[vsnet-grb-info 16198] Trigger 631747: Swift detection of 4U 0614+09

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17479
SUBJECT: Trigger 631747: Swift detection of 4U 0614+09
DATE:    15/02/19 17:02:25 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

A. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC),
N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC) and
D. M. Palmer (LANL) report on behalf of the Swift Team:

At 16:42:23 UT, the Swift Burst Alert Telescope (BAT) triggered on a burst
from the source 4U 0614+09 (trigger=631747).  Swift slewed immediately to
the location.  The BAT on-board calculated location is 
RA, Dec 94.300, +9.116 which is 
   RA(J2000) = 06h 17m 12s
   Dec(J2000) = +09d 06' 57"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak
burst with a duration of about 2 sec.  The peak count rate
was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 16:44:26.2 UT, 122.6 seconds after
the BAT trigger. XRT found a bright X-ray source located at RA, Dec
94.2808, 9.1369 which is equivalent to:
   RA(J2000)  = +06h 17m 7.39s
   Dec(J2000) = +09d 08' 12.8"
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This
location is 101 arcseconds from the BAT onboard position, within the
BAT error circle. This position is 1.4 arcseconds from a known X-ray
source: 4U 0614+09. This source is in the Swift XRT 1SXPS
catalogue with a mean 0.3-10 keV count-rate of 30.40 +/- 0.30 ct/sec;
see http://www.swift.ac.uk/1SXPS/1SXPSJ061707.4%2B090811 for details of
these previous observations. No event data are yet available to
determine the column density using X-ray spectroscopy. 

The initial flux in the 2.5 s image was 2.10e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White
filter  starting 130 seconds after the BAT trigger. UVOT detects an
18th mag source  whose position is consistent with a catalogued
optical source. The 2.7'x2.7' sub-image covers 100% of  the XRT error
circle. The typical 3-sigma upper limit has been about 19.6 mag.  The
8'x8' region for the list of sources generated on-board covers 100% of
the  XRT error circle. The list of sources is typically complete to
about 18 mag. No  correction has been made for the large, but
uncertain extinction expected. 

This LMXRB has been seen many times by Swift.  This is the brightest
burst seen since September 2012.