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GCN Circular 6796

GRB 070917: Swift-XRT observations
2007-09-18T08:53:44Z (17 years ago)
Phil Evans at U of Leicester <>
P.A. Evans, A.P. Beardmore, K.L. Page, R.L.C. Starling (U. Leicester)
and J.R. Cummings (NASA/UMBC) report on behalf of the Swift-XRT team:

We have analysed 2.3 ks of Swift XRT data for GRB 070917 (Cummings et
al. GCN Circ 6791) beginning 35 ks after the trigger. The data are
entirely in Photon Counting mode. An uncatalogued X-ray source is
clearly detected at RA, Dec= 293.91913, +2.41055 degrees, which is
equivalent to:

RA (J2000) =  19h 35m 40.59s
Dec(J2000) = +02d 24' 38.0"

with an estimated uncertainty of 8.0 arcsec (radius, 90% containment
including boresight uncertainty). This is 37 arcsec from the BAT refined
position  (Tueller et al. GCN Circ 6792). The source has a count rate of
0.016 counts s^-1. At present we are unable to determine whether the
source is fading, however observations are ongoing.

Using the C-statistic in xspec we fit the PC mode spectrum from
T0+35000-42000 s with an absorbed power-law. The absorption is
consistant with the Galactic value of 1.73e21 cm^-2 (Kalberla et al.
2005). The spectral slope is gamma=1.17 (+0.44/-0.45), which is
consistent with the BAT value of 1.52 +/- 0.04. The observed
(unabsorbed) flux is 1.31e-12 (1.44e-12) erg/cm^2/s.

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