTH-India telescope. We obtained a 600s g band image starting at UT 2019-04-27T20:07:44, and a 600s r band image starting at UT 2019-04-27T19:42:49. The source was not detected in either of the images, down to a limiting magnitude of 21.0.
GCN Circular 24303
Subject
Correction to GCN Circular 24301: LIGO/Virgo S190425z: Lulin observations of the Swift/UVOT transient
Date
2019-04-27T21:07:09Z (6 years ago)
From
Albert Kong at NTHU <akhkong@gmail.com>
The start time in the previous circular is incorrect and has been corrected
here.
LIGO/Virgo S190425z: Lulin observations of the Swift/UVOT transient
Albert Kong (NTHU), Han-Jie Tan (NCU), Po-Chieh Yu (NCU), Chow-Choong
Ngeow (NCU), Wing-Huen Ip (NCU)
On behalf of Global Relay of Observatories Watching Transients
Happen (GROWTH) collaborations
We used the 1m telescope at the Lulin Observatory in Taiwan to obtain
g- and r-band images of the transient found by Swift/UVOT (GCN 24296).
The observations started at 2019-04-27 19:30 UT and the exposure time is
300s for both filters. With a limiting magnitude of about 21.5 (AB) by
comparing to PS1 images, we do not detect the UVOT transient.
GCN Circular 24302
Subject
LIGO/Virgo S190425z: ZTF photometry of the UVOT transient candidate hours before discovery
Date
2019-04-27T21:06:42Z (6 years ago)
From
Igor Andreoni at Caltech <igor.andreoni@gmail.com>
Igor Andreoni (Caltech), S. Bradley Cenko (NASA GSFC), F. Masci (IPAC), M. Graham (Caltech)
On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations
We report pre-detection forced photometry upper limits for the Swift/UVOT transient candidate (Breeveld et al., GCN 24296