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trinitree88
2010-Nov-23, 04:20 PM
OK. New stuff on supernovae I like...but you knew that. Measuring ejecta velocity improves type 1a distances SEE:http://arxiv.org/PS_cache/arxiv/pdf/1011/1011.4517v1.pdf

antoniseb
2010-Nov-23, 06:54 PM
It's nice to have a filter that gets SN 1a to withing 0.1 magnitudes of being a true standard candle.

trinitree88
2010-Nov-23, 08:20 PM
It's nice to have a filter that gets SN 1a to withing 0.1 magnitudes of being a true standard candle.

Antoniseb. Yep. Anything that can standardize our candles better,.. is welcome.. Pete

Jerry
2011-Jun-18, 05:45 AM
] arXiv:1106.3071 [pdf, ps, other]
Title: Super-Chandrasekhar SNe Ia Strongly Prefer Metal-Poor Environments
Authors: Rubab Khan, K. Z. Stanek, R. Stoll, J. L. Prieto
Comments: 12 pages, 4 figures, submitted to ApJ
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
We discuss the emerging trend that super-Chandrasekhar Type Ia Supernovae (SCSNe) with progenitor mass estimates significantly exceeding 1.4 M_sun tend to explode in metal-poor environments. While Taubenberger et al. 2011 noted that some of the SCSNe host galaxies are relatively metal-poor, we focus quantitatively on their locations in the hosts to point out that in three out of four cases, the SCSNe explosions occurred in the outer edge of the disks of their hosts. It is therefore very likely that their progenitors had far lower metallicities than those implied by the metallicity of their hosts' central regions. In two cases (SN 2003fg and SN 2009dc) the explosion sites were outside 99% of the host's light, and in one case (SN 2006gz) the host's radial metallicity slope indicates that the explosion site is in a metal-poor region. The fourth case (SN 2007if) has the lowest spectroscopically measured SN Ia host metallicity (Childress et al. 2011. It may be possible to explain each of these unusually bright events through some progenitor scenario specific to that case, but a much simpler and straightforward conclusion would be to ascribe the controlling factor to the only physical aspect they have in common --- metal poor environments.