GRB 211225B
GCN Circular 31305
Subject
GRB 211225B: Swift detection of a burst
Date
2021-12-25T13:27:21Z (3 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
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
Subject
Swift GRB 211225B: Global MASTER-Net observations report
Date
2021-12-26T06:56:11Z (3 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
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
Subject
GRB 211225B: Swift-BAT refined analysis
Date
2021-12-27T00:17:54Z (3 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
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
Subject
GRB 211225B: CALET Gamma-Ray Burst Monitor detection
Date
2021-12-29T07:10:45Z (3 years ago)
From
Valentin Pal'shin at AGU <val@phys.aoyama.ac.jp>
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.