Gamma-ray Burst 250107A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 07 Jan 25 05:02:53 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     757918955
GRB_RA:          301.650d {+20h 06m 36s} (J2000),
                 301.819d {+20h 07m 17s} (current),
                 301.311d {+20h 05m 15s} (1950)
GRB_DEC:         +51.867d {+51d 52' 00"} (J2000),
                 +51.940d {+51d 56' 24"} (current),
                 +51.721d {+51d 43' 17"} (1950)
GRB_ERROR:       9.02 [deg radius, statistical plus systematic]
GRB_INTEN:       155 [cnts/sec]
DATA_SIGNIF:     11.60 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        20682 TJD;     7 DOY;   25/01/07
GRB_TIME:        18150.29 SOD {05:02:30.29} UT
GRB_PHI:          40.00 [deg]
GRB_THETA:        15.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      1.01
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       1,1,0, 0,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       288.58d {+19h 14m 20s}  -22.34d {-22d 20' 09"}
SUN_DIST:         75.18 [deg]   Sun_angle= -0.9 [hr] (East of Sun)
MOON_POSTN:       17.78d {+01h 11m 07s}   +9.40d {+09d 24' 08"}
MOON_DIST:        73.97 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       86.46, 10.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      332.40, 68.55 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_lc_medres34_bn250107210.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 121.63,22.27 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 07 Jan 25 05:03:31 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      0
TRIGGER_NUM:     757918955
GRB_RA:          309.510d {+20h 38m 02s} (J2000),
                 309.737d {+20h 38m 57s} (current),
                 309.057d {+20h 36m 14s} (1950)
GRB_DEC:         +41.060d {+41d 03' 36"} (J2000),
                 +41.149d {+41d 08' 56"} (current),
                 +40.884d {+40d 53' 01"} (1950)
GRB_ERROR:       4.82 [deg radius, statistical only]
DATA_SIGNIF:     16.70 [sigma]
DATA_INTERVAL:   6.144 [sec]
GRB_DATE:        20682 TJD;     7 DOY;   25/01/07
GRB_TIME:        18150.29 SOD {05:02:30.29} UT
GRB_PHI:          40.00 [deg]
GRB_THETA:        27.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       288.58d {+19h 14m 20s}  -22.34d {-22d 20' 09"}
SUN_DIST:         66.45 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       17.79d {+01h 11m 09s}   +9.40d {+09d 24' 18"}
MOON_DIST:        67.34 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.56, -0.09 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      330.41, 56.52 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_lc_medres34_bn250107210.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_757918955.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 07 Jan 25 05:03:40 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      1
TRIGGER_NUM:     757918955
GRB_RA:          311.880d {+20h 47m 31s} (J2000),
                 312.112d {+20h 48m 27s} (current),
                 311.417d {+20h 45m 40s} (1950)
GRB_DEC:         +40.630d {+40d 37' 48"} (J2000),
                 +40.723d {+40d 43' 23"} (current),
                 +40.445d {+40d 26' 42"} (1950)
GRB_ERROR:       2.95 [deg radius, statistical only]
DATA_SIGNIF:     21.40 [sigma]
DATA_INTERVAL:   10.240 [sec]
GRB_DATE:        20682 TJD;     7 DOY;   25/01/07
GRB_TIME:        18150.29 SOD {05:02:30.29} UT
GRB_PHI:          43.00 [deg]
GRB_THETA:        28.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       288.58d {+19h 14m 20s}  -22.34d {-22d 20' 09"}
SUN_DIST:         66.75 [deg]   Sun_angle= -1.6 [hr] (East of Sun)
MOON_POSTN:       17.79d {+01h 11m 09s}   +9.41d {+09d 24' 20"}
MOON_DIST:        65.51 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       81.33, -1.76 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      332.89, 55.31 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_lc_medres34_bn250107210.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_757918955.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 07 Jan 25 05:03:58 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      3
TRIGGER_NUM:     757918955
GRB_RA:          308.530d {+20h 34m 07s} (J2000),
                 308.738d {+20h 34m 57s} (current),
                 308.115d {+20h 32m 28s} (1950)
GRB_DEC:         +45.950d {+45d 57' 00"} (J2000),
                 +46.037d {+46d 02' 13"} (current),
                 +45.777d {+45d 46' 39"} (1950)
GRB_ERROR:       2.12 [deg radius, statistical only]
DATA_SIGNIF:     23.90 [sigma]
DATA_INTERVAL:   17.408 [sec]
GRB_DATE:        20682 TJD;     7 DOY;   25/01/07
GRB_TIME:        18150.29 SOD {05:02:30.29} UT
GRB_PHI:          43.00 [deg]
GRB_THETA:        22.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       288.58d {+19h 14m 20s}  -22.34d {-22d 20' 09"}
SUN_DIST:         70.78 [deg]   Sun_angle= -1.3 [hr] (East of Sun)
MOON_POSTN:       17.79d {+01h 11m 10s}   +9.41d {+09d 24' 25"}
MOON_DIST:        68.75 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       84.05,  3.42 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      333.80, 61.14 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_lc_medres34_bn250107210.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_757918955.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 07 Jan 25 05:02:53 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     757918955
GRB_RA:          305.180d {+20h 20m 43s} (J2000),
                 305.361d {+20h 21m 27s} (current),
                 304.819d {+20h 19m 16s} (1950)
GRB_DEC:         +50.840d {+50d 50' 24"} (J2000),
                 +50.920d {+50d 55' 14"} (current),
                 +50.680d {+50d 40' 49"} (1950)
GRB_ERROR:       11.23 [deg radius, statistical only]
DATA_SIGNIF:     13.40 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        20682 TJD;     7 DOY;   25/01/07
GRB_TIME:        18150.29 SOD {05:02:30.29} UT
GRB_PHI:          45.00 [deg]
GRB_THETA:        17.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       288.58d {+19h 14m 20s}  -22.34d {-22d 20' 09"}
SUN_DIST:         74.74 [deg]   Sun_angle= -1.1 [hr] (East of Sun)
MOON_POSTN:       17.78d {+01h 11m 07s}   +9.40d {+09d 24' 08"}
MOON_DIST:        71.66 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       86.78,  8.05 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      335.59, 66.45 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_lc_medres34_bn250107210.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_757918955.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 07 Jan 25 05:11:49 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     757918955
GRB_RA:          309.400d {+20h 37m 36s} (J2000),
                 309.612d {+20h 38m 27s} (current),
                 308.977d {+20h 35m 55s} (1950)
GRB_DEC:         +45.330d {+45d 19' 48"} (J2000),
                 +45.419d {+45d 25' 07"} (current),
                 +45.154d {+45d 09' 15"} (1950)
GRB_ERROR:       3.49 [deg radius, statistical only]
GRB_DATE:        20682 TJD;     7 DOY;   25/01/07
GRB_TIME:        18150.29 SOD {05:02:30.29} UT
GRB_PHI:          44.00 [deg]
GRB_THETA:        23.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       288.59d {+19h 14m 22s}  -22.34d {-22d 20' 06"}
SUN_DIST:         70.40 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       17.86d {+01h 11m 26s}   +9.44d {+09d 26' 32"}
MOON_DIST:        68.07 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       83.91,  2.56 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      334.22, 60.29 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_lc_medres34_bn250107210.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_locplot_all_bn250107210.png
COMMENTS:        Fermi-GBM Final Position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
COMMENTS:        This notice was generated completely by automated pipeline processing.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.

GCN Circular #38836
The Fermi GBM team reports the detection of a likely LONG GRB
At 05:02:30 UT on 7 Jan 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250107A (trigger 757918955.285842 / 250107210).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 309.4, Dec = 45.3 (J2000 degrees, equivalent to J2000 20h 37m, 45d 17'), with a statistical uncertainty of 3.5 degrees.
The angle from the Fermi LAT boresight is 23.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_skymap_all_bn250107210.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/bn250107210/quicklook/glg_healpix_all_bn250107210.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250107210/quicklook/glg_lc_medres34_bn250107210.gif
GCN Circular #38840
James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 250107A onboard (T0: 2025-01-07T05:02:30.29 UTC, Fermi Trig 757918955).
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), detects the burst in a 16.384 s analysis time bin starting at T0 - 0.0 s with a sqrt(TS) of 21.8. An arcminute localization is found with DeltaLLHOut of 19.3 and a DeltaLLHPeak of 10.5.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.
The BAT position is RA, Dec = 302.52, 45.564 deg which is
```
   RA(J2000)  = 20h 10m 04.80s
   Dec(J2000) = 45d 33' 50.4″
```
with an estimated uncertainty of 4 arcmin radius.
XRT and UVOT follow-up has been requested. Results of follow-up observations will be reported in future circulars.
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 Circular #38841
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Swift/BAT GRB 250107A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021754
Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Swift/BAT event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular #38844
O. Mukherjee (USRA), A. Myers (NPP/GSFC) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 05:02:30.29 UT on 07 January 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250107A (trigger 757918955/250107210). which was also detected by Swift/BAT-GUANO (DeLaunay et al. 2025, GCN 38840). The Fermi GBM on-ground location is consistent with the Swift/BAT-GUANO position.
The angle from the Fermi LAT boresight is 21 degrees.
The GBM light curve consists of a single emission episode with multiple peaks with a duration (T90) of about 53 s (50-300 keV). The time-averaged spectrum from T0-2.8 to T0+35.1 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.22 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 390 +/- 80 keV.
The event fluence (10-1000 keV) in this time interval is (7.8 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6.85 s in the 10-1000 keV band is 3.6 +/- 0.24 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 Circular #38922
A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration.
The long-duration GRB 250107A (Fermi/GBM detection: GCN 38836; Swift/BAT-GUANO detection: GCN 38840; INTEGRAL/SPI-ACS peak detection at 2025-01-07 ~05:02:35 UTC) was detected by the GRB detector on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).
The data acquisition was performed by the GRB detector unit no. 1. The detection was confirmed at the peak time 2025-01-07 05:02:34 UTC. The T90 duration is 21 s and the significance during T90 reaches 9 sigma.
The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB250107A_GCN_VZLUSAT2.pdf
All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/ The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral.

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