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GCN Circular 756

GRB 990510 Host Galaxy Discovery
2000-07-30T00:32:12Z (24 years ago)
Josh Bloom at CIT <>
GRB 990510 Host Galaxy Discovery

J. S. Bloom, on behalf of the larger Caltech-NRAO-CARA GRB
Collaboration, reports:

"We have discovered a faint extended source nearly coincident with the
position of GRB 990510. This source, which we identify as the host galaxy
of GRB 990510, is visible in new HST/STIS imaging taken on 29 April 2000
as part of the HST proposal #8189 (see Fruchter et al. GCN #386) and made
public on 28 July 2000. The total integration time is 5840 s taken in 8
individual exposures. Registration of the early epoch (17 June 1999) where
the OT was bright reveals the OT occurred (0.064" +/- 0.009") West
and (0.015" +/- 0.012") North of the center of the host
galaxy.  This amounts to a significant displacement of (66 +/- 9) mas or
~600 pc at a distance of z=1.62 (Galama et al. 1999), though the OT does
appear to reside within the detectable light of the galaxy.  The galaxy
extension is PA=80.5 +/- 1.5 deg with an ellipticity of about ~0.5.  
Preliminary magnitude estimates reveal that V_host = 28.5 +/- 0.5 mag
(referenced to star C of Beuermann et al. 1999).  The host does appear to
be marginally detected in the July 1999 imaging as well (although see GCN

An image of the field from both epochs as well as a close-up of the
host and the 3-sigma location of the GRB can be found at:

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