2010CBET.2156....1C

Further to CBET 2151, E. Christensen, Gemini Observatory; A. J. Drake, S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology; J. L. Prieto, Carnegie Observatories; 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 a supernova in unfiltered Catalina Sky Survey (CSS) images.

---------------------------------------------------------------------------— SN 2009 UT R.A. (2000.0) Decl. Mag. ---------------------------------------------------------------------------— 2009ny Oct. 20.14 22 11 23.59 - 9 12 44.4 18.2 ---------------------------------------------------------------------------—

Further CSS magnitudes for 2009ny: 2009 Sept. 27.17, [20.8; Oct. 9.18, 19.7; Nov. 11.11, 19.6; Dec. 19.07, [20.0. The supernova matches the location of a 23rd-magnitude object detected in a number of VR-filter images taken via the NOAO Deep Wide Field Survey from 2000 to 2003. A confirming spectrogram (range 500-870 nm) was obtained using the Gemini South 8-m telescope (+ GMOS) on Nov. 8 UT. Cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (Blondin and Tonry 2007, Ap.J. 666, 1024) shows the best match for 2009ny to be with the type-Ib supernova 1999di at one month past maximum light at redshift z = 0.057. However, the spectral lines are clearly weaker than the closest SNID match, and the photometry suggests that the event was near two weeks past maximum.