Central Bureau for Astronomical Telegrams
IAUC 6557: 1997Y; 1996cd, 1997T; 1997W, 1996bw
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Circular No. 6557
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 1997Y IN NGC 4675
A. V. Filippenko, D. C. Leonard, A. M. Gilbert, and W. C. G.
Ho, University of California at Berkeley, report that a CCD
spectrum (range 430-700 nm) obtained on Feb. 9 with the Shane 3-m
reflector at Lick Observatory shows that SN 1997Y (cf. IAUC 6556)
is of type Ia, close to maximum brightness. The spectrum resembles
that of the prototypical type-Ia supernova 1981B. There is
prominent Na I D interstellar absorption (equivalent width roughly
0.13 nm), indicating that the object is significantly reddened.
P. Garnavich and R. Kirshner, Harvard-Smithsonian Center for
Astrophysics, write: "A spectrum of SN 1997Y was obtained by J.
Mader on Feb. 9.4 UT with the 1.5-m Tillinghast telescope. The
spectrum shows that the object is a type-Ia supernova at maximum
brightness. Narrow emission lines from the galaxy give a redshift
of z = 0.0162. An absorption line at 598.71 nm is identified as
interstellar Na I in the host galaxy and has an equivalent width of
0.16 nm. CCD images obtained by D. Kim with the Whipple
Observatory 1.2-m telescope on Feb. 9.5 show SN 1997Y to be 3".8
west and 1".7 north of the galaxy's nucleus, at V = 15.3 +/- 0.1."
SUPERNOVAE 1996cd AND 1997T
Filippenko et al., observing as above, also report that SN
1996cd (cf. IAUC 6531) is indeed a supernova, probably of type Ib
or Ic. No broad features are seen at the expected positions of H-
alpha or Si II 635.5-nm, but there is a strong absorption trough
at the position of He I 587.6-nm (or Na I D). The redshift of the
object is 0.048, determined from absorption lines in the nucleus of
the host galaxy and from narrow emission lines at the position of
the supernova. SN 1997T (cf. IAUC 6543) is of type Ia, roughly one
month past maximum brightness; the redshift of the host galaxy is
0.042, determined from narrow emission lines in the nucleus.
SUPERNOVAE 1997W AND 1996bw IN NGC 664
C. Hergenrother, Lunar and Planetary Laboratory, reports the
following position for SN 1997W from the discovery image (cf. IAUC
6551): R.A. = 1h43m44s.48, Decl. = +4 13'17".1 (equinox 2000.0).
The position end figures for SN 1996bw are 44s.51, 19".0 (cf. IAUC
6516).
(C) Copyright 1997 CBAT
1997 February 9 (6557) Daniel W. E. Green
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