GRB 221201A
GCN Circular 32997
Subject
GRB 221201A: Fermi GBM Final Real-time Localization
Date
2022-12-01T12:35:06Z (3 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 12:24:45 UT on 1 Dec 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 221201A (trigger 691590290.314944 / 221201517).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 263.4, Dec = -70.4 (J2000 degrees, equivalent to J2000 17h 33m, -70d 24'), with a statistical uncertainty of 1.5 degrees.
The angle from the Fermi LAT boresight is 130.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221201517/quicklook/glg_skymap_all_bn221201517.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221201517/quicklook/glg_healpix_all_bn221201517.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn221201517/quicklook/glg_lc_medres34_bn221201517.gif
GCN Circular 32998
Subject
GRB 221201A: Swift detection of a burst
Date
2022-12-01T12:47:26Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
E. Troja (NASA/GSFC/UMCP), M. G. Bernardini (INAF-OAB),
R. Brivio (INAF-OAB), P. D'Avanzo (INAF-OAB), S. Dichiara (PSU),
P. A. Evans (U Leicester), R. A. J. Eyles-Ferris (U Leicester),
M. Ferro (INAF-OAB), J.D. Gropp (PSU), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB),
K. L. Page (U Leicester), D. M. Palmer (LANL),
C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB) and
B. Sbarufatti (INAF-OAB) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 12:25:05 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 221201A (trigger=1142847). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 266.933, -68.260 which is
RA(J2000) = 17h 47m 44s
Dec(J2000) = -68d 15' 33"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single peak
structure with a duration of about 40 sec. The peak count rate
was ~5000 counts/sec (15-350 keV), at ~-13 sec after the trigger.
(The peak occurred during a pre-planned slew and the nominal trigger
time is the start of the first post-slew image.)
The XRT began observing the field at 12:27:56.2 UT, 170.6 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 266.9228, -68.2510 which is equivalent to:
RA(J2000) = 17h 47m 41.47s
Dec(J2000) = -68d 15' 03.6"
with an uncertainty of 5.7 arcseconds (radius, 90% containment). This
location is 35 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.
The initial flux in the 0.1 s image was 2.34e-08 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 202 seconds with the U filter starting
337 seconds after the BAT trigger. No credible afterglow candidate has been
found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the
XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. Data
from the list of sources generated on-board are not available at this time. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.065.
Burst Advocate for this burst is E. Troja (nora.gsfc 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 33000
Subject
Swift GRB 221201A: Global MASTER-Net observations report
Date
2022-12-01T18:36:55Z (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, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(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),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
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 Swift GRB 221201A ( E. Troja et al., GCN 32998) errorbox 21718 sec after notice time and 21801 sec after trigger time at 2022-12-01 18:28:26 UT, with upper limit up to 16.2 mag. Observations started at twilight. The observations began at zenith distance = 64 deg. The sun altitude is -11.5 deg.
The galactic latitude b = -20 deg., longitude l = 325 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2172144
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
21891 | MASTER-SAAO | C | 180 | 16.2 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 33001
Subject
GRB 221201A: Enhanced Swift-XRT position
Date
2022-12-01T19:58:22Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1465 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 221201A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 266.92463, -68.24884 which is equivalent
to:
RA (J2000): 17h 47m 41.91s
Dec (J2000): -68d 14' 55.8"
with an uncertainty of 2.1 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
GCN Circular 33002
Subject
GRB 221201A: Swift-XRT refined Analysis
Date
2022-12-01T22:31:42Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), T.
Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Tohuvavohu (U.
Toronto), D.N. Burrows (PSU) and E. Troja report on behalf of the
Swift-XRT team:
We have analysed 6.4 ks of XRT data for GRB 221201A (Troja et al. GCN
Circ. 32998), from 159 s to 30.1 ks after the BAT trigger. The data
comprise 375 s in Windowed Timing (WT) mode (the first 10 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 33001).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=5.33 (+0.28, -0.27). At T+214 s the decay
steepens to an alpha of 6.37 (+0.24, -0.17) before breaking again at
T+368 s to a final decay with index alpha=0.907 (+/-0.026).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 3.18 (+/-0.06). The
best-fitting absorption column is 3.41 (+0.17, -0.16) x 10^21 cm^-2,
in excess of the Galactic value of 7.5 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.93 (+0.13, -0.12)
and a best-fitting absorption column of 2.7 (+/-0.5) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.8 x 10^-11 (5.3 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.7 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 7.5 x 10^20 cm^-2
Excess significance: 6.5 sigma
Photon index: 1.93 (+0.13, -0.12)
If the light curve continues to decay with a power-law decay index of
0.907, the count rate at T+24 hours will be 0.049 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.9 x
10^-12 (2.6 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01142847.
This circular is an official product of the Swift-XRT team.
GCN Circular 33003
Subject
GCN: GRB 221201A: Swift/UVOT Upper Limits
Date
2022-12-02T13:27:29Z (3 years ago)
From
Samantha Oates at MSSL <samantha.oates@alumni.ucl.ac.uk>
S. R. Oates (U.Birmingham) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 221201A
179 s after the BAT trigger (Troja et al., GCN Circ. 32998).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 33001)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 179 329 147 >20.1
white 179 1970 225 >20.2
v 1479 2020 78 >17.8
b 1404 2107 85 >18.8
u 337 2094 277 >19.2
w1 1529 2069 78 >18.4
m2 1504 2045 78 >18.5
w2 1454 1996 78 >18.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.066 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 33011
Subject
GRB 221201A: Fermi GBM observation
Date
2022-12-03T08:49:40Z (3 years ago)
From
Christian Malacaria at ISSI <cmalacaria.astro@gmail.com>
GRB 221201A: Fermi GBM observation
C. Malacaria (ISSI) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 12:24:45.31 UT on 01 December 2022, the Fermi Gamma-Ray Burst
Monitor (GBM)
triggered and located GRB 221201A (trigger 691590290 / 221201517).
This event was also observed by Swift/BAT and�� Swift/XRT (GCN 32998).
The GBM position is reported in the Fermi-GBM Final on-ground
Localization (GCN 32997)
and is consistent with the Swift position.
The angle from the Fermi LAT boresight is 125 degrees.
The GBM light curve shows a single pulse with a duration (T90) of about
29 s (50-300 keV).
The time-averaged spectrum from T0-0 s to T0+15 s is best fit by a Band
function
with Epeak = 144 +/- 7 keV, alpha = -0.57 +/- 0.07, and beta = -2.5 +/- 0.1
The event fluence (10-1000 keV) in this time interval is (1.59 +/-
0.03)E-05 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+6.8 s in the
10-1000 keV band
is 20.5 +/- 0.6 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 33013
Subject
GRB 221201A: Swift-BAT refined analysis
Date
2022-12-03T15:01:15Z (3 years ago)
From
Tyler Parsotan at UMBC/GSFC/CRESST II <parsotat@umbc.edu>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF),, S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa),, C. B. Markwardt (GSFC),
D. M. Palmer (LANL),, T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), (i.e. the Swift-BAT team):
Using the data set from T-239 to T+941 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 221201A (trigger #1142847)
(Troja et al., GCN Circ. 32998). The BAT ground-calculated position is
RA, Dec = 266.903, -68.230 deg which is
RA(J2000) = 17h 47m 36.6s
Dec(J2000) = -68d 13' 48.2"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 51%.
The mask-weighted light curve shows a single peaked pulse.
T90 (15-350 keV) is 33.71 +- 2.03 sec (estimated error including
systematics).
The time-averaged spectrum from T-20.88 to T+22.92 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
1.63 +- 0.05. The fluence in the 15-150 keV band is 8.6 +- 0.2 x 10^-06
erg/cm2.
The 1-sec peak photon flux measured from T-13.51 sec in the 15-150 keV band
is 11.2 +- 0.6 ph/cm2/sec. 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/1142847/BA/