Central Bureau for Astronomical Telegrams
IAUC 4721: 1989A; 1988Z; NGC 4151
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Circular No. 4721
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 or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
SUPERNOVA 1989A IN NGC 3687
S. Perlmutter and C. Pennypacker, Berkeley Automated Supernova
Search, report the discovery of a supernova in NGC 3687 (R.A. =
11h25m.3, Decl. = +29d47', equinox 1950.0) on three images taken during
Jan. 19.45-19.50 UT. The supernova, of mag 15.3, is 20" west and 18"
south of the galaxy's nucleus and was observed again on Jan. 20 and 21;
it did not appear (95-percent confidence level) on an image taken on
Jan. 6 to a limiting magnitude of 18.
SUPERNOVA 1988Z IN MCG +03-28-022
R. A. Stathakis and E. M. Sadler, Anglo-Australian Observatory,
report that a spectrum (range 530-1020 nm, resolution 20 nm) taken at
the AAT on Jan. 15 shows broad (FWZI 28 000 km/s) emission lines of H alpha
and the Ca II infrared triplet, as well as narrow (unresolved) emission
lines of H alpha and He I 587.6, 667.8 and 706.5 nm. No forbidden lines
were seen in this spectral region. CCD photometry obtained at the AAT by
W. Couch on Jan 4.73 UT gives B = 16.92, V = 16.62, R = 16.16, I = 16.01
(uncertainty +/- 0.04). The slow decline in brightness suggests the
object is a type IIP supernova. The spectrum resembles that of SN 1984E
(in NGC 3169) near maximum light. If SN 1988Z is a similar object, the
narrow lines may soon show a rapid drop in intensity. Regular
monitoring would be valuable.
NGC 4151
J. Clavel, European Space Agency; and M. H. Ulrich, European
Southern Observatory, on behalf of the European Extragalactic
Collaboration; and W. Wamsteker, ESA, report the following results from
the ongoing observing campaign on the Seyfert I galaxy NGC 4151 with the
IUE satellite. After the bright state of 1988 Nov. 29 (IAUC 4686), the
far-ultraviolet continuum intensity at 145.5 nm and the C IV 155.0-nm
emission line intensity faded rapidly and reached a minimum on Dec. 31.
Both started increasing again, and on 1989 Jan. 17 they were almost
back to their level of 1988 Nov. 29. The overall amplitude of the
variations reached a factor of 3.4 and 2.3 in the continuum and in the
line, respectively. The sharp and well-sampled minimum allows for the
first time a proper cross-correlation analysis of the lightcurves of
this object. It is found that the C IV 155.0-nm line intensity lags
behind the 145.5-nm continuum by 4.7 +/- 1.4 days, where the error is
estimated as in Gaskell and Peterson (1987, Ap.J. Suppl. 65, 1).
1989 January 24 (4721) Brian G. Marsden
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