TITLE: GCN CIRCULAR
NUMBER: 34304
SUBJECT: LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
DATE: 23/07/31 23:47:05 GMT
FROM: Satoshi Sugita at Aoyama Gakuin U. <sugita(a)phys.aoyama.ac.jp>
M. Nakajima, H. Negoro, (Nihon U.),
T. Mihara, N. Kawai (RIKEN),
S. Sugita, M. Serino, H. Hiramatsu, H. Nishikawa, Y. Kondo (AGU),
Y. Kawakubo (LSU)
report on behalf of the MAXI team:
We examined MAXI/GSC all-sky X-ray images (2-20 keV)
after compact binary merger candidate S230731an at 2023-07-31 21:53:07
UTC (GCN 34303).
At the trigger time of S230731an, the high-voltage of MAXI/GSC was off,
and it was turned on at T0+628 sec (+10.5 min).
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 22:03:35 to
23:07:43 UTC (T0+628 to T0+4476 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.
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TITLE: GCN CIRCULAR
NUMBER: 34303
SUBJECT: LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate
DATE: 23/07/31 22:22:25 GMT
FROM: J. C. Driggers at California Institute of Technology, LIGO Hanford Observatory <jenne(a)caltech.edu>
The LIGO Scientific Collaboration, the Virgo Collaboration, and the
KAGRA Collaboration report:
We identified the compact binary merger candidate S230731an during
real-time processing of data from LIGO Hanford Observatory (H1) and
LIGO Livingston Observatory (L1) at 2023-07-31 21:53:07.889 UTC (GPS
time: 1374875605.889). The candidate was found by the CWB [1], MBTA
[2], GstLAL [3], PyCBC Live [4], and SPIIR [5] analysis pipelines.
S230731an is an event of interest because its false alarm rate, as
estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2
years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S230731an
The classification of the GW signal, in order of descending
probability, is BBH (70%), NSBH (15%), Terrestrial (15%), or BNS
(<1%).
Assuming the candidate is astrophysical in origin, the probability
that the lighter compact object is consistent with a neutron star mass
(HasNS) is <1%. [6] Using the masses and spins inferred from the
signal, the probability of matter outside the final compact object
(HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the
support of several neutron star equations of state. The probability
that either of the binary components lies between 3 and 5 solar masses
(HasMassgap) is 5%.
Two sky maps are available at this time and can be retrieved from the
GraceDB event page:
* bayestar.multiorder.fits,1, an initial localization generated by
BAYESTAR [7], distributed via GCN notice about 30 seconds after the
candidate event time.
* bayestar.multiorder.fits,2, an initial localization generated by
BAYESTAR [7], distributed via GCN notice about 5 minutes after the
candidate event time.
The preferred sky map at this time is bayestar.multiorder.fits,2. For
the bayestar.multiorder.fits,2 sky map, the 90% credible region is 646
deg2. Marginalized over the whole sky, the a posteriori luminosity
distance estimate is 1056 +/- 279 Mpc (a posteriori mean +/- standard
deviation).
For further information about analysis methodology and the contents of
this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide
https://emfollow.docs.ligo.org/userguide/.
[1] Klimenko et al. PRD 93, 042004 (2016)
[2] Aubin et al. CQG 38, 095004 (2021)
[3] Tsukada et al. arXiv:2305.06286 (2023) and Ewing et al.
arXiv:2305.05625 (2023)
[4] Dal Canton et al. ApJ 923, 254 (2021)
[5] Chu et al. PRD 105, 024023 (2022)
[6] Chatterjee et al. ApJ 896, 54 (2020)
[7] Singer & Price PRD 93, 024013 (2016)
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TITLE: GCN CIRCULAR
NUMBER: 34302
SUBJECT: LIGO/Virgo/KAGRA S230729z: Updated Sky localization
DATE: 23/07/31 19:51:04 GMT
FROM: Christopher P L Berry at LVK Collaboration <christopher.berry(a)ligo.org>
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230729z (GCN Circular 34293). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the
GraceDB event page:
https://gracedb.ligo.org/superevents/S230729z
For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 1945 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1495 +/- 444 Mpc (a posteriori mean +/- standard deviation).
For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/.
[1] Ashton et al. ApJS 241, 27 (2019)
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TITLE: GCN CIRCULAR
NUMBER: 34301
SUBJECT: GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
DATE: 23/07/31 19:40:10 GMT
FROM: Sam Guns at S Pole Telescope & UC Berkeley <sguns(a)berkeley.edu>
S. Guns (UC Berkeley), A. Foster (CWRU), C. Tandoi (UIUC), K. Phadke (UIUC), N. Whitehorn (MSU), G. Holder (UIUC), J. Vieira (UIUC) on behalf of the South Pole Telescope Collaboration:
On 26 July 2023 at 16:48 UTC the South Pole Telescope detected a millimeter-band transient candidate at RA = 43.5275, Dec = -70.4770 (J2000 degrees, uncertainty 12 arcseconds) using the SPT-3G camera in 2 bands centered at 95 GHz and 150 GHz. Peak emission was observed two hours later at 19:14 UTC with flux levels of 18.5 mJy in both bands, after which the SPT slewed away from the observing field. The next series of observations on 28 July showed flux levels consistent with zero. The spatial location of the emission is consistent (1.5 sigma) with GRB 230723A which was detected by Fermi-GBM on 23 July 2023 at RA = 21.0, Dec = -71.2 (J2000 degrees, uncertainty 4.8 degrees). From the SPT-3G transients program, short duration (<1 week) millimeter-band transients that are not associated with nearby stars are rare (<3 events per year). A table of SPT-3G observations is given below.
The lightcurve can be found at:
https://pole.uchicago.edu/public/data/transients/lightcurves/SPT-SVJ025406.…
Observation time | Flux (95 GHz) | Error (95 GHz) | Flux (150 GHz) | Error (150 GHz)
2023-7-22 05:04 UTC | -3.0 mJy | 2.5 mJy | -3.3 mJy | 3.0 mJy
2023-7-26 16:48 UTC | 13.3 mJy | 4.4 mJy | 14.0 mJy | 4.9 mJy
2023-7-26 19:14 UTC | 18.5 mJy | 4.4 mJy | 18.5 mJy | 4.9 mJy
2023-7-28 08:12 UTC | 1.7 mJy | 2.5 mJy | 1.8 mJy | 2.8 mJy
The South Pole Telescope is a 10-meter telescope located at Amundsen-Scott South Pole Station and supported by the National Science Foundation and the US Dept. of Energy. The SPT online transient program providing data in this circular is supported by NSF grants AST-1716965 and OPP 1852617, and observes 1500 square degrees of the southern sky at 95, 150, and 220 GHz with an average revisit cadence of 12 hours. For more details on the SPT transient program and survey strategy, please see https://arxiv.org/abs/2103.06166.
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TITLE: GCN CIRCULAR
NUMBER: 34300
SUBJECT: Fermi trigger No 712390645: Global MASTER-Net observations report
DATE: 23/07/31 15:47:35 GMT
FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB230730.26 (trigger No 712390645,13h 39m 00.00s , +32d 54m 00.0s, R=33.9) errorbox 1 days 29758 sec after notice time and 1 days 29791 sec after trigger time at 2023-07-31 14:33:51 UT, with upper limit up to 16.8 mag. Observations started at twilight. The observations began at zenith distance = 74 deg. The sun altitude is -12.4 deg.
The galactic latitude b = 78 deg., longitude l = 63 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2247493
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
116222 | 2023-07-31 14:33:51 | MASTER-Tunka | (12h 01m 31.40s , +20d 20m 14.0s) | C | 60 | 16.8 |
116308 | 2023-07-31 14:35:18 | MASTER-Tunka | (11h 54m 21.62s , +22d 12m 47.3s) | C | 60 | 16.2 |
116982 | 2023-07-31 14:46:32 | MASTER-Tunka | (11h 54m 28.70s , +22d 12m 35.0s) | C | 60 | 16.4 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
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TITLE: GCN CIRCULAR
NUMBER: 34299
SUBJECT: GRB 230728A: Swift-BAT refined analysis
DATE: 23/07/31 12:57:17 GMT
FROM: Tyler Parsotan at NASA GSFC <tyler.parsotan(a)nasa.gov>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), (i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230728A (trigger #1181187)
(Salvaggio, et al., GCN Circ. 34282). The BAT ground-calculated position is
RA, Dec = 343.514, 28.169 deg which is
RA(J2000) = 22h 54m 03.4s
Dec(J2000) = +28d 10' 09.5"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 49%.
He mask-weighted light curve shows a complex multi-peaked structure with some
emission prior to the trigger time.
T90 (15-350 keV) is 15.10 +- 0.89 sec (estimated error including systematics).
The time-averaged spectrum from T-5.62 to T+10.74 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.58 +- 0.13. The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+0.41 sec in the 15-150 keV band
is 2.5 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1181187/BA/
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TITLE: GCN CIRCULAR
NUMBER: 34298
SUBJECT: Fermi-LAT gamma-ray observations of IceCube-230727A
DATE: 23/07/30 20:23:26 GMT
FROM: Simone Garrappa at DESY <simone.garrappa(a)desy.de>
S. Garrappa (Weizmann Institute of Science), C. Bartolini (INFN Bari), S. Buson (Uni Wuerzburg) and J. Sinapius (DESY) on behalf of the Fermi-LAT collaboration:
We report an analysis of observations of the vicinity of the IC230727A high-energy neutrino event (GCN 34276) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The IceCube event was detected on 2023-07-27 at 16:05:39.63 UT (T0) with J2000 position RA = 33.66 (+1.16, -0.77) deg, Decl. = 7.63 (+0.70, -0.64) deg (90% PSF containment). There are no Fermi 4FGL-DR4 cataloged gamma-ray (>100 MeV; The Fermi-LAT collaboration 2022, ApJS, 260, 53; Ballet et al. 2023, arXiv:2307.12546) sources in the 90% IC230727A uncertainty localization region.
We searched for intermediate (days to years) timescale emission from a new gamma-ray source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission (> 100 MeV) at the IC230727A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC230727A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 1.2e-10 ph cm^-2 s^-1 for ~15-years (2008-08-04 to 2023-07-27 UTC), and < 4.1e-9 (< 6.0e-8) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0.
Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this region will continue. For these observations the Fermi-LAT contact persons are S. Garrappa (simone.garrappa at weizmann.ac.il), C. Bartolini (chiara.bartolini at ba.infn.it), S. Buson (sara.buson at uni-wuerzburg.de) and J. Sinapius (jonas.sinapius at desy.de).
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.
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TITLE: GCN CIRCULAR
NUMBER: 34297
SUBJECT: GRB 230723B: Swift-BAT refined analysis
DATE: 23/07/30 13:50:12 GMT
FROM: Tyler Parsotan at NASA GSFC <tyler.parsotan(a)nasa.gov>
T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+60 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230723B (trigger #1180410)
(Page, et al., GCN Circ. 34234). The BAT ground-calculated position is
RA, Dec = 250.391, -5.319 deg which is
RA(J2000) = 16h 41m 33.8s
Dec(J2000) = -05d 19' 08.1"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 39%.
The light curve shows a fast rise exponential decay type profile.
T90 (15-350 keV) is 6.64 +- 0.81 sec (estimated error including systematics).
The time-averaged spectrum from T-0.22 to T+7.94 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.09 +- 0.38,
and Epeak of 65.9 +- 15.8 keV (chi squared 41.57 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.7 +- 0.1 x 10^-06 erg/cm2
and the 1-sec peak flux measured from T+1.64 sec in the 15-150 keV band is
5.1 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.77 +- 0.08 (chi squared 52.21 for 57 d.o.f.). All the quoted errors
are at the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1180410/BA/
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TITLE: GCN CIRCULAR
NUMBER: 34296
SUBJECT: Fermi trigger No 712306969: Global MASTER-Net observations report
DATE: 23/07/30 12:30:43 GMT
FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB230729.29 (trigger No 712306969,00h 02m 12.00s , -62d 14m 59.6s, R=12.01) errorbox 1 days 12030 sec after notice time and 1 days 12066 sec after trigger time at 2023-07-30 10:23:50 UT, with upper limit up to 19.5 mag. Observations started at twilight. The observations began at zenith distance = 28 deg. The sun altitude is -13.0 deg.
The galactic latitude b = -54 deg., longitude l = 312 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2246802
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
98556 | 2023-07-30 10:23:50 | MASTER-OAFA | (00h 28m 55.99s , -50d 15m 13.2s) | C | 180 | 19.5 |
98788 | 2023-07-30 10:27:42 | MASTER-OAFA | (00h 15m 39.42s , -48d 22m 17.4s) | C | 180 | 19.2 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
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