The Delay Time Distribution of Type Ia Supernovae: Constraints on Progenitors Chris Pritchet (U. Victoria), Mark Sullivan (Oxford), Damien LeBorgne (IAP), Matt Taylor (PUC Chile), + SNLS Collaboration

UWO Sep In the Garden of Flux Variables CC SNe.Ia's? LRNe? Kulkarni et al LRNe=luminous red novae like the M85 transient SN Ia

UWO Sep Mt Wash Feb 2009 brightness L sun, Std candle progenitor 1 or 2 white dwarfs: mechanism mass transfer or merger progenitor age ~ yr: evolution with z Little: Remnant (ns/bh) no Metals ejected Fe, Ni … 10 9 L sun Not std candle massive star core collapse: ~10 7 yr (1+z) 2-4 : yes O, Ne, Si … or SNe Ia CC SNe

brightness L sun, Std candle progenitor 1 or 2 white dwarfs: mechanism mass transfer or merger progenitor age ~ yr: evolution with z Little: Remnant (ns/bh) no Metals ejected Fe, Ni … UWO Sep Mt Wash Feb 2009 or SNe Ia energy release CO  Fe no H in spectrum light curve shape presence in old stellar pops progenitor mechanism – 2 broad classes

5 SN Ia Progenitors - 2 Broad Classes Single Degenerate - white dwarf + 2ndary evol. (M ~ 1.4 M sun at explosion) Double Degenerate - 2 white dwarfs (M tot >= 1.4 M sun at explosion) Key point: white dwarf maximum mass M = 1.4 M sun (Chandrasekhar mass)

brightness L sun, Std candle progenitor 1 or 2 white dwarfs: mechanism mass transfer or merger progenitor age ~ yr: evolution with z Little: Remnant (ns/bh) no Metals ejected Fe, Ni … UWO Sep Mt Wash Feb 2009 or SNe Ia energy release CO  Fe no H in spectrum light curve shape presence in old stellar pops progenitor mechanism – 2 broad classes

7 Type Ia SNe as Standard Candles  Bright - seen to cosmological distances  Max brightness makes an excellent standard candle - ±6% distance errors  Standard candle seems to have a physical basis  SNeIa are “well-understood” - thermonuclear disruptions of C+O white dwarfs - std physics  Systematics – possibly, but ample opportunity to study with potentially hundreds of objects  But …  explanation of stretch – L relation  explanation of colour – L relation  nature of scatter in L after calibration  nature of progenitor

Delay time distribution DTD(t) = rate of supernovae as a function of time from a burst of star formation SNR(t) = SFR(t) ★ DTD(t) log t SFR(t) DTD(t) SNe/yr/10 10 M 

Importance of DTD(t) potential to discriminate among progenitor models Greggio 2005

DTD History pre-1990 – “prevailing wisdom” was that all SN Ia were old because they occur in E/S0 galaxies by 2004 – SNe Ia have higher rates in young galaxies – both young and old progenitors

Recent DTD Determinations Totani et al 2008: Subaru/XMM survey 65 variable objects ages from SED fitting from age/SFH estimates of SN host and field galaxies (SN age ~ galaxy age)

Recent DTD Determinations from age/SFH estimates of SN host and field galaxies Maoz Maoz et al 2010: LOSS survey 82 SNeIa SFH from SDSS

Supernova Legacy Survey (SNLS) , 4 deg 2, ugriz, 4d samples, CFHT 3.6m+MegaCam spec types and z (VLT, Gemini, Keck) SNe Ia (0.2<z<1)

DTD from SNLS completeness estimate and weight for each supernova host galaxy age for each supernova … assumes host age = SN progenitor age … and an age for all other objects too gives total available mass at a given age

z distribution and completeness Perrett et al 2011 SNIa* SNIa

SN weighting Perrett et al 2011 length of each observing season SNe / year (all fields, rest-frame) # of observing seasons

Pegase/zpeg ages and redshifts mass, SFR, age, z for different evol scenarios

DTD Calculation Use only SNe with hosts in magnitude-limited catalogue assumes that SN DTD does not depend on host galaxy mass In each time bin of DTD t1  t2, sum w i values for SNe with t 1 <t i <t 2 ; normalize by host mass in time bin:

2 different M(t) methods 0.2 < z < 0.75, 4 SNLS fields (3.6 deg 2 ) dashed=SFR(z), solid=zpeg SED fits log t log M(t) log M Hopkins and Beacom 2006 SFR(z)

DTD other z ranges give the same result

DTD from 2 different M(t) methods 0.2 < z < 0.75, red=SFR(z), black=obs

Comparison with Totani et al 2008 Mannucci Totani t -1

Power-law fit t -1.35

Two power laws t -0.7 t -3 cutoff real

Comparison with DD solid – Mennekens et al 2010 dotted – Ruiter et al 2009 dashed – Yungelson and Livio 2000

Comparison with SD solid – Mennekens et al 2010 dotted – Ruiter et al 2009 dashed – Hachisu et al 1999 dash dot – Han and Podsiadlowski 2004

Further corrections Have assumed that T SN =. Not necessarily true iterative approach to correct statistically correction for dead stars slope steeper by ~0.1 effects of bursts effects of catastrophic errors in M or age

Making a standard candle Supernova light curve stretch s aka Phillips relation

Stretch dependence of DTD not due to age systematics two types of progenitors?? or …

Conclusions SNIa DTD may be more complex than a simple ~ 1/t power-law match to DD population synthesis models pop syn needs further work s 1 show differences in DTD below 10 9 yr – different progenitors? or PDF of ages?