TITLE:   GCN CIRCULAR
NUMBER:  43043
SUBJECT: GRB 251208D: Swift-XRT observations
DATE:    25/12/09 02:01:30 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

P.A. Evans (U. Leicester), J.A. Kennea (PSU), E. Ambrosi  (INAF-IASFPA) , A.P.
Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), R. Brivio (INAF-OAB), D.N.
Burrows (PSU), S. Campana (INAF-OAB), M. Capalbi (INAF-OAR), A. D'Ai (INAF-IASFPA),
P. D'Avanzo (INAF-OAB), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), M. Ferro
(INAF-OAB), A. Melandri (INAF-OAR), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), M. Perri (SSDC & INAF-OAR), C. Salvaggio (INAF-OAB), T. Sbarrato
(INAF-OAB), B. Sbarufatti (INAF-OAB), M.A. Williams (PSU) report on behalf of the
Swift-XRT team:

Swift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected source
sb25120806 (GCN 43032), collecting 2.4 ks of Photon Counting (PC) mode data between
T0+5.2 ks and T0+11 ks after the trigger. We have detected 2 sources.  These have
been automatically classified as follows:
  * 0 likely counterparts
  * 0 candidate counterparts
  * 1 uncatalogued X-ray source
  * 1 known X-ray source

Uncatalogued X-ray sources
--------------------------

  Source 2 (SWIFT J223038.6-003107):
  ==================================
    RA (J2000.0):   337.6610  =  22 30 38.64
    Dec (J2000.0):  -0.5186  =	-00 31 07.0
    Error:	    5.8 (arcsec, radius, 90% confidence).
    Detect flag:    GOOD
    Distance:	    10.7 arcmin from the SVOM/ECLAIRs position.
    Mean rate:	    (4.6 [+2.2, -1.7])e-3 ct s^-1
    Mean flux:	    (4.6 [+2.2, -1.7])e-13 erg cm^-2 s^-1
    Peak rate:	    (4.6 [+2.2, -1.7])e-3 ct s^-1
    Peak flux:	    (4.6 [+2.2, -1.7])e-13 erg cm^-2 s^-1
    ECF:	    1.02e-10 erg cm^-2 ct^-1
		      assuming NH=3.34e+21 cm^-2, gamma=0.47
		      determined from a spectral fit.
    RASS UL:	    1.6e-01 ct s^-1 (converted to XRT; 0.3-10 keV)
		      so the source is not above this 3-sigma upper limit.
    There is no evidence for fading.
    A SIMBAD object `SDSS J223038.66-003108.3' is 1.2" away.


Known X-ray sources
-------------------

  Source 1 (SWIFT J222951.0-001338):
  ==================================
    RA (J2000.0):   337.4626  =  22 29 51.02
    Dec (J2000.0):  -0.2273  =	-00 13 38.3
    Error:	    5.2 (arcsec, radius, 90% confidence).
    Detect flag:    GOOD
    Distance:	    10.8 arcmin from the SVOM/ECLAIRs position.
    Mean rate:	    (5.6 [+2.4, -1.9])e-3 ct s^-1
    Mean flux:	    (2.41 [+1.05, -0.81])e-13 erg cm^-2 s^-1
    Peak rate:	    (5.6 [+2.4, -1.9])e-3 ct s^-1
    Peak flux:	    (2.41 [+1.05, -0.81])e-13 erg cm^-2 s^-1
    This matches a catalogued X-ray source 4XMM J222950.9-001339
    in the XMM-NEWTON/XMMSSC catalogue. Details:
    Separation:     2.0" from the XRT source
    Cat Rate:	    5.9e-02 +/- 8.2e-03 ct s^-1 
    Cat Flux:	    6.0e-13 +/- 8.3e-14 erg cm^-2 s^-1 (0.3-10 keV)
		      so the source is not above the catalogued flux.
    There is no evidence for fading.
    A SIMBAD object `TYC 5226-156-1' is 1" away.
    There is 1 2MASS object within the source's 3-sigma error radius.

All fluxes are 0.3-10 keV, observed. For all flux conversions and comparisons with
catalogues and upper limits  from other missions, we assumed a power-law spectrum
with NH=3x10^20 cm^-2 and photon index (Gamma)=1.7 unless otherwise stated.

The results of the XRT-team automatic analysis of the XRT observations, including a
position-specific upper limit calculator, are available at
https://www.swift.ac.uk/SVOM/SVOM_FIELD00056.

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