GRB 140909A
GCN Circular 16816
Subject
GRB 140909A: Confirmation of the Swift-XRT afterglow
Date
2014-09-12T10:36:45Z (12 years ago)
From
Claudio Pagani at U of Leicester <cp232@star.le.ac.uk>
C. Pagani (U. Leicester) and E. Sonbas (Adiyaman U.) report on behalf of
the Swift team:
A second epoch of XRT data was collected on the field of the Swift/BAT
ground detected GRB 140909A (Palmer, GCN Circ. 16808), from 148 ks to
252 ks after the Swift/BAT trigger.
The X-ray source reported in GCN Circ. 16811, Pagani et al., at a mean
count rate of 6.9e-03 ct/sec, is now no longer detected, having faded
below a 3-sigma upper limit of 2.3 x 10^-3 count s^-1 (0.3-10 keV). We
therefore confirm that this is the X-ray afterglow of GRB 140909A
This circular is an official product of the Swift-XRT team.
GCN Circular 16812
Subject
GRB 140909A: Swift/UVOT Upper Limits
Date
2014-09-10T19:02:50Z (12 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
GRB 140909A: Swift/UVOT Upper Limits
M. H. Siegel (PSU) and E. Sonbas (Adiyaman Univ.)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 140909A
44028 s after the BAT trigger (Palmer et al., GCN Circ. 16808).
No optical afterglow consistent with the XRT position
(Pagani et al. GCN Circ. 16811) is detected in the initial UVOT exposure.
The preliminary 3-sigma upper limit using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposure is:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 44028 56310 3213 >22.0
The magnitude is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.015 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 16811
Subject
GRB 140909A: Swift-XRT observations
Date
2014-09-10T07:13:30Z (12 years ago)
From
Claudio Pagani at U of Leicester <cp232@star.le.ac.uk>
C. Pagani, K.L. Page and P.A. Evans (U. Leicester) report on behalf of
the Swift-XRT team:
We have analysed 5.0 ks of XRT data for the Swift/BAT-detected burst:
GRB 140909A, from 44.0 ks to 56.5 ks after the Swift/BAT trigger. The
data are entirely in Photon Counting (PC) mode. An X-ray source is
detected within the Swift/BAT error circle. Using 1945 s of PC mode
data and 1 UVOT images, we find an enhanced XRT position (using the
XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue): RA, Dec = 193.61156, +63.51677 which is equivalent to:
RA (J2000): 12h 54m 26.78s
Dec(J2000): +63d 31' 00.4"
with an uncertainty of 7.2 arcsec (radius, 90% confidence). This
position is 92 arcsec from the Swift/BAT position. The source has a
mean count rate of 6.9e-03 ct/sec; we cannot determine at the present
time whether it is fading.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020417.
This circular is an official product of the Swift-XRT team.
GCN Circular 16808
Subject
GRB 140909A: Swift detection of a GRB
Date
2014-09-09T17:59:24Z (12 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
David Palmer reports on behalf of the Swift Team:
In two successive 64-second images, beginning at 06:56:51, BAT detected a source at a consistent
location. Although the individual images were below threshold, the combined detection
is highly significant, in excess of 8 sigma. A 320 s image that includes the data
from both 64 s images indicates additional flux outside of the 128 s time interval.
The BAT on-board calculated location is RA,dec = 193.638,63.494 (J2000), which is
RA(J2000) = 12h 54m 33s
Dec(J2000) = +63d 29� 38�
As is usual for image triggers, there is no obvious variation in the BAT lightcurve.
Because the individual images were below threshold, Swift did not automatically
slew to the location. However, a ToO has been requested.
--
David Palmer palmer@lanl.gov (505)665-6863 (voice) (505)665-4414 (fax)