Spectral Classification of MASTER J221505.32+101812.6
ATel #4229; J. M. Silverman, D. P. Cohen, and A. V. Filippenko (University of California, Berkeley)
on 30 Jun 2012; 04:05 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Alexei V. Filippenko (alex@astro.berkeley.edu)
Subjects: Optical, Supernovae
We report that inspection of a CCD spectrum (range 340-1000 nm), obtained on June 27.4 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that MASTER J221505.32+101812.6 (ATel #4213) is a Type Ia supernova (SN Ia). Cross-correlation with a library of SN spectra using the "SuperNova IDentification" code (SNID; Blondin & Tonry 2007, Ap.J. 666, 1024) indicates that the object is a normal SN Ia near maximum brightness at a redshift of 0.090. At this redshift, the reported unfiltered magnitude of 16.8 mag (ATel #4213) implies an absolute magnitude of -21.3 mag, which is much more luminous than nearly all SN Ia (and certainly more luminous than spectroscopically normal SN Ia). Also, the object appeared fainter than mag 16.8 on the TV guider during the spectroscopic observations. We suggest that there may be a mistake in the observed (and limiting) magnitudes presented in ATel #4213.
