Method for determining maximum-likelihood distance moduli for groups of galaxies

Journal Article · Sun Feb 01 04:00:00 EST 1976 · Astrophys. J., v. 203, no. 3, pp. 557-568

DOI:https://doi.org/10.1086/154112· OSTI ID:4028339

Schechter, P; Press, W H

Two new procedures for estimating distance moduli for groups of galaxies are set forth. Both procedures construct a synthetic, characteristic apparent magnitude m*, using the measured apparent m$sub 1$,...,m/sub N/ of the N brightest group memebers. The distance modulus m*-M* then follows from a known universal absolute magnitude M*. The observer may choose any convenient value for N> or =1, with larger N giving better accuracy. The procedures for computing m*, derived here from a maximum-likelihood statistical analysis and an empirical galaxy luminosity function, are reduced to simple numerical tables. One of the two procedures, useful only for rich clusters, is a generalization of Sandage's ''single-brightest'' standard candle. The other one is closely related to Abell's luminosity-function break'' method, and is useful for sparse groups as well as for rich clusters. Various tests of the procedures on actual data are shown, and a detailed example of their use is included. (AIP)

• Research Organization: Institute for Advanced Study
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-030814
• OSTI ID: 4028339
• Journal Information: Astrophys. J., v. 203, no. 3, pp. 557-568, Journal Name: Astrophys. J., v. 203, no. 3, pp. 557-568; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

*GALAXY CLUSTERS-- DISTANCE
640105* --Physics Research--Astrophysics & Cosmology-- Galaxies
CEPHEIDS
COSMOLOGY
LUMINOSITY
MAXIMUM- LIKELIHOOD FIT
N56500* --Physics (Astrophysics & Cosmology)--Galaxies
PHOTOMETRY
RADIAL VELOCITY