A1 Refereed original research article in a scientific journal
A statistical analysis of circumstellar material in Type Ia supernovae
Authors: Maguire K, Sullivan M, Patat F, Gal-Yam A, Hook IM, Dhawan S, Howell DA, Mazzali P, Nugent PE, Pan YC, Podsiadlowski P, Simon JD, Sternberg A, Valenti S, Baltay C, Bersier D, Blagorodnova N, Chen TW, Ellman N, Feindt U, Foerster F, Fraser M, Gonzalez-Gaitan S, Graham ML, Gutierrez C, Hachinger S, Hadjiyska E, Inserra C, Knapic C, Laher RR, Leloudas G, Margheim S, McKinnon R, Molinaro M, Morrell N, Ofek EO, Rabinowitz D, Rest A, Sand D, Smareglia R, Smartt SJ, Taddia F, Walker ES, Walton NA, Young DR
Publisher: OXFORD UNIV PRESS
Publication year: 2013
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Journal acronym: MON NOT R ASTRON SOC
Volume: 436
Issue: 1
First page : 222
Last page: 240
Number of pages: 19
ISSN: 0035-8711
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/stt1586
Web address : https://academic.oup.com/mnras/article/436/1/222/973872
A key tracer of the elusive progenitor systems of Type Ia supernovae (SNe Ia) is the detection of narrow blueshifted time-varying Na I D absorption lines, interpreted as evidence of circumstellar material surrounding the progenitor system. The origin of this material is controversial, but the simplest explanation is that it results from previous mass-loss in a system containing a white dwarf and a non-degenerate companion star. We present new single-epoch intermediate-resolution spectra of 17 low-redshift SNe Ia taken with XShooter on the European Southern Observatory Very Large Telescope. Combining this sample with events from the literature, we confirm an excess (similar to 20 per cent) of SNe Ia displaying blueshifted narrow Na I D absorption features compared to redshifted Na I D features. The host galaxies of SNe Ia displaying blueshifted absorption profiles are skewed towards later-type galaxies, compared to SNe Ia that show no Na I D absorption and SNe Ia displaying blueshifted narrow Na I D absorption features have broader light curves. The strength of the Na I D absorption is stronger in SNe Ia displaying blueshifted Na I D absorption features than those without blueshifted features, and the strength of the blueshifted Na I D is correlated with the B - V colour of the SN at maximum light. This strongly suggests the absorbing material is local to the SN. In the context of the progenitor systems of SNe Ia, we discuss the significance of these findings and other recent observational evidence on the nature of SN Ia progenitors. We present a summary that suggests that there are at least two distinct populations of normal, cosmologically useful SNe Ia.
