Central Bureau for Astronomical Telegrams
IAUC 8084: 2003bh, 2003bi; NO 2003aw; 2003aa, 2003bg
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Circular No. 8084
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVAE 2003bh AND 2003bi
Further to IAUC 8082, W. M. Wood-Vasey, G. Aldering, and P.
Nugent report the discovery of two supernovae on Palomar NEAT
images.
SN 2003 UT R.A. (2000.0) Decl. Mag. Offset
2003bh Feb. 21.32 10 00 06.27 +28 16 52.0 19.9 7".5 W, 2".0 N
2003bi Feb. 22.43 10 44 05.97 +12 31 34.7 19.6 2".3 E, 3".1 N
Additional magnitudes from NEAT images: SN 2003bh, Jan. 10.52 UT,
[20.7 (S/N = 3). SN 2003bi, Jan. 28.52, [20.4 (S/N = 3); Feb.
23.49, 19.6.
A. V. Filippenko and R. Chornock, University of California,
Berkeley, report that inspection of CCD spectra (range 310-1000 nm),
obtained on Feb. 27 UT with the Keck I 10-m telescope (+ LRIS),
shows that SN 2003bh is of type Ia, about 1 month past maximum
brightness; its host galaxy has a redshift of 0.089. A spectrum
from Feb. 28 shows that SN 2003bi is also of type Ia, close to
maximum; its host galaxy has a redshift of 0.093.
NO SUPERNOVA 2003aw
Chornock and Filippenko add that inspection of CCD spectra,
obtained as above on Feb. 28 UT, shows that the object 2003aw (IAUC
8077) is not a supernova, but rather is probably a hydrogen-
deficient dwarf nova similar to that proposed for 1998di = KL Dra
on IAUC 6983. The spectrum consists of a nearly featureless, quite
blue continuum. Very-low-contrast He I lines are present near zero
redshift in emission, and there is Ca II H and K absorption at
essentially zero redshift; they are too broad to be interstellar,
and no interstellar Na I D absorption is visible.
SUPERNOVAE 2003aa AND 2003bg
Filippenko and Chornock also report that inspection of CCD
spectra, obtained as above on Feb. 27 or 28 UT, shows that SN
2003aa (IAUC 8063) appears to be a type-Ia supernova similar to the
subluminous SN 1991bg (e.g., Filippenko et al. 1992, A.J. 104,
1543), a few weeks past maximum brightness, rather than a type-Ic
supernova as suggested in IAUC 8064. However, the expansion
velocity of the ejecta is very low, resembling that of SN 2002es
(IAUC 7965). SN 2003bg (IAUC 8082) is very similar to the peculiar
type-Ic supernovae (called 'hypernovae' by some workers) 1997ef,
1998bw, 2002ap, and 2002bl, perhaps 2 weeks after the explosion
(Iwamoto et al. 2000, Ap.J. 534, 660, Fig. 1).
(C) Copyright 2003 CBAT
2003 February 28 (8084) Daniel W. E. Green
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