{
  "bibcode": "2000GCN...777....1H",
  "body": "HST/STIS observations of the chaotic environment of GRB 980613\n\nStephen Holland, Bjarne Thomsen (University of Aarhus),\nJens Hjorth, Johan Fynbo (University of Copenhagen),\nMichael Andersen (University of Oulu),\nGunnlaugur Bjornsson (University of Iceland),\nAndreas Jaunsen (ESO),\nPriya Natarajan (University of Cambridge, & Yale), and\nNial Tanvir (University of Hertfordshire)\n\n     We have used the Space Telescope Imaging Spectrograph (STIS) on\nthe Hubble Space Telescope to image the environment where GRB 980613\noccurred.  We obtained 5851 seconds of STIS/CCD images with the 50CCD\n(clear) aperture and 5936 seconds of images with the F28X50LP (long\npass) aperture.  This data was taken as part of the Survey of the Host\nGalaxies of Gamma-Ray Bursts (Holland et al., GCN 698) approximately\n799 days after the burst.  Combined images are now available at\n\"http://www.ifa.au.dk/~hst/grb_hosts/data/index.html\".\n\n     A comparison with ground-based R-band images of the optical\nafterglow associated with GRB 980613, taken with from the Nordic\nOptical Telescope (NOT) (Hjorth et al., GCN 109) suggests that the GRB\noccurred at X = 1023.95 +/- 1.52, Y = 1068.73 +/- 0.96 on the drizzled\n50CCD image.  The quoted uncertainties are the uncertainties in the\ntransformation between the NOT and STIS images.  They do not reflect\nthe uncertainty in the position of the optical afterglow in the NOT\nimages due to the GRB being superimposed on a fragmented, extended\nstructure (object A in Djorgovski et al., astro-ph/0008029).  This\nsystematic uncertainty means that the position of the optical\nafterglow may be consistent with the position of a blue, compact\nsource at the southeast end of the A complex.  This source has a\nfull-width at half-maximum of 0.13 arcsec (the resolution of the\ndrizzled STIS images is 0.089 arcsec), and AB magnitudes of CL = 26.3\n+/- 0.1 and LP = 26.2 +/- 0.1 in an aperture of radius 0.25 arcsec.\n\n     An image of the complex structure where GRB 980613 occurred is\navailable at \"http://www.ifa.au.dk/~hst/grb_hosts/data/grb980613cd.gif\".\nThere are several extended objects within a few arcseconds of the GRB\n(Djorgovski et al., astro-ph/0008029).  These objects have a wide\nrange of colours, significant substructure, and some of them appear to\nhave extended tails that may be due to tidal interactions.  The total\ndiameter of the chaotic environment around GRB 980613 is approximately\neight arcseconds.  If we assume that all of the structure lies at the\nsame redshift (z = 1.0969, Djorgovski et al., astro-ph/008029), and\nadopt a cosmology with H0 = 70, Omega_matter = 0.3, and Omega_lambda =\n0.7, then this corresponds to a diameter of approximately 65 proper\nkpc.  The total light in this region is CL = 23.0 +/- 0.1, LP = 22.9\n+/- 0.2.  A detailed analysis of this data is in progress (Hjorth et\nal., in preparation).",
  "circularId": 777,
  "createdOn": 966889898000,
  "email": "holland@ifa.au.dk",
  "subject": "HST/STIS observations of the chaotic environment of GRB 980613",
  "submitter": "Stephen Holland at IFA, U of Aarhus  <holland@ifa.au.dk>",
  "eventId": "GRB 980613"
}