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GCN Circular 2517

SN 2003dh/GRB030329 late-time optical spectroscopy
2004-01-15T22:10:26Z (20 years ago)
Ryan Chornock at UC Berkeley <>
A. V. Filippenko, R. Chornock, and R. J. Foley, University of California,
Berkeley, report that CCD spectra (range 310-940 nm) of SN 2003dh, associated
with GRB 030329 (GCN 1985; GCN 2107), were obtained on Dec. 21 UT with the
Keck I 10-m telescope (+LRIS). Skies were clear, the seeing was about 1",
and the exposure time was 2.5 hours (five dithered half-hour integrations).
The object continues to exhibit broad [O I] 630 nm emission typical of Type
Ib/Ic supernovae in the nebular phase (e.g., Foley et al. 2003, PASP, 115,
1220). There is also evidence for weak, significantly narrower [Ca II] 730 nm
emission. There may be some weak, broad features in other parts of the
spectrum, but subtraction of a template spectrum of the host galaxy (which
dominates the continuum at this time) will be necessary to confirm these.
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