Central Bureau for Astronomical Telegrams
IAUC 5496: 1992T; Mkn 421; 1991h1
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Circular No. 5496
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 1992T IN ANONYMOUS GALAXY
J. Maza, University of Chile; and M. Hamuy, Cerro Tololo
Interamerican Observatory, report the discovery by M. Wischnjewsky of
a supernova located about 4" east and 6" south of the nucleus of an
anonymous spiral galaxy at R.A. = 13h40m10s, Decl. = -31d38'.4
(equinox 1950.0). The supernova, of mpg about 18, was found on a
20-min unfiltered IIa-O plate taken by R. Antezana with the CTIO
Curtis Schmidt telescope on Apr. 9.201 UT. The supernova was also
present at mpg about 20 on a IIa-O plate taken with the same telescope
by L. Wells on Apr. 3. Confirmation was made by Y.-C. Kim from B and
V CCD images obtained on Apr. 13.2 with the CTIO 0.9-m telescope,
these yielding V = 18.69 and B-V = +0.72 for the supernova.
MARKARIAN 421
M. Fiorucci and G. Tosti, Cattedra di Astrofisica, Universita di
Perugia, e-mail: "Broad-band Cousins BVRI photometry of Mrk 421 have
been obtained with a 0.4-m reflector and CCD camera. For each
photometric band the instrumental magnitude of Mrk 421 was derived
using an aperture of 20" x 17" on the sky. After transformation to the
standard system we derived the following data (error < 0.05): Feb.
23.90 UT, V = 12.61, B-V = +0.38, V-R = +0.57, V-I = +0.87; 24.83,
12.57, -, +0.31, -; 27.94, 12.54, +0.31, +0.36, +0.79; 29.96, 12.46,
+0.40, +0.38, +0.75; 29.98, 12.45, -, +0.37, +0.76; Mar. 7.98, 12.54,
+0.38, +0.29, +0.82; 10.88, 12.74, +0.20, +0.57, +0.99; 10.96, 12.72,
-, +0.54, +0.97; 16.88, 12.58, +0.37, +0.39, +0.81. Our observations
support the visual magnitude estimates reported earlier (cf. IAUC 5471).
Moreover, during the period covered, Mrk 421 was bright in all four
bands, with small variations in V but almost constant in I."
COMET MUELLER (1991h1)
Total visual magnitude estimates (cf. IAUC 5464): Mar. 1.79 UT,
7.9 (A. Diepvens, Balen, Belgium, 0.15-m refractor); 5.11, 8.1 (A.
Hale, Las Cruces, NM, 10 x 50 binoculars). In addition to the
unsuccessful infrared attempt to detect the comet on Mar. 24 (cf. IAUC
5482), the following limiting magnitudes correspond to unsuccessful
detections at optical wavelengths: Apr. 1, [8.5 (Hale); Apr. 5, [12 (T.
Kobayashi, Oizumi, Japan); Apr. 10-11, [17-18 (T. Seki, Geisei, Japan).
1992 April 14 (5496) Brian G. Marsden
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