GRB250109A

This page lists all entries on GRB250109A in GRBweb

Summary Fermi GBM IPN GCN 38873 GCN 38883 GCN 38887 GCN 38889 GCN 38899 GCN 38900 GCN 38901 GCN 38915 GCN 38920

Summary table
Variable Value Source
GRB_name_Fermi GRB250109262
T0 6:17:01.940 UTC Fermi_GBM
ra 88.8042° IPN
decl -12.5000° IPN
pos_error 5.00e-03° IPN
T90 15.104 s Fermi_GBM
T90_error 3.083 s Fermi_GBM
T90_start 6:17:01.940 UTC Fermi_GBM
fluence 6.30e-07 erg/cm² Fermi_GBM
fluence_error 1.24e-08 erg/cm² Fermi_GBM
T100 15.104 s
GBM_located False
mjd 60684.26182800926 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB250109262
trigger_name bn250109262
ra 88.8054°
decl -12.4967°
pos_error 8.19e+00°
datum 2025-01-09
t_trigger 6:17:08.596 UTC
T90 15.104 s
T90_error 3.083 s
T90_start 6:17:01.940 UTC
fluence 6.30e-07 erg/cm²
fluence_error 1.24e-08 erg/cm²
flux_1024 1.28e+00 erg/cm²/s
flux_1024_error 1.74e-01 erg/cm²/s
flux_1024_time 2.88e+00 erg/cm²/s
flux_64 3.04e+00 erg/cm²/s
flux_64_error 1.07e+00 erg/cm²/s
IPN table
GRB_name GRB250109A
ra 88.8042°
decl -12.5000°
pos_error 5.00e-03°
GCN 38873 table
GRB_name GRB250109A
GCN_number 38873
Detection_method Fermi GBM Other
ra 84.4300°
decl 2.2600°
Circular_text TITLE: GCN CIRCULAR NUMBER: 38873 SUBJECT: GRB 250109A /EP250109a: Fermi GBM Final Localization DATE: 25/01/09 16:02:55 GMT FROM: Utkarsh Pathak at IIT Bombay The Fermi GBM team reports the detection of a likely LONG GRB At 06:17:08.60 UT on 9 January 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250109A (trigger 758096233/250109262). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 84.43, Dec = 2.26 (J2000 degrees, equivalent to J2000 05h 37m, 02d 15'), with a statistical uncertainty of 13.52 degrees. This event is associated with EP250109a (Li et al. 2025, GCN 38864). The angle from the Fermi LAT boresight is 69.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250109262/quicklook/glg_skymap_all_bn250109262.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250109262/quicklook/glg_healpix_all_bn250109262.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250109262/quicklook/glg_lc_medres34_bn250109262.gif
GCN 38883 table
GRB_name GRB250109A
GCN_number 38883
Detection_method correction
Circular_text TITLE: GCN CIRCULAR NUMBER: 38883 SUBJECT: GRB 250109a: GMG Optical Upper Limit DATE: 25/01/10 03:05:29 GMT FROM: wangbaiting@ynao.ac.cn B.-T. Wang, R.-Z. Li, F.-F. Song, J. Mao, X.-L. Zhang and J.-M. Bai (YNAO, CAS) report: We observed the field of EP250109a (EP team, GCN 38864; Kennea et. al, GCN 38867; Kumar et. al, GCN 38868; Lipunov et. al, GCN 38871; Fermi GBM team, GCN 38873）with the GMG-2.4m telescope at the Lijiang Observatory. The observation began at 2025-01-09T13:30:50 (UT), about 7.2 hours after the trigger. No new uncataloged optical counterpart was detected within the EP/FXT error circle (GCN 38864). The preliminary photometry is as follows: ----------------------------------------------------------------------------- UT EXP(s) filter mag ----------------------------------------------------------------------------- 2025-01-09T13:30:50 1800 sdss-z >23.0 ----------------------------------------------------------------------------- The magnitudes were calibrated using nearby stars of Pan-STARRS DR1 field and without corrections for Galactic extinction. We acknowledge the staff at the Lijiang Observatory for conducting the observation.
GCN 38887 table
GRB_name GRB250109A
GCN_number 38887
Detection_method Fermi GBM Det
t_trigger 6:17:08.600 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 38887 SUBJECT: GRB 250109A: Fermi GBM Observation DATE: 25/01/10 06:40:17 GMT FROM: Utkarsh Pathak at IIT Bombay U. Pathak (IITB) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 06:17:08.60 UT on 09 January 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250109A (trigger 758096233/250109262). which was also detected by EP-WXT and EP-FXT (Li et al. 2025, GCN 38864). The Fermi GBM on-ground location is consistent with the EP-FXT position. A possible optical counterpart was also detected by SVOM/VT (Qiu et al. 2025, GCN 38872). The angle from the Fermi LAT boresight is 72 degrees. The GBM light curve consists of multiple weak spikes from a single emission episode with a duration (T90) of about 15 s (50-300 keV). The time-averaged spectrum from T0-8.2 to T0+9.2 s is best fit by a power law function. The power law index is -1.57 +/- 0.05. The event fluence (10-1000 keV) in this time interval is (1.9 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.9 s in the 10-1000 keV band is 1.3 +/- 0.2 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/"
GCN 38889 table
GRB_name GRB250109A
GCN_number 38889
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 38889 SUBJECT: EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation DATE: 25/01/10 09:43:01 GMT FROM: EP Team at NAOC/CAS R.-Z. Li (YNAO, CAS), X.-L. Chen (YNU), K. Chatterjee (YNU), Y.-L. Hua (PMO, CAS), H. Sun and Y. Liu (NAO, CAS) report on behalf of the Einstein Probe team: Since 2025-01-09 06:17:58 (UTC, T0), EP250109a (Li et al., GCN 38864) has been detectable with high significance using the WXT onboard the EP, peaking about 60 seconds post-trigger. The observed peak flux in the 0.5–4 keV range is about 2.5 x 10^-9 erg/s/cm^2. The flux then rapidly decayed to background levels within 200 seconds post-trigger. The average 0.5-4 keV WXT spectrum can be fitted with an absorbed power law with a photon index of 2.9 +/- 1.0 (with a fixed Galactic equivalent hydrogen column density of 3.04 x 10^21 cm^-2). The derived lower limit of the intrinsic column density is 5.0 (-0.3, +0.4) x 10^21 cm^-2 when the redshift is fixed at 0. The derived average unabsorbed 0.5-4 keV flux is 2.5 (-1.2, +4.6) x 10^-9 erg/s/cm^2. In addition to the follow-up observation, we conducted a follow-up observation of EP241217a using the FXT onboard the EP. The observation began at 2025-01-09T08:06:40 (UTC, 1.8 hours post-trigger), with an exposure time of approximately 4.2 ks. The average 0.5–4 keV FXT spectrum can be modeled with an absorbed power law, featuring a photon index of 1.9 (-0.7, +1.9) and a fixed Galactic equivalent hydrogen column density of 3.04 x 10^21 cm^-2). The derived lower limit of the intrinsic column density is about 3 x 10^20 cm^-2 when the redshift is fixed at 0. The estimated average unabsorbed 0.5–4 keV flux is about 4.9 (-1.2, +2.0) x 10^13 erg/s/cm^2. The detection of EP-WXT/FXT (GCN 38864) and Fermi-GBM (GCN 38873 and GCN 38887), combined with the non-detection by Swift-XRT (GCN 38867), indicates that the flux of this transient has decreased very rapidly. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with onboard X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics).
GCN 38899 table
GRB_name GRB250109A
GCN_number 38899
Detection_method Swift Det
ra 88.8070°
decl -12.4958°
Circular_text TITLE: GCN CIRCULAR NUMBER: 38899 SUBJECT: GRB 250109A / EP250109a: Swift detection of the X-ray afterglow DATE: 25/01/10 20:57:21 GMT FROM: Jamie Kennea at Penn State J. A. Kennea (PSU), P. A. Evans and K. L. Page (Leicester) report on behalf of the Swift/XRT team: Swift/XRT performed a further 3.1ks of exposure on GRB 250109A (GCN #38887) AKA EP250109a (GCN #38864), following on from a rapid 1ks observation which did not detect the counterpart (GCN #38867). Combining the two datasets, we detect one point source inside the EP WXT error circle, at the following position: RA/Dec(J2000) = 88.80698, -12.4958, which is equivalent to: RA(J2000) = 05h 55m 13.67s, Dec(J2000) = -12° 29′ 44.8″, with an estimated uncertainty of 5.8 arc-seconds radius (90% containment). This position lies 6 arc-seconds from the EP FXT position, and 1.1 arc-seconds from the SVOM-VT reported optical position (GCN #38872). Given the localization coincidence, this source is likely to be the afterglow of GRB 250109A. The combined XRT flux from this afterglow is 9(+5,-4) x 10^-14 erg/s/cm^2 (0.3-10 keV).
GCN 38900 table
GRB_name GRB250109A
GCN_number 38900
Detection_method Swift Other
ra 88.8060°
decl -12.4580°
Circular_text TITLE: GCN CIRCULAR NUMBER: 38900 SUBJECT: GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst DATE: 25/01/10 21:06:43 GMT FROM: Jimmy DeLaunay at Penn State James DeLaunay (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (Caltech), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT did not localize GRB 250109A onboard (T0: 2025-01-09T06:17:08.60 UTC, Fermi trig 758096233) The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 12.1 in a 16.384 s analysis time bin, starting at T0 - 8.192 s. Using the NITRATES analysis, parameter estimation was performed to obtain the localization of this burst in the form of a HEALPIX Multi-Order Coverage (MOC) skymap. This localization accounts for both statistical and systematic errors. More details in the creation and calibration of these maps will soon be published (DeLaunay et al. 2025. in prep) The 90% credible area is 0.06 deg2 and the 50% credible area is ~0.01 deg2. The integrated probability inside the coded field of view is 98%. 55% of the NITRATES localization probability is contained within a 0.1 deg radius circle around the maximum probability position. The majority of the remaining probability is contained within similarly sized peaks of probability across the BAT coded field of view. The maximum probability position of the NITRATES skymap is, RA, Dec = 88.806, -12.458 deg which is RA(J2000) = 05h 55m 13.4s Dec(J2000) = -12d 27′ 28.8″ The NITRATES skymap is consistent with the Fermi localization reported in the final position notice (GCN 38873). It is also consistent with the position of the X-ray transient EP250109a (GCN 38864, GCN 38889), with the position lying on the 0.28 credible region contour. The spatial and temporal coincidence of GRB 250109A and EP250109a make it very likely that they originate from the same cosmic event. A plot of the probability skymap can be viewed here: [skymap_plot](https://guano.swift.psu.edu/trigger_report?id=758096263/#:~:text=Probability%20Skymap) The probability skymap file can be downloaded from the link here [skymap_fits_file](https://guano.swift.psu.edu/files/758096263/0_n_PROBMAP) Instructions on how to read and manipulate this map can be found here: https://guano.swift.psu.edu/documentation More details about this burst can be found on the trigger report page here: https://guano.swift.psu.edu/trigger_report?id=758096263 GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/
GCN 38901 table
GRB_name GRB250109A
GCN_number 38901
Detection_method Fermi GBM Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 38901 SUBJECT: GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations DATE: 25/01/10 22:51:16 GMT FROM: Moskvitin Alexander at SAO RAS A. Moskvitin, O. Spiridonova (SAO), A. Pozanenko (IKI), N. Kapitanov (INASAN), N. Pankov (IKI, HSE) report on behalf of larger GRB follow-up GRB IKI FuN collaboration. We observed the field of the GRB 250109A / EP250109a (Li et al., GCN 38864; Fermi GBM team, GCN 38873) with two telescopes, 2-m Zeiss-2000 of Terskol observatory and 1-m Zeiss-1000 of SAO RAS on January 9. We obtained 100 x 60 sec. images R band on Jan. 09, 19:36:42--21:28:07 UT with 2-m telescope and 11 x 300 sec. images in Rc band on Jan. 09, 21:12:33--22:23:56 UT with 1-m telescope. In the stacked image of Zeiss-2000 observation we marginally detect the afterglow candidate (Qiu et al., GCN 38872) within XRT error circle (Kennea et al., GCN 38899). Photometry of the staked images is the following: Date UT start t-T0, h(mid) Filter Exp.,s OT, err, UL(3sigma) Telescope 25-01-09 19:36:42 14.254 R 100 x 60 22.5 0.4 22.4 Zeiss-2000 25-01-09 21:12:33 15.518 Rc 11 x 300 n/d n/d 22.2 Zeiss-1000 The photometry is based on nearby stars of the PS1 catalog (Lupton 2005 transformations) and not corrected for the Galactic extinction.
GCN 38915 table
GRB_name GRB250109A
GCN_number 38915
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 38915 SUBJECT: GRB 250109A / EP250109a: Mephisto optical upper limits DATE: 25/01/12 04:25:54 GMT FROM: Chenxu Liu at Mephisto Team Xingzhu Zou, Chenxu Liu, Guowang Du, Brajesh Kumar, Tao Wang, Edoardo Lagioia, Yuan Fang, Xinlei Chen, Yu Pan (all SWIFAR, YNU), Xuhui Han, Pinpin Zhang, Liping Xin, Chao Wu (all NAOC), Xiangkun Liu, Xiaowei Liu (all SWIFAR, YNU) report on behalf of the Mephisto Team: The Mephisto team observed the field of the GRB 250109A / EP250109a (EP Team , GCN 38864, GCN 38889; Fermi GBM team, GCN 38873, GCN 38887; the Swift XRT team, GCN 38867, GCN 38899; James DeLaunay et al., GCN 38900; A. Moskvitin et al. GCN 38901; the SVOM team, GCN 38904) with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Simultaneous uvgriz band photometric observations were conducted starting from 12:27:02 2025-01-09 UT (6.15 hr after the EP-WXT trigger) under fair observational conditions. Several frames with different exposure time were taken. No new uncatalogued optical sources were detected within the EP-WXT error circle in our stacked images of uvgriz bands. The preliminary photometry and 3 sigma upper limits are below. Start_Time(UT) | Band | Exp(s) | LimMag (AB) --------------------|------|--------|------------ 2025-01-09T12:27:02 | u | 180*2 | >20.02 2025-01-09T12:34:13 | v | 180*2 | >20.15 2025-01-09T12:27:03 | g | 50*6 | >20.64 2025-01-09T12:34:14 | r | 50*6 | >20.73 2025-01-09T12:27:02 | i | 79*4 | >20.14 2025-01-09T12:34:14 | z | 79*4 | >19.19 ------------------------------------------------------------------------------------------------- Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6-m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21. -------------------------------------------------------------------------------------------------
GCN 38920 table
GRB_name GRB250109A
GCN_number 38920
Detection_method Fermi GBM Det
t_trigger 6:17:11.300 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 38920 SUBJECT: GRB 250109A / EP250109a: GRBAlpha detection DATE: 25/01/13 11:54:38 GMT FROM: Andras Pal at Konkoly Observatory A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, M. Kolar, N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 250107D (EP/WXT detection: GCN 38864; Fermi/GBM detection: GCN 38873; Swift/BAT-GUANO detection: GCN 38900) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2025-01-09 06:17:11.3 UTC. The T90 duration measured by GRBAlpha is 0.5 s and the overall significance during T90 reaches 6.6 sigma in the ~120-400 keV band. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB250109A_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.