[vsnet-grb-info 3788] GRB 060926: Swift XRT refined analysis

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5622
SUBJECT: GRB 060926: Swift XRT refined analysis
DATE:    06/09/27 00:24:50 GMT
FROM:    Matteo Perri at ISAC/ASDC  <perri at asdc.asi.it>

M. Perri, M. Capalbi, M.L. Conciatore (ASDC), D.N. Burrows (PSU)
and S.T. Holland (GSFC/USRA) report on behalf of the Swift XRT team:

We have analysed the first three orbits of Swift XRT data on the BAT GRB
060926 (Holland, et al., GCN Circ. 5612). A 4.7 ks Photon Counting
mode image provides a refined XRT position:

RA(J2000)  =  17h 35m 43.93s
Dec(J2000) = +13d 02' 18.4"

with an uncertainty of 5.9" (90% containment). This is 29.8" away from
the center of the BAT refined position (Cummings et al., GCN Circ. 5621).
This localization lies 11.3" from the XRT position and 4.0" from the
UVOT position quoted in GCN Circ. 5612 (Holland, et al.).

The 0.3-10 keV X-ray light curve during the first orbit shows a flare
at T+430s. Between second and third orbit a power-law decline with a
temporal index of -1.6+/-0.4 is observed.

The X-ray spectrum covering the time period from T+67s to T+878s is
well fit by an absorbed power-law with a photon index of 2.1(+/-0.3)
and column density of (2.2+/-0.9)e21 cm**-2. We note the Galactic
column density in the direction of the source is 7.3e20 cm**-2.

Assuming the X-ray emission continues to decline at the same rate, we
predict a 0.3-10 keV XRT count rate of ~1e-3 count/s at T+24hr, which
corresponds to an observed 0.3-10 keV flux of ~4e-14 erg/cm**2/s.

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