[vsnet-grb-info 5639] GRB 080212: Swift-XRT Team refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7299
SUBJECT: GRB 080212: Swift-XRT Team refined analysis 
DATE:    08/02/13 00:48:16 GMT
FROM:    Kim Page at U.of Leicester  <kpa at star.le.ac.uk>

K.L. Page, D. Perez (U Leicester) and H. Ziaeepour (UCL-MSSL) report on 
behalf of the Swift-XRT team:

We have analysed the first three orbits of data obtained for GRB 080212 
(Ziaeepour et al., GCN Circ. 7296). Most of the initial orbit of data were 
collected in Windowed Timing (WT mode), and show strong flaring activity. 
Using the second two orbits [Photon Counting (PC) mode data; 5.2 ks of 
exposure time], we obtained a refined position of RA, Dec (J2000) = 
231.1468, -22.7420, which is equivalent to

RA(J2000) =   15 24 35.24
Dec(J2000) = -22 44 31.0

with an estimated uncertainty of 3.6 arcsec. This is 3.7 arcsec from the 
onboard XRT position (GCN Circ. 7296).

Following the flares in the first orbit of data, the X-ray light-curve can 
be fitted with a power-law, with the decay slope, alpha = 0.8 +/- 0.1.

There is strong spectral evolution during the flaring WT data. A spectrum 
formed from the PC mode data can be modelled with an absorbed power-law, 
with Gamma = 2.3 +/- 0.2 and NH = (2.1 +/- 0.4)e21 cm^-2, significantly in 
excess of the Galactic value of 7.26e20 cm^-2. The 0.3-10 keV observed 
(unabsorbed) flux during this time (~3.5 - 12 ks after the trigger) is 
8.4e-12 (1.5e-11) erg cm^-2 s^-1.

If the light-curve continues to decay at this rate, the predicted count 
rate at 24 hours will be 0.024 count s^-1. Using the PC data, a counts to 
flux conversion of 4.0e-11 erg cm^-2 count^-1 can be estimated, implying 
the predicted flux at 24 hours would be 9.6e-13 erg cm^-2 s^-1.

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