The redshift-distance relation. II. The Hubble diagram and its scatter for first-ranked cluster galaxies: a formal value for q0.

1972 ◽  
Vol 178 ◽  
pp. 1 ◽  
Author(s):  
A. Sandage
Keyword(s):  
Hubble Diagram ◽  
Cluster Galaxies ◽  
Distance Relation

scholarly journals The K-Band Hubble Diagram for X-Ray Selected Brightest Cluster Galaxies

1998 ◽  
Vol 179 ◽  
pp. 339-341
Author(s):  
R.G. Mann ◽  
C.A. Collins
Keyword(s):  
Star Formation ◽  
List Type ◽  
Type Number ◽  
Hubble Diagram ◽  
Technical Problems ◽  
X Ray ◽  
Cluster Galaxies ◽  
Brightest Cluster Galaxies ◽  
The Absolute ◽  
Small Dispersion

The Hubble (magnitude-redshift) diagram for brightest cluster galaxies (BCGs) is a classic cosmological tool, widely studied because of the remarkably small dispersion (∼ 0.3 mag) in the absolute optical magnitudes of low redshift BCGs (Postman and Lauer 1995). Extending the BCG Hubble diagram to higher redshifts would greatly enhance its role as a cosmological probe, but this has been frustrated by several technical problems: – the conventional means of cluster selection in the optical become increasingly compromised by projection effects at z > 0.1– at higher redshifts the interpretation of optical magnitudes becomes increasingly complicated by the effects of possible star formation.

scholarly journals MODIFICATIONS OF THE HUBBLE LAW IN SCALE-DEPENDENT COSMOLOGY

1996 ◽  
Vol 11 (31) ◽  
pp. 5519-5539 ◽  
Author(s):  
C.W. KIM ◽  
J. SONG ◽  
T.H. LEE
Keyword(s):  
Cosmological Model ◽  
Mass Density ◽  
Numerical Results ◽  
Luminosity Distance ◽  
Hubble Diagram ◽  
Inhomogeneous Universe ◽  
Open Universe ◽  
The Universe ◽  
Distance Relation ◽  
Increasing Function

We study some observational consequences of a recently proposed scale-dependent cosmological model for an inhomogeneous universe. In this model the universe is pictured as being inside a highly dense and rapidly expanding shell with the underdense center. For nearby objects (z≪1), the linear Hubble diagram is shown to remain valid even in this model, which has been demonstrated both analytically and numerically. For large z, we present some numerical results of the redshift luminosity distance relation and the behavior of the mass density as a function of the redshift. It is shown that the Hubble diagram in this model for a locally open universe (Ω(t0, r~0)=0.1) resembles that of the flat Friedmann cosmology. This implies that the study of the Hubble diagram cannot uniquely determine the value of q0 or Ω0. The model also accounts for the fact that Ω0 is an increasing function of the redshift.

scholarly journals The Redshift-Magnitude Relation for Radio Galaxies

1977 ◽  
Vol 74 ◽  
pp. 279-293 ◽  
Author(s):  
Harding E. Smith
Keyword(s):  
Radio Galaxies ◽  
Hubble Diagram ◽  
Great Expectations ◽  
Cluster Galaxies ◽  
The Past ◽  
Near Future ◽  
Luminosity Evolution ◽  
Test Objects ◽  
Radio Power

We examine the Hubble diagram for radio galaxies and compare radio galaxies and first-ranked cluster galaxies as cosmological test objects. Radio source identification programs are now producing reliable identifications with galaxies as faint as V ≈ 23 and spectroscopy of these objects has already resulted in the discovery of galaxies with redshifts as high as 0.75, thus there are great expectations for progress in the near future. As in the past, indeterminate corrections, notably luminosity evolution and a possible correlation between radio power and optical luminosity, preclude the determination of qo.

Sign in / Sign up

Export Citation Format

Share Document