Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 10167

GRB091111: Swift XRT refined analysis
2009-11-13T14:19:06Z (15 years ago)
Vanessa Mangano at INAF-IASFPA <>
V. Mangano, B. Sbarufatti (INAF-IASF PA),
H. A. Krimm (CRESST/GSFC/USRA) and D. M. Palmer (LANL)
report on behalf of the Swift-XRT team:

The INTEGRAL burst GRB091111 (Gotz et al. GCN Circ. 10159)
has been observed by Swift on 2009 11 12 with a 5 ks ToO started
at 19:00 UT (trigger 020120).
We have analysed 5.4 ks of XRT data in PC mode, from 100361 s
to 115.3 ks after the INTEGRAL trigger.

An X-ray source is detected at
RA, Dec 137.82427, -45.92541 which is equivalent to:
   RA(J2000)  = 09h 11m 17.82s
   Dec(J2000) = -45d 55' 31.5"
with an uncertainty of 5.1 arcseconds (radius, 90% containment).

The light curve is probably decaying but more data are needed
to estimate the decay slope.

A spectrum formed from the PC mode data (30 counts within a
circular region of 15 pixel radius) can be fitted with an absorbed
power-law with a photon spectral index of 2.5 (+5, -3.4)
The best-fitting absorption column is < 5 x 10^22 cm-2, consistent
with the Galactic value of 6.2 x 10^21 cm-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 7.0 x 10^-11 (2.7 x 10^-10) erg
cm^-2 count^-1.

The results of the XRT-team automatic analysis are available at

At the time of GRB 091111, the Swift/BAT was active, sensitive and pointing
such that the burst was in the BAT field of view with 25% mask coding.
There is no count rate increase detected in any of the four BAT energy bands

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

[GCN OPS NOTE(30dec12): In response to S.Mereghetti's communication,
this Subject-line was changed from "09111" to "091111".]
Looking for U.S. government information and services? Visit