GRB250108B

This page lists all entries on GRB250108B in GRBweb

Summary IPN Swift GCN 38848 GCN 38850 GCN 38855 GCN 38858 GCN 38859 GCN 38874 GCN 38875 GCN 38876 GCN 38877

Summary table
Variable Value Source
T0 10:23:06 UTC Swift
ra 201.3265° Swift
decl 25.6152° Swift
pos_error 2.85e-04° Swift
redshift 0.2900 GCN_circulars,Optical
GBM_located False
mjd 60683.432708333334 Swift
IPN table
GRB_name GRB250108B
ra 201.2958°
decl 25.6167°
pos_error 5.00e-02°
redshift 2.1970
Swift table
GRB_name GRB250108B
t_trigger 10:23:06 UTC
ra 201.3265°
decl 25.6152°
pos_error 2.85e-04°
GCN 38848 table
GRB_name GRB250108B
GCN_number 38848
Detection_method Swift-XRT Det
ra 201.3265°
decl 25.6152°
Circular_text TITLE: GCN CIRCULAR NUMBER: 38848 SUBJECT: GRB 250108B: Enhanced Swift-XRT position DATE: 25/01/08 12:44:36 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 558 s of XRT Photon Counting mode data and 1 UVOT images for GRB 250108B, 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 = 201.32654, +25.61519 which is equivalent to: RA (J2000): 13h 25m 18.37s Dec (J2000): +25d 36' 54.7" 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 38850 table
GRB_name GRB250108B
GCN_number 38850
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 38850 SUBJECT: GRB 250108B: Swift/UVOT Upper Limits DATE: 25/01/08 14:32:24 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and N. J. Klingler (GSFC/UMBC/CRESSTII) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250108B 117 s after the BAT trigger (Klingler et al., GCN Circ. 38847). No optical afterglow consistent with the enhanced XRT position (Osborne et al., GCN Circ. 38848) 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 117 267 147 >20.7 white 117 980 247 >21.2 u_FC 275 525 246 >20.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.012 in the direction of the burst (Schlegel et al. 1998).
GCN 38855 table
GRB_name GRB250108B
GCN_number 38855
Detection_method Optical
ra 201.3271°
decl 25.6155°
redshift 0.2900
Circular_text TITLE: GCN CIRCULAR NUMBER: 38855 SUBJECT: GRB 250108B: Gemini-North Candidate Optical Afterglow Detection DATE: 25/01/08 16:51:54 GMT FROM: Jillian Rastinejad at Northwestern Univ. Jillian Rastinejad (Northwestern), Andrew J. Levan (Radboud), Wen-fai Fong, Charlie Kilpatrick (Northwestern), Daniele B. Malesani (DAWN/ NBI and Radboud), Nial R. Tanvir (U. Leicester), Gavin P Lamb (LJMU), Benjamin P. Gompertz (U. Birmingham) and Brian D. Metzger (Columbia/CCA) report on behalf of a larger collaboration: We observed the location of the X-ray afterglow of GRB 250108B (Klinger et al., GCN 38847; Osborne et al., GCN 38848) with the Gemini Multi-Object Spectrograph (GMOS-N) mounted on Gemini-North under Program GN-2024B-Q-107. We obtained 15x120-s imaging in r-band at a mid-time of 2025-01-08 12:42:45.8 UT (2.33 hours post-burst), at a median airmass of 1.7 and seeing < 1.2''. We clearly detect a faint source not present in archival Legacy Survey DR10 r-band imaging but within the XRT localization at a position of RA (J2000) = 13:25:18.50 Dec (J2000) = 25:36:55.82 with an uncertainty of 0.7''. We suggest that this is the afterglow of GRB 250108B. We note that the candidate afterglow is 16.8'' offset from a bright galaxy (r = 19.5 AB mag). This galaxy has a Legacy Survey DR9 photometric redshift of z = 0.29 +/- 0.04 (Zhou et al., 2021) and an SDSS photometric redshift of z = 0.22 +/- 0.04 (Alam et al., 2015), corresponding to projected separations of 74 kpc and 60 kpc from the transient, respectively. We determine a probability of chance coincidence between this galaxy and the candidate afterglow of Pcc = 0.13 (Bloom et al., 2002). With present data we cannot rule out the presence of a faint, underlying host at the position of the transient. Calibrated to SDSS, we measure a preliminary brightness for the optical source of r = 23.4 +/- 0.1 AB mag, not corrected for Galactic extinction. At a redshift of z = 0.29, this corresponds to an optical luminosity of 2.1 x 10^42 erg/s. Further observations are planned to monitor the variability of the source. We thank Jen Miller, Leila Alamos, Brian Lemaux and additional Gemini staff for excellent support in the rapid planning and execution of these observations.
GCN 38858 table
GRB_name GRB250108B
GCN_number 38858
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 38858 SUBJECT: Swift GRB 250108B: Global MASTER-Net observations report DATE: 25/01/08 21:47:28 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 250108B ( N. J. Klingler et al., GCN 38847) errorbox 35528 sec after notice time and 35573 sec after trigger time at 2025-01-08 20:16:00 UT, with upper limit up to 17.8 mag. The observations began at zenith distance = 84 deg. The sun altitude is -65.6 deg. The galactic latitude b = 82 deg., longitude l = 23 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2737810 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 35664 | MASTER-Kislovodsk | C | 180 | 16.7 | 35664 | MASTER-Kislovodsk | C | 180 | 16.7 | 35864 | MASTER-Kislovodsk | C | 180 | 16.7 | 35864 | MASTER-Kislovodsk | C | 180 | 16.7 | 36908 | MASTER-Kislovodsk | C | 180 | 17.5 | 36908 | MASTER-Kislovodsk | C | 180 | 17.5 | 38307 | MASTER-Kislovodsk | C | 180 | 17.6 | 38307 | MASTER-Kislovodsk | C | 180 | 17.6 | 38757 | MASTER-Kislovodsk | C | 120 | 17.6 | 38757 | MASTER-Kislovodsk | C | 120 | 17.6 | 39177 | MASTER-Kislovodsk | C | 120 | 17.5 | 39177 | MASTER-Kislovodsk | C | 120 | 17.5 | 39547 | MASTER-Kislovodsk | C | 180 | 17.8 | 39547 | MASTER-Kislovodsk | C | 180 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 38859 table
GRB_name GRB250108B
GCN_number 38859
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 38859 SUBJECT: GRB 250108B: Swift-XRT refined Analysis DATE: 25/01/09 01:41:47 GMT FROM: Phil Evans at U of Leicester M. Capalbi (INAF-IASFPA), D.N. Burrows (PSU), M. A. Williams (PSU), S. Dichiara (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 8.5 ks of XRT data for GRB 250108B, from 97 s to 33.7 ks after the BAT trigger. The data comprise 608 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+5.5 ks) can be modelled with a power-law decay with a decay index of alpha=0.35 (+/-0.13). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.37 (+/-0.04). The best-fitting absorption column is 1.47 (+/-0.09) x 10^21 cm^-2, in excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.07 (+0.17, -0.16) and a best-fitting absorption column of 1.3 (+0.5, -0.4) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.3 (+0.5, -0.4) x 10^21 cm^-2 Galactic foreground: 1.2 x 10^20 cm^-2 Excess significance: 4.8 sigma Photon index: 2.07 (+0.17, -0.16) If the light curve continues to decay with a power-law decay index of 0.35, the count rate at T+24 hours will be 0.045 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.5 x 10^-12 (2.0 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01280056. This circular is an official product of the Swift-XRT team.
GCN 38874 table
GRB_name GRB250108B
GCN_number 38874
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 38874 SUBJECT: GRB 250108B: REM optical/NIR upper limits DATE: 25/01/09 16:12:35 GMT FROM: Riccardo Brivio at INAF-OAB R. Brivio, M. Ferro, P. D’Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 250108B detected by Swift (Klingler et al., GCN 38847) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2025 January 09 at 07:02:48 UT (i.e. 21.07 hours after the Swift trigger), and lasting for about 1 hour. Within the XRT-enhanced position (Osborne et al., GCN 38848), from preliminary photometry we do not detect any optical or NIR counterpart consistent with the candidate optical afterglow (Rastinejad et al., GCN 38855), down to the following 3sigma magnitude upper limits: r > 20.1 (AB; calibrated against the PanSTARRS catalogue) at a mid-time of t - t0 = 21.2 hr after the trigger, H > 17.0 (Vega; calibrated against the 2MASS catalogue) at a mid-time of t - t0 = 21.1 hr after the trigger.
GCN 38875 table
GRB_name GRB250108B
GCN_number 38875
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 38875 SUBJECT: GRB 250108B: 1.3m DFOT upper limit DATE: 25/01/09 16:23:09 GMT FROM: Amit Kumar Ror at ARIES Amit K. Ror, Anshika Gupta, RKS Yadav, Shashi B. Pandey, Kuntal Mishra (ARIES) report: We observed the field of GRB 250108B detected by Swift (Swift Observatory Team, Klingler et al. 2025, GCN 38847) with the 1.3m Devasthal Fast Optical Telescope (DFOT), located at the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2025-01-08 at 21:58:57 UT, i.e., ~ 0.48 days after the Swift-BAT trigger. We have taken multiple frames with an exposure time of 300s in the R filter. We stacked the images after the alignment. We could not detect the optical emission reported by Rastinejad et al. (2025, GCN 38855) in our stacked image within the error box enhanced Swift-XRT position (Osborne et al. 2025, GCN 38848). We obtain the following 3-sigma upper limit in the stacked image: Date Start_UT T_start-T0 (days) Filter Exp time (s) Magnitude ========================================================= 2025-01-08 21:58:57 ~ 0.48 R 300s*12 >21.8 The non-detection of the burst is consistent with the upper limits reported by Breeveld et al. 2025, GCN 38850 and Lipunov et al. 2025, GCN 38858. The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalogue. This circular may be cited.
GCN 38876 table
GRB_name GRB250108B
GCN_number 38876
Detection_method Swift-BAT Det
ra 201.3120°
decl 25.6220°
Circular_text TITLE: GCN CIRCULAR NUMBER: 38876 SUBJECT: GRB 250108B: Swift-BAT refined analysis DATE: 25/01/09 16:42:39 GMT FROM: Rahul Gupta at NASA GSFC S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), R. Gupta (GSFC), N. J. Klingler (GSFC/UMBC/CRESSTII), H. A. Krimm (NSF), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+792 sec from the recent telemetry downlink, we report further analysis of BAT GRB 250108B (trigger #1280056) (Klinger et al., GCN Circ. 38847). The BAT ground-calculated position is RA, Dec = 201.312, 25.622 deg which is RA(J2000) = 13h 25m 14.8s Dec(J2000) = +25d 37' 19.4" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%. The mask-weighted light curve exhibits multi-peaked structures, including evidence of precursor emission prior to the main burst. T90 (15-350 keV) is 229.66 +- 43.30 sec (estimated error including systematics). The time-averaged spectrum from T-63.14 to T+218.21 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.63 +- 0.19. The fluence in the 15-150 keV band is 1.7 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+1.56 sec in the 15-150 keV band is 0.6 +- 0.2 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/1280056
GCN 38877 table
GRB_name GRB250108B
GCN_number 38877
Detection_method Optical
ra 201.3280°
decl 25.6202°
redshift 0.2900
Circular_text TITLE: GCN CIRCULAR NUMBER: 38877 SUBJECT: GRB 250108B: Gemini-North likely redshift z = 2.197 DATE: 25/01/09 17:37:07 GMT FROM: Jillian Rastinejad at Northwestern Univ. Daniele B. Malesani (DAWN/ NBI and Radboud), Jillian C. Rastinejad (Northwestern), Andrew J. Levan (Radboud), Wen-fai Fong, Charlie Kilpatrick (Northwestern), Gavin P. Lamb (LJMU), and Nial R. Tanvir (Leicester) report on behalf of a larger collaboration: Following the detection of the optical afterglow (Rastinejad et al., GCN 38855) of GRB 250108B (Klinger et al., GCN 38847), we obtained optical spectroscopy using the Gemini Multi-Object Spectrograph (GMOS-N) mounted on Gemini-North, under Program GN-2024B-Q-107 (P.I. Rastinejad). The mean time of the observation was 15:12 UT on 2025 Jan 8 (4.81 hr post-burst). The total exposure time was 4x400 s using the R400 grating, which covers the wavelength range 4650-9450 AA. Given the faintness of the target (r ~ 23.4; Rastinejad et al., GCN 38855), only a weak trace is detected, with most of the signal apparent at the red end of the spectrum. A few absorption features are weakly detected. A possible redshift solution, based on the detection of Mg I 2852, Mg II 2796,2803, Fe II 2600, and Fe II 2586, yields z = 2.197, which we suggest to be the redshift of GRB 250108B. The slit was aligned in order to cover also the nearby galaxy (Rastinejad et al., GCN 38855) at coordinates RA = 13:25:18.72, Dec = +25:37:12.7, with photometric redshift z = 0.2-0.3, resulting in a bright trace. We detect Halpha, [N II], and [S II] at z = 0.302, consistent with the Legacy Survey photometric redshift of z = 0.29 +/- 0.04 (Zhou et al., 2021). Our observations indicate that this object is unlikely to be physically connected to the GRB. We thank Jen Miller, Leila Alamos, Brian Lemaux and additional Gemini staff for excellent support in the rapid planning and execution of these observations.