DTD of SNe Ia from SNLS - Preliminary Results

1. The DTD of SNe Ia from SNLS – Preliminary Results Chris Pritchet (U. Victoria) Mark Sullivan (Oxford U.) Damien Le Borgne (IAP) + SNLS Collaboration

2. Delay time distribution • DTD(t) = rate of supernovae as a function of time from a burst of star formation DTD(t) SNe/yr/1010 M SFR(t) t

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

4. 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

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

6. Recent DTD Determinations • from SFR(z) • from age/SFH estimates of SN host and field galaxies (SN age ≈ galaxy age) Maoz et al 2010: LOSS survey 82 SNeIa SFH from SDSS Maoz

7. Supernova Legacy Survey (SNLS) • 2003-2008, 4 deg2, ugriz, 4d samples, CFHT 3.6m+MegaCam • spec types and z (VLT, Gemini, Keck) - 370 SNeIa (0.2<z<1)

8. z distribution and completeness SNIa* SNIa • Perrett et al 2011

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

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

11. 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 wi values for SNe with t1<ti<t2; normalize by host mass in time bin:

12. 2 different M(t) methods • 0.2 < z < 0.75, 4 SNLS fields (3.6 deg2) • dashed=SFR(z), solid=observed SFR(z) log M log M(t) Hopkins and Beacom 2006 log t

13. DTD • other z ranges give the same result

14. Comparison with Totani et al 2008 t-1 Totani Mannucci

15. Power-law fit t-1.35

16. Two power laws t-0.7 t-3 cutoff real

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

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

19. Further corrections • Have assumed that TSN=<Thost>. 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

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

21. stretch dependence of DTD • not due to age systematics • two types of progenitors??

22. Conclusions • simple DTD ~ 1/t may not be the best description of the SN Ia DTD • excellent match to Mennekens et al 2010 population synthesis models • s<1 and >1 show differences in DTD below 109 yr – different progenitors?

28. t-1 Totani Mannucci

29. t-1 Totani Mannucci

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

32. Making a standard candle

33. Making a standard candle