GRB 141222A
GCN Circular 17218
Subject
GRB 141222A: Fermi-LAT detection
Date
2014-12-22T17:22:49Z (10 years ago)
From
Julie McEnery at NASA/GSFC <julie.e.mcenery@nasa.gov>
J. McEnery (GSFC), D. Kocevski (GSFC), J. Racusin (GSFC), F. Longo
(University of Trieste and INFN), E.Bissaldi (University of Trieste and
INFN), and M. Axelsson (KTH Royal Institute of Technology) report on
behalf of the Fermi-LAT team:
At 07:09:04 UT Mon on Month 22, 2014, Fermi-LAT detected high-energy
emission from GRB 141222A,
which was also detected by Fermi-GBM (trigger 440924940/141222298).
The best LAT on-ground location is found to be RA, Dec 178.04, -57.35
(J2000) with an error radius of 0.1 deg (90% containment, statistical
error only) based on a 500s integration. This was 46 deg from the LAT
boresight at the time of the trigger.
The data from the Fermi-LAT show a significant increase in the event
rate within 15 degree of the GBM location after the GBM trigger that is
spatially and temporally correlated with the GBM emission with high
significance. More than 5 photons above 100 MeV and more than 1 photon
above 1 GeV are observed within 1 seconds. The highest-energy prompt
photon is a 20 GeV event which is observed 0.1 seconds after the GBM
trigger.
The Fermi-LAT point of contact for this burst is Magnus Axelsson
(magnusa@astro.su.se <mailto:magnusa@astro.su.se>).
The Fermi-LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between NASA and DOE
in the U.S. and many scientific institutions across France, Italy, Japan
and Sweden.
GCN Circular 17220
Subject
GRB 141222A: Fermi GBM detection
Date
2014-12-22T18:56:06Z (10 years ago)
From
Peter Jenke at MSFC <peter.a.jenke@nasa.gov>
P. Jenke (UAH) reports on behalf of the Fermi GBM Team:
"At 07:08:57.40 UT on December 22 2014, the Fermi Gamma-Ray Burst
Monitor triggered and located
GRB 141222A (trigger 440924940/141222298), which was also detected
by Fermi/LAT (J. McEnery et al. 2014, GCN 17218).
The GBM on-ground location, using the Fermi GBM trigger data, is consistent with
the Fermi/LAT location.
The angle of the burst direction to the Fermi LAT boresight is
46 degrees.
The GBM light curve consists of a narrow peak followed by a broad peak with a tail.
The duration (T90) is about 2.4 s (50-300 keV).
The time-averaged spectrum from T0-0.06 s to T0+1.41 s is
adequately fit by a Band function with Epeak = 2427 +/- 580 keV,
Alpha =-1.49 +/- 0.01 and Beta = -1.74 +/- 0.05.
The event fluence (10-1000 keV) in this time interval is
(8.16 +/- 0.08)E-06 erg/cm^2. The 64 ms peak photon flux measured
starting from T0+0.64 s in the 10-1000 keV band
is 121 +/- 3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 17223
Subject
IPN Triangulation of GRB 141222A (very intense)
Date
2014-12-23T14:53:35Z (10 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
V. Connaughton, M. S. Briggs, C. Meegan, and V. Pelassa,
and A. Goldstein, on behalf of the Fermi GBM team, and
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
report:
The hard-spectrum, very intense GRB 141222A has been observed by
Fermi (GBM: Jenke, GCN Circ. 17220; LAT: McEnery et al., GCN Circ.
17218), Konus-Wind, INTEGRAL (SPI-ACS), and MESSENGER (GRNS), so far, at
about 25737 s UT (07:08:57).
We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
178.156 (11h 52m 38s) -57.280 (-57d 16' 47")
Corners:
178.029 (11h 52m 07s) -57.604 (-57d 36' 15")
178.063 (11h 52m 15s) -57.239 (-57d 14' 20")
178.284 (11h 53m 08s) -56.954 (-56d 57' 15")
178.250 (11h 53m 00s) -57.321 (-57d 19' 15")
---------------------------------------------
The error box area is 138 sq. arcmin, and its maximum
dimension is 40 arcmin (the minimum one is 6 arcmin).
This box may be improved.
The box overlaps with about a half of the Fermi-LAT error circle,
reported in GCN Circular 17218, with the center of the circle lying
slightly outside the box.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB141222_T25735/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 17224
Subject
GRB 141222A: First MASTER-SAAO optical observation
Date
2014-12-23T16:08:15Z (10 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
D.Buckley, S. Potter, A. Kniazev
South African Astronomical Observatory
E. Gorbovskoy,V. Lipunov, P.Balanutsa, D.Denisenko,
M.Pruzhinskaya,A.Kuznetsov, V.Kornilov, D.Kuvshinov, N.Tyurina
Lomonosov Moscow State University,
Sternberg Astronomical Institute
O.Gres, K.Ivanov, S.Yazev, N.M.Budnev, V.A.Poleshchuk
Irkutsk State University
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory
V.Krushinsky, I.Zalozhnih, A. Popov
Ural Federal University, Kourovka
H. Levato and C. Saffe
Instituto de Ciencias Astronomicas de la Tierra y del Espacio (ICATE),
San Juan, Argentina
C. Mallamacci, C. Lopez and F. Podest
Observatorio Astronomico Felix Aguilar (OAFA), San Juan National
University, Argentina
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
instaleted several days ago in South African Astronomical
Observatory (Sutherland) automaticaly was pointed
to the Fermi_LAT GRB141222A (McEnery et al., GCN 17218) after error box
rised at 2014-12-22 22:34:35 UT (15.5 hours after trigger time) in
unfiltered regime.
Because we have no reference images we can only use DSS stars.
There is no any optical transients brighter 20.8 unfiltered magnitude
inside error box (between 2014-12-22 22:34:35 and 2014-12-23 00:26:09).
We note that error box has small Galactic Latitude b = 4.3 but no very
big absorption in R and I, they are 0.9 and 0.7 correspondently (Schlafly
& Finkbeiner 2011, ApJ 737, 103).
This message may be cited.
GCN Circular 17225
Subject
Konus-Wind observation of GRB 141222A
Date
2014-12-23T16:53:34Z (10 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration, hard-spectrum, very intense GRB 141222A
(Fermi-LAT detection: McEnery et al., GCN Circ. 17218;
IPN triangulation: Golenetskii et al., GCN Circ. 17223)
triggered Konus-Wind at T0=25735.342 s UT (07:08:55.342).
The burst light curve starts with a short bright pulse with negligible
spectral lag followed by two broader, less intense, pulses. The total
burst duration is about 3.2 s. The emission is seen up to 5 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB141222_T25735/
The background variations in the soft KW band are due to solar activity.
As observed by Konus-Wind, the burst
had a fluence of 1.1(-0.2,+0.4)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.038 s,
of 1.2(-0.3,+0.3)x10^-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 5 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.50 (-0.10,+0.12)
and Ep = 858 (-375,+1067) keV (chi2 = 89/79 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.9
(chi2 = 89/78 dof).
The spectrum near the maximum count rate
(measured from T0 to T0+0.064 s)
is best fit in the 20 keV - 5 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.78 (-0.15,+0.17)
and Ep = 1532 (-359,+493) keV (chi2 = 25/29 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.2
(chi2 = 25/28 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 17226
Subject
Swift XRT and UVOT observations of GRB141222A
Date
2014-12-23T19:34:00Z (10 years ago)
From
Massimiliano de Pasquale at IASF-Palermo <mdp@ifc.inaf.it>
M. De Pasquale (IASF/INAF Palermo) and M. Siegel (PSU) report on behalf of the Swift-XRT team:
We have analysed 4.7 ks of XRT data for GRB 141222A, detected by the Fermi/LAT
(McEnery et al. GCN 17218), Fermi/GBM (Jenke et al., GCN 17220) and IPN (Svinkin et al.
GCN 17223), from 42.0 ks to 53.4 ks after the Fermi/LAT trigger. The data are entirely
in Photon Counting (PC) mode. No source is detected within the LAT error circle; we
determined a 3 sigma upper limit of 2.3e-3 count/s at the LAT coordinates.
�
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020454.
The Swift/UVOT began settled observations of the field of GRB 141222
41986 s after the LAT trigger. �No optical afterglow is detected in the initial UVOT
exposures within the LAT error circle. �Preliminary 3-sigma upper limits using the
UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the
initial exposures are:
Filter � � � � T_start(s) � T_stop(s) � � �Exp(s) � � � � Mag
v � � � � � � � �41986 � � � �53434 � � � � 2510 � � � � >20.5
u � � � � � � � �43226 � � � �50158 � � � � 2375 � � � � >20.5
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.42 in the direction of the burst
(Schlegel et al. 1998).
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