TITLE: GCN CIRCULAR
NUMBER: 35436
SUBJECT: GRB 231230A: Swift detection of a burst
DATE: 23/12/30 01:44:18 GMT
FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk>
M. J. Moss (GSFC), C. Gronwall (PSU), J.D. Gropp (PSU),
H. A. Krimm (NSF), A. Y. Lien (U Tampa), K. L. Page (U Leicester) and
M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 01:29:08 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 231230A (trigger=1205319). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 245.197, +58.120 which is
RA(J2000) = 16h 20m 47s
Dec(J2000) = +58d 07' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a multi-peaked
structure with a duration of about 30 sec. The peak count rate
was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 01:32:45.0 UT, 216.3 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 245.21706, 58.12324 which is equivalent
to:
RA(J2000) = 16h 20m 52.09s
Dec(J2000) = +58d 07' 23.7"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 39 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper. We
cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.31 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.3
(+4.82/-3.83) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 145 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag.
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.015.
Burst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)
View this GCN Circular online at https://gcn.nasa.gov/circulars/35436.
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TITLE: GCN CIRCULAR
NUMBER: 35435
SUBJECT: Swift GRB231230.06: Global MASTER-Net observations report
DATE: 23/12/30 01:39:58 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, V.Senik, D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(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. Gress, N.M. Budnev, O.Ershova
(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),
V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)
MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB231230.06 (trigger No 1205319,16h 20m 47.28s , +58d 07m 12.0s, R=0.05) errorbox 12 sec after notice time and 68 sec after trigger time at 2023-12-30 01:30:17 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 54 deg. The sun altitude is -39.8 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB231230.06 errorbox 16 sec after notice time and 72 sec after trigger time at 2023-12-30 01:30:20 UT, with upper limit up to 17.2 mag. The observations began at zenith distance = 51 deg. The sun altitude is -34.0 deg.
The galactic latitude b = 42 deg., longitude l = 88 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2346177
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
73 | MASTER-Tavrida | C | 10 | 16.1 |
77 | MASTER-Kislovodsk | P- | 10 | 16.0 |
97 | MASTER-Kislovodsk | P- | 50 | 16.7 | Coadd
77 | MASTER-Kislovodsk | P| | 10 | 15.8 |
96 | MASTER-Tavrida | C | 20 | 17.7 |
100 | MASTER-Kislovodsk | P- | 20 | 16.3 |
100 | MASTER-Kislovodsk | P| | 20 | 16.0 |
122 | MASTER-Tavrida | C | 20 | 17.7 |
128 | MASTER-Kislovodsk | P- | 20 | 16.2 |
128 | MASTER-Kislovodsk | P| | 20 | 16.0 |
155 | MASTER-Tavrida | C | 30 | 17.7 |
161 | MASTER-Kislovodsk | P- | 30 | 16.6 |
206 | MASTER-Kislovodsk | P- | 120 | 17.3 | Coadd
161 | MASTER-Kislovodsk | P| | 30 | 16.5 |
196 | MASTER-Tavrida | C | 40 | 17.9 |
206 | MASTER-Kislovodsk | P- | 40 | 16.5 |
206 | MASTER-Kislovodsk | P| | 40 | 16.6 |
242 | MASTER-Tavrida | C | 40 | 17.9 |
259 | MASTER-Kislovodsk | P- | 50 | 16.6 |
259 | MASTER-Kislovodsk | P| | 50 | 16.5 |
294 | MASTER-Tavrida | C | 50 | 17.8 |
322 | MASTER-Kislovodsk | P- | 60 | 16.8 |
322 | MASTER-Kislovodsk | P| | 60 | 16.6 |
361 | MASTER-Tavrida | C | 70 | 18.3 |
444 | MASTER-Tavrida | C | 80 | 18.5 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
View this GCN Circular online at https://gcn.nasa.gov/circulars/35435.
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TITLE: GCN CIRCULAR
NUMBER: 35433
SUBJECT: GRB 231210B: BOOTES-7 optical upper limit
DATE: 23/12/29 07:22:12 GMT
FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct(a)iaa.es>
A. J. Castro-Tirado, Y.-D. Hu, E. Fernandez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia, S.-Y. Wu, S. Guziy (IAA-CSIC Granada), C. Perez del Pulgar, A. Castellon, A. Reina (Univ. de Malaga), B.-B. Zhang (Nanjing Univ.) and A. Maury (Space, San Pedro de Atacama), report:
Following the detection of GRB 231210B by Swift (Page et al., GCNC 35314) and Konus-Wind (Frederiks et al. GCNC 35359), the 0.6m BOOTES-7 robotic telescope at San Pedro de Atacama (Chile) pointed to the burst position on Dec. 21 at 01:32 UT (i.e. ~10.2 days after trigger). Images were gathered in different optical bands. In the co-added r-band image (8 x 300 s, SDSS-r filter), the optical afterglow reported by MASTER (Lipunov et al. GCNC 35313), UVOT (Page et al., GCNC 35314), LCOGT (Pérez-Fournon et al. GCNC 35316), VLT (Saccardi et al. GCNC 35317) and MeerLICHT (de Wet et al. GCNC 35323) is not detected within the enhanced Swift/XRT position (Beardmore et al. GCNC 35318) down to 21.0 mag, which is consistent with the REM results (Ferro et al. GCNC 35333).
Regarding the source reported at the Greenhill Observatory (Siellez et al. GCNC 35406), we cannot clearly identify it since it is blended with a nearby and brighter star 0.4" away. In any case, we notice that this object is present on the DESI catalog and it is far from the enhanced Swift/XRT position and therefore unrelated to GRB 231210B.
BOOTES-7 is the last observatory completing the BOOTES Global Network of robotic telescopes in all the continents (Castro-Tirado 2023, Nat. Astron. 7, 1136), 25 years after the first astronomical station was deployed in south Spain.
We thank the staff at San Pedro de Atacama Celestial Explorations observatory for their excellent support.
View this GCN Circular online at https://gcn.nasa.gov/circulars/35433.
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TITLE: GCN CIRCULAR
NUMBER: 35432
SUBJECT: Swift Triggers 1205103, 1205104, 1205107 and 1205110 are not astrophysical events
DATE: 23/12/28 09:28:58 GMT
FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk>
K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift
Observatory Team:
Swift Triggers 1205103, 1205104, 1205107 and 1205110, between
2023-12-28 08:13 and 08:58 UT, were caused by a star tracker
loss-of-lock event, and are not interesting astrophysical events.
View this GCN Circular online at https://gcn.nasa.gov/circulars/35432.
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TITLE: GCN CIRCULAR
NUMBER: 35431
SUBJECT: LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
DATE: 23/12/28 03:22:19 GMT
FROM: Samuele Ronchini at PSU <sjs8171(a)psu.edu>
Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Tyler Parsotan (NASA GSFC), Jamie A. Kennea (PSU), James DeLaunay (PSU) report:
Swift/BAT was observing 90.3% of the GW localization probability (Bilby.multiorder.fits) at merger time. A fraction 20% of the GW localization posterior is contained inside the BAT coded FoV.
The LVK notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
Using the NITRATES analysis (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), we searched for emission on 8 timescales from 0.128s to 16.384s in the interval [-20,+20] seconds around the merger time. We find no evidence for a signal, and derive the following upper limits.
We quote the 5-sigma flux upper limits in the 15-350 keV band, weighted over the GW localization, for four spectral templates (soft, normal, and hard GRB-like templates described in [arXiv:1612.02395], and spectral shape from GRB170817A [arXiv:1710.05446]) and for four time bins.
In units of 10^-7 erg/s/cm^2:
time_bin (s) soft normal hard GRB170817
------------------------------------
0.256 12.9 9.3 8.3 10.4
1.024 6.6 4.8 4.2 5.3
4.096 3.5 2.5 2.3 2.8
16.38 2.1 1.6 1.4 1.7
The upper limits as function of sky position are plotted here, alongside the GW localization:
https://doi.org/10.5281/zenodo.10433190
The solid and dashed lines indicate the 90% and 50% GW contour levels, respectively.
The corresponding fits file can be found here:
https://doi.org/10.5281/zenodo.10433196
GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/
View this GCN Circular online at https://gcn.nasa.gov/circulars/35431.
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TITLE: GCN CIRCULAR
NUMBER: 35430
SUBJECT: IPN triangulation of GRB 231224A (short)
DATE: 23/12/27 12:51:08 GMT
FROM: Dmitry Svinkin at Ioffe Institute <dmitrysvinkin(a)gmail.com>
D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
on behalf of the IPN,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
and
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
report:
The short-duration GRB 231224A
(Fermi-GBM detection: The Fermi GBM team, GCN 35426)
was detected by Fermi (GBM trigger 725143760) and
INTEGRAL (SPI-ACS) at about 74956 s UT (20:49:16).
We have triangulated it to a GBM-SPI-ACS annulus centered at
RA(2000)=230.929 deg (15h 23m 43s) Dec(2000)=-83.517 deg (-83d 30' 60"),
whose radius is 32.644 +/- 5.664 deg (3 sigma).
The annulus combined with the Fermi-GBM final position (GCN 35426;
glg_healpix_all_bn231224868_v00) gives ~792 sq. deg (3 sigma) localization region.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB231224_T74955/IPN/
View this GCN Circular online at https://gcn.nasa.gov/circulars/35430.
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TITLE: GCN CIRCULAR
NUMBER: 35429
SUBJECT: LIGO/Virgo/KAGRA S231226av: Updated Sky localization
DATE: 23/12/26 16:24:40 GMT
FROM: Aaron Zimmerman at U. of Texas at Austin <aaron.zimmerman(a)utexas.edu>
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 S231226av (GCN Circular 35428). 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/S231226av
For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 199 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1218 +/- 171 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) and Morisaki et al. arXiv:2307.13380 (2023)
View this GCN Circular online at https://gcn.nasa.gov/circulars/35429.
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TITLE: GCN CIRCULAR
NUMBER: 35428
SUBJECT: LIGO/Virgo/KAGRA S231226av: Identification of a GW compact binary merger candidate
DATE: 23/12/26 11:23:48 GMT
FROM: D. Belardinelli at INFN (Rome ToV) <belardinelli(a)roma2.infn.it>
The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report:
We identified the compact binary merger candidate S231226av during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2023-12-26 10:15:20.306 UTC (GPS time: 1387620938.306). The candidate was found by the CWB [1], GstLAL [2], MBTA [3], and PyCBC Live [4] analysis pipelines.
S231226av is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.1e-50 Hz, or about one in 1e42 years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S231226av
The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<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%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] 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 <1%.
Two sky maps are available at this time and can be retrieved from the GraceDB event page:
* bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 30 seconds after the candidate event time.
* bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time.
The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 244 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1041 +/- 235 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] Tsukada et al. PRD 108, 043004 (2023) and Ewing et al. arXiv:2305.05625 (2023)
[3] Aubin et al. CQG 38, 095004 (2021)
[4] Dal Canton et al. ApJ 923, 254 (2021)
[5] Chatterjee et al. ApJ 896, 54 (2020)
[6] Singer & Price PRD 93, 024013 (2016)
View this GCN Circular online at https://gcn.nasa.gov/circulars/35428.
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TITLE: GCN CIRCULAR
NUMBER: 35427
SUBJECT: Fermi trigger No 725143760: Global MASTER-Net observations report
DATE: 23/12/24 21:16:05 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, V.Senik, D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(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. Gress, N.M. Budnev, O.Ershova
(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),
V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB231224.87 (trigger No 725143760,06h 49m 09.60s , -71d 10m 12.0s, R=11.88) errorbox 348 sec after notice time and 390 sec after trigger time at 2023-12-24 20:55:46 UT, with upper limit up to 19.0 mag. The observations began at zenith distance = 36 deg. The sun altitude is -29.4 deg.
The galactic latitude b = -26 deg., longitude l = 282 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2342087
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
420 | 2023-12-24 20:55:46 | MASTER-SAAO | (05h 53m 02.24s , -65d 19m 23.8s) | C | 60 | 17.9 |
420 | 2023-12-24 20:55:46 | MASTER-SAAO | (06h 13m 27.52s , -65d 30m 39.0s) | C | 60 | 18.1 |
511 | 2023-12-24 20:57:16 | MASTER-SAAO | (06h 03m 17.13s , -63d 24m 19.9s) | C | 60 | 18.3 |
511 | 2023-12-24 20:57:16 | MASTER-SAAO | (06h 22m 19.48s , -63d 35m 38.8s) | C | 60 | 18.6 |
590 | 2023-12-24 20:58:36 | MASTER-SAAO | (06h 21m 12.31s , -67d 12m 33.5s) | C | 60 | 18.1 |
590 | 2023-12-24 20:58:36 | MASTER-SAAO | (06h 43m 11.91s , -67d 23m 56.6s) | C | 60 | 18.4 |
681 | 2023-12-24 21:00:07 | MASTER-SAAO | (05h 41m 42.60s , -67d 14m 18.9s) | C | 60 | 17.3 |
681 | 2023-12-24 21:00:07 | MASTER-SAAO | (06h 03m 44.79s , -67d 25m 34.9s) | C | 60 | 17.6 |
765 | 2023-12-24 21:01:31 | MASTER-SAAO | (06h 29m 42.58s , -65d 19m 28.2s) | C | 60 | 19.0 |
765 | 2023-12-24 21:01:31 | MASTER-SAAO | (06h 50m 06.29s , -65d 30m 55.7s) | C | 60 | 18.7 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
View this GCN Circular online at https://gcn.nasa.gov/circulars/35427.
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