GRB 240726A
GCN Circular 36935
Subject
GRB 240726A: Fermi GBM Final Real-time Localization
Date
2024-07-26T08:18:24Z (10 months ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely SHORT GRB
At 08:07:48 UT on 26 Jul 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240726A (trigger 743674073.990914 / 240726339).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 111.9, Dec = 66.8 (J2000 degrees, equivalent to J2000 07h 27m, 66d 47'), with a statistical uncertainty of 6.2 degrees.
The angle from the Fermi LAT boresight is 16.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240726339/quicklook/glg_skymap_all_bn240726339.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240726339/quicklook/glg_healpix_all_bn240726339.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240726339/quicklook/glg_lc_medres34_bn240726339.gif
GCN Circular 36937
Subject
GRB 240726A: AstroSat CZTI detection of a short burst
Date
2024-07-26T16:50:05Z (10 months ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
S. Srijan (IITB), A. Dasgupta (BITS Pilani, Hyderabad), G. Waratkar (IITB), U. Pathak (IITB), J. Joshi (IUCAA), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of the short-duration GRB 240726A which was also detected by Fermi/GBM (Fermi GBM team, GCN Circ. 36935).
The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-07-26 08:07:48.942 UTC. The measured peak count rate associated with the burst is 1882 (+1349, -579) counts/s above the background in the combined data of all quadrants, with a total of 28 (+23, -12) counts. The local mean background count rate was 311 (+5, -182) counts/s. Using cumulative rates, we measure a T90 of 0.07 (+0.02, -0.06) s. We note that the Fermi localization of 111.9, 66.8 (RA, Dec) is close to the Earth limb for AstroSat and is occulted by Earth immediately after this short burst. We also note that the relative intensities among the 4 CZT quadrants are unexpected given the GBM localization; however, this is likely impacted by the small number statistics.
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 36944
Subject
GRB 240726A: SVOM/GRM observation
Date
2024-07-27T11:14:22Z (10 months ago)
From
Chenwei Wang at IHEP <cwwang@ihep.ac.cn>
Via
Web form
SVOM/GRM team: Chen-Wei Wang, Yan-Ting Zhang, Yong-Wei Dong, Jiang-Tao Liu, Shi-Jie Zheng, Jian-Chao Sun, Jiang He, Wen-Jun Tan, Min Gao, Hao-Xuan Guo, Yue Huang, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming Song, You-Li Tuo, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Ping Wang, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Lin Xiong, Jian-Ying Ye, Yi-Tao Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zhang, Shuang-Nan Zhang, Wen-Long Zhang, Shu-Min Zhao, Xiao-Yun Zhao, Chao Zheng (IHEP), Maria-Grazia Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Patrick Maeght (LUPM), Frédéric Piron (LUPM), Stéphane Schanne (CEA), Jingwei Wang (IAP)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), JeanLuc Attéia (IRAP), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (UNLV)
report on behalf of the SVOM team:
During the commissioning phase, the SVOM/GRM was triggered in-flight by a short GRB 240726A at 2024-07-26T08:07:49 UT (T0). which was also observed by Fermi/GBM (GCN 36935) and AstroSat/CZTI (GCN 36937).
The real-time alert data and light curves of SVOM/GRM were downlinked to the ground through the VHF system with low latency. The GRM light curve shows that this burst consists of double pulses with a duration of about 0.1 s.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn/admin/static/svgrb240726A.png
The SVOM/GRM on-ground localization of this burst is (J2000):
RA: 173.6 deg
DEC: -2.6 deg
Error: 34.1 deg (1 sigma, statistical only)
We caution that the calibration of SVOM/GRM is undergoing and this localization is subject to systematic errors. The SVOM/GRM localization is consistent with that of Fermi/GBM within 3 sigma error. The localization may be improved in the refined analysis.
At the time of the burst, the field of view of ECLAIRs does not cover the error region given by GRM and was largely obscured by the Earth.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS.
The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang@ihep.ac.cn)
GCN Circular 36951
Subject
Fermi GRB 240726A: Global MASTER-Net observations report
Date
2024-07-27T19:45:22Z (10 months ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
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) started inspect of the Fermi GRB 240726A ( Fermi GBM team, GCN 36935) errorbox 1 days 37487 sec after notice time and 1 days 37518 sec after trigger time at 2024-07-27 18:33:07 UT, with upper limit up to 17.8 mag. Observations started at twilight. The observations began at zenith distance = 66 deg. The sun altitude is -12.7 deg.
The galactic latitude b = 29 deg., longitude l = 149 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2541434
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
123949 | 2024-07-27 18:33:07 | MASTER-Tavrida | (07h 29m 45.02s , +67d 15m 35.0s) | C | 60 | 17.0 |
124021 | 2024-07-27 18:34:20 | MASTER-Tavrida | (07h 32m 21.89s , +65d 55m 08.3s) | C | 60 | 17.2 |
124095 | 2024-07-27 18:35:34 | MASTER-Tavrida | (07h 06m 51.82s , +65d 56m 42.9s) | C | 60 | 17.1 |
124190 | 2024-07-27 18:37:08 | MASTER-Tavrida | (07h 03m 09.14s , +67d 36m 51.4s) | C | 60 | 14.7 |
124284 | 2024-07-27 18:38:43 | MASTER-Tavrida | (07h 27m 03.71s , +68d 33m 26.0s) | C | 60 | 17.5 |
124357 | 2024-07-27 18:39:56 | MASTER-Tavrida | (07h 10m 39.52s , +64d 37m 28.3s) | C | 60 | 17.1 |
124668 | 2024-07-27 18:45:06 | MASTER-Tavrida | (06h 58m 49.49s , +68d 53m 16.9s) | C | 60 | 16.0 |
125157 | 2024-07-27 18:53:16 | MASTER-Tavrida | (07h 29m 49.29s , +67d 15m 40.6s) | C | 60 | 17.7 |
125230 | 2024-07-27 18:54:28 | MASTER-Tavrida | (07h 50m 32.61s , +67d 14m 19.2s) | C | 60 | 17.6 |
125303 | 2024-07-27 18:55:41 | MASTER-Tavrida | (07h 32m 24.67s , +65d 55m 29.8s) | C | 60 | 17.5 |
125376 | 2024-07-27 18:56:55 | MASTER-Tavrida | (07h 52m 09.01s , +65d 55m 40.9s) | C | 60 | 17.6 |
125471 | 2024-07-27 18:58:29 | MASTER-Tavrida | (07h 07m 07.62s , +66d 19m 47.9s) | C | 60 | 15.2 |
125566 | 2024-07-27 19:00:04 | MASTER-Tavrida | (07h 26m 34.24s , +65d 56m 25.9s) | C | 60 | 17.4 |
125666 | 2024-07-27 19:01:44 | MASTER-Tavrida | (07h 03m 09.83s , +67d 37m 37.3s) | C | 60 | 15.4 |
125761 | 2024-07-27 19:03:20 | MASTER-Tavrida | (07h 23m 33.94s , +67d 15m 10.3s) | C | 60 | 17.0 |
125857 | 2024-07-27 19:04:55 | MASTER-Tavrida | (07h 27m 20.53s , +68d 56m 05.3s) | C | 60 | 15.9 |
125951 | 2024-07-27 19:06:29 | MASTER-Tavrida | (07h 49m 11.27s , +68d 33m 08.8s) | C | 60 | 17.8 |
126045 | 2024-07-27 19:08:04 | MASTER-Tavrida | (07h 10m 55.30s , +65d 00m 19.5s) | C | 60 | 13.6 |
126140 | 2024-07-27 19:09:38 | MASTER-Tavrida | (07h 29m 31.59s , +64d 38m 26.1s) | C | 60 | 17.2 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.