GCN Circular 4952

Subject

GRB060403: XRT refined analysis

Event

Date

2006-04-04T12:43:28Z (20 years ago)

From

Vanessa Mangano at INAF-IASFPA <vanessa@ifc.inaf.it>

T. Mineo, V. Mangano, V. La Parola, G. Cusumano (INAF-IASFPA),
J. Kennea (PSU), P.T. Boyd (NASA/GSFC), D.N. Burrows (PSU)
report on behalf of the Swift XRT team:

We analyzed the Swift XRT data of GRB 060403 (Boyd et al. GCN 4945Loading...
 
 ).
The observation started 52 s after the BAT trigger in Windowed Timing (WT)
mode because before slewing to the GRB position, XRT was observing
SGR1900+14 in manual state. The instrument then switched to auto state,
taking the initial image frame for on board centroiding 222 s after the
trigger, as reported in GCN 4945Loading...
 
 .
The data we report on consisted of 5.5 ks exposure in WT mode
and 15 ks exposure in Photon Counting (PC) mode.

The 0.2-10 keV light curve shows a clear power law decay with
slope -1.49+/-0.04.

The average WT spectrum accumulated during the first orbit (from 52 s
to 300 s after the trigger) is well fitted by a power law with photon
index 1.61+/-0.22, absorbed at lower energies by a column of
(8.1+/-2.1) x 10^21 cm^-2, higher than the galactic value (4.9 x 10^21
cm^-2).
The 0.2-10 keV unabsorbed flux is 1.61 x 10^-11 ergs cm^-2 s^-1.
If the burst continues decaying at the current rate we
estimate an XRT count rate of 1 x 10^-4 counts/s at T+48hr,
which corresponds to an unabsorbed 0.2-10 keV flux
of 1x 10^-14 ergs cm^-2 s^-1.

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