A high intrinsic peculiarity rate among Type Ia supernovae

Citation
Wd. Li et al., A high intrinsic peculiarity rate among Type Ia supernovae, ASTROPHYS J, 546(2), 2001, pp. 734-743
Citations number
62
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004-637X → ACNP
Volume
546
Issue
2
Year of publication
2001
Part
1
Pages
734 - 743
Database
ISI
SICI code
0004-637X(20010110)546:2<734:AHIPRA>2.0.ZU;2-8
Abstract
We have compiled a sample of 45 Type Ia supernovae (SNe Ia) discovered by t he Lick Observatory Supernova Search (LOSS) and the Beijing Astronomical Ob servatory Supernova Survey (BAOSS), and determined the rate of spectroscopi cally peculiar SNe Ia (i.e., SN 1986G-like, SN 1991bg-like, and SN 1991T-li ke objects) and the luminosity function of SNe Ia. Because of the nature of the two surveys (distance-limited with small baselines and deep limiting m agnitudes), nearly all SNe Ia have been discovered in the sample galaxies o f LOSS and BAOSS; thus, the observed peculiarity rate and luminosity functi on of SNe Ia are intrinsic. We find that 36% +/- 9% of nearby SNe Ia are pe culiar; specifically, the luminosity function of SNe Ia consists of 20% SN 1991T-like, 64% normal, and 16% SN 1991bg-like objects. We have compared ou r results to those found by earlier studies, and to those found at high red shift. The apparent dearth of SN 1991T-like objects at high redshift may be due to extinction, and especially to the difficulty of recognizing them fr om spectra obtained past maximum brightness or from spectra with low signal -to-noise ratios. Implications of the high peculiarity rate for the progeni tor systems of SNe Ia are also briefly discussed.