Central Bureau for Astronomical Telegrams
IAUC 5660: 1992bk; 1992bl
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Circular No. 5660
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
SUPERNOVA 1992bk IN ESO 156-G8
M. Hamuy, Cerro Tololo Interamerican Observatory; and J. Maza,
University of Chile, report the discovery of a supernova (mpg about
18) by M. Wischnjewsky (University of Chile) on a 20-min unfiltered
IIa-O plate taken by G. Valladares with the CTIO Curtis Schmidt
telescope on Nov. 19.23 UT. SN 1992bk is located about 12" east
and 21" north of the nucleus of the elliptical galaxy ESO 156-G8
(R.A. = 3h41m43s.4, Decl. = -53 46'55", equinox 1950.0); this galaxy
is near the center of the rich cluster of galaxies CA 0340-538
(Sersic 1974, Ap. Space Sci. 28, 365). Confirmation of SN 1992bk
was made by K.-P. Cheng (Goddard Space Flight Center) on CCD B and
V images obtained on Nov. 21.25 with the CTIO 0.9-m telescope. A
spectrogram (range 320.0-750.0 nm) was obtained by Maza on Nov.
21.2 with the CTIO 4-m telescope, revealing the characteristic Si
II 635.5-nm feature of type-Ia supernovae. The minimum of the Si
II absorption yields an expansion velocity of about 10 700 km/s
with respect to the galaxy's rest frame. This spectrum shows
resemblance to the spectrum of the type-Ia SN 1992A taken 7 days past
maximum light. The spectrum of the nucleus of the parent galaxy
yields a redshift of z = 0.058.
SUPERNOVA 1992bl IN ESO 291-G11
Hamuy and Maza further report the discovery of a supernova
(mpg about 17) by R. Antezana (University of Chile), found on a 20-
min unfiltered IIa-O Curtis Schmidt plate taken by Valladares on
Nov. 20.07 UT. SN 1992bl is located about 15" east and 22" south
of the nucleus of the spiral galaxy ESO 291-G11 (R.A. = 23h12m25s.0,
Decl. = -45 00'36", equinox 1950.0). A spectrogram (taken as above
by Maza) on Nov. 22.1 again shows the characteristic Si II 635.5-nm
feature of type-Ia supernovae. The minimum of the Si II absorption
yields an expansion velocity of about 11 400 km/s with respect to
the galaxy's rest frame. This spectrum shows resemblance to that
of SN 1992A taken at maximum light. The spectrum of the nucleus of
the parent galaxy yields a redshift of z = 0.044. Confirmation of
SN 1992bk was also made by Cheng (as above) on Nov. 23.06.
Photoelectric photometry was obtained for this object by A. U. Landolt
(Louisiana State University) with the CTIO 1-m telescope on Nov.
23.08, yielding V = 17.2, B-V = +0.07, U-B = -0.14.
1992 November 25 (5660) Daniel W. E. Green
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