Gamma-ray Burst 211225B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 25 Dec 21 13:13:07 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1090853,   Seg_Num: 0
GRB_RA:          258.568d {+17h 14m 16s} (J2000),
                 258.813d {+17h 15m 15s} (current),
                 258.013d {+17h 12m 03s} (1950)
GRB_DEC:         +17.262d {+17d 15' 45"} (J2000),
                 +17.238d {+17d 14' 19"} (current),
                 +17.319d {+17d 19' 08"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       9849 [cnts]    Image_Peak=347 [image_cnts]
TRIGGER_DUR:     4.096 [sec] 
TRIGGER_INDEX:   307     E_range: 50-350 keV
BKG_INTEN:       73926 [cnts]
BKG_TIME:        47483.68 SOD {13:11:23.68} UT
BKG_DUR:         40 [sec]
GRB_DATE:        19573 TJD;   359 DOY;   21/12/25
GRB_TIME:        47539.10 SOD {13:12:19.10} UT
GRB_PHI:         -113.51 [deg]
GRB_THETA:         4.09 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.78 [sigma]
IMAGE_SIGNIF:    9.17 [sigma]
MERIT_PARAMS:     +1  +0  +0  +2  +3  +0 -100  +0 -72  +0 
SUN_POSTN:       274.32d {+18h 17m 17s}  -23.38d {-23d 22' 34"}
SUN_DIST:         43.35 [deg]   Sun_angle= 1.0 [hr] (West of Sun)
MOON_POSTN:      168.40d {+11h 13m 35s}  +10.49d {+10d 29' 35"}
MOON_DIST:        87.30 [deg]
MOON_ILLUM:      66 [%]
GAL_COORDS:       38.51, 29.01 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      255.67, 40.13 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 351.01,-5.10 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 25 Dec 21 13:16:04 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1090853,   Seg_Num: 0
GRB_RA:          258.568d {+17h 14m 16s} (J2000),
                 258.813d {+17h 15m 15s} (current),
                 258.013d {+17h 12m 03s} (1950)
GRB_DEC:         +17.262d {+17d 15' 45"} (J2000),
                 +17.238d {+17d 14' 19"} (current),
                 +17.319d {+17d 19' 08"} (1950)
GRB_DATE:        19573 TJD;   359 DOY;   21/12/25
GRB_TIME:        47539.10 SOD {13:12:19.10} UT
TRIGGER_INDEX:   307
GRB_PHI:         -113.51 [deg]
GRB_THETA:         4.09 [deg]
DELTA_TIME:      58.00 [sec]
TRIGGER_DUR:     4.096 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     13.78 [sigma]
IMAGE_SIGNIF:    9.17 [sigma]
LC_URL:          sw01090853000msb.lc
SUN_POSTN:       274.32d {+18h 17m 18s}  -23.38d {-23d 22' 34"}
SUN_DIST:         43.35 [deg]   Sun_angle= 1.0 [hr] (West of Sun)
MOON_POSTN:      168.42d {+11h 13m 41s}  +10.48d {+10d 28' 56"}
MOON_DIST:        87.28 [deg]
MOON_ILLUM:      66 [%]
GAL_COORDS:       38.51, 29.01 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      255.67, 40.13 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 351.01,-5.10 [deg].  
COMMENTS:        The 2nd packet (of 3) was missing in the lightcurve data stream.

GCN Circular #31305
K. L. Page (U Leicester), S. D. Barthelmy (GSFC), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (U Tampa), F. E. Marshall (NASA/GSFC), T. M. Parsotan (GSFC/UMBC/CRESSTII) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team:
At 13:12:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 211225B (trigger=1090853). Swift did not slew because of Sun constraint. The BAT on-board calculated location is RA, Dec 258.568, +17.262 which is
```
   RA(J2000)  =  17h 14m 16s
   Dec(J2000) = +17d 15' 45"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is missing data from T+8 to T+108 sec, but there is an increase of 1400 event/sec at ~T+5 sec.
Due to a Sun observing constraint, Swift cannot slew to the BAT position until 23:13 UT on 2022 January 02. There will thus be no XRT or UVOT data for this trigger before this time.
Burst Advocate for this burst is K. L. Page (kimlpage1978 AT gmail.com). 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 Circular #31308
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, T.Pogrosheva, E.Minkina, A.Chasovnikov, V.Topolev, V.Grinshpun, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
B.L.Carrasco, J.R.Valdes,V.Chavushyan, C.J.Martinez, V.M.Patino Alvarez, M.L.H.Rodriguez (INAOE, OAGH)
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)
MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 211225B ( K. L. Page et al., GCN 31305) errorbox 50155 sec after notice time and 50206 sec after trigger time at 2021-12-26 03:09:05 UT, with upper limit up to 16.5 mag. Observations started at twilight. The observations began at zenith distance = 67 deg. The sun altitude is -16.1 deg.
The galactic latitude b = 28 deg., longitude l = 39 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1826927
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   50296 |   MASTER-Kislovodsk |   C |   180 | 16.5 |        
   50296 |   MASTER-Kislovodsk |   C |   180 | 15.5 |        
   51607 |   MASTER-Kislovodsk |   C |   180 | 13.3 |        
   51607 |   MASTER-Kislovodsk |   C |   180 | 13.2 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #31312
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 211225B (trigger #1090853) (Page et al., GCN Circ. 31305). The BAT ground-calculated position is RA, Dec = 258.545, 17.277 deg which is
```
   RA(J2000)  =  17h 14m 10.9s
   Dec(J2000) = +17d 16' 37.2"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve shows a multi-peaked structure that starts at ~T-25 s and likely lasts beyond ~T+152 s when the burst went out of the BAT field of view. The main peak occurs at ~T+50 s. T90 (15-350 keV) estimated from the available data when the burst was inside the BAT field of view is 121.54 +- 2.94 sec (estimated error including systematics).
The time-averaged spectrum from T-24.78 to T+139.82 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.31 +- 0.14, and Epeak of 139.9 +- 51.5 keV (chi squared 52.29 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.5 +- 0.03 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+50.19 sec in the 15-150 keV band is 6.1 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.59 +- 0.03 (chi squared 64.87 for 57 d.o.f.). All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1090853/BA/
GCN Circular #31332
N. Cannady (GSFC/UMBC), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration:
The long GRB 211225B (Swift detection and refined analysis: Page et al., GCN Circ. 31305, Laha et al., GCN Circ. 31312; https://gcn.gsfc.nasa.gov/other/211225B.gcn3) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 13:13:05.685 UTC on 25 December 2021 while exiting the radiation belts. The burst signal was seen by all CGBM detectors. Because of a problem in one of the ground alert processing script, the GCN notice was not distributed automatically for this event.
The burst light curve shows a single pulse which starts at T-2.2 sec, peaks at T+3.6 sec and ends at T+42.0 sec. The extended tail is seen in the low energy channels as long as a hint of the preceding emission (which is clearly seen in the Swift-BAT light curve: Laha et al. GCN Circ. 31312). The T90 and T50 durations measured by the SGM data are 32.7 +- 8.1 sec and 14.6 +- 1.9 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1324473176/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.

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Jochen Greiner, last update: 29-Dec-2021 [Disclaimer]