Gamma-ray Burst 250211B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Tue 11 Feb 25 21:28:04 UT
NOTICE_TYPE:    INTEGRAL Weak
TRIGGER_NUM:    11044,   Sub_Num: 0
GRB_RA:         276.3582d {+18h 25m 26s} (J2000),
                276.7667d {+18h 27m 04s} (current),
                275.5447d {+18h 22m 11s} (1950)
GRB_DEC:        -31.9789d {-31d 58' 43"} (J2000),
                -31.9629d {-31d 57' 45"} (current),
                -32.0077d {-32d 00' 27"} (1950)
GRB_ERROR:      3.53 [arcmin, radius, statistical only]
GRB_INTEN:      6.93 [sigma]
GRB_TIME:       77265.77 SOD {21:27:45.77} UT
GRB_DATE:       20717 TJD;    42 DOY;   25/02/11
SC_RA:          268.54 [deg] (J2000)
SC_DEC:         -27.65 [deg] (J2000)
SUN_POSTN:      325.74d {+21h 42m 58s}  -13.71d {-13d 42' 45"}
SUN_DIST:        48.20 [deg]   Sun_angle= 3.3 [hr] (West of Sun)
MOON_POSTN:     138.83d {+09h 15m 20s}  +19.52d {+19d 30' 56"}
MOON_DIST:      140.40 [deg]
GAL_COORDS:       1.50, -8.98 [deg] galactic lon,lat of the burst
ECL_COORDS:     275.45, -8.66 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates -- this is the weak/subthreshold trigger
+notice.  
COMMENTS:       This notice may or may not be followed by a Wakeup/Refined/Offline
+notice.  
COMMENTS:       Time_Scale=25.0000 and Time_Error=25.0000.  
COMMENTS:       Possibly real GRB event (WEAK detection)

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Tue 11 Feb 25 21:28:09 UT
NOTICE_TYPE:    INTEGRAL Wakeup
TRIGGER_NUM:    11044,   Sub_Num: 1
GRB_RA:         276.3895d {+18h 25m 33s} (J2000),
                276.7979d {+18h 27m 11s} (current),
                275.5761d {+18h 22m 18s} (1950)
GRB_DEC:        -31.9603d {-31d 57' 36"} (J2000),
                -31.9442d {-31d 56' 38"} (current),
                -31.9893d {-31d 59' 20"} (1950)
GRB_ERROR:      3.20 [arcmin, radius, statistical only]
GRB_INTEN:      8.67 [sigma]
GRB_TIME:       77277.77 SOD {21:27:57.77} UT
GRB_DATE:       20717 TJD;    42 DOY;   25/02/11
SC_RA:          268.54 [deg] (J2000)
SC_DEC:         -27.65 [deg] (J2000)
SUN_POSTN:      325.74d {+21h 42m 58s}  -13.71d {-13d 42' 45"}
SUN_DIST:        48.17 [deg]   Sun_angle= 3.3 [hr] (West of Sun)
MOON_POSTN:     138.83d {+09h 15m 20s}  +19.52d {+19d 30' 55"}
MOON_DIST:      140.43 [deg]
GAL_COORDS:       1.53, -8.99 [deg] galactic lon,lat of the burst
ECL_COORDS:     275.48, -8.64 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=10.0000 and Time_Error=10.0000.  
COMMENTS:       Possibly real GRB event

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Tue 11 Feb 25 21:31:09 UT
NOTICE_TYPE:    INTEGRAL Refined
TRIGGER_NUM:    11044,   Sub_Num: 2
GRB_RA:         276.3702d {+18h 25m 29s} (J2000),
                276.7787d {+18h 27m 07s} (current),
                275.5568d {+18h 22m 14s} (1950)
GRB_DEC:        -31.9745d {-31d 58' 27"} (J2000),
                -31.9585d {-31d 57' 30"} (current),
                -32.0034d {-32d 00' 11"} (1950)
GRB_ERROR:      2.88 [arcmin, radius, statistical only]
GRB_INTEN:      11.96 [sigma]
GRB_TIME:       77290.77 SOD {21:28:10.77} UT
GRB_DATE:       20717 TJD;    42 DOY;   25/02/11
SC_RA:          268.54 [deg] (J2000)
SC_DEC:         -27.65 [deg] (J2000)
SUN_POSTN:      325.74d {+21h 42m 59s}  -13.71d {-13d 42' 42"}
SUN_DIST:        48.20 [deg]   Sun_angle= 3.3 [hr] (West of Sun)
MOON_POSTN:     138.86d {+09h 15m 26s}  +19.51d {+19d 30' 20"}
MOON_DIST:      140.38 [deg]
GAL_COORDS:       1.51, -8.98 [deg] galactic lon,lat of the burst
ECL_COORDS:     275.46, -8.66 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=50.0000 and Time_Error=50.0000.  
COMMENTS:       Possibly real GRB event

GCN Circular #39295
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Integral GRB250211.89 (trigger No 11044,18h 25m 33.49s , -31d 57m 36.2s, R=0.0533333) errorbox 12195 sec after notice time and 12210 sec after trigger time at 2025-02-12 00:51:28 UT, with upper limit up to 16.7 mag. The observations began at zenith distance = 81 deg. The sun altitude is -36.1 deg.
The galactic latitude b = -10 deg., longitude l = 2 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2775663
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   12300 |         MASTER-SAAO |   C |   180 | 16.1 |        
   12480 |         MASTER-SAAO |   C |   540 | 15.8 |  Coadd 
   12500 |         MASTER-SAAO |   C |   180 | 16.2 |        
   12699 |         MASTER-SAAO |   C |   180 | 16.4 |        
   12904 |         MASTER-SAAO |   C |   180 | 16.4 |        
   13103 |         MASTER-SAAO |   C |   180 | 16.5 |        
   13302 |         MASTER-SAAO |   C |   180 | 16.6 |        
   13502 |         MASTER-SAAO |   C |   180 | 16.7 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #39296
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the SVOM/ECLAIRs GRB 250211A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021776
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 SVOM/ECLAIRs 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 #39298
S.Mereghetti (INAF, IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC, Versoix) and J.Borkowski (CAMK, Torun) report:
a gamma ray burst lasting about 60 s has been detected by IBAS in the IBIS/ISGRI data at 21:27:10 UT of 2025 February 11.
The refined coordinates (J2000) are:
```
R.A.=    276.3784 deg
DEC.=   -31.9655  deg
```
with an uncertainty of 2 arcmin (90% c.l.).
The burst had a peak flux of about 0.2 ph/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 4e-7 erg/cmq.
A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html

GCN NOTICE

TITLE:          GCN/INTEGRAL NOTICE
NOTICE_DATE:    Wed 12 Feb 25 07:47:15 UT
NOTICE_TYPE:    INTEGRAL Offline
TRIGGER_NUM:    11044,   Sub_Num: 3
GRB_RA:         276.3783d {+18h 25m 31s} (J2000),
                276.7867d {+18h 27m 09s} (current),
                275.5649d {+18h 22m 16s} (1950)
GRB_DEC:        -31.9653d {-31d 57' 54"} (J2000),
                -31.9493d {-31d 56' 56"} (current),
                -31.9943d {-31d 59' 38"} (1950)
GRB_ERROR:      2.00 [arcmin, radius, statistical only]
GRB_INTEN:      11.96 [sigma]
GRB_TIME:       77290.77 SOD {21:28:10.77} UT
GRB_DATE:       20717 TJD;    42 DOY;   25/02/11
SC_RA:          268.54 [deg] (J2000)
SC_DEC:         -27.65 [deg] (J2000)
SUN_POSTN:      326.17d {+21h 44m 40s}  -13.57d {-13d 34' 09"}
SUN_DIST:        48.61 [deg]   Sun_angle= 3.3 [hr] (West of Sun)
MOON_POSTN:     144.20d {+09h 36m 47s}  +17.43d {+17d 25' 54"}
MOON_DIST:      134.94 [deg]
GAL_COORDS:       1.52, -8.99 [deg] galactic lon,lat of the burst
ECL_COORDS:     275.47, -8.65 [deg] ecliptic lon,lat of the burst
COMMENTS:       INTEGRAL GRB Coordinates.  
COMMENTS:       Time_Scale=50.0000 and Time_Error=50.0000.  
COMMENTS:       refined_coordinates_after_offline_analysis

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Jochen Greiner, last update: 12-Feb-2025 [Disclaimer]