GRB250322A

This page lists all entries on GRB250322A in GRBweb

Summary Swift GCN 39835 GCN 39838 GCN 39841 GCN 39842 GCN 39844 GCN 39845 GCN 39846 GCN 39847 GCN 39849 GCN 39852 GCN 39855 GCN 39861 GCN 39863 GCN 39868 GCN 39873 GCN 40036

Summary table
Variable Value Source
T0 16:06:12 UTC GCN_circulars,Swift Det
ra 106.7605° Swift
decl 7.1931° Swift
pos_error 3.24e-04° Swift
T90 0.62 s Swift
T90_start 16:06:12 UTC Swift
fluence 1.50e-07 erg/cm² Swift
redshift 0.4200
T100 0.62 s
GBM_located False
mjd 60756.67097222222 GCN_circulars,Swift Det
Swift table
GRB_name GRB250322A
t_trigger 16:06:12 UTC
ra 106.7605°
decl 7.1931°
pos_error 3.24e-04°
T90 0.62 s
fluence 1.50e-07 erg/cm²
redshift 0.4200
GCN 39835 table
GRB_name GRB250322A
GCN_number 39835
Detection_method Swift Det
t_trigger 16:06:12 UTC
ra 106.7340°
decl 7.1990°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39835 SUBJECT: GRB 250322A: Swift detection of a short burst DATE: 25/03/22 16:26:08 GMT FROM: David Palmer at LANL R. Gupta (NASA GSFC), R. Brivio (INAF-OAB), M. Ferro (INAF-OAB), J. A. Kennea (PSU), H. A. Krimm (NSF), M. J. Moss (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB), M. H. Siegel (PSU) and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 16:06:12 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250322A (trigger=1297832). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 106.734, +7.199 which is RA(J2000) = 07h 06m 56s Dec(J2000) = +07d 11' 56" 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 1 sec. The peak count rate was ~10,000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 16:07:25.4 UT, 73 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 106.76025, 7.19285 which is equivalent to: RA(J2000) = 07h 07m 02.46s Dec(J2000) = +07d 11' 34.2" with an uncertainty of 1.9 arcseconds (radius, 90% containment). 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 consistent with the Galactic value of 2.70 x 10^21 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 76 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 0.154. Burst Advocate for this burst is R. Gupta (rahulbhu.c157 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/)
GCN 39838 table
GRB_name GRB250322A
GCN_number 39838
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 39838 SUBJECT: GRB 250322A: MASTER optical observation DATE: 25/03/22 18:47:54 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Lipunov, E.Gorbovskoy, A.Kuznetsov, G.Antipov,D.Vlasenko,K.Zhirkov, P.Balanutsa, N.Tyurina, Ya.Kechin, A.Chasovnikov, V.Topolev, V.Senik, K.Labzina (Lomonosov MSU), D.Buckley (SAAO), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A.Sosnovskij (Crao RAS), O.Gress, N.Budnev, O.Ershova (ISU), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South African Astronomical Observatory was pointed to the SWIFT (GCN 39835, Gupta et al.) GRB250322A (trigger No 1297832,07h 06m 56.00s , +07d 11m 56.0s, R=0.05) errorbox 4876 sec after notice time (5017 sec after trigger time) at 2025-03-22 17:29:49 UT,with upper limit up to 18.5 mag. Observations started at twilight. The observations began at zenith distance = 39 deg. The sun altitude is -9.8 deg. The galactic latitude b = 7 deg., longitude l = 209 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2820337 We obtain the following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment 5032 | MASTER-SAAO | C | 30 | 16.7 | 5077 | MASTER-SAAO | C | 120 | 17.4 | Coadd 5082 | MASTER-SAAO | C | 30 | 16.8 | 5146 | MASTER-SAAO | C | 60 | 16.9 | 5226 | MASTER-SAAO | C | 60 | 17.0 | 5320 | MASTER-SAAO | C | 90 | 17.0 | 5415 | MASTER-SAAO | C | 60 | 17.4 | 5494 | MASTER-SAAO | C | 60 | 17.4 | 5559 | MASTER-SAAO | C | 30 | 17.4 | 5604 | MASTER-SAAO | C | 120 | 18.2 | Coadd 5608 | MASTER-SAAO | C | 30 | 17.5 | 5672 | MASTER-SAAO | C | 60 | 17.6 | 5752 | MASTER-SAAO | C | 60 | 17.7 | 5812 | MASTER-SAAO | C | 180 | 18.3 | Coadd 5831 | MASTER-SAAO | C | 60 | 17.8 | 5910 | MASTER-SAAO | C | 60 | 17.8 | 6020 | MASTER-SAAO | C | 120 | 17.6 | 6129 | MASTER-SAAO | C | 60 | 17.8 | 6209 | MASTER-SAAO | C | 60 | 17.9 | 6289 | MASTER-SAAO | C | 60 | 17.9 | 6398 | MASTER-SAAO | C | 120 | 17.8 | 6537 | MASTER-SAAO | C | 120 | 17.8 | 6677 | MASTER-SAAO | C | 120 | 17.9 | 6816 | MASTER-SAAO | C | 120 | 17.9 | 6961 | MASTER-SAAO | C | 120 | 17.7 | 7036 | MASTER-SAAO | C | 270 | 18.1 | Coadd 7100 | MASTER-SAAO | C | 120 | 17.6 | 7194 | MASTER-SAAO | C | 30 | 17.8 | 7243 | MASTER-SAAO | C | 30 | 17.9 | 7273 | MASTER-SAAO | C | 90 | 18.5 | Coadd 7292 | MASTER-SAAO | C | 30 | 17.8 | 7342 | MASTER-SAAO | C | 30 | 17.8 | 7391 | MASTER-SAAO | C | 30 | 17.9 | 7421 | MASTER-SAAO | C | 90 | 18.4 | Coadd 7440 | MASTER-SAAO | C | 30 | 17.8 | 7490 | MASTER-SAAO | C | 30 | 17.8 | 7539 | MASTER-SAAO | C | 30 | 17.8 | 7569 | MASTER-SAAO | C | 90 | 18.5 | Coadd 7588 | MASTER-SAAO | C | 30 | 17.8 | 7637 | MASTER-SAAO | C | 30 | 17.9 | 7687 | MASTER-SAAO | C | 30 | 17.7 | 7736 | MASTER-SAAO | C | 30 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 39841 table
GRB_name GRB250322A
GCN_number 39841
Detection_method Swift-XRT Det
ra 106.7605°
decl 7.1931°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39841 SUBJECT: GRB 250322A: Enhanced Swift-XRT position DATE: 25/03/22 21:33:49 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 1707 s of XRT Photon Counting mode data and 1 UVOT images for GRB 250322A, 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 = 106.76048, +7.19313 which is equivalent to: RA (J2000): 07h 07m 2.52s Dec (J2000): +07d 11' 35.3" with an uncertainty of 2.6 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 39842 table
GRB_name GRB250322A
GCN_number 39842
Detection_method Optical
ra 106.7608°
decl 7.1927°
Circular_text TITLE: GCN CIRCULAR NUMBER: 39842 SUBJECT: GRB 250322A: NOT optical upper limits DATE: 25/03/22 23:10:07 GMT FROM: Antonio Martin-Carrillo at UCD,Space Science Group A. Martin-Carrillo (UCD), B. Schneider (LAM), D. B. Malesani (DAWN/NBI and Radboud Univ.), L. Izzo (INAF/OACn and DARK/NBI), D. Xu (NAOC), A. A. Djupvik (NOT), and A. Kadela (NOT and NBI), report on behalf of a larger collaboration: We observed the field of the GRB 250322A (Gupta et al., GCN 39835) using the ALFOSC camera mounted on the Nordic Optical Telescope (NOT). We obtained 5 exposures of 300 s each in the SDSS-r and SDSS-z band, starting at 20:45:22 UT on 2025-03-22 (4.65 hr after the trigger). Preliminary analysis shows that no new source is detected within the Swift/XRT enhanced error box (Goad et al., GCN 39841), down to the 5-sigma AB limiting magnitudes r > 24.3 and z > 22.6, calibrated with nearby Pan-STARRS stars and without Galactic extinction correction. We note that the XRT location includes an extended object (J2000 coordinates RA = 07:07:02.60, Dec = +07:11:33.8) also visible in the Pan-STARRS images, which is a host galaxy candidate for the GRB. Photometry of this source reveals a magnitude consistent with that reported in the Pan-STARRS catalogue, indicating no bright additional component on top of it.
GCN 39844 table
GRB_name GRB250322A
GCN_number 39844
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39844 SUBJECT: GRB 250322A: VLT near-infrared observations DATE: 25/03/23 02:40:38 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma Rosa Becerra (U Rome), Yu-Han Yang (U Rome), Eleonora Troja (U Rome) report on behalf of the ERC BHianca team: We observed the field of GRB 250322A (Gupta et al., GCN 39835) with the HAWKI imager on the ESO VLT UT4 (Yepun). Observations began at T+7.4 hr with a total exposure of 360 sec in the J filter, and were carried out at an average airmass of about 1.2 and seeing of 0.56’’. We do not detect any new source at the enhanced Swift-XRT position (Goad et al. GCN 39841) down to the following 5-sigma limit J>23.0 mag (Vega) calibrated using nearby stars in the 2MASS Catalogue. We detect the host galaxy candidate reported by Martin-Carrillo et al. 2025 (GCN 39842) in our image. We estimate a preliminary magnitude of J=18.9±0.2 mag (Vega). Further observations are planned to investigate potential variations in the brightness. We thank the staff at the VLT, especially Thomas Rivinius, for the rapid execution of these observations.
GCN 39845 table
GRB_name GRB250322A
GCN_number 39845
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 39845 SUBJECT: GRB 250322A: VLT optical observations DATE: 25/03/23 02:42:36 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma Rosa Becerra (U Rome), Yu-Han Yang (U Rome), Eleonora Troja (U Rome) report on behalf of the ERC BHianca team: We observed the field of GRB 250322A (Gupta et al., GCN 39835, Goad et al. GCN 39841) with the FORS2 imager on the ESO VLT UT1 (Antu). Observations began at T+8.1 hours after the trigger and were carried out in the R filter with a total exposure of 1200 seconds, at an average seeing of 0.5" and airmass about 1.2. We do not detect any new source at the enhanced Swift-XRT position (Goad et al. GCN 39841) down to the following 5-sigma limit R>25.8 AB mag (Vega) calibrated with nearby Pan-STARRS stars and without Galactic extinction correction. In our images, we detect the host galaxy candidate reported by Martin-Carrillo et al. (GCN 39842) with no significant variation in brightness. We thank the staff at the VLT for the rapid execution of these observations.
GCN 39846 table
GRB_name GRB250322A
GCN_number 39846
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 39846 SUBJECT: GRB 250322A: Gemini-South optical observations DATE: 25/03/23 03:06:38 GMT FROM: Charles Kilpatrick at Northwestern U C. D. Kilpatrick and W. Fong (Northwestern) report on behalf of a larger collaboration: We observed the location of the short-duration GRB 250322A (Gupta et al., GCN 39835) with the Gemini Multi-Object Spectrograph (GMOS) mounted on Gemini-South under Program GS-2025A-Q-112 (PI: Fong). We obtained 10x120-sec imaging each in the r- and i-bands starting at 2025-03-23 00:06:31 UT (8.0 hrs post-burst), at a median airmass of 1.3 and seeing of 0.6-0.9’’. Within or proximate to the enhanced XRT localization (Goad et al., GCN 39841), we do not detect any additional sources relative to Pan-STARRS1, to 3-sigma limits of r > 24.2 AB mag and i > 24.4 AB mag (calibrated to Pan-STARRS), consistent with the non-detections reported (Martin-Carrillo et al., GCN 39842; Becerra et al. GCN 39845). Regarding the galaxy within the XRT position, first pointed out by Martin-Carrillo et al. (GCN 39842), we measure magnitudes of r = 21.7 +/- 0.1 AB mag and i = 21.1 +/- 0.1 AB mag. We note that these are ~0.3-0.6 mag brighter than the catalogued Pan-STARRS values (Flewelling et al., 2020, ApJS, 251, 7). We caution that these differences are not significant enough to claim presence of an afterglow and could instead be due to a combination of filter differences or aperture differences for the catalog values. Further observations are planned to monitor the variability of the source. We thank Jennifer Andrews, Veronica Firpo, Daniel May, and Aleksandar Cipota for the rapid scheduling and execution of these observations.
GCN 39847 table
GRB_name GRB250322A
GCN_number 39847
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 39847 SUBJECT: GRB250322A: STEP/T80S optical limits DATE: 25/03/23 04:56:42 GMT FROM: André Santos at Centro Brasileiro de Pesquisas Físicas (CBPF) A. Santos (CBPF), C. R. Bom (CBPF), C. D. Kilpatrick (Northwestern), L. Santana-Silva (CBPF), P. Darc (CBPF), Gabriel Teixeira (CBPF), C. Mendes de Oliveira (IAG-USP) report on behalf of the STEP collaboration: We conducted optical follow up with the T80S 0.8-m robotic telescope (Santos et al., 2024, MNRAS, 529, 59) of the short gamma-ray burst GRB250322A discovered by the Swift-BAT and XRT instruments (GCN [39835](https://gcn.nasa.gov/circulars/39835), [39841](https://gcn.nasa.gov/circulars/39841)). The T80S observations started on Mar 23 00:08:38 UT (~8 hours after the trigger). We obtained images totaling 1800s (6x300s) in g-band with the T80S camera centered at the position of the latest XRT position (GCN [39841](https://gcn.nasa.gov/circulars/39841)) at R.A.=07:07:02.52 and Decl.=+07:11:35.3 (J2000). After subtracting a Pan-STARRS template image from the T80S frames using photpipe (Rest et al., 2005), we do not detect any transient source in our difference image within the XRT error circle and derive a 3-sigma limiting magnitude of g > 22.48 mag.
GCN 39849 table
GRB_name GRB250322A
GCN_number 39849
Detection_method AstroSat CZTI
Circular_text TITLE: GCN CIRCULAR NUMBER: 39849 SUBJECT: GRB 250322A: AstroSat CZTI detection of a short burst DATE: 25/03/23 08:02:08 GMT FROM: Gaurav Waratkar at IIT Bombay M. Tembhurnikar(IUCAA), J. Joshi (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 short-duration GRB 250322A which was also detected by Swift/BAT (Gupta et.al., GCN Circ. 39835). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-03-22 16:06:12.85 UTC. The measured peak count rate, as measured with 10 ms binning, associated with the burst is 1322 (+851, -197) counts/s above the background in the combined data of all quadrants, with a total of 113 (+37, -25) counts. The local mean background count rate was 426 (+24, -61) counts/s. Using cumulative rates, we measure a T90 of 0.18 (+0.04, -0.03) s. 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 39852 table
GRB_name GRB250322A
GCN_number 39852
Detection_method Other
redshift 0.4200
Circular_text TITLE: GCN CIRCULAR NUMBER: 39852 SUBJECT: GRB 250322A: Gemini-North redshift of candidate host galaxy DATE: 25/03/23 13:40:27 GMT FROM: Wen-fai Fong at Northwestern University W. Fong (Northwestern), A. J. Levan (Radboud), J.C. Rastinejad (Northwestern), N. R. Tanvir (Leicester), C. D. Kilpatrick (Northwestern) report on behalf of a larger collaboration: We observed the putative host galaxy within the XRT localization (Goad et al., GCN 39841) of the short-duration GRB 250322A (Gupta et al., GCN 39835; Tembhurnikar et al., GCN 39849) using the Gemini Multi-Object Spectrograph (GMOS-N) mounted on Gemini-North telescope in Hawaii. We obtained 4x900-sec exposures using the R400 grating, spanning approximately 5000A to 9500A, starting at 2025-03-23 05:33:34 UT (approx 13.5 hr post-burst), under Program GN-2025A-Q-114 (PI: Fong). The continuum is well-detected along with several prominent emission lines. In particular, we identify emission lines of H-alpha, NII, OIII (5007), H-beta and H-gamma, corresponding to a common redshift of z=0.42. We thank Jennifer Andrews, Adam Smith, and Hyewon Suh for the rapid scheduling and execution of these observations.
GCN 39855 table
GRB_name GRB250322A
GCN_number 39855
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39855 SUBJECT: GRB 250322A: Swift-XRT refined Analysis DATE: 25/03/23 16:54:19 GMT FROM: Phil Evans at U of Leicester M. Perri (SSDC & INAF-OAR), J.A. Kennea (PSU), D.N. Burrows (PSU), M. A. Williams (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 3.7 ks of XRT data for GRB 250322A, from 58 s to 22.2 ks after the BAT trigger. The data comprise 7 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The light curve can be modelled with a power-law decay with a decay index of alpha=2.28 (+0.18, -0.17). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.09 (+0.49, -0.26). The best-fitting absorption column is consistent with the Galactic value of 2.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (5.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.7 (+/-2.3) x 10^21 cm^-2 Galactic foreground: 2.7 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 2.09 (+0.49, -0.26) If the light curve continues to decay with a power-law decay index of 2.28, the count rate at T+24 hours will be 2.2 x 10^-7 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.9 x 10^-18 (1.2 x 10^-17) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01297832. This circular is an official product of the Swift-XRT team.
GCN 39861 table
GRB_name GRB250322A
GCN_number 39861
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 39861 SUBJECT: GRB 250322A: Swift/UVOT Upper Limits DATE: 25/03/24 12:52:39 GMT FROM: Sam Shilling at Lancaster University S. P. R. Shilling (Lancaster U.) and R. Gupta (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250322A 77 s after the BAT trigger (Gupta et al., GCN Circ. 39835). No optical afterglow consistent with the enhanced XRT position (Goad et al., GCN Circ. 39841) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 77 226 147 >20.5 u_FC 291 541 246 >19.8 white 77 1711 411 >20.9 v 620 1760 136 >18.9 b 546 1686 117 >19.7 u 291 1661 343 >20.0 w1 669 1807 134 >19.2 m2 644 1785 136 >19.0 w2 596 1736 136 >19.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.153 in the direction of the burst (Schlegel et al. 1998).
GCN 39863 table
GRB_name GRB250322A
GCN_number 39863
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 39863 SUBJECT: GRB 250322A: further NOT optical observations DATE: 25/03/24 16:33:39 GMT FROM: Benjamin Schneider at MIT B. Schneider (LAM), A. Martin-Carrillo (UCD), D. B. Malesani (DAWN/NBI and Radboud), A. M. Kadela (NOT and NBI) report on behalf of a larger collaboration: We secured a second observation of the field of GRB 250322A (Gupta et al., GCN 39835; Tembhurnikar et al., GCN 39849) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. Our observation consisted of 7x360 s in the r-band, with mean time 2025 Mar 23.88 UT (29.7 hr after the GRB). Unfortunately, the delivered seeing is worse than in our first epoch (Martin-Carrillo et al., GCN 39842), taken 4.65 hr after the GRB (1.5 vs 1.0"). The galaxy noted by Martin-Carrillo et al. (GCN 39842), Becerra et al. (GCN 39844, 39845), Kilpatrick & Fong (GCN 39846), and Fong et al. (GCN 39852) is detected in our second epoch. Image subtraction was carried out using Hotpants. No residuals are detected in the difference image, corresponding to a limiting magnitude of r > 23.2 (AB). For the galaxy, we measure (in our first epoch) r = 22.04 +/- 0.12 (AB), calibrated against nearby Pan-STARRS point-like objects. Considering a 2.5”-radius XRT error circle (Goad et al., GCN 39841; Perri et al., 39855), we estimate a chance association probability of 2%, which provides moderate evidence for a physical association with the GRB.
GCN 39868 table
GRB_name GRB250322A
GCN_number 39868
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 39868 SUBJECT: GRB 250322A: third epoch of NOT optical observations DATE: 25/03/25 17:11:56 GMT FROM: Benjamin Schneider at MIT D. B. Malesani (DAWN/NBI and Radboud), B. Schneider (LAM), A. Martin-Carrillo (UCD), A. M. Kadela (NOT and NBI) report on behalf of a larger collaboration: We secured a third observation of the field of GRB 250322A (Gupta et al., GCN 39835; Tembhurnikar et al., GCN 39849) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. Our observation consisted of 5x600 s in the r-band, with mean time 2025 Mar 24.86 UT (2.19 days after the GRB). This observation reaches a depth comparable to our first epoch (Martin-Carrillo et al., GCN 39842), taken at 4.65 hr after the GRB, unlike our second epoch (Schneider et al., GCN 39863), which suffered from worse seeing. Image subtraction of our third epoch from the first was carried out using HOTPANTS. No residuals are detected in the difference image, down to a limiting magnitude r > 23.8 AB (calibrated against Pan-STARRS). This limit is consistent with, but strengthens, our earlier determination r > 23.2 (Schneider et al., GCN 39863).
GCN 39873 table
GRB_name GRB250322A
GCN_number 39873
Detection_method Konus-Wind Det
t_trigger 16:06:14.215 UTC
redshift 0.4200
Circular_text TITLE: GCN CIRCULAR NUMBER: 39873 SUBJECT: Konus-Wind detection of GRB 250322A (short) DATE: 25/03/26 12:50:11 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The short-duration GRB 250322A (Swift-BAT detection: Gupta et al., GCN 39835; Sadaula et al., GCN 39867; AstroSat-CZTI detection: Tembhurnikar et al., GCN 39849) triggered Konus-Wind at T0=57974.215 s UT (16:06:14.215). The burst light curve shows a multipeaked structure, which starts at T0-0.102 s and has a total duration of ~0.18 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250322_T57974/ As observed by Konus-Wind, the burst had a fluence of 1.02(-0.13,+0.14)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0-0.086 s, of 1.05(-0.24,+0.25)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). Since the brightest peak of the burst light curve was detected before the trigger, the spectral analysis was performed using the KW 3-channel light curve data. Modelling the KW 3-channel time-integrated spectrum (measured from T0-0.102 s to T0+0.078 s) by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), yields alpha = 0.22(-0.39,+0.52) and Ep = 472(-64,+85) keV. Assuming the redshift z=0.42 (Fong et al., GCN 39852; Yang et al. GCN 39859) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the following rest-frame parameters: the isotropic energy release E_iso is 4.9(-0.6,+0.7)x10^50 erg, the peak luminosity L_iso is 7.1(-1.6,+1.7)x10^51 erg/s, the rest-frame peak energy of the time-averaged spectrum Ep,i,z is 670(-91,+121) keV. With the obtained estimates, GRB 250322A is a clear outlier in the 'Amati' relation derived for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021). Meanwhile, in both Eiso-Ep,z and Liso-Ep,z planes, the GRB 250322A position is consistent with short-hard (Type I) GRB population, see http://www.ioffe.ru/LEA/GRBs/GRB250322_T57974/GRB250322A_rest_frame.pdf All the quoted errors are at the 68% confidence level. All the quoted values are preliminary.
GCN 40036 table
GRB_name GRB250322A
GCN_number 40036
Detection_method Other
redshift 0.4200
Circular_text TITLE: GCN CIRCULAR NUMBER: 40036 SUBJECT: GRB 250322A: 10 GHz VLA radio upper limits DATE: 25/04/04 01:52:21 GMT FROM: Genevieve Schroeder at Cornell University G. Schroeder (Cornell), T. Laskar (Utah), W. Fong, J. Rastinejad (Northwestern) report: We observed the position of the short GRB 250322A (Gupta et al., GCN 39835; Tembhurnikar et al., GCN 39849; Ridnaia et al., GCN 39873) with the Karl G. Jansky Very Large Array (VLA) under program 25A-063 (PI Schroeder) beginning on 2025 March 25 at 22:07 UT (3.25 days post-burst) for 1 hour at a mean frequency of 10 GHz. Based on preliminary analysis, we do not detect any radio emission at or near the position of the XRT afterglow (Perri et al., GCN 39855), to a 3 sigma limit of 20 microJy. We additionally do not detect the putative host galaxy in our image (Martin-Carrillo et al., GCN 39842; Becerra et al., GCN 39844; 39845l; Kilpatrick & Fong, GCN 39846; Fong et al., GCN 39852, Schneider et al., GCN 39863). Assuming a redshift of z = 0.42 (Fong et al., GCN 39852; Yang et al. GCN 39859), these observations imply a limit on the radio-inferred star formation rate of < 18 M_sol/year (following the formalism of Greiner et al. 2016). Using the putative host redshift, the lack of radio afterglow detection implies a radio luminosity of < 1.3e29 erg/Hz/s, which is a factor of >~4 lower than the median radio luminosity of radio-detected short GRBs at a similar epoch and rest frame time (Laskar et. al. 2022). Overall, this limit places GRB 250322A in the bottom 25% of radio-observed short GRBs with redshift determinations, in terms of radio luminosity. We thank the VLA staff for quickly approving and executing these observations.