Spectroscopic signatures of SN Ia progenitorsA talk not about the Palomar Transient Factory

Avishay Gal-Yam,

Weizmann Institute of Science

Leiden workshop 2010

Preamble

• Lots of time for questions

• What is a type Ia SN?

• Not going to cover: CSM interaction, CSM absorption

The basics: data+models

Sauer et al. 2008

• Chandrasekhar-mass C/O models fit the data well

Progenitor signatures: 1

• Hydrogen and helium: no convincing evidence

Progenitor signatures: 2

• Carbon: evidence for C/O progenitor (not O/Ne)

• Indicative of deflagration

• Strong in super-C events (Howell)

Mazzali 2001

Tanaka et al. 2010

Howell et al. 2006

Progenitor signatures: 3

• Ca high-velocity features – CSM (SD)?

• Or else, 3D effects?

Tanaka et al. 2008

Faint events (1991bg-like)

• High velocity oxygen shell

• No outer He shell

Mazzali et al. 1997

Interim summary

• SNe Ia are explosions of C/O WDs with mass ~MCh

• How much C survives ?

• There are no traces of H or He (no outer He shell)

• H CSM may be indicated (SD)

What are SNe Ia? What can we learn from other SNe?

Shy cousins: SN 2005E

LOSS discovery

Graham & Li 2005

Type Ib (UCB; CCCP)

Member of the Ca-rich Subclass (Filippenko et al.)

Hagai Perets, Nature, in press

Dave Arnett, Paolo Mazzali, Daniel Kagan, UCB SN group,

CCCP, Anderson & James, Ofek, Bildsten & Co., Quataert & Co.

A massive star?No star formation to deep limits … unlikely also on theoretical grounds

Perets et al. 2009

r<25.3 (25.9) at 3(2)

A hyper-velocity SN (HVSN) ?Life in the fast lane?

SN 2005E

11.3 kpc

22.9 kpc

Not likely: chances to observe HVSNe with LOSS are < 1/100

So what, then?What will nebular spectra reveal?

Peculiar abundances (C, O, Ca, Ni56) = (0.1 0.037 0.135 0.003) solarTotal ejected mass is <0.3 solar !

Mazzali

Not a single event!6-10 additional siblings, additional early hosts

What can it be?A double WD (O/Ne+He): accretion induced collapse ?

Or else, CO/He DD merger (Waldman models)

NucleosynthesisCan you make so much Ca with no Si and S? (Ca/S >6)

*No (if you burn C/O)

*Yes (if you burn He)Models by Arnett}

Confirmed by details models by Waldman et al.

Can we start mapping?

Normal SNe Ia:

SD?

SN 2005E

CO/He DD?

Faint SNe Ia:

CO/CO DD?

Thanks