//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26879 SUBJECT: GRB 200125B: Fermi GBM Final Real-time Localization DATE: 20/01/25 20:53:50 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 20:43:31 UT on 25 Jan 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200125B (trigger 601677816.188054 / 200125864). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 7.5, Dec = 64.7 (J2000 degrees, equivalent to J2000 00h 30m, 64d 42'), with a statistical uncertainty of 1.0 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/2020/bn200125864/quicklook/glg_skymap_all_bn200125864.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200125864/quicklook/glg_healpix_all_bn200125864.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200125864/quicklook/glg_lc_medres34_bn200125864.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26880 SUBJECT: GRB 200125B: BALROG localization (Fermi Trigger 601677816 / GRB 200125864) DATE: 20/01/25 21:20:59 GMT FROM: Jochen Greiner at MPE,Garching B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 601677816 at 20:43:31 on 25 Jan. 2020 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position (1 sigma statistical errors) is: RA(2000.0) = 7.7+/-0.8 deg Decl.(2000.0) = 64.4+/-0.4 deg We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB200125864/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB200125864/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB200125864/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26888 SUBJECT: GRB 200125B: Insight-HXMT/HE detection DATE: 20/01/26 14:10:22 GMT FROM: Ce Cai at IHEP C. Cai, S. Xiao, Y. F. Du, Y. G. Zheng, Q. Luo, Q. B. Yi, Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: At 2020-01-25T20:43:31.90 (T0), Insight-HXMT/HE detected GRB 200125B (trigger ID: HEB200125863) in a routine search of the data, which also triggered Fermi/GBM (GCN #26879). The Insight-HXMT/HE light curve mainly consists of multiple pulses with a duration (T90) of 4.66 s measured from T0-0.11 s. The 1-ms peak rate, measured from T0+0.57 s, is 9038 cnts/sec. The total counts from this burst is 18553 counts. URL_LC: http://www.hxmt.org/images/GRB/HEB200125863_lc.jpg All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26893 SUBJECT: GRB 200125B: Fermi GBM observations DATE: 20/01/27 02:06:37 GMT FROM: Peter Veres at UAH P. Veres, S. Poolakkil and C. Meegan (all UAH) report on behalf of the Fermi GBM Team: "At 20:43:31.19 UT on 25 January 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200125B (trigger 601677816 / 200125864) (Fermi GBM Team, GCN #26879), which was also detected by Insight-HXMT/HE (Cai et al., GCN #26888). The GBM light curve consists of multiple overlapping pulses with a duration (T90) of about 5.8 s (50-300 keV). The time-averaged spectrum from T0 s to T0+12 s is best fit by a Band function with Epeak = 175 +/- 3 keV, alpha = -0.74 +/- 0.01, and beta = -2.23 +/- 0.02. The event fluence (10-1000 keV) in this time interval is (5.48 +/- 0.03)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.3 s in the 10-1000 keV band is 103.7 +/- 0.6 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/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26911 SUBJECT: GRB 200125B: DDOTI/OAN optical observations report DATE: 20/01/28 06:04:23 GMT FROM: Emma Margarita Pereyra Talamantes at IA-UNAM Ensenada Margarita Pereyra (UNAM), Nat Butler (ASU), Alan M. Watson (UNAM), Eleonora Troja (GSFC/UMD), Diego Gonzalez (UNAM), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), and Tanner Wolfram (ASU), Simone Dichiara (GSFC/UMD) report: We observed the field of GRB 200125B detected by Fermi Gamma-ray Burst Monitor (Fermi GBM Team, GCN Circ. 26879, Veres et al., GCN Circ. 26893), with the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir (http://ddoti.astroscu.unam.mx) from 2020-01-26 02:18 to 2020-01-26 06:53 UTC (5.58 to 10.16 hours after the event). We observed a region of 6.8 degrees in RA by 10.2 degrees in declination centered on the GBM Final Position 00:29:47 +64:41:22 J2000. This region contains about 70 square degrees. We obtained about 3.1 hrs total exposure across the region. We calibrated our images against the APASS catalog. Our 10-sigma limiting magnitude is w = 20.04 for a 2.0 degrees radius error region centered at the GBM Final Position. Comparing to the USNO-B1 and PAN-STARRS DR1 catalogs we do not detect any uncataloged source with significant fading or rising to our 10-sigma limit. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. -- *Dr. Margarita Pereyra * *FFTF, Schlumberger Foundation Alumnae* ---------------------------------------------------------------------------------------------------------------- *Catedrático Conacyt* *Instituto de Astronomía de la UNAM,* *Km. 107 Carretera Tijua**na-Ensenada, * *Ensenada Baja California, México. C.P. 22860* Oficina: 405 Skype: margarita-pereyra //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26918 SUBJECT: IPN triangulation of GRB 200125B DATE: 20/01/28 16:20:12 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, and S. Xiao, C. K. Li, X. B. Li, Y. Huang, and S. L. Xiong on behalf of the Insight-HXMT/HE GRB team, report: The long-duration, very bright GRB 200125B (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 26879; BALROG localization: Biltzinger et al., GCN Circ. 26880; Insight-HXMT/HE detection: Cai et al., GCN Circ. 26888) was detected by Fermi (GBM trigger 601677816), Konus-Wind, and Insight (HXMT/HE) at about 74611 s UT (20:43:31). We have triangulated this GRB to a Konus-GBM annulus centered at RA(2000)=321.900 deg (21h 27m 36s) Dec(2000)=-14.917 deg (-14d 55' 02") whose radius is 86.537 +/- 0.136 deg (3 sigma) and a wider Konus-HXMT annulus. These annuli may be improved. The annulus is consistent with, but reduces the area of, the final Fermi-GBM (GCN Circ. 26879) and BALROG (GCN Circ. 26880) localizations. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB200125_T74611/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26951 SUBJECT: Konus-Wind observation of GRB 200125B DATE: 20/01/31 16:11:49 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, very bright GRB 200125B (Fermi-GBM observations: The Fermi GBM team, GCN Circ. 26879; Veres et al., GCN Circ. 26893; BALROG localization: Biltzinger et al., GCN Circ. 26880; Insight-HXMT/HE detection: Cai et al., GCN Circ. 26888; IPN triangulation: Svinkin et al., GCN Circ. 26918) triggered Konus-Wind at T0=74611.206 s UT (20:43:31.206). The burst light curve shows a multipeaked structure which starts at ~T0-0.5 s and has a total duration of ~10 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB200125_T74611/ As observed by Konus-Wind, the burst had a fluence of 6.01(-0.36,+0.37)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.312 s, of 3.92(-0.44,+0.46)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+12.288 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.91(-0.06,+0.07), the high energy photon index beta = -2.48(-0.15,+0.12), the peak energy Ep = 211(-15,+16) keV (chi2 = 98/97 dof). The spectrum near the maximum count rate (measured from T0+1.280 to T0+1.536 s) is best fit in the 20 keV - 4 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.43(-0.14,+0.16), the high energy photon index beta = -2.64(-0.34,+0.21), the peak energy Ep = 295(-36,+39) keV (chi2 = 63/51 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.