NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-20 T00:28:53 PDT
Help | Comment | NED Home

For refcode 2012ApJ...754L..21F:
Retrieve 50 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2012ApJ...754L..21F Evidence for Asymmetric Distribution of Circumstellar Material around Type Ia Supernovae Forster, Francisco; Gonzalez-Gaitan, Santiago; Anderson, Joseph; Marchi, Sebastian; Gutierrez, Claudia; Hamuy, Mario; Pignata, Giuliano; Cartier, Regis Abstract. We study the properties of low-velocity material in the line of sight toward nearby Type Ia supernovae (SNe Ia) that have measured late phase nebular velocity shifts (v_neb_), thought to be an environment-independent observable. We have found that the distribution of equivalent widths of narrow blended Na I D1 and D2 and Ca II H and K absorption lines differs significantly between those SNe Ia with negative and positive v_neb_, with generally stronger absorption for SNe Ia with v_neb_ >= 0. A similar result had been found previously for the distribution of colors of SNe Ia, which was interpreted as a dependence of the temperature of the ejecta with viewing angle. Our work suggests that (1) a significant part of these differences in color should be attributed to extinction, (2) this extinction is caused by an asymmetric distribution of circumstellar material (CSM), and (3) the CSM absorption is generally stronger on the side of the ejecta opposite to where the ignition occurs. Since it is difficult to explain (3) via any known physical processes that occur before explosion, we argue that the asymmetry of the CSM is originated after explosion by a stronger ionizing flux on the side of the ejecta where ignition occurs, probably due to a stronger shock breakout and/or more exposed radioactive material on one side of the ejecta. This result has important implications for both progenitor and explosion models. Key words: distance scale, supernovae: general
Retrieve 50 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home