Spectroscopic classification of three supernovae from Asiago
ATel #4019; L. Tomasella, S. Benetti, E. Cappellaro, A. Pastorello, P. Ochner, M. Turatto and S. Valenti (Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica)
on 6 Apr 2012; 08:49 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Stefano Benetti (stefano.benetti@oapd.inaf.it)
Subjects: Optical, Supernovae, Transient
We report the spectroscopic confirmation of three transients on observations taken with the 1.82-m Copernico Telescope (+ AFOSC; range 340-790 nm, resolution about 2.2 nm).
A spectrogram of CRTS Transient CSS120330:101639-064636 obtained on Mar. 31.81 shows H-alpha and H-beta lines with a complex shape superimposed on a relatively blue continuum. The Balmer lines consist of a broad component (FWHM about 6000 km/s) in emission, superimposed by a second component having a narrow but resolved emission profile (expansion velocity about 1000 km/s and emission peaks measured at 683.8 and 506.0 nm). From these peaks
we derive a redshift of 0.0415 for the parent galaxy. The comparison with a library of supernovae spectra via GELATO (Harutyuyan et al. 2008, A.Ap. 488, 383), gives a best fit with the type IIn SN 1995G (Pastorello et al. 2002, MNRAS 333, 27).
A spectrum of CRTS Transient CSS120328:122417+185529 obtained on Apr. 01.06 UT shows that this transient is a type II SN with strong Balmer lines, in particular a broad H-alpha emission with FWHM corresponding to about 11000 km/s.
Cross-correlation with a library of supernova spectra via the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) returns a best fit with the type IIP SN 2004et soon after explosion and a redshift z=0.019.
A spectrum of CRTS Transient CSS120328:152302+071141 obtained on Apr. 01.12 UT shows that the transient is a type Ia SN.
Cross-correlation with a library of supernova spectra via the SNID code shows a best fit with several standard SN Ia near maximum and a redshift z=0.066. Hereafter the expansion velocity derived from the deep SiII absorption is about 11500 km/s.
