{
  "circularId": 1609,
  "subject": "XRF 020903 spectrum",
  "body": "R. Chornock and A. V. Filippenko, University of California, Berkeley, report\nthat an optical spectrum (range 300-940 nm) of the proposed optical transient\n(OT) associated with XRF 020903 (GCN 1554) was obtained with the Low Resolution\nImaging Spectrometer on the Keck-I 10-m telescope on Oct. 8 UT.  Our spectrum\nis similar to that obtained by Hamuy & Shectman (GCN 1554), revealing a rich\nset of narrow emission lines associated with the host galaxy. The host is\nclearly a low-metallicity, high-excitation starburst galaxy, with high\n[O III]/H-beta and low [N II]/H-alpha intensity ratios; [Ne III] is also\nvisible. The shape of the underlying continuum suggests the presence of an\nolder population of stars as well. While we cannot yet rule out a contribution\nfrom an optical supernova (rather than some other type of OT), at this time\nthere is little if any direct spectroscopic evidence for supernova\nfeatures. Specifically, the deficit at rest wavelengths below 4000A (mentioned\nin GCN 1554) is consistent with a population of old to intermediate-age stars.\n\nThis message may be cited.",
  "editedOn": 1777052651665,
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov>",
  "submitter": "Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>",
  "eventId": "XRF 020903",
  "email": "chornock@astro.berkeley.edu",
  "bibcode": "2002GCN..1609....1C",
  "version": 2,
  "createdOn": 1034146317000
}