GRB 250510A
GCN Circular 40415
Subject
GRB 250510A: SVOM possible detection of a burst
Date
2025-05-10T05:51:17Z (19 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Y.H. Cheng (SWIFAR,YNU), B.-T. Wang (YNAO, CAS), W. J. Xie, D. H. ZHAO (NAO, CAS) on behalf of the SVOM mission team.
SVOM/ECLAIRs triggered and located GRB 250510A (SVOM burst-id sb25051002) at 2025-05-10T04:38:52.34 UTC (Tb). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.
The burst was only detected by the Count-Rate Trigger (CRT), which produced a sequence of 1 alert. CRT provided the alert with the best signal-to-noise-ratio (SNR) of 7.16 in the [20-120] keV energy band over a time window of 10.20 seconds starting at Tb.
The localization of the best alert is R.A., Dec. 284.17, 18.37 degrees:
R.A. (J2000) = 18h56m41.69s
Dec. (J2000) = 18d22m20.68s
with a 90% confidence level (C.L.) radius of 10.94 arcmin (including systematic error of 2 arcmin added in quadrature).
Due to the trigger SNR less than the slew threshold, no immediate slew was performed on this burst.
The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe.
The Burst Advocate (BA) on shift for this burst is Yehao Cheng: yhcheng@mail.ynu.edu.cn.
Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst.
GCN Circular 40417
Subject
GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
Date
2025-05-10T09:43:41Z (19 days ago)
From
Sarah Antier at OCA <sarah.antier@oca.eu>
Via
Web form
Sarah Antier (OCA), Noémie Globus (UNAM), Benjamin Schneider (LAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Fredd Alvarez (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (AUS), Rosa L. Becerra (U Roma), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Antonio de Ugarte Postigo (LAM), Y.H. Cheng (SWIFAR,YNU) and B.-T. Wang (YNAO, CAS):
We imaged the field of the SVOM GRB 250510A (Cheng et al., GCN Circ. 40415) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2025-05-10 06:02:26 to 06:20:28 UTC (from 1.4 to 1.7 hours after the trigger) and obtained 16 minutes of exposure in the i filter under regular weather conditions.
The data were reduced and coadded with the COLIBRÍ pipeline and analyzed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS catalog, is in the AB system, and is not corrected for Galactic extinction.
In the stacked image, we do not detect any new source at the ECLAIRs source position (Cheng et al., GCN Circ. 40415) down to the following 5-sigma limit:
i > 20.84
Further observations and analysis are ongoing.
We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams.
COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico.
GCN Circular 40420
Subject
GRB 250510A: follow-up observation with EP-FXT
Date
2025-05-10T15:12:36Z (19 days ago)
From
EP Team at NAOC/CAS <ep_ta@bao.ac.cn>
Via
Web form
A. Li, B. B. Zhang (BNU), Q. C. Liu (THU), Z. X. Ling (NAOC, CAS) on behalf of the Einstein Probe (EP) team:
Following the possible detection of the GRB 250510A (Cheng et al., GCN 40415) and its multi-wavelength follow-up observations (Antier et al., GCN 40417), we performed an observation with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe mission.
The observations began at 2025-05-10T07:54:01 (UTC), about 3.3 hours after the SVOM-ECLAIRs detection. The exposure time is 4035 seconds. Preliminary analysis shows there are three source was detected in this epoch within the ECLAIRs error circle:
------------------------------------------------------------------------------------------------------
| Source Name | RA | DEC | Flux(erg/s/cm2) | Flux_err |
------------------------------------------------------------------------------------------------------
|EPF_J185647.0+182414| 284.1957 | 18.4041 | 9.91e-14 | 3.41e-14 |
------------------------------------------------------------------------------------------------------
|EPF_J185624.3+182129| 284.1012 | 18.3581 | 1.07e-13 | 2.59e-14 |
------------------------------------------------------------------------------------------------------
|EPF_J185624.8+181937| 284.1033 | 18.3269 | 1.35e-13 | 2.92e-14 |
------------------------------------------------------------------------------------------------------
EP-FXT will continue monitoring the source. More follow-up observations are encouraged.
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).
GCN Circular 40423
Subject
GRB 250510A: Swift-XRT observations
Date
2025-05-10T16:54:51Z (19 days ago)
From
Simone Dichiara at Pennsylvania State University <sbd5667@psu.edu>
Via
Web form
S. Dichiara (PSU), K.L. Page (U. Leicester), J.A. Kennea (PSU),
P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi
(INAF-IASFPA) , M. A. Williams (PSU), J.P. Osborne (U. Leicester),
A.P. Beardmore (U. Leicester) and P.A. Evans (U. Leicester) reports
on behalf of the Swift-XRT team:
We have analysed 1.8 ks of XRT data for GRB 250510A, from 10.2 ks to
20.8 ks after the SVOM/ECLAIRs trigger. The data are entirely in
Photon Counting (PC) mode.
Within the SVOM/ECLAIRs 90% C.L. error region (GCN #40415) we detect
the EP-FXT source EPF_J185624.8+181937 (GCN#40420) at RA, Dec =
284.10364, +18.3267 which is equivalent to:
RA (J2000): 18h 56m 24.87s
Dec (J2000): +18d 19′ 36.0″
with an uncertainty of 5.7 arcsec (radius, 90% confidence).
The source has a mean count rate of 7.3e-03 ct/sec and a flux of 3.2
(+1.3, -1.1) × 10^-13 erg cm^-2 s^-1 (0.3-10 keV); we note that this
position is also consistent with a known 2MASS source,
2MASS J18562485+1819380.
No other X-ray sources have been detected. The 3-sigma upper limit in
the field ranges from ~4.4e-03 to ~1.0e-02 ct s^-1, corresponding to a
0.3-10 keV observed flux of 1.9e-13 to 4.4e-13 erg cm^-2 s^-1 (assuming
a typical GRB spectrum).
The results of the XRT-team automatic analysis are available at
https://www.swift.ac.uk/SVOM/SVOM_FIELD00016/.
This circular is an official product of the Swift-XRT team.