1. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology The “Union” Supernova Ia Compilation and new Cosmological Constraints Marek Kowalski Humboldt Universität zu Berlin for the Supernova Cosmology Project Moriond 2008

2. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology The Union SNe Compilation    M 1 0 0.72 0.28 0 1 fainter 8 new SNe

3. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Analysis aspects Consistent Lightcurve Fits SALT fitter used for all SNe using mostly original band-passes (Guy et al 2005/2007). Blind analysis The analysis (i.g. cuts) were developed on a blinded data set, all luminosities were offset by a hidden redshift-dependent amount. Robust analysis Initial cosmological fit using median statistics. 3-sigma outliers removed. Assignment of sample dependent dispersion. Stretch and color corrected luminosity: Large sample of SNe allows new studies of systematic errors

4. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology A heterogenous data sample

5. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Study of - mean deviation - residual slope A heterogenous data sample

6. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Test for Tension high-z low-z mean deviation: OK

7. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Test for Tension high-z low-z residual slope: (OK)

8. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Testing SN evolution by subdividing the sample Evolution test: Redshift No significant evidence for evolution! Evolution test: Population

9. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Systematic errors Nuisance parameters for systematic errors: common for all z>0.2 SNe sample dependent

10. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Comparison with previous compilations Union Riess Gold Davis 2007 Union w/o New SCP SNe without the 8 new nearby SNe 184 SNe192 SNe307 SNe

11. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Perlmutter et al., 1999 Results: Cosmological fit parameters MM  MM Combination of SNe with: BAO (Eisenstein et. al., 2005) CMB (WMAP-5 year data, 2008) For a flat Universe: … and with curvature:

12. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Equation of state: w =p/  SNe + BAO + CMB... and allowing for curvature: With systematics

13. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Redshift dependent w w=w 0 + (1-a) w a w 0 + w a = 0

14. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Redshift dependent w Assuming step-wise constant w: A floating non-SNe bin to decouple low from high-redshift constraints

15. 17.3.2008 Marek Kowalski Moriond 2008 - Cosmology Summary The Union SN compilation provides a consistently analyzed data set, and with new nearby SNe, is the largest available. Investigations of systematics show no significant tension between the individual samples as well as no evidence for SN evolution. The strongest constraints to date on the dark energy density and the equation of state parameter w, however, essentially no constraints at z>1. A detailed paper has been submitted to ApJ and the data will soon be made available on the web (see http://supernova.lbl.gov)http://supernova.lbl.gov)