[IAUC] CBET 1769: 20090417 : SUPERNOVA 2009dl

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                                                  Electronic Telegram No. 1769
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2009dl
     G. Pignata, J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, P. Gonzalez, P.
Lopez, S. Silva, G. Folatelli, D. Iturra, R. Cartier, F. Forster, S. Marchi,
and A. Rojas, Universidad de Chile; B. Conuel, Wesleyan University; and D.
Reichart, K. Ivarsen, A. Crain, D. Foster, M. Nysewander, and A. LaCluyze,
University of North Carolina at Chapel Hill, on behalf of the CHASE project,
report the discovery of an apparent supernova (mag approximately 18.2 +/- 0.4)
on an unfiltered image taken on Apr. 15.13 UT with the 0.41-m 'PROMPT 4'
telescope located at Cerro Tololo.  The new object, which is also present in
images taken on Apr. 3.32 (at mag approximately 18.8 +/- 0.5) and 17.08 (at
mag approximately 18.1 +/- 0.4), is located at R.A. = 12h08m07s.21 +/- 0".1,
Decl. = -31o59'25".3 +/- 0".1 (equinox 2000.0), which is about 1".6 west and
6".5 north of center of the presumed host galaxy.  Nothing is visible at this
position on archival images taken on Mar. 27.19 (limiting mag 19.2) and 30.31
(limiting mag 18.9) or on Digitized Sky Survey (limiting mag 19.0, though no
passband or dates indicated).
     J. Anderson and N. Morrell, on behalf of the Millenium Center for
Supernova Science and the Carnegie Supernova Project collaboration, obtained
spectroscopy (range 390-940 nm) of 2009dl and its host galaxy with the
Magellan II Clay 6.5-m telescope (+ LDSS3) at Las Campanas Observatory on
Apr. 17.2 UT.  Inspection of the data reveals that 2009dl is a type-Ia
supernova around maximum brigtness.  From emission lines in the host-galaxy
spectrum, they derive a redshift z = 0.1429 +/- 0.0001.  Adopting that
redshift, the Si II 635.5-nm absorption in the supernova spectrum is
blueshifted by roughly 9000 km/s.  Cross-correlation with a library of
supernova spectra via the "Supernova Identification" tool (Blondin and Tonry
2007, Ap.J. 666, 1024) provides excellent matches with a variety of normal
type-Ia supernovae, between 5 days before and 5 days after maximum light.


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                         (C) Copyright 2009 CBAT
2009 April 17                    (CBET 1769)              Daniel W. E. Green