January 2026 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 41599] EP260119a: Assy AZT-20 optical observations
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43500 SUBJECT: EP260119a: Assy AZT-20 optical observations DATE: 26/01/22 12:09:42 GMT FROM: Alina Volnova at IKI RAS <alinusss(a)gmail.com> A. Volnova (IKI), A. Pozanenko (IKI), M. Krugov (FAI), N. Pankov (IKI) report on behalf of IKI-GRB-FuN: We observed the field of the EP260119a (Jiang et al., GCN 43447; GCN 43465; Cheng et al., GCN 43449) at the redshift of z ~ 5.47 (Corcoran et al., GCN 43469) with the AZT-20 telescope of Assy-Turgen observatory starting on 2026-01-20 (UT) 14:53 and taking several 60-second exposures in i' filter. In the stacked frame we detect the optical counterpart (Fortin et al., GCN 43450; GCN 43455; Eyles-Ferris et al., GCN 43452; Moskvitin and Spiridonova, GCN 43463; Liu et al., GCN 43464; Ma et al., GCN 43466; Zheng et al., GCN 43468; Corcoran et al., GCN 43469; Bochenek and Perley, GCN 43472; Pankov et al., GCNs 43476, 43499; Jin et al., GCN 43496). Preliminary photometry and observational details are the following: Date UT start t-T0 Exp. Filter Obj. Err. UL Site/Telescope (mid,days) (n*s) (3sigma) 2026-01-20 14:53:00 1.63500 63*60 i' 22.7 0.2 23.2 Assy-Turgen/AZT-20 The photometry is based on several nearby SDSS stars (i-magnitudes) and is not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/43500. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41598] EP260119a: Mondy and SAO RAS optical upper limits
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43499 SUBJECT: EP260119a: Mondy and SAO RAS optical upper limits DATE: 26/01/22 10:50:53 GMT FROM: Alina Volnova at IKI RAS <alinusss(a)gmail.com> N. Pankov (IKI), A. Moskvitin (SAO RAS), A. Volnova (IKI), O. Spiridonova (SAO RAS), E. Klunko (ISTP), A. Pozanenko (IKI) report on behalf of the IKI-GRB-FuN collaboration: We observed the field of the EP260119a (Jiang et al., GCN 43447; GCN 43465; Cheng et al., GCN 43449) at the redshift of z ~ 5.47 (Corcoran et al., GCN 43469) using the AZT-33IK telescope of the Mondy observatory starting on 2026-01-20 (UT) 18:52:22 and 2026-01-21 (UT) 19:10:23, and the Zeiss-1000 of the SAO RAS starting on 2026-01-21 (UT) 03:05:44. In the stacked frame of each observational epoch we do not detect the optical source reported previously (Fortin et al., GCN 43450; GCN 43455; Eyles-Ferris et al., GCN 43452; Moskvitin and Spiridonova, GCN 43463; Liu et al., GCN 43464; Ma et al., GCN 43466; Zheng et al., GCN 43468; Corcoran et al., GCN 43469; Bochenek and Perley, GCN 43472; Pankov et al., GCN 43476; Jin et al., GCN 43496). Preliminary photometry and observation details are listed below: Date UT start t-T0 Exp. Filter Mag MagErr. UL Site/Telescope (mid,days) (n*s) (3sigma) 2026-01-20 18:52:22 1.80804 45x120 I n/d n/d 22.3 Mondy/AZT-33IK 2026-01-21 03:05:44 2.13449 8*300 Ic n/d n/d 21.9 SAO RAS/Zeiss-1000 2026-01-21 19:10:23 2.82417 52*120 I n/d n/d 21.7 Mondy/AZT-33IK Photometric data are based on nearby SDSS stars (I-magnitudes obtained using the 2005 Lupton transform) and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/43499. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41597] GRB 260122A: Fermi GBM Final Real-time Localization
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43498 SUBJECT: GRB 260122A: Fermi GBM Final Real-time Localization DATE: 26/01/22 09:44:17 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 09:33:43 UT on 22 Jan 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260122A (trigger 790767228.420398 / 260122398). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 307.8, Dec = -12.8 (J2000 degrees, equivalent to J2000 20h 31m, -12d 48'), with a statistical uncertainty of 6.5 degrees. The angle from the Fermi LAT boresight is 65.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260122398/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260122398/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260122398/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43498. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41596] IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43497 SUBJECT: IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility DATE: 26/01/22 08:15:17 GMT FROM: Jannis Necker at DESY <jannis.necker(a)desy.de> Akshay Eranhalodi (DESY), Robert Stein (JSI), Jannis Necker (Leiden University), and Anna Franckowiak (Ruhr University Bochum) report, On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: As part of the ZTF neutrino follow up program (Stein et al. 2023), we observed the localization region of the neutrino event IceCube-260115A (Zegarelli et. al, GCN 43421) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2026-01-16 05:53 UTC, approximately 12.3 hours after event time. We covered 99.2% (8.2 sq deg) of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019, Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019) . We are left with one transient candidate by our pipeline within the 90.0% localization of the skymap. +--------------------------------------------------------------------------------+ | ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr | +--------------------------------------------------------------------------------+ | ZTF26aabnqai | AT2026azb | 145.5760425 | +13.0239392 | r | 21.08 | 0.15 | +--------------------------------------------------------------------------------+ ZTF26aabnqai was first detected on 2026-01-16 at an apparent magnitude of about 21 mag in r-band. The g-r color is around 0.5 mag. Forced photometry revealed previous detections up to a week earlier with a fading rate of about 0.5 mag per day. The host galaxy has a photometric redshift of 0.23 +/- 0.08 in Legacy Survey. During our latest observatiosn the transient was no longer detectable, consistent with continued fading. This makes the transients too faint for our spectroscopic programs. However, the color, fade time and inferred absolute magnitude are all broadly consistent with a Type Ia supernova. These are not expected to emit high-energy neutrinos and thus we consider ZTF26aabnqai unlikely to be related to IceCube-260115A. We further identify following quasars without contemporaneous flaring activity. The hosts of ZTF22aaejlfn (SDSS J094112.55+131224.9), ZTF25aadwsdp (SDSS J093659.79+124616.6), ZTF25aadxqgk (SDSS J094449.16+120545.5), and ZTF25aarudkx (SDSS J094755.84+125346.4) are listed in MILLIQUAS (Flesch et al., 2023). ZTF24abwkvpl was first detected on 2024-11-05. Its host, SDSS J093633.62+131948.5, is part of a selection of quasars by SDSS photometry (Richards et al., 2009). The hosts of ZTF25aaedxfb, and ZTF25aadxmes show red, AGN-like WISE colors with W1-W2>0.8 (Stern et al., 2012). ZTF25abttvfc was consistently detected over the last 100 days with varying brightness. ZTF18acqfhyp, ZTF25aadnych, and ZTF25aadoovh were sporadically detected before the neutrino arrival and are likely variable sources at the sensitivity limit. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; DESY, Germany; TANGO, Taiwan; UW Milwaukee, USA; LANL, USA; TCD, Ireland; IN2P3, France. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering is performed with the nuztf (Stein et al. 2021, https://github.com/desy-multimessenger/nuztf ). View this GCN Circular online at https://gcn.nasa.gov/circulars/43497. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41595] EP260119a: Xinglong optical upper limit
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43496 SUBJECT: EP260119a: Xinglong optical upper limit DATE: 26/01/22 03:29:52 GMT FROM: Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong(a)nao.cas.cn> Junjie-Jin (NAOC), Haiyang-Mu (NAOC), Sen-Liu (NAOC), Pengliang-Du (NAOC), Zhou-Fan (NAOC), Hong-Wu (NAOC) report: Following the detection of EP260119a by EP-WXT (GCN Circular 43447,GCN Circular 43452), we observed the field of EP260116a using the 2.16-m telescope at Xinglong Observatory, NAOC. We obtained 600s clear-band frames with a median time of 2026-01-19T18:38:00 hr after the EP trigger. No uncatalogued optical transient is detected in the stacked images within the 3 arcmin EP/WXT error circle (GCN Circular 43447), down to 5-sigma limiting magnitudes of z ~ 19.8(not good day with thin cloud and bad seeing), calibrated with Pan-STARRS sources in the field. Also there is no apparent brightening for the catalogued sources within the error circle. Based on the location of the report(GCN Circular 43452), the target was not observed. View this GCN Circular online at https://gcn.nasa.gov/circulars/43496. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41594] The EP-WXT trigger 01709251871 is likely a flaring star
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43495 SUBJECT: The EP-WXT trigger 01709251871 is likely a flaring star DATE: 26/01/22 01:53:51 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.D. Liang (NAOC), Z. X. Li, G. L. Huang, C. Wang (IHEP) and Y. Liu (NAOC) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709251871 at the time of 2026-01-22T00:00:14, is likely a stellar flare associated with [M81] I-308. The estimated flux of the flare is around 1x10^-10 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 8.5x10^31 erg/s. 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). View this GCN Circular online at https://gcn.nasa.gov/circulars/43495. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41593] The EP-WXT trigger 01709251871 is likely a flaring star
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43495 SUBJECT: The EP-WXT trigger 01709251871 is likely a flaring star DATE: 26/01/22 01:53:51 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.D. Liang (NAOC), Z. X. Li, G. L. Huang, C. Wang (IHEP) and Y. Liu (NAOC) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709251871 at the time of 2026-01-22T00:00:14, is likely a stellar flare associated with [M81] I-308. The estimated flux of the flare is around 1x10^-10 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 8.5x10^31 erg/s. 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). View this GCN Circular online at https://gcn.nasa.gov/circulars/43495. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41592] Fermi GRB 260120C: Global MASTER-Net observations report
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43494 SUBJECT: Fermi GRB 260120C: Global MASTER-Net observations report DATE: 26/01/22 00:30:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 260120C ( Fermi GBM team, GCN 43482) errorbox 1 days 3994 sec after notice time and 1 days 4027 sec after trigger time at 2026-01-22 00:14:13 UT, with upper limit up to 16.8 mag. The observations began at zenith distance = 81 deg. The sun altitude is -47.2 deg. The galactic latitude b = 20 deg., longitude l = 26 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3110218 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 44777 | 2026-01-21 11:32:53 | MASTER- | (17h 17m 02.82s , +06d 50m 25.2s) | C | 60 | 18.4 | 44777 | 2026-01-21 11:32:53 | MASTER- | (17h 18m 05.82s , +06d 16m 01.2s) | C | 60 | 18.4 | 44847 | 2026-01-21 11:34:03 | MASTER- | (17h 25m 13.44s , +06d 50m 33.0s) | C | 60 | 18.3 | 44847 | 2026-01-21 11:34:03 | MASTER- | (17h 26m 16.06s , +06d 16m 06.1s) | C | 60 | 18.2 | 45387 | 2026-01-21 11:43:03 | MASTER- | (17h 18m 07.00s , +06d 16m 05.5s) | C | 60 | 18.6 | 45387 | 2026-01-21 11:43:03 | MASTER- | (17h 17m 03.38s , +06d 50m 02.6s) | C | 60 | 18.5 | 45457 | 2026-01-21 11:44:13 | MASTER- | (17h 26m 15.40s , +06d 16m 14.1s) | C | 60 | 18.5 | 45457 | 2026-01-21 11:44:13 | MASTER- | (17h 25m 12.21s , +06d 50m 13.9s) | C | 60 | 18.4 | 46057 | 2026-01-21 11:54:13 | MASTER- | (17h 17m 05.56s , +06d 51m 19.0s) | C | 60 | 18.6 | 46057 | 2026-01-21 11:54:13 | MASTER- | (17h 18m 09.53s , +06d 17m 03.8s) | C | 60 | 18.8 | 46127 | 2026-01-21 11:55:23 | MASTER- | (17h 25m 09.25s , +06d 49m 58.4s) | C | 60 | 18.5 | 46127 | 2026-01-21 11:55:23 | MASTER- | (17h 26m 12.91s , +06d 15m 41.0s) | C | 60 | 18.6 | 46661 | 2026-01-21 12:04:17 | MASTER- | (17h 18m 10.15s , +06d 16m 41.1s) | C | 60 | 19.0 | 46661 | 2026-01-21 12:04:17 | MASTER- | (17h 17m 05.20s , +06d 51m 05.2s) | C | 60 | 18.7 | 46730 | 2026-01-21 12:05:26 | MASTER- | (17h 25m 08.92s , +06d 49m 31.9s) | C | 60 | 18.5 | 46730 | 2026-01-21 12:05:26 | MASTER- | (17h 26m 13.45s , +06d 15m 06.0s) | C | 60 | 18.8 | 47327 | 2026-01-21 12:15:23 | MASTER- | (17h 17m 06.31s , +06d 49m 15.8s) | C | 60 | 18.7 | 47327 | 2026-01-21 12:15:23 | MASTER- | (17h 18m 11.40s , +06d 14m 44.7s) | C | 60 | 19.0 | 47398 | 2026-01-21 12:16:33 | MASTER- | (17h 25m 11.28s , +06d 50m 36.4s) | C | 60 | 18.6 | 47398 | 2026-01-21 12:16:34 | MASTER- | (17h 26m 16.13s , +06d 16m 02.5s) | C | 60 | 18.9 | 47994 | 2026-01-21 12:26:30 | MASTER- | (17h 17m 04.57s , +06d 49m 46.2s) | C | 60 | 18.7 | 47994 | 2026-01-21 12:26:30 | MASTER- | (17h 18m 10.96s , +06d 15m 15.9s) | C | 60 | 19.1 | 48064 | 2026-01-21 12:27:40 | MASTER- | (17h 25m 06.47s , +06d 50m 37.4s) | C | 60 | 18.7 | 48064 | 2026-01-21 12:27:40 | MASTER- | (17h 26m 12.55s , +06d 16m 04.5s) | C | 60 | 19.1 | 90457 | 2026-01-22 00:14:13 | MASTER-Kislovodsk | (16h 55m 40.00s , +10d 25m 13.1s) | C | 60 | 16.7 | 90573 | 2026-01-22 00:16:09 | MASTER-Kislovodsk | (17h 02m 50.35s , +12d 18m 51.1s) | C | 60 | 16.7 | 90811 | 2026-01-22 00:20:07 | MASTER-Kislovodsk | (16h 45m 12.41s , +06d 36m 17.1s) | C | 60 | 16.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43494. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41591] GRB 260120B: Swift-BAT refined analysis
by GCN Circulars 21 Jan '26

21 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43493 SUBJECT: GRB 260120B: Swift-BAT refined analysis DATE: 26/01/21 23:08:12 GMT FROM: D. R. Sadaula at NASA GSFC <dev.r.sadaula(a)nasa.gov> D. M. Palmer (LANL), S. D. Barthelmy (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-769 to T+303 sec from the recent telemetry downlink, we report further analysis of BAT GRB 260120B (trigger #1442454) (Ferro et al., GCN Circ. 43479). The BAT ground-calculated position is RA, Dec = 284.701, 61.905 deg which is RA(J2000) = 18h 58m 48.3s Dec(J2000) = +61d 54' 19.2" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 9%. The BAT light curve showed a single-peaked structure with a duration of about 10 sec. T90 (15-350 keV) is 4.48 +- 0.94 sec (estimated error including systematics). The time-averaged spectrum from T-0.34 to T+4.59 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.93 +- 1.35, and Epeak of 103.9 +- 38.6 keV (chi squared 48.41 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+0.48 sec in the 15-150 keV band is 3.1 +- 0.8 ph/cm2/sec. A fit to a simple power law gives a photon index of 0.95 +- 0.21 (chi squared 57.22 for 57 d.o.f.). 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/1442454 View this GCN Circular online at https://gcn.nasa.gov/circulars/43493. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41590] GRB 260120B: Swift-XRT refined Analysis
by GCN Circulars 21 Jan '26

21 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43492 SUBJECT: GRB 260120B: Swift-XRT refined Analysis DATE: 26/01/21 20:20:55 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), S. Lanava (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 5.6 ks of XRT data for GRB 260120B, from 130 s to 29.5 ks after the trigger. The data comprise 13 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 light curve can be modelled with a power-law decay with a decay index of alpha=0.84 (+/-0.06). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.97 (+0.29, -0.27). The best-fitting absorption column is 2.1 (+1.2, -1.0) x 10^21 cm^-2, in excess of the Galactic value of 7.4 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.1 (+1.2, -1.0) x 10^21 cm^-2 Galactic foreground: 7.4 x 10^20 cm^-2 Excess significance: 2.4 sigma Photon index: 1.97 (+0.29, -0.27) The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/01442454. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/43492. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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