GRB200131A

This page lists all entries on GRB200131A in GRBweb

Summary IPN Swift GCN 26953 GCN 26954 GCN 26956 GCN 26957 GCN 26958 GCN 26959 GCN 26960 GCN 26961 GCN 26962 GCN 26964 GCN 26965 GCN 26967 GCN 26972 GCN 26975 GCN 27035 GCN 26977

Summary table
Variable Value Source
T0 22:41:13.507 UTC GCN_circulars,Konus-Wind Det
ra 3.0940° Swift
decl 51.1168° Swift
pos_error 5.44e-05° Swift
T90 32.74 s Swift
T90_start 22:41:15 UTC Swift
fluence 7.00e-06 erg/cm² Swift
T100 34.233 s
GBM_located False
mjd 58879.945295219906 GCN_circulars,Konus-Wind Det
IPN table
GRB_name GRB200131A
ra 3.0958°
decl 51.1167°
pos_error 5.00e-02°
Swift table
GRB_name GRB200131A
t_trigger 22:41:15 UTC
ra 3.0940°
decl 51.1168°
pos_error 5.44e-05°
T90 32.74 s
fluence 7.00e-06 erg/cm²
GCN 26953 table
GRB_name GRB200131A
GCN_number 26953
Detection_method Swift Det
t_trigger 22:41:15 UTC
ra 3.0950°
decl 51.1240°
Circular_text TITLE: GCN CIRCULAR NUMBER: 26953 SUBJECT: GRB 200131A: Swift detection of a burst with an optical counterpart DATE: 20/01/31 22:53:30 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT B. Sbarufatti (PSU), D. N. Burrows (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 22:41:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200131A (trigger=953689). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 3.095, +51.124 which is RA(J2000) = 00h 12m 23s Dec(J2000) = +51d 07' 25" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 5 sec. There might be a small pulse at T+30 s. The peak count rate was ~60000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 22:42:24.7 UT, 68.7 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 3.0942, 51.1158 which is equivalent to: RA(J2000) = 00h 12m 22.61s Dec(J2000) = +51d 06' 56.9" with an uncertainty of 4.9 arcseconds (radius, 90% containment). This location is 29 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 3.76e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 77 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 00:12:22.57 = 3.09403 DEC(J2000) = +51:07:00.4 = 51.11678 with a 90%-confidence error radius of about 0.61 arc sec. This position is 3.6 arc sec. from the center of the XRT error circle. The estimated magnitude is 15.44 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.17. Burst Advocate for this burst is B. Sbarufatti (bxs60 AT psu.edu). 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 26954 table
GRB_name GRB200131A
GCN_number 26954
Detection_method Optical
ra 3.0940°
decl 51.1167°
Circular_text TITLE: GCN CIRCULAR NUMBER: 26954 SUBJECT: GRB 200131A: MASTER optical transient detection DATE: 20/01/31 23:13:16 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, N.Tyurina, E. Gorbovskoy, O.Gress, V.Kornilov, P.Balanutsa,A.Kuznetsov, V. Vladimirov, D. Vlasenko, F.Balakin, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D. Kuvshinov, V.Shumkov (Lomonosov Moscow State University, SAI, Physics Department), D. Buckley(South African Astronomical Observatory), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA), H. Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,v. 2010, 30L) started Swift GRB 200131A (Sbarufatti et al. GCN 26953) alert observation 50s after trigger time (Lipunov et al. GCN 26952) at MASTER-Tunka and 78s after trigger time at MASTER-IAC. MASTER auto-detection system found MASTER OT J001222.56+510700.3 at RA,Dec(2000) = 00h 12m 22.56s , +51d 07m 00s.3 with m_OT=14.5 (unfiltered) at the first exposition (10s) with optical decay , also detected by Swift UVOT (GCN 26953) Observation and reduction will be continued
GCN 26956 table
GRB_name GRB200131A
GCN_number 26956
Detection_method Swift-XRT Det
ra 3.0944°
decl 51.1168°
Circular_text TITLE: GCN CIRCULAR NUMBER: 26956 SUBJECT: GRB 200131A: Enhanced Swift-XRT position DATE: 20/02/01 03:59:52 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 2283 s of XRT Photon Counting mode data and 6 UVOT images for GRB 200131A, 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 = 3.09439, +51.11676 which is equivalent to: RA (J2000): 00h 12m 22.65s Dec (J2000): +51d 07' 00.4" with an uncertainty of 1.5 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 26957 table
GRB_name GRB200131A
GCN_number 26957
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 26957 SUBJECT: GRB 200131A: RATIR Optical Observations DATE: 20/02/01 04:26:12 GMT FROM: Nat Butler at UC berkeley Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 200131A (Sbarufatti et al., GCN 26953) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2020/02 1.10 to 2020/02 1.14 UTC (3.79 to 4.61 hours after the BAT trigger), obtaining a total of 0.64 hours exposure in the r and i bands. The optical transient (see, also, Lipunov et al., GCN 26954) is well-detected. We find: r = 19.97 +/- 0.04 i = 19.75 +/- 0.02 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN 26958 table
GRB_name GRB200131A
GCN_number 26958
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 26958 SUBJECT: GRB 200131A: KAIT Optical Upper Limit DATE: 20/02/01 04:34:37 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 200131A (Sbarufatti et al., GCN 26953) starting at 4.15 hours after the burst. Observations were performed in the clear (roughly R) filters, a total of 11 images were obtained and the exposure time was 60 s per image. We do not detect the optical afterglow reported by UVOT (Sbarufatti et al., GCN 26953; see also Lipunov et al. GCN 26954; Butler et al. GCN 26957), neither in single image nor in the co-add image. The limiting magnitude estimated from our coadd image is about 19.5 mag.
GCN 26959 table
GRB_name GRB200131A
GCN_number 26959
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 26959 SUBJECT: GRB 200131A: LCO Optical Detection DATE: 20/02/01 05:13:29 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 200131A (Kennea et al., GCN 26953) with the LCO 1-m Sinistro instrument at the McDonald Observatory, Texas, USA site on January 31, from 01:59 to 02:22 UT (corresponding to 3.1 to 3.6 hours after the GRB trigger time) with the Bessel R and I filters. We performed a series of 5x120s exposures in each band. We detect a source in the Swift-BAT refined error region (Evans et al., GCN 26956) that is not present in either USNO-B1.0 or 2MASS surveys with the following magnitudes: R = 19.75 +/- 0.13 I = 19.31 +/- 0.14 This flux measurement is calibrated against several USNO-B1.0 objects near the GRB location and is not corrected for Galactic Extinction.
GCN 26960 table
GRB_name GRB200131A
GCN_number 26960
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 26960 SUBJECT: GRB 200131A: VIRT optical transient detection DATE: 20/02/01 05:23:11 GMT FROM: Priyadarshini Gokuldass at U. of the Virgin Islands P. Gokuldass (UVI), D. Morris (UVI), N. Orange (OrangeWave Innovative Science, LLC), A. Cucchiara (College of Marin), R. Strausbaugh (UVI) report: We observed the field of GRB 200131A (Sbarufatti et al. GCN 26953) with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 01-31-2020 starting at 23:28:45 UT (T+67 minutes). We performed a series of exposures in R filter. The weather conditions were variable during the hours of observation and the zenith angle at the start of observations was 54 degrees and setting. The midpoint of the exposures is ~T+1.6 hrs. We observed the Swift XRT position with a 20'x20' field of view We detect an uncatalogued source consistent with the UVOT position (Sbarufatti et al. GCN 26953) and MASTER OT position (Lipunov et al. 26954) with magnitude: R= 16.8 +/- 0.2 The magnitude is estimated from comparison to nearby USNO B1 stars and is not corrected for Galactic extinction. The VIRT is still in the commissioning phase. This work is supported by NASA-MUREP-MIRO grant NNX15AP95A, NSF EiR AST Award 1901296, and NSF HBCU-UP AST Award 1831682. This message can be cited.
GCN 26961 table
GRB_name GRB200131A
GCN_number 26961
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 26961 SUBJECT: GRB 200131A: Swift-XRT refined Analysis DATE: 20/02/01 08:55:16 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU) and B. Sbarufatti report on behalf of the Swift-XRT team: We have analysed 6.1 ks of XRT data for GRB 200131A (Sbarufatti et al. GCN Circ. 26953), from 61 s to 17.4 ks after the BAT trigger. The data comprise 249 s in Windowed Timing (WT) mode (the first 5 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 26956). We cannot determine at the present time whether the source is fading. A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.83 (+0.04, -0.03). The best-fitting absorption column is consistent with the Galactic value of 1.8 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.81 (+0.15, -0.14) and a best-fitting absorption column of 2.3 (+0.6, -0.4) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.3 (+0.6, -0.4) x 10^21 cm^-2 Galactic foreground: 1.8 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 1.81 (+0.15, -0.14) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00953689. This circular is an official product of the Swift-XRT team.
GCN 26962 table
GRB_name GRB200131A
GCN_number 26962
Detection_method Swift-UVOT Det
ra 3.0940°
decl 51.1168°
Circular_text TITLE: GCN CIRCULAR NUMBER: 26962 SUBJECT: GRB 200131A: Swift/UVOT Detection DATE: 20/02/01 14:37:48 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and B. Sbarufatti (PSU)report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200131A 78 s after the BAT trigger (Sbarufatti et al., GCN Circ. 26953). A source consistent with the XRT position (Goad et al. GCN Circ. 26956) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 00:12:22.57 = 3.09405 (deg.) Dec (J2000) = +51:07:00.3 = 51.11675 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). The source has been detected also by MASTER (Lipunov et al. GCN Circ. No. 26954), RATIR (Butler et al., GCN Circ. No. 26957), MacDonalds Observatory (Strausbaugh et al., GCN Circ. No. 26959), and VIRT (Gokuldass et al., GCN Circ. No. 26960. Preliminary detections 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 78 227 147 15.47 +/- 0.02 v 4281 5919 393 19.57 +/- 0.28 b 5103 5303 197 19.53 +/- 0.16 u 290 323 32 16.09 +/- 0.08 w1 4692 4892 197 18.48 +/- 0.18 m2 4486 6124 393 18.98 +/- 0.20 w2 4076 5714 393 19.06 +/- 0.19 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.17 in the direction of the burst (Schlegel et al. 1998).
GCN 26964 table
GRB_name GRB200131A
GCN_number 26964
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 26964 SUBJECT: GRB 200131A: CDK700 optical observations DATE: 20/02/02 21:01:36 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Pozanenko (IKI), V. Kim (AFIF, Pulkovo Observatory), I. Reva (AFIF), M. Krugov (AFIF), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf of larger GRB IKI FuN collaboration: We observed the field of the GRB 200131A (Sbarufatti al., GCN 26953) with CDK700 (0.7m) telescope of Assy-Turgen observatory starting on Feb. 01 (UT) 14:58:49 in R-filter. We marginally detect the optical afterglow (Sbarufatti al., GCN 26953; Lipunov al., GCN 26954; Butler al., GCN 26957; Strausbaugh al., GCN 26959; Kuin al., GCN 26962). Preliminary photometry of the afterglow is following. Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2019-02-01 14:58:49 0.76733 R 14*360 21.4 0.3 21.5 The photometry is based on nearby USNO-B1.0 stars (R2 magnitudes).
GCN 26965 table
GRB_name GRB200131A
GCN_number 26965
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 26965 SUBJECT: GRB 200131A: ISON-Castelgrande optical observations DATE: 20/02/02 21:30:37 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Pozanenko (IKI), S. Schmalz (KIAM), V. Kim (AFIF, Pulkovo Observatory), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM) report on behalf of larger GRB follow-up collaboration: We observed the field of the GRB 200131A (Sbarufatti al., GCN 26953) with ORI-22 telescope of ISON-Castelgrande observatory starting on Jan. 31 (UT) 23:11:28. We obtained 120 images of 60 s exposure in Clear filter. The optical afterglow (Sbarufatti al., GCN 26953; Lipunov al., GCN 26954; Butler al., GCN 26957; Strausbaugh al., GCN 26959; Kuin al., GCN 26962) is best detected in the stacked image of the first 60 images. Preliminary photometry of the afterglow is following Date UT start t-T0 Filter Exp. OT Err. (mid, days) (s) 2019-01-31 23:11:28 0.04353 Clear 60*60 18.35 0.25 The photometry is based on nearby USNO-B1.0 stars (R2 magnitude).
GCN 26967 table
GRB_name GRB200131A
GCN_number 26967
Detection_method Swift-BAT Det
ra 3.0670°
decl 51.1210°
Circular_text TITLE: GCN CIRCULAR NUMBER: 26967 SUBJECT: GRB 200131A: Swift-BAT refined analysis DATE: 20/02/03 00:35:33 GMT FROM: Amy Lien at GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), J. P. Norris (BSU), D. M. Palmer (LANL), B. Sbarufatti (PSU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-200 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200131A (trigger #953689) (Sbarufatti et al., GCN Circ. 26953). The BAT ground-calculated position is RA, Dec = 3.067, 51.121 deg which is RA(J2000) = 00h 12m 16.2s Dec(J2000) = +51d 07' 15.6" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 96%. The mask-weighted light curve shows several bright overlapping pulses that starts from ~T-3.5 s and ends at ~T+3. It is followed by another weaker pulse at ~T+30 s and some weak emission that lasts till ~T+60 s. The burst went out of the BAT FOV at T+472 s. T90 (15-350 keV) is 32.74 +- 0.88 sec (estimated error including systematics). The time-averaged spectrum from T-3.45 to T+46.56 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.32 +- 0.04. The fluence in the 15-150 keV band is 7.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.02 sec in the 15-150 keV band is 26.9 +- 0.6 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The spectral lag of the initial bright structure from ~T-2.5 s to ~T+3 s is 49 (+3, -3) ms for the 100-350 keV to 25-50 keV bands, and 43 (+5, -7) ms for the 50-100 keV to 15-25 keV bands. These values are consistent with this of long GRBs. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/953689/BA/
GCN 26972 table
GRB_name GRB200131A
GCN_number 26972
Detection_method CALET
Circular_text TITLE: GCN CIRCULAR NUMBER: 26972 SUBJECT: GRB 200131A: CALET Gamma-Ray Burst Monitor detection DATE: 20/02/03 07:07:14 GMT FROM: Valentin Pal'shin at AGU S. Ricciarini (U of Florence), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The bright GRB 200131A detected by Swift (Sbarufatti et al., GCN Circ. 26953, Sakamoto et al., GCN Circ. 26967; https://gcn.gsfc.nasa.gov/other/200131A.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 22:41:11.299 UTC on 31 January 2020. The burst signal was seen by all CGBM detectors. The burst light curve shows a multi-peaked structure which starts at T+3.3 sec, peaks at T+3.8 sec and ends at T+6.4 sec. The T90 and T50 durations measured by the SGM data are 2.2 +- 0.1 sec and 1.4 +- 0.1 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1264545439/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN 26975 table
GRB_name GRB200131A
GCN_number 26975
Detection_method Konus-Wind Det
t_trigger 22:41:13.507 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 26975 SUBJECT: Konus-Wind observation of GRB 200131A DATE: 20/02/03 16:09:21 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, report: The long-duration, bright GRB 200131A (Swift-BAT detection: Sbarufatti et al., GCN Circ. 26953; Sakamoto et al., GCN Circ. 26967; CALET Gamma-Ray Burst Monitor detection: Ricciarini et al., GCN 26972) triggered Konus-Wind at T0=81673.507 s UT (22:41:13.507). The burst light curve shows a bright, multi-peaked structure which starts at ~T0-0.1 s and has a duration of ~3 s, followed by a weaker episode at ~T0+32 s. The emission is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB200131_T81673/ As observed by Konus-Wind, the burst had a fluence of 1.60(-0.08,+0.09)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+0.068 s, of 1.64(-0.27,+0.28)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The spectrum of the brightest episode (measured from T0 to T0+9.984 s) is best fit in the 20 keV - 4 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.80(-0.09,+0.10) and Ep = 228(-15,+17) keV (chi2 = 43/72 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.2 (chi2 = 43/71 dof). The spectrum near the maximum count rate (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 4 MeV range by a power law with exponential cutoff model: with alpha = 0.01(-0.19,+0.21) and Ep = 266(-22,+25) keV (chi2 = 49/38 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.8 (chi2 = 46/37 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN 27035 table
GRB_name GRB200131A
GCN_number 27035
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 27035 SUBJECT: GRB 200131A: Tautenburg observations DATE: 20/02/11 15:39:37 GMT FROM: Sylvio Klose at TLS Tautenburg B. Stecklum, S. Klose, A. Nicuesa Guelbenzu, and C. Hoegner (all Tautenburg) report: We observed the field of GRB 200131A (T0=22:41:15 UT; Sbarufatti et al., GCN 26953) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k x 6k CCD camera and the wide V-band filter (VB). The transmission curve of this filter closely follows the Gaia GBP filter. Based on several Gaia DR2 stars in the field within 1 arcmin radius about the afterglow position, we measure for the optical transient (Lipunov et al., GCN 26954; Butler et al., GCN 26957; Strausbaugh et al., GCN 26959; Gokuldass et al., GCN 26960; Kuin et al., GCN 26962; Pozanenko et al., GCN 26964, 26965; Watson et al., GCN 26977) the following Vega magnitudes: mean time t = Jan 31, 23:12:15 UT; t-T0 = 00h 31m 00s; VB = 18.00 +/- 0.10 mean time t = Feb 01, 20:41:47 UT; t-T0 = 22h 00m 32s; VB = 21.85 +/- 0.30.
GCN 26977 table
GRB_name GRB200131A
GCN_number 26977
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 26977 SUBJECT: GRB 200131A: Further RATIR Optical Observations DATE: 20/02/03 19:22:08 GMT FROM: Nat Butler at Az State U Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 200131A (Sbarufatti et al., GCN 26953) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2020/02 2.10 to 2020/02 2.17 UTC (27.70 to 29.45 hours after the BAT trigger), obtaining a total of 1.42 hours exposure in the r and i bands, and from 2020/02 3.10 to 2020/02 3.12 UTC (51.69 to 52.28 hours after the BAT trigger), obtaining a total of 0.49 hours exposure in the r and i bands. The optical transient (Lipunov et al., GCN Circ. 26954, Butler et al., GCN Circ. 26957, Strausbaugh et al., GCN Circ. 26959, Gokuldass et al., GCN Circ. 26960, Pozanenko et al., GCN Circ. 26964 & 26965) is detected on 2020/02/02 with: r = 21.39 +/- 0.11 i = 21.39 +/- 0.07 and on 2020/02/03 with: r = 22.26 +/- 0.29 i = 22.45 +/- 0.35 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.