[IAUC] CBET 2106: 20091231 : SUPERNOVAE 2009nl AND 2009nm

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                                                  Electronic Telegram No. 2106
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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SUPERNOVAE 2009nl AND 2009nm
     Further to CBET 2101, E. Christensen, Gemini Observatory; A. J. Drake,
S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams, California
Institute of Technology; M. Catelan, Pontificia Universidad Catolica de
Chile; and E. C. Beshore and S. M. Larson, Lunar and Planetary Laboratory,
University of Arizona, report the CRTS discovery of supernovae in unfiltered
Catalina Sky Survey (CSS) images:

  SN       2009 UT        R.A. (2000.0) Decl.      Mag.     Offset
  2009nl   Oct. 23.37    3 39 47.78  -11 13 25.0   18.7   0".9 E, 1".8 S
  2009nm   Nov. 20.48   10 05 24.54  +51 16 38.7   18.8   0".3 W, 0".4 N

Further magnitudes for 2009nl:  Jan. 19.45 UT, [19.8 (CSS); Sept. 22.42, 19.7
(CSS); Sept. 29.39, 19.0 (CSS); Nov. 3.25, g = 19.4, r = 18.4, i = 19.0
(Palomar 1.5-m reflector); Nov. 11.40, 18.8 (CSS); Dec. 17.22, 19.0 (CSS).
Further CSS magnitudes for 2009nm:  Apr. 24.21, [21.3; Nov. 6.48, 18.9; Dec.
18.39, 19.6.
     A spectrogram (range 460-1000 nm) of 2009nl was obtained with the Gemini
South 8-m telescope (+ GMOS-S) on Dec. 11.12 UT, and one of 2009nm (range
470-880 nm) was obtained with the Gemini North 8-m telescope (+ GMOS-N) on
Dec. 27.51.  Cross-correlation performed with a library of supernova spectra
using the "SuperNova IDentification" code (Blondin and Tonry 2007, Ap.J. 666,
1024) shows 2009nl to be most similar to the type-Ic supernova 1998bw at
66 days past maximum light.  The spectrogram of 2009nm exhibits narrow
H_alpha and H_beta lines, clearly showing that it is a type-IIn supernova at
redshift z = 0.21.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2009 CBAT
2009 December 31                 (CBET 2106)              Daniel W. E. Green