[AAVSO-HEN] GRB 070309: Swift-XRT afterglow confirmation

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
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TITLE:   GCN CIRCULAR
NUMBER:  6369
SUBJECT: GRB 070309: Swift-XRT afterglow confirmation
DATE:    07/04/30 18:16:34 GMT
FROM:    Pat Romano at OAB-Swift  <patrizia.romano at brera.inaf.it>

S.D. Vergani (Dunsink observatory-DIAS, DCU), P. Romano
(INAF-OAB, Univ. Bicocca), C. Guidorzi (INAF-OAB, Univ. Bicocca)
report on behalf of the Swift-XRT team:

XRT observed again the field of INTEGRAL GRB 070309 (Paizis, et
al. 2007, GCN Circ. 6182) between 26 and 27 April (about 50
days after the trigger) for a total exposure time of about 17ks
to verify the nature of the afterglow candidate reported
by Vergani et al. in GCN Circ.'s 6187 and 6200.
There is no source detected at the afterglow candidate position
(RA(J2000) = 17h 34m 39.1s  Dec(J2000) = -37d 55' 48.2")
down to a count rate of 1.43E-3 counts/s (3 sigma).
We therefore confirm that the candidate suggested in GCN
Circ. 6187 is the afterglow of GRB 070309.

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