Du Pont Classification of ASASSN-15ou
ATel #8011; Benjamin J. Shappee (Hubble Fellow, Carnegie Observatories), Jose L. Prieto (Diego Portales; MAS), Mark Seibert (Carnegie Observatories), Evelyn Johnston (ESO)
on 7 Sep 2015; 21:21 UT
Credential Certification: Benjamin Shappee (bshappee@obs.carnegiescience.edu)
Subjects: Optical, Supernovae
We report optical spectroscopy (range 370-910 nm) of ASASSN-15ou obtained on Sept. 4 UT with the du Pont 2.5-m telescope (+ WFCCD) at Las Campanas Observatory.
ASASSN-15ou was discovered (ATel #7944) with no nearby galaxy listed within an arcminute of ASASSN-15ou position in NED. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates the spectrum of ASASSN-15ou is a Type Ia a few weeks after maximum brightness with z=0.048(0.005). The sub-type is not certain, but the best-fit template SNe were the peculiar SNe 1999aa (at +20.1 days) and 1991T (at +17.3 days). These epochs are consistent with the photometry reported in ATel #7944.
Assuming the redshift fit by SNID gives a distance of 210 (20) Mpc, a distance modulus of 36.6 (0.2) mag, and an absolute V-band magnitude of approximately -19.7 (0.2) mag with negligible Milkyway reddening (A_V = 0.02 mag).
