GRB250516A

This page lists all entries on GRB250516A in GRBweb

Summary Fermi GBM IPN Swift GCN 40466 GCN 40467 GCN 40468 GCN 40471 GCN 40472 GCN 40473 GCN 40475 GCN 40477 GCN 40486 GCN 40487

Summary table
Variable Value Source
GRB_name_Fermi GRB250516608
T0 14:35:29 UTC GCN_circulars,Fermi GBM final loc
ra 334.6098° Swift
decl -9.1195° Swift
pos_error 2.85e-04° Swift
T90 21.821 s Fermi_GBM
T90_error 0.768 s Fermi_GBM
T90_start 14:35:29.278 UTC Fermi_GBM
fluence 4.49e-06 erg/cm² Fermi_GBM
fluence_error 3.36e-08 erg/cm² Fermi_GBM
T100 22.099 s
GBM_located False
mjd 60811.60797453704 GCN_circulars,Fermi GBM final loc
Fermi GBM table
GRB_name_Fermi GRB250516608
trigger_name bn250516608
ra 333.1700°
decl 0.1400°
pos_error 3.90e+00°
datum 2025-05-16
t_trigger 14:35:29.275 UTC
T90 21.821 s
T90_error 0.768 s
T90_start 14:35:29.278 UTC
fluence 4.49e-06 erg/cm²
fluence_error 3.36e-08 erg/cm²
flux_1024 5.78e+00 erg/cm²/s
flux_1024_error 2.55e-01 erg/cm²/s
flux_1024_time 5.06e+00 erg/cm²/s
flux_64 9.52e+00 erg/cm²/s
flux_64_error 1.46e+00 erg/cm²/s
IPN table
GRB_name GRB250516A
ra 334.5625°
decl -9.1333°
pos_error 5.00e-02°
Swift table
GRB_name GRB250516A
t_trigger 14:35:29 UTC
ra 334.6098°
decl -9.1195°
pos_error 2.85e-04°
GCN 40466 table
GRB_name GRB250516A
GCN_number 40466
Detection_method Fermi GBM final loc
t_trigger 14:35:29 UTC
ra 333.2000°
decl 0.1000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 40466 SUBJECT: GRB 250516A: Fermi GBM Final Real-time Localization DATE: 25/05/16 14:46:00 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 14:35:29 UT on 16 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250516A (trigger 769098934.27533 / 250516608). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 333.2, Dec = 0.1 (J2000 degrees, equivalent to J2000 22h 12m, 0d 06'), with a statistical uncertainty of 8.5 degrees. The angle from the Fermi LAT boresight is 27.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250516608/quicklook/glg_skymap_all_bn250516608.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250516608/quicklook/glg_healpix_all_bn250516608.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250516608/quicklook/glg_lc_medres34_bn250516608.gif
GCN 40467 table
GRB_name GRB250516A
GCN_number 40467
Detection_method Swift Det
t_trigger 14:35:29 UTC
ra 334.5610°
decl -9.1300°
Circular_text TITLE: GCN CIRCULAR NUMBER: 40467 SUBJECT: GRB 250516A: Swift detection of a burst DATE: 25/05/16 14:57:08 GMT FROM: K.L. Page at U Leicester A. P. Beardmore (U Leicester), P. A. Evans (U Leicester), R. Gupta (NASA GSFC), K. L. Page (U Leicester), S. P. R. Shilling (Lancaster U.) and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 14:35:29 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250516A (trigger=1314210). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 334.561, -9.130 which is RA(J2000) = 22h 18m 15s Dec(J2000) = -09d 07' 48" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 30 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 14:37:13.2 UT, 104.3 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 334.60979, -9.11941 which is equivalent to: RA(J2000) = 22h 18m 26.35s Dec(J2000) = -09d 07' 09.9" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 177 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (5.84 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 1.8 (+1.47/-1.34) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 108 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 none of the XRT error circle. 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 0.062. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 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/)
GCN 40468 table
GRB_name GRB250516A
GCN_number 40468
Detection_method Swift-XRT Det
ra 334.6098°
decl -9.1195°
Circular_text TITLE: GCN CIRCULAR NUMBER: 40468 SUBJECT: GRB 250516A: Enhanced Swift-XRT position DATE: 25/05/16 17:05:53 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 1717 s of XRT Photon Counting mode data and 2 UVOT images for GRB 250516A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 334.60978, -9.11949 which is equivalent to: RA (J2000): 22h 18m 26.35s Dec (J2000): -09d 07' 10.2" with an uncertainty of 2.2 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN 40471 table
GRB_name GRB250516A
GCN_number 40471
Detection_method Swift-UVOT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 40471 SUBJECT: GRB 250516A: Swift/UVOT Detection DATE: 25/05/16 22:17:55 GMT FROM: Sam Shilling at Lancaster University S. P. R. Shilling (Lancaster U.) and A. P. Beardmore (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250516A 108 s after the BAT trigger (Beardmore et al., GCN Circ. 40467). A source consistent with the enhanced XRT position (Evans et al., GCN Circ. 40468) is detected in the initial UVOT exposures. The preliminary detection and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 108 1715 411 20.5 +/- 0.3 v 650 1765 136 >18.5 b 576 1691 117 >19.2 u 320 1838 362 >19.7 w1 699 1814 117 >18.8 w2 626 1741 97 >19.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.062 in the direction of the burst (Schlegel et al. 1998).
GCN 40472 table
GRB_name GRB250516A
GCN_number 40472
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 40472 SUBJECT: GRB 250516A: Swift-XRT refined Analysis DATE: 25/05/16 23:13:02 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), J.A. Kennea (PSU), D.N. Burrows (PSU), M.A. Williams (PSU), J.P. Osborne (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 6.8 ks of XRT data for GRB 250516A, from 108 s to 23.8 ks after the trigger. The data comprise 151 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+5.9 ks) can be modelled with a power-law decay with a decay index of alpha=1.45 (+0.18, -0.17). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.44 (+0.13, -0.12). The best-fitting absorption column is 3.5 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 5.8 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.98 (+/-0.12) and a best-fitting absorption column of 3.0 (+/-0.5) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.8 x 10^-11 (5.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.0 (+/-0.5) x 10^21 cm^-2 Galactic foreground: 5.8 x 10^20 cm^-2 Excess significance: 8.2 sigma Photon index: 1.98 (+/-0.12) If the light curve continues to decay with a power-law decay index of 1.45, the count rate at T+24 hours will be 5.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.2 x 10^-13 (3.3 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01314210. This circular is an official product of the Swift-XRT team.
GCN 40473 table
GRB_name GRB250516A
GCN_number 40473
Detection_method Fermi GBM Det
t_trigger 14:35:29.280 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 40473 SUBJECT: GRB 250516A: Fermi GBM Observation DATE: 25/05/16 23:59:42 GMT FROM: oindabimukherjee@gmail.com O. Mukherjee (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 14:35:29.28 UT on 16 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250516A (trigger 769098934/250516608). which was also detected by Swift BAT (A. P. Beardmore et al. 2025, GCN 40467). The Fermi GBM on-ground location is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 36 degrees. The GBM light curve consists of two peaks with a duration (T90) of about 21.8 s (50-300 keV). The time-averaged spectrum from T0-1.4 to T0+25.2 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.26 +/- 0.07 and the cutoff energy, parameterized as Epeak, is 200 +/- 30 keV. The event fluence (10-1000 keV) in this time interval is (4.8 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+5.1 s in the 10-1000 keV band is 5.8 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN 40475 table
GRB_name GRB250516A
GCN_number 40475
Detection_method AstroSat CZTI
Circular_text TITLE: GCN CIRCULAR NUMBER: 40475 SUBJECT: GRB 250516A: AstroSat CZTI detection DATE: 25/05/17 04:54:01 GMT FROM: Gaurav Waratkar at IIT Bombay M. Tembhurnikar (IUCAA), G. Waratkar (IITB), 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 a long duration GRB 250516A which was also detected by Fermi/GBM (Fermi GBM Team, GCN Circ. 40466), and Swift/BAT (Beardmore et al., GCN Circ. 40467). The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed a single burst of emission that peaked at 2025-05-16 14:35:33.81 UTC. The measured peak count rate associated with the burst is 333 (+66, -72) counts/s above the background in the combined data of all quadrants, with a total of 527 (+187, -195) counts. The local mean background count rate was 1349 (+8, -9) counts/s. We measure a T90 of 2.4 (+1.8, -1.2) s from the cumulative Veto light curve. We note that our T90 is low since we detect just the brightest burst episode from the lightcurve seen in other missions (Fermi/GBM, Swift/BAT). This is likely due to the unfavourable orientation of our detectors with respect to the GRB. 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 40477 table
GRB_name GRB250516A
GCN_number 40477
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 40477 SUBJECT: Swift GRB 250516A: Global MASTER-Net observations report DATE: 25/05/17 05:58:24 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) 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) was pointed to the Swift GRB 250516A ( A. P. Beardmore et al., GCN 40467) errorbox 54907 sec after notice time and 54930 sec after trigger time at 2025-05-17 05:50:59 UT, with upper limit up to 15.5 mag. The observations began at zenith distance = 77 deg. The sun altitude is -68.5 deg. The galactic latitude b = -50 deg., longitude l = 53 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2872228 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 55020 | MASTER-OAFA | C | 180 | 15.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 40486 table
GRB_name GRB250516A
GCN_number 40486
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 40486 SUBJECT: GRB 250516A: COLIBRÍ optical upper limit DATE: 25/05/18 16:00:54 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma Francis Fortin (IRAP), Kin Ocelotl López (UNAM), Rosa L. Becerra (U Roma), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Fredd Alvarez (UNAM), Dalya Akl (AUS), Camila Angulo (UNAM), Sarah Antier (OCA), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Leonardo García García (UNAM), Noémie Globus (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Benjamin Schneider (LAM) and Antonio de Ugarte Postigo (LAM): We imaged the field of the GRB 250516A (Fermi GBM team GCN Circ. 40466; Beardmore et al., GCN Circ. 40467; Frederiks et al., GCN Circ. 40485) using the DDRAGO wide-field imager on the COLIBRÍ telescope. We observed from 2025-05-18 09:59 to 11:20 UTC (from 43.4 to 44.8 hours after the trigger) and obtained 64 minutes of exposure in the r filter. The data were reduced and coadded with the COLIBRÍ pipeline and analysed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS DR1 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 XRT source position (Evans et al., GCN Circ. 40468) down to the following 3-sigma limit: r > 22.08 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 40487 table
GRB_name GRB250516A
GCN_number 40487
Detection_method Swift-BAT Det
ra 334.6120°
decl -9.1200°
Circular_text TITLE: GCN CIRCULAR NUMBER: 40487 SUBJECT: GRB 250516A: Swift-BAT refined analysis DATE: 25/05/19 03:04:35 GMT FROM: Amy T. Sakamoto (AGU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), (i.e. the Swift-BAT team): Using the data set from T-240 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 250516A (trigger #1314210) (Beardmore et al., GCN Circ. 40467). The BAT ground-calculated position is RA, Dec = 334.612, -9.120 deg which is RA(J2000) = 22h 18m 26.8s Dec(J2000) = -09d 07' 11.9" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 61%. The mask-weighted light curve shows a multi-peaked structure that starts at ~T-20 s and ends at ~T+23 s. The highest peak occurs at ~T+20 s. T90 (15-350 keV) is 30.04 +- 6.01 sec (estimated error including systematics). The time-averaged spectrum from T-19.96 to T+22.70 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.69 +- 0.08. The fluence in the 15-150 keV band is 2.3 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+19.39 sec in the 15-150 keV band is 3.8 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1314210