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CRTS discovery of a long timescale type-IIn SN

ATEL # 2149; A.J. Drake, S.G. Djorgovski, D. Levitan, A.A. Mahabal, M.J. Graham, R. Williams (Caltech); A. Myers (UIUC); M. Catelan (PUC); E.C. Beshore, S.M. Larson (LPL/UA); E. Christensen (Gemini Observatory)
on 6 Aug 2009; 7:52 UT
Password Certification: Andrew J. Drake (

Subjects: Optical, Nova, Supernova, Transients

We report on the discovery of an energetic type-IIn SN by the Catalina Real-Time Transient Survey (CRTS).

IDDisc. DateRADec
CSS080701:234413+075224 2008-07-01 UT 10:16:39 23:44:12.82 07:52:23.6

The CSS and Palomar 60" light curves show that the SN's brightness rose from V-mag~20.2 to 18.5 by Dec 30th 2008, and then very slowly decline to mag ~19.3 by July 31st 2009. A spectrum was taken with the Palomar 5m+DBSP on 2009 July 23 UT and shows strong, broad, asymmetric H-alpha emission along with H-beta, H-gamma, and Helium lines at redshift z=0.069. The spectrum most resembles the type-IIn SN 2007rt at 260 days past explosion (Trundle et al. 2009).

A faint host galaxy is seen in SDSS data (mags: u=23.2, g=22.0, r=21.4, i=20.9, z=20.6). The peak absolute magnitude of the SN, derived from the redshift, is Mv= -18.8 (typical for a type-IIn). Such slow evolution suggests significant ongoing interaction with CSM similar to the very long timescale type-IIn 2008iy (ATEL#2010).

Current CRTS candidate and confirmed SNe can be found at here.
More details of the CRTS project are available at

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