{
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov>",
  "version": 2,
  "email": "anl@star.le.ac.uk",
  "eventId": "XRF 020903",
  "subject": "XRF 020903 : HST observations",
  "submitter": "Andrew Levan at U.of Leicester  <anl@star.le.ac.uk>",
  "bibcode": "2002GCN..1761....1L",
  "circularId": 1761,
  "createdOn": 1040151553000,
  "editedOn": 1777052653110,
  "body": "Andrew Levan (U. Leicester/STScI), Andrew Fruchter, Lou Strolger, Ingunn\nBurud and James Rhoads (STScI) report for the GOSH collaboration.\n\nThe candidate optical transient for XRF 020903 (Soderberg et al, GCN 1554)\nwas imaged with HST/ACS in F606W on 3rd Dec 2002. 4 dithered exposures\nwere obtained with a total exposure time of 1840s.\n\nThe candidate appears to be within an irregular galaxy, with four\n(possibly interacting) components. Astrometry with images obtained\nwith the CTIO 4-m telescope and Mosaic imager on Sept 4th and 9th 2002\n(Fruchter et al, GCN 1558) shows that the transient source is located at\na position coincident with the peak of the most western of these compact\nknots (with a positional accuracy of approximately ~0.\"1). The knot has\nan F606W AB magnitude of 22.6 and a FWHM of ~0.\"14, greater than the PSF\nof ACS. Hence the source is resolved at this resolution, indicating that\nan AGN does not dominate the optical light from this object.\n\nThe galaxy, named G2 by Soderberg et al, (GCN 1554) is clearly an\ninteracting system. However, as noted by Soderberg et al the redshift\ndifference (z=0.23 for G2 and z=0.25 for the host of the candidate OT)\nindicate that the systems are not associated.\n\nUsing a 1\" aperture the magnitude of the entire system in F606W is\napproximately R=21, roughly consistent with the late time magnitudes\ndetermined by Gorosabel et al (GCN 1631).\n\nObservations taken at a later date will allow a search for further\nvariability in this source.\n\nImages of the host galaxy, and surrounding field can be found at\n\nhttp://www.stsci.edu/~fruchter/GRB/020903"
}