| Title | Determination of the Hubble Constant, the Intrinsic Scatter of Luminosities of Type Ia Supernovae, and Evidence for Nonstandard Dust in Other Galaxies |
| Authors | Wang, Xiaofeng; Wang, Lifan; Pain, Reynald; Zhou, Xu; Li, Zongwei |
| Bibcode | 2006ApJ...645..488W Search ADS ↗ |
| Abstract | A sample of 109 Type Ia supernovae (SNe Ia) with recession velocity <~30,000 km s-1 is compiled from published SN Ia light curves to explore the expansion rate of the local universe. Based on the color parameter ∆C12 and the decline rate ∆m15, we found that the average absorption-to-reddening ratios for SN Ia host galaxies are RUBVI=4.37+/-0.25, 3.33+/-0.11, 2.30+/-0.11, and 1.18+/-0.11, which are systematically lower than the standard values in the Galaxy. We investigated the correlations of the intrinsic luminosity with light-curve decline rate, color index, and SN environmental parameters. In particular, we found that SNe Ia in E/S0 galaxies close to the central region are brighter than those in the outer region, which may suggest a possible metallicity effect on SN luminosity. The dependence of SN luminosity on galactic environment disappears after corrections for the extinction and ∆C12. The Hubble diagrams constructed using 73 Hubble flow SNe Ia yield a 1 σ scatter of <~0.12 mag in BVI bands and ~0.16 mag in U band. The luminosity difference between normal SNe Ia and peculiar objects (including SN 1991bg-like and SN 1991T-like events) has now been reduced to within 0.15 mag via ∆C12 correction. We use the same precepts to correct the nearby SNe Ia with Cepheid distances and found that the fully corrected absolute magnitudes of SNe Ia are MB=-19.33+/-0.06 and MV=-19.27+/-0.05. We deduced a value for the Hubble constant of H0=72+/-6 (total) km s-1 Mpc-1. |
| Objects | 218 Objects Search NED ↙ |
