SN Ia diversity as an indicator of multiple

progenitors?

Andy HowellUniversity of California, Santa Barbara

Las Cumbres Observatory Global TelescopeImage:

UC Santa Barbara

The Astonomer by CandlelightGerrit Dou (~1665-1660)

Getty Museum, Los Angeles, CA

Dou was Rembrandt's first student and later the leader of the "fijnschilders" (fine painters), a group of painters in Leiden.

Fijnschilders were known for their meticulous attention to detail in striving to reproduce reality as closely as possible. They are also known for everyday subjects, nocturnal scenes, and “trompe l’oeil” (niche) paintings.Quote from the Getty:“The prominent candle and hourglass are traditional symbols of the brevity of life, suggesting that the astronomer symbolizes the vanity of the human desire to comprehend the infinite”

Zoals de ouden zongen piepen de jongen As the old sang, so do the young shriekJan Steen (Leiden)

About the old corrupting the young

Cubist version!So there is a progenitor!

Outline: SN Ia diversity as an indicator of multiple progenitors

What counts as a SN Ia? Rates / Delay Time DistributionsEnvironmentSpectraCSMReddening Pros / Cons of models

SN 2007if +5d; Scalzo et al. 2010

Foley et al. 2010

What counts as a SN Ia?

MMNiNi MMejej refref

NormalNormal ~0.2-0.9

1-1.4Stritzing

er

SN SN 2007if2007if

1.6 2.4 Scalzo

08ha08ha ~0.001?

~0.2? Foley

Data: McClelland et al. 2010, Scalzo et al. 2010

Fact

or

of

60

0

Fact

or

of

20

What counts as a SN Ia?

Sullivan et al. 2010 (SNLS)

Environment

Sullivan et al. 2010 (SNLS)Environment

Maoz et al. 2010 (LOSS)

Brandt et al. 2010 (SDSS)

Probably not two clearly distinct channels. A continuum? But stretch, luminosity depend on age!Can one model explain all?

Rates / Delay Time Distributions

Branch et al. 2009: SiII phenomenology. Combines abundance, temperature, velocity effects

Spectra

X. Wang et al. 2009

Benetti et al. 2006

Spectra: Velocities

X. Wang et al. 2009

Reddening

Maeda et al. 2010

Spectra

Maeda et al. 2010

Spectra

Reddening

Folatelli et al. 2010 (CSP)

CSM: Variable Sodium

Simon et al. 2009 SN 2007le: Na I D strengthens over time. Consistent with dense (107 cm-3) cloud ~0.1 pc from SN. EB-V=0.27

Blondin et al. 2009 Out of 31 low-res spectra where variable Na I D at the level in SN 2006X could have been detected, only 2 (6%), SN 2006X and SN 1999cl, showed variable Na I D. These were the most highly reddened objects in the sample: EB-V(host)>1 mag

Patat et al. 2007 SN 2006X: Na I D strengthens over time (but not Ca II H&K). Consistent with CSM ionization, then recombination.

Hamuy et al. 2003, Aldering et al. 2006 SN Ia in CSM. Recent mass loss. Secondary is AGB star?

Some say not a Ia: Benetti et al. 2006

But Hydrogen not seen even at late times in two SNe with good limits: Leonard et al. 2007

CSM: SNe IIn-Ia, SN 2002ic and SN 2005gj

ConclusionsWhat counts as a SN Ia?-We aren’t sure. Large Diversity.Rates / Delay Time Distributions- Probably not a bimodal distribution- But stretch/luminosity depends on delay time- SD model has a hard time explaining all SNeEnvironment- Galaxy size plays a role, possibly implicating metallicity- Age of progenitor probably matters- SNe correct to different abolute magnitudes in different environments- Reddening or color depends on host galaxySpectra- SNe Ia can be grouped based on spectra features- This is especially true of velocity. - Geometric effects may unify some of the diversityCSM- Some SNe show signs of CSM, but they are the minority- Different progenitors or geometric effects?Reddening - Reddening depends on host- Reddening probably depends on dust amount / density - Some may be intrinsic SN color/luminosity relaion- Some may be circumstellar.

Howell et al. 2010