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GCN Circular 6255

Subject
GRB 070406: Swift XRT Team analysis - Possible X-ray counterpart
Date
2007-04-07T19:36:58Z (17 years ago)
From
Eleonora Troja at INAF-IASFPA <nora@ifc.inaf.it>
E. Troja (U. Leicester/INAF-IASFPa), Kim Page (U. 
Leicester) and S. McBreen (MPE) report on behalf of the 
Swift XRT team:

We analysed the first 13 orbits of Swift XRT data for
GRB 070406 (Cummings et al., GCN Circ. 6247), taken 
between
20.6 hr and 35.5 hr after the BAT trigger. Swift did not
autonomously slew because the burst was below the trigger
threshold.

In the Photon Counting mode image (13 ks of exposure)
no source is detected at the position of the optical
candidate, proposed by Xin et al. (GCN Circ. 6253), with a
3-sigma upper limit of 1.5E-03 cts/s.

A faint uncatalogued X-ray source is detected within the 
BAT
error circle. The source is located at:

RA(J2000)= 13h 15m 51.35s
Dec(J2000)=+16d 30' 46.9"

with an error radius of 5" (90% containment). This lies
68 arcsec from the BAT position given in GCN Circ. 6247.
We note that the projected offset of the source from the
bright galaxy quoted in Ofek et al. (GCN Circ. 6249)
is 45". At a redshift of z=0.11 it corresponds to 89 kpc.

With the data so far available we can not tell if the
source is fading. Further Swift observations are ongoing.

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

[GCN OPS NOTE(09apr07): Per author's request, the word 'counterpart'
was added to the Subject line, and the Instituitional trailer
signifying it is virus-free was removed.]
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