GRB 140824B
GCN Circular 16743
Subject
GRB 140824B: Fermi GBM Detection
Date
2014-08-25T16:46:21Z (11 years ago)
From
Binbin Zhang at UAH <binbin.zhang@uah.edu>
Bin-Bin Zhang (UAH) reports on behalf of the Fermi GBM Team:
"At 14:33:12.04 ��UT on the 24th of August 2014, the Fermi Gamma-Ray Burst
Monitor triggered and located GRB 140824B (trigger 430583595 / 140824606),��
which has been followed up by MASTER II robotic telescope (Tyurina et al.��
GCNs 16740, 16741). The GBM on-ground location is consistent with the Fermi��
flight software position.
The angle from the Fermi LAT boresight is 79 degrees.
The GBM light curve consists of three main peaks with a total duration (T90)��
of about 109 s (50-300 keV). The time-averaged spectrum from T0+3 s to T0+112 s��
is well fit by Band function parameterized as Ep=186+/-20 keV, alpha=-0.9+/-0.1
and beta=-2.5+/-0.5.
The event fluence (10-1000 keV) in this time interval is
(1.5+/-0.1)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+111 s in the 10-1000 keV band is ��6.9+/-0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 16746
Subject
GRB 140824B: Swift observations
Date
2014-08-26T14:33:02Z (11 years ago)
From
Claudio Pagani at U of Leicester <cp232@star.le.ac.uk>
C. Pagani (U. Leicester), N. P. M. Kuin (UCL-MSSL) and J. R. Cummings
(GSFC/UMBC) report on behalf of the Swift team:
We report on Swift follow-up observations of the Fermi/GBM GRB 140824B
(Zhang, GCN Circ. 16743) centred at the position of the candidate
optical counterpart reported by the MASTER II robotic telescope (Tyurina
et al., GCNs 16740, 16741).
In 4.9 ks of XRT Photon Counting (PC) mode data, from 90.6 ks to 103.4
ks after the Fermi/GBM trigger, no X-ray source is detected at the
MASTER II position. The 3-sigma upper limit on the count rate is 1.8E-03
cts/s, which is 9.2E-14 erg cm^-2 s^-1 using a typical flux conversion
of 5E-11 erg cm^-2 count^-1.
The UVOT detected the reported candidate OT. The preliminary UVOT
position is:
RA (J2000) = 01:11:01.14 = 17.75473 (deg.)
Dec (J2000) = +60:33:38.6 = 60.56071 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).
Preliminary detections using the UVOT photometric system (Breeveld et
al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 91250 91850 590 17.97 � 0.05
white 96997 97610 603 17.94 � 0.05
white 102774 103372 590 18.09 � 0.05
v 91857 92457 590 17.47 � 0.07
v 97617 98230 603 17.61 � 0.07
u 90644 91244 590 17.65 � 0.06
u 96991 96991 603 17.62 � 0.06
u 102158 102768 600 17.91 � 0.07
The magnitudes in the table are not corrected for the large, but
uncertain Galactic extinction due to the reddening of E(B-V) = 0.79 in
the direction of the burst (Schlegel et al. 1998). The UVOT magnitudes
when compared to the reported unfiltered magnitudes of 17.0 and 17.5 by
MASTER, suggest a slowly varying source.
Based on the Swift observations, the optical transient detected by
MASTER II is therefore unlikely to be the GRB afterglow.
GCN Circular 16750
Subject
IPN Triangulation of GRB 140824B
Date
2014-08-27T16:09:57Z (11 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@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 on behalf of the IPN,
V. Connaughton, M. S. Briggs, C. Meegan, 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 long-duration GRB 140824B (Zhang, GCN 16743) has
been observed by Konus-Wind, Fermi(GBM trigger 430583595), and INTEGRAL
(SPI-ACS), so far, at about 52392 s UT (14:33:12).
We have triangulated it to a Konus-GBM annulus centered at
RA(2000)=355.371 deg (23h 41m 29s) Dec(2000)=-1.147 deg (-1d 08' 51"),
whose radius is 61.534 � 1.149 deg (3 sigma).
The OT reported by MASTER (Tyurina et al., GCNs 16740, 16741) is well
outside of the annulus (at 3.6 deg from the annulus center line).
Therefore, we conclude that this OT is not related to the burst (as was
already suggested by Tyurina et al. (GCN 16741) and Pagani et al. (GCN
16746) basing on the optical observations).
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB140824_T52472/IPN/