Central Bureau for Astronomical Telegrams
IAUC 8159: 2003gh; 2001co, 2003H, 2003dg,, 2003dr
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Circular No. 8159
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)
SUPERNOVA 2003gh IN NGC 2466
Further to IAUC 8137, L. A. G. Monard reports his discovery of
an apparent supernova on unfiltered CCD images taken on June 29.737
(mag about 15.7 +/- 0.3) and 30.694 UT (mag 15.6). SN 2003gh is
located at R.A. = 7h45m17s.93, Decl. = -71o24'37".3 (equinox
2000.0), which is 6" west and 0".5 south of the nucleus of NGC 2466.
The new object is not present on the Digitized Sky Survey (limiting
red mag 19) or on an image taken by Monard on June 7.707 (limiting
red mag 18.5).
SUPERNOVAE 2001co, 2003H, 2003dg, AND 2003dr
A. V. Filippenko, R. Chornock, and B. Swift, University of
California, Berkeley; M. Modjaz, Harvard-Smithsonian Center for
Astrophysics; R. Simcoe, California Institute of Technology; and M.
Rauch, Carnegie Observatories, report that inspection of CCD
spectra (range 320-1000 nm) obtained on 2001 June 29, July 16, and
27 UT with the Shane 3-m telescope at Lick Observatory, and on 2001
Aug. 17 with the Keck-I telescope (+ LRIS), reveal that SN 2001co
(IAUC 7643) is a peculiar type-Ib or type-Ic supernova. Lines of H
and He are absent, but the Ca II near-infrared triplet is very
strong in emission, and the [Ca II] doublet near 730 nm is also
present. No other clear emission or absorption features are
visible in the combined, noisy spectrum. The spectral
characteristics of this 'calcium-rich supernova' were unprecedented,
and perhaps suspect (given the low signal-to-noise ratio), until
Keck-I observations of SN 2003H (IAUC 8045, 8046), obtained on 2003
Feb. 28 UT by Filippenko and Chornock, revealed a very similar-
looking spectrum: the only strong features are the [Ca II] and
especially the near-infrared Ca II emission lines. SN 2003H had
been classified as type Ib by Hamuy (IAUC 8047, 8049), but the Keck
spectrum about 2 months after explosion is clearly very unusual; in
normal type-Ib and type-Ic supernovae, prominent [O I] emission
emerges in the nebular phase. Filippenko and Chornock add that
inspection of CCD spectra (range 320-990 nm) obtained on June 29
with the Keck-I telescope (+ LRIS) reveals that SN 2003dg (IAUC
8113) and SN 2003dr (IAUC 8117) are peculiar type-Ib or type-Ic
supernovae of the 'calcium-rich' variety described above, but
evidently at a later phase than seen for SN 2001co and SN 2003H
because the [Ca II] emission is stronger than the near-infrared Ca
II triplet. [O I] 630.0- and 636.4-nm emission is much weaker than
in normal type-Ib and type-Ic supernovae many months after the
explosion.
(C) Copyright 2003 CBAT
2003 June 30 (8159) Daniel W. E. Green
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