Central Bureau for Astronomical Telegrams
IAUC 7781: 2001ir; 2001ig
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Circular No. 7781
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)
SUPERNOVA 2001ir IN MCG -02-22-22
W. D. Li, University of California at Berkeley, reports the
discovery by LOTOSS (cf. IAUC 7514) of an apparent supernova (mag
about 17.5) in an unfiltered image taken with the Katzman Automatic
Imaging Telescope (KAIT) on Dec. 19.5 UT. The new object is
confirmed on an earlier KAIT image taken on Dec. 10.5 under poor
conditions. SN 2001ir is located at R.A. = 8h36m28s.12, Decl. =
-11o50'03".5 (equinox 2000.0), which is 24".0 west and 11".9 south
of the nucleus of MCG -02-22-22. An image taken by M. Schwartz
with the Tenagra III 0.5-m telescope on Nov. 12.5 showed nothing at
this position (limiting mag about 18.5).
SUPERNOVA 2001ig IN NGC 7424
A. Clocchiatti and J. L. Prieto, Pontificia Universidad
Catolica de Chile, report on their spectroscopic observations of SN
2001ig (IAUC 7772) obtained on Dec. 16.1 with the European Southern
Observatory 3.6-m New Technology Telescope (+ the red arm of the
dual imager/spectrograph EMMI). A spectrum (range 398-938 nm;
resolution of 0.9 nm) with good S/N was fully reduced by
Clocchiatti and shows a very blue continuum with a blackbody-
fitting temperature of approximately 14 500 K. The spectrum has
some strong P-Cyg profiles; the most prominent has a blueshifted
minimum centered at 618 nm and appears to be H-alpha at an
expansion velocity of approximately 18 600 km/s, followed by
another feature at 817 nm that could be Ca II (849.8, 854.2, 866.2
nm) at 15 000 km/s. Other minor features are located at 463 nm
(consistent with H-beta at 15 000 km/s), at 505 nm (which should
be Fe II 516.9-nm at approximately 7900 km/s), and at 562 nm (which
could be Na I D at a velocity of 15 000 km/s, or He I 587.6-nm at
1330.0 nm). Overall, the spectrum resembles that of SN 1993J at a
similar epoch (Clocchiatti et al. 1995, Ap.J. 446, 167), although
the absorption profile of the H-alpha line is stronger in SN
2001ig, and the continuum bluer. The spectrum of SN 2001ig is also
very similar to a spectrum of SN 1987K taken on 1987 Aug. 7
(Filippenko 1988, A.J. 96, 1941). There are still no signs of
strong He I lines. Observations of this strange supernova are
encouraged, especially with its solar elongation decreasing
noticeably.
Unfiltered CCD magnitudes by C. Bembrick, Bathurst, N.S.W.:
Dec. 10.492 UT, 15.14; 11.445, 14.86; 12.422, 14.83; 13.421, 14.75;
16.422, 14.27. Visual magnitude estimates: Dec. 15.562, 13.8 (A.
Pearce, Nedlands, W. Australia); 16.549, 13.5 (Pearce); 17.5, 13.9
(R. O. Evans, Linden, N.S.W.); 19.5, 13.5 (Evans); 19.539, 13.0
(Pearce).
(C) Copyright 2001 CBAT
2001 December 21 (7781) Daniel W. E. Green
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