Central Bureau for Astronomical Telegrams
IAUC 7965: 2002en, 2002eo, 2002es,, 2002eu
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Circular No. 7965
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)
SUPERNOVAE 2002en, 2002eo, 2002es, AND 2002eu
A. Pastorello, S. Benetti, G. Altavilla, A. Della Valle, E.
Giro, M. Riello, and M. Turatto, Osservatorio Astronomico di
Padova; and E. Cappellaro, Osservatorio Astronomico di Capodimonte,
communicate that a noisy spectrum (range 400-780 nm, resolution 2.5
nm) of SN 2002eo (cf. IAUC 7958), obtained on Aug. 31.63 UT with
the Asiago 1.82-m telescope (+ AFOSC), shows it to be a type-II
supernova, with a relatively broad (FWHM about 5000 km/s) H-alpha
emission line."
R. Chornock, B. Swift, A. V. Filippenko, and W. D. Li,
University of California at Berkeley, write that, based on CCD
spectra (range 310-1000 nm) obtained on Sept. 3 UT with the Shane
3-m reflector at Lick Observatory, SN 2002es (IAUC 7959) is a
type-Ia supernova similar to the subluminous SN 1991bg (e.g.,
Filippenko et al. 1992, A.J. 104, 1543): "However, the expansion
velocity of the ejecta, as measured from the Si II 615-nm
absorption, is only 6400 km/s, far lower than normal even for
subluminous type-Ia supernovae." SNe 2002en (IAUC 7956) and 2002eo
are of type II, with broad hydrogen Balmer lines exhibiting P-Cyg
profiles; in both cases, the emission component of the H-alpha line
profile greatly dominates the absorption component. SN 2002eu (cf.
IAUC 7963) is of type Ia near maximum brightness; the relative
strengths of the Ti II/Si II 580-nm and Si II 615-nm features
suggest that it should be very subluminous, but its apparent
magnitude seems inconsistent with this, and the spectrum lacks the
strong Ti II 420-nm absorption characteristic of SN 1991bg-like
objects.
T. Matheson, P. Challis, and R. Kirshner, Harvard-Smithsonian
Center for Astrophysics, report that a spectrum (range 370-750 nm)
of SN 2002es, obtained by P. Berlind on Sept. 3.44 UT with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST spectrograph), shows it
to be a peculiar type-Ia supernova near maximum. The spectrum
resembles that of SN 1991bg at maximum (Filippenko et al. 1992, op.
cit.). They add: "Adopting the NED recession velocity of 5394
km/s for the host galaxy, the supernova expansion velocity is about
5700 km/s for Si II (rest 635.5 nm), a notably low value. To match
the expansion velocity of SN 1991bg, the recession velocity of SN
2002es would have to be about 9500 km/s." A spectrum of SN 2002eu,
obtained by Berlind on Sept. 3.45, shows it to be a type-Ia
supernova past maximum. The spectral-feature age of the supernova
is 5 +/- 2 days after maximum light.
(C) Copyright 2002 CBAT
2002 September 4 (7965) Daniel W. E. Green
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