GRB 140901B
GCN Circular 16773
Subject
GRB 140901B found in ground analysis of BAT data
Date
2014-09-04T13:59:36Z (11 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <james.r.cummings@nasa.gov>
J. R. Cummings reports on behalf of the Swift science team:
At 06:17:24 Swift-BAT rate-triggered on GRB 140901B (trigger # 611389).
Fermi-GBM also triggered on this event (trigger 431245045). No source
was found onboard. In ground analysis, a significant source was found
at RA, Dec 112.184, -29.209, which is
RA (J2000) 07h 28m 44.2s
Dec (J2000) -29d 12' 31"
with an estimated 90% uncertainty radius of 2.0 arcmin. This location
is 3.0 degrees from the reported GBM location
(http://gcn.gsfc.nasa.gov/other/431245045.fermi), within the GBM error
circle.
The background in BAT was high, since Swift was near the SAA. The BAT
lightcurve shows a single FRED peak, with T90 about 10 +- 1 sec.
The BAT spectrum with 10.0 seconds of data is best fit by a simple power-
law function with a photon index of 1.20 +- 0.22. Using this model, the
fluence was (9.5 +- 1.3) x 10^-7 ergs/cm^2. Errors are 90% confidence.
A Swift TOO request has been submitted, but this burst is already 3.5
days old, and moreover is rather close to the Sun.
GCN Circular 16775
Subject
GRB 140901B: Fermi GBM detection
Date
2014-09-04T17:30:20Z (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 06:17:22.79 UT on 01 September 2014, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 140901B (trigger 431245045 / 140901262), which
was also detected by the Swift/BAT (Cummings 2014, GCN 16773)
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 34 degrees.
The GBM light curve consists of a single pulse
with a duration (T90) of about 65 +/- 14 s (50-300 keV).
The time-averaged spectrum from T0-0 s to T0+65 s is
best fit by a power law function with an exponential
high-energy cutoff. ��The power law index is -1.2 +/- 0.2 ��and
the cutoff energy, parameterized as Epeak, is 219 +/- 82 keV.
The event fluence (10-1000 keV) in this time interval is
(3.8 +/- 0.6)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+0.9 s in the 10-1000 keV band
is 2.6 +/- 0.2 ��ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 16782
Subject
GRB 140901B: Swift XRT observation
Date
2014-09-05T13:30:05Z (11 years ago)
From
Valerio D'Elia at ASDC <delia@asdc.asi.it>
V. D'Elia (ASDC), L. Izzo (URoma/ICRA) and A. Maselli (INAF-IASFPA)
report on behalf of the Swift-XRT
team:
XRT began a target of opportunity observation of GRB140901B, detected
by Swift-BAT (Cummings, GCN Circ. 16773) and Fermi-GBM (Zhang, Circ.
16775). Swift slewed to the burst on 2014-09-05.
Observations with the XRT began at 01:23:58 UT, i.e., 330 ks after the
trigger, and comprised a total of 2.97 ks in photon counting mode.
We do not detect any X-ray sources, within the BAT error circle
(Cummings, GCN Circ. 16773), with S/N>2. We place a 3-sigma upper
limit on the count rate at the BAT position of 3.85E-03 cts/s.
This circular is an official product of the Swift-XRT team.