The Hubble diagram for supernovae.
Abstract
The distribution of 47 type I and 13 type II supernovae (SN) in the Hubble diagram is presented and evaluated. Values of the parameter Mpg(100) and the dispersion are determined by least-squares fits to various data subsets, and the results are compared with those of previous studies. Sources of scatter are considered, specifically inaccurate corrections for interstellar extinction in the Galaxy, systematic and random departure from a strict proportionality between velocity and distance, errors in estimates of apparent magnitudes at maximum brightness, and interstellar extinction in the parent galaxies. It is found that: (1) the observed dispersion among type I SN in elliptical galaxies is comparable to that expected from the first three sources of scatter; (2) only two of the type I SN occurred in irregular galaxies; (3) the distribution of type I SN in spirals shows a steeper slope than would be expected in the absence of scatter; and (4) the best value for the mean absolute magnitude should be that obtained for SN in ellipticals, corresponding to Mpg(100) = -18.70, provided the intrinsic properties of type I SN do not depend on parent-galaxy type
- Publication:
-
The Astronomical Journal
- Pub Date:
- March 1978
- DOI:
- 10.1086/112196
- Bibcode:
- 1978AJ.....83..224B
- Keywords:
-
- Hubble Diagram;
- Supernovae;
- Elliptical Galaxies;
- Interstellar Extinction;
- Least Squares Method;
- Spiral Galaxies;
- Astronomy;
- Hubble Diagram:Supernovae;
- Luminosities:Supernovae