Central Bureau for Astronomical Telegrams
IAUC 6381: 1996X
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Circular No. 6381
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)
SUPERNOVA 1996X IN NGC 5061
N. B. Suntzeff reports that spectrophotometry (range 370-730
nm, resolution 0.35 nm) obtained by M.-T. Ruiz with the Cerro
Tololo 4-m telescope on Apr. 14.2 UT confirms that this is a type-
Ia supernova near maximum (cf. IAUC 6380). The spectrum is similar
to that of SN 1981B at maximum, which is considered a typical type-
Ia supernova. The spectrum shows some unresolved interstellar Na I
D (0.03 nm total) and Ca II H (0.04 nm) and K (0.02 nm) absorption.
The Galatic reddening to this galaxy is E(B-V) = 0.25 (Burstein and
Heiles 1984, Ap.J. Suppl. 54, 33). D. Depoy estimates V = 13.3 on
Apr. 14.1 UT with the Cerro Tololo 0.9-m telescope.
L. Wang, and J. C. Wheeler, University of Texas at Austin and
McDonald Observatory, report: "SN 1996X was observed on Apr. 14.3
UT using the 2.1-m telescope (+ Imaging Grism Instrument) at
McDonald Observatory. Preliminary inspection of a spectrum (range
424.7-813.5 nm, resolution 2.0 nm) shows that SN 1996X is a type-Ia
supernova before optical maximum."
S. Benetti and F. Patat, European Southern Observatory (ESO);
and J. Beuing report that inspection of a fully-reduced CCD
spectrogram (range 465-667 nm, resolution 0.29 nm) obtained on Apr.
14.02 UT with the ESO 1.5-m telescope (+ Boller & Chivens
spectrograph) confirms that SN 1996X is a type-Ia supernova, about
1 week before maximum light. The spectrum is dominated by P-Cyg
lines of intermediate-mass elements superimposed on a blue
continuum. Visible lines include Si II at 505.1, 595.8, and (very
strong) 635.5 nm; Si III at 574.0 nm; Fe III at 512.9 nm; and S II
at 532.2, 546.8, 561.2, and 565.4 nm. The expansion velocity
deduced from the minimum of Si II at 635.5 nm, corrected by the
redshift (2032 km/s) of the parent galaxy, is about 11 150 km/s.
Preliminary photometry from CCD frames taken with the Dutch 0.9-m
telescope at La Silla (ESO) on Apr. 14.29 gives V = 13.38, B-V =
-0.02, U-B = -0.59, V-R = +0.09, V-I = +0.02.
Also, L. Germany and B. Schmidt, Mount Stromlo and Siding
Spring Observatories (MSSSO), report that examination of a spectrum
(range 330-1000 nm) taken on Apr. 14.4 UT by K. Freeman (MSSSO) on
the MSSSO 2.3-m telescope (+ Imager + Grism) shows this to be a
type-Ia supernova about 2 days past maximum. Likewise, P.
Garnavich and R. Kirshner, Harvard-Smithsonian Center for
Astrophysics, report that a spectrogram obtained by E. Barton with
the 1.5-m Tillinghast telescope on Apr. 14.3 shows this to be a
type-Ia supernova near maximum brightness.
(C) Copyright 1996 CBAT
1996 April 15 (6381) Daniel W. E. Green
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