GRB 160622A

A. D'Ai (INAF-IASFPA), N. Gehrels (NASA/GSFC), C. Gronwall (PSU),
J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA),
T. Sakamoto (AGU) and M. H. Siegel (PSU) report on behalf of the Swift
Team:

At 02:03:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located possible GRB 160622A (trigger=700791).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 244.373, -51.045 which is 
   RA(J2000) = 16h 17m 30s
   Dec(J2000) = -51d 02' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a short pulse
with a duration of about 0.1 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 02:04:44.8 UT, 91.1 seconds after
the BAT trigger. No source was detected in the 2.5-s promptly available
image. We are waiting for the full dataset to detect and localise the
XRT counterpart. 

UVOT took a finding chart exposure of	3 seconds with the White filter
starting 95 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. Because of the density of catalogued stars, further
analysis is required to report an upper limit for any afterglow in the
sub-image. Results from the list of sources generated on-board are not
available at this time. No correction has been made for the large, but
uncertain extinction expected. 

This source is at a low galactic latitude of -0.37 degrees and may be 
an SGR.  While the BAT lightcurve looks like a short GRB, it is not
dissimilar from an SGR.  We need the full  dataset to determine the
nature of this trigger. 

Burst Advocate for this burst is A. D'Ai (antonino.dai AT ifc.inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

A. D'Ai(INAF-IASFPA), P.Evans (U. Leicester), N. Gehrels (NASA/GSFC), C. 
Gronwall (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. 
Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), T. Sakamoto (AGU) and M. 
H. Siegel (PSU) report on behalf of the Swift Team:

Swift has gathered 5.8 ks of WT mode data and 463 s of PC mode data on 
the field of the BAT trigger 700791 (= possible GRB 160622A, GCN 19547
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 ).

The XRT image is dominated by diffuse emission from the supernova 
remnant RCW 103 (Frank et al., ApJ, 2015, 810,113), with a bright 
central source at RA,Dec. = 244.40282,  -51.03916,  which is equivalent to:

RA (J2000.0) = 16h 17m 36.68s
Dec (J2000.0) = -51d 02' 21.0"

with an uncertainty of 3.5" (radius, 90% confidence). This is consistent 
with the catalogued X-ray source 3XMM J161736.1-510224. Analysis is 
complicated by the presence of the diffuse emission from the SNR, 
however the source count rate is ~2 ct/sec, with a flux of approximately 
9.1 (+2.0, -1.6) �� 10^-11 erg cm^-2 s^-1 (derived from a power-law 
spectrum with NH=7.0 (+3.6, -2.5)e21 cm^-2, and a photon index of 2.2 
(+/- 0.4). This is substantially above the 3XMM count rate of 2.567 (+/- 
0.020)e-12 erg cm^-2 s^-1.

Observations and analysis are ongoing.

This circular is an official product of the Swift XRT team.

[GCN OPS NOTE(22jun16): Per author's request, A.D'A's name was corrected,
and the missing minus sign for the sexagesimal form of the Dec value
was added.]

D. A. Kann (TLS Tautenburg), P. Schady, and J. Greiner (both MPE Garching)
report on behalf of the GROND team.

We observed the field of GRB 160622A/SNR RCW 103/SGR 1617-5103 (Swift
trigger 700791; D'Ai et al., GCN #19547
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 ) simultaneously in g'r'i'z'JHK
with
GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG 
telescope at ESO La Silla Observatory (Chile).

Observations started at 02:19 UT, 0.26 hrs after the GRB trigger, and 
continued for around 1 hr. They were performed at an average seeing of
1".4 and at an average airmass of 1.

In stacked data amounting to about 30 min exposure time in g'r'i'z' and
about 15 min in JHK, we do not detect any sources within the enhanced
Swift-XRT error circle (Evans et al., GCN #19551
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 ) down to the following 3
sigma upper limits (AB magnitudes):

g� > 23.4 mag,
r' > 23.3 mag,
i' > 23.1 mag,
z' > 23.0 mag,
J > 19.8 mag,
H > 18.9 mag, and
K > 18.7 mag.

We detect two sources just outside the XRT error circle. One to the south,
which is likely a blended double source, and a faint source to the west.
The PSF wing of the southern source lies within the XRT error circle,
reducing our limiting magnitude there.

Given magnitudes are calibrated against GROND zeropoints as well as 2MASS
field stars and are not corrected for the very high expected Galactic
foreground extinction in the direction of the burst (Schlafly &
Finkbeiner, 2011).