Electronic Telegram No. 2017
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 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://www.cfa.harvard.edu/iau/cbat.html


SUPERNOVA 2009la IN NGC 1572
     L. A. G. Monard, Pretoria, South Africa, reports his independent
discovery of 2009la (cf. CBET 2013) at magnitude 16.1 (+/- 0.2) on an
unfiltered CCD image taken on Nov. 11.878 UT.  Monard measures the position
of 2009la to be R.A. = 4h22m45s.88, Decl. = -40o36'50".4 (equinox 2000.0),
which is 32" east and 47" south of the galaxy core of NGC 1572, adding that
nothing is visible at this position in Digitized Sky Survey images (limiting
red mag 20.5) or on images taken at his Bronberg Observatory prior to Oct. 15.
(on an image taken on Oct. 15.046, the object was fainter than mag 18.0,
evidently not visible).  He also measured mag 15.7 on Nov. 14.829.
     E. Kankare and J. Datson, Nordic Optical Telescope; S. Mattila, Tuorla
Observatory, University of Turku; and A. Pastorello, Queen's University,
Belfast, report that they obtained a low-resolution spectrum of 2009la on
Nov. 15.1 UT with the Nordic Optical Telescope (+ ALFOSC; range 320-910 nm).
The spectrum shows 2009la to be a type-Ia supernova a few days before maximum
light.  Comparison of the observed spectrum with a library of supernova
spectra using the "GELATO" code (Harutyunyan et al. 2008, A.Ap. 488, 383),
gives a good match with the spectum of SN 1992A at five days before maximum.
A close match is also found with the slightly underluminous type-Ia supernova
2004eo at seven days before the maximum.  Adopting a host-galaxy recession
velocity of 6111 km/s (Mathewson et al. 1992, Ap.J. Suppl. 81, 413), the Si
II 635.5-nm absorption minimum is measured to be blue-shifted by roughly
13000 km/s.  The measured R-band magnitude of 15.8 for 2009la corresponds to
an absolute magnitude of -18.9, assuming a distance of 84 Mpc (H_o = 73
km/s/Mpc) and a Galactic extinction of A_R = 0.1 (Schlegel et al. 1998, Ap.J.
500, 525).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2009 CBAT
2009 November 15                 (CBET 2017)              Daniel W. E. Green