GRB250516B

This page lists all entries on GRB250516B in GRBweb

Summary GCN 40469 GCN 40484 GCN 40496 GCN 40506 GCN 40507

Summary table
Variable Value Source
T0 6:31:32 UTC GCN_circulars,IPN Triangulation
ra 143.0800° GCN_circulars,IPN Triangulation
decl 21.2900° GCN_circulars,IPN Triangulation
GBM_located False
mjd 60811.271898148145 GCN_circulars,IPN Triangulation
GCN 40469 table
GRB_name GRB250516B
GCN_number 40469
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 40469 SUBJECT: GRB 250516B: GECAM-B detection of a bright long burst DATE: 25/05/16 19:33:50 GMT FROM: Chenwei Wang at IHEP Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight by a bright long burst GRB 250516B at 2025-05-16T06:31:34.7 UTC (denoted as T0). According to the GECAM-B light curves in about 40-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 40.6 +0.9/-0.7 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecamgrb250516B.png GECAM-B localized this burst to the following position (J2000): Ra: 137.5 deg Dec: 41.4 deg Err: 7.0 deg (1-sigma, statistical only) The time-averaged spectrum from T0-5 s to T0+75 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.00 +/-0.07 and the cutoff energy, parameterized as Epeak, is 367 +46/-36 keV. The event fluence (10-1000 keV) in this time interval is (2.3 +/-0.1)E-04 erg/cm^2. Thus GRB 250516B is consistent with Type II GRBs in the 'Amati' relation diagram, as shown at: https://www.bursthub.cn//admin/static/grb250516B_amati.png Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
GCN 40484 table
GRB_name GRB250516B
GCN_number 40484
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 40484 SUBJECT: GRB 250516B: NuSTAR Detection of the Prompt Emission DATE: 25/05/17 19:08:14 GMT FROM: Brian Grefenstette at Caltech/NuSTAR B. Grefenstette (Caltech) reports on behalf of the NuSTAR Search for INteresting Gamma-ray Signals (SINGS) working group: The NuSTAR SINGS working group reports the detection of prompt emission from the Long GRB 250516B in both the NuSTAR CsI anti-coincidence shields and in the CdZnTe detectors. This GRB was identified through a blind search using the CsI shield rates. Details of the search algorithm will be described in a future paper. The NuSTAR SINGS algorithm triggered at 2025-05-16 06:31:39 with a resolution ~5-seconds. This is consistent with the GECAM-B reported time of 2025-05-16T06:31:34.7 (Wang et al., GCN circ. 40469). The GRB is a broad burst with multiples peaks. The brightest has a peak count rates in the anti-coincidence shields near 4,000 cps over a baseline of ~1,000 cps. The burst is also clearly seen in the CdZnTe detectors. Discovery report and a preliminary lightcurves for this GRB can be found here: https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2025/250516B/ Information on NuSTAR SINGS can be found here: https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/ NuSTAR is a NASA Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington.
GCN 40496 table
GRB_name GRB250516B
GCN_number 40496
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 40496 SUBJECT: GRB 250516B: GRBAlpha detection DATE: 25/05/20 08:49:07 GMT FROM: Marianna Dafčíková at Masaryk University <500025@mail.muni.cz> M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 250516B (GECAM-B detection: GCN 40469; NuSTAR detection: GCN 40484; Insight-HXMT/HE detection: GCN 40489; Wind/Konus detection trigger at 2025-05-16 06:31:32.766 UTC) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2025-05-16 06:31:54.3 UTC. The T90 duration measured by GRBAlpha is 40 s and the overall significance during T90 reaches 83 sigma. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB250516B_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
GCN 40506 table
GRB_name GRB250516B
GCN_number 40506
Detection_method IPN Triangulation
t_trigger 6:31:32 UTC
ra 143.0800°
decl 21.2900°
Circular_text TITLE: GCN CIRCULAR NUMBER: 40506 SUBJECT: IPN triangulation of GRB 250516B DATE: 25/05/20 21:24:50 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, E. Burns on behalf of the IPN, S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, C. Wang, S. Xiong, S. Zheng and Y. Zhang, on behalf of the Insight-HXMT and GECAM team, and M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), F. Munz (Masaryk U.), on behalf of the GRBAlpha team, report: The bright, long-duration GRB 250516B (GECAM-B detection: Wang et al., GCN 40469; NuSTAR-ACS detection: Grefenstette et al., GCN 40484; Insight-HXMT-HE detection: Wang et al., GCN 40489; GRBAlpha detection: Dafcikova et al., GCN 40496) was detected by GECAM-B, GECAM-A, Konus-Wind, NuSTAR (ACS), Insight-HXMT (HE), Swift (BAT), and GRBAlpha at about 23492 s UT (06:31:32). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: ------------------------------- RA(2000), deg Dec(2000), deg ------------------------------- Center: 143.08 21.29 Corners: 144.27 24.01 143.64 24.28 141.81 18.37 142.40 18.15 ------------------------------- The error box area is 4.2 sq. deg, and its maximum dimension is 6.3 deg (the minimum one is 41 arcmin). The Sun distance was 82 deg. This localization may be improved. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250516_T23492/IPN The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
GCN 40507 table
GRB_name GRB250516B
GCN_number 40507
Detection_method Konus-Wind Det
t_trigger 6:31:32.766 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 40507 SUBJECT: Konus-Wind detection of GRB 250516B DATE: 25/05/20 21:30:43 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The bright, long-duration GRB 250516B (GECAM-B detection: Wang et al., GCN 40469; NuSTAR-ACS detection: Grefenstette et al., GCN 40484; Insight-HXMT-HE detection: Wang et al., GCN 40489; GRBAlpha detection: Dafcikova et al., GCN 40496; IPN triangulation: Svinkin et al., GCN 40506) triggered Konus-Wind at T0=23492.766 s UT (06:31:32.766). The burst light curve shows multi-peaked structure which starts at ~T0-0.5 s and has a total duration of ~56 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250516_T23492/ As observed by Konus-Wind, the burst had a fluence of 3.00(-0.07,+0.07)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+19.232 s, of 2.16(-0.19,+0.19)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+60.416 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.80(-0.03,+0.03), the high energy photon index beta = -2.52(-0.07,+0.06), the peak energy Ep = 356(-10,+11) keV (chi2 = 124/97 dof). The spectrum near the maximum count rate (measured from T0+18.688 to T0+19.712 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.82(-0.07,+0.07), the high energy photon index beta = -2.92(-0.50,+0.26), the peak energy Ep = 482(-37,+41) keV (chi2 = 46/53 dof). All the quoted errors are at the 68% confidence level. All the quoted values are preliminary.