[IAUC] CBET 1152: 20071203 : SUPERNOVA 2007rv IN NGC 689

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                                                  Electronic Telegram No. 1152
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS en CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT en CFA.HARVARD.EDU (science)
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SUPERNOVA 2007rv IN NGC 689
     T. G. Tan, Mt. Claremont, Western Australia, reports the discovery of
an apparent supernova on unfiltered CCD images taken on Nov. 7.52 UT with
a 9.25-cm Celestron reflector, the new object reported as being located at
R.A. = 1h49m52s.86, Decl. = -27o28'04".1 (equinox 2000.0; image scale
2"/pixel), or 14" east and 4" south of the nucleus of the galaxy NGC 689;
galaxy light may have contaminated the magnitude measured for 2007rv, but a
V-band image taken by Tan on Nov. 11.51 yielded mag 15.9 for the new object
(unfiltered images taken by Tan on both nights showed a 0.9-mag brightening
between the four nights).  Digitized Sky Survey reference images were
saturated at the location of 2007rv, and so additional confirmation was
sought by the Central Bureau via its unconfirmed-objects webpage and via
direct communication with numerous observers, including M. Suzuki
(Utsunomiya, Tochigi, Japan), who obtained images remotely with a 0.25-m
f/6 reflector at Moorook, Australia, on Nov. 23.650 and 24.495, measuring
2007rv to be V = 14.9 and 15.1, respectively, and having position end
figures 52s.88 +/- 0".02, 02".6 +/- 0".1 (offset 15".2 east and 3".3 south
of the nucleus of NGC 689).  Suzuki adds that a USNO-B1.0-catalogue star
(red mag 16.8) has position end figures 52s.79, 02".1.  S. Nakano (Sumoto,
Japan) reports that images taken by K. Nishiyama (Kurume, Fukuoka-ken,
Japan), and F. Kabashima (Miyaki-cho, Saga-ken, Japan), presumably with a
40-cm f/9.8 reflector + unfiltered CCD, yield the following magnitudes for
2007rv:  Nov. 7.52, 15.4; 28.563, 15.6; 29.607, 16.1.  Nishiyama and
Kabashima also provide the following position end figures from their
images on Nov. 28 and 29:  52s.85 +/- 0s.02, 02".2 +/- 0".1
     G. Folatelli and F. Olivares, University of Chile, on behalf of the
Millennium Center for Supernova Studies and Carnegie Supernova Project
collaboration, report that a spectrogram (range 350-900 nm) of 2007rv,
obtained on Dec. 1.18 UT with the European Southern Observatory 3.6-m
telescope (+ EFOSC2) at La Silla, shows this to be a type-Ia supernova
about two weeks after maximum light.  Cross-correlation with a library of
supernova spectra using the "Supernova Identification" code (SNID; Blondin
and Tonry 2007, Ap.J. 666, 1024) provides the best match to SN 1994M at
13 days after maximum light.  Adopting the NED recession velocity of 4210
km/s for the host galaxy (from Mathewson and Ford 1996, Ap.J. Suppl. 107,
97), the maximum absorption of the Si II 635.5-nm line indicates an
expansion velocity of about 12500 km/s.


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                         (C) Copyright 2007 CBAT
2007 December 3                  (CBET 1152)              Daniel W. E. Green