The Malmquist bias and the value of H zero from the Tully-Fisher relation.
Abstract
A large sample (n = 395) of spiral (Sab to Sd type) galaxies having corrected apparent magnitudes BT0 and 21-cm line data (H I line widths and radial velocities) is used to investigate in a new way the influence of the Malmquist bias on the determination of the extragalactic distance scale and the Hubble constant derived from application of the B-band Tully-Fisher relation. This effect is clearly identified by using relative kinematic distances derived from a classical local velocity field model and the concept of normalized relative kinematic distance. It results in an unbiased estimate of the Hubble constant H0 which appears quite insensitive to the parameters (mean velocity of Virgo and infall velocity of the Local Group towards Virgo) adopted for the local velocity field model. A similar effect is found from a sample of galaxies (n = 72) which are "sosies" of 14 primary galaxies. According to the local distance scale adopted - due to de Vaucouleurs (deV), or Sandage and Tammann (ST) - the results are (in km s-1Mpc-1): H0 = 72±3 (deV scale), H0 = 56±3 (old ST scale), H0 = 63±3 (new ST scale). It is suggested that the presently derived H0 represents the global value of the Hubble constant.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1986
- Bibcode:
- 1986A&A...156..157B
- Keywords:
-
- Distance;
- Hubble Constant;
- Spiral Galaxies;
- Bias;
- H Lines;
- Local Group (Astronomy);
- Radial Velocity;
- Spectral Line Width;
- Velocity Distribution;
- Virgo Galactic Cluster;
- Astrophysics