Showing papers on "Brightest cluster galaxy published in 1971"
189 citations
TL;DR: New observational evidence of X-ray emission is presented which limits the amount of hot intracluster gas to less than 2 % of that required for gravitational binding.
Abstract: THE Coma cluster of galaxies is usually considered to contain insufficient matter in the form of galaxies to be gravitationally bound, but the high degree of symmetry of the cluster, and the presumed age of its galaxies, suggest that the cluster is, in fact, gravitationally bound. It is possible that the missing mass takes the form of ionized intracluster gas, and Woolf1 has used radio, visible light and X-ray observations to set upper limits for the amount of such matter and, more recently, Turnrose and Rood2 have discussed the problems of heating and supporting such a gas against gravitational collapse. We present here new observational evidence of X-ray emission which limits the amount of hot intracluster gas to less than 2 % of that required for gravitational binding.
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TL;DR: In this article, corrected NGC and IC identifications are given for galaxies in the Hercules cluster, as well as accurate positions, revised types, apparent diameters, and luminosity classes for the brighter spirals.
Abstract: Corrected NGC and IC identifications are given for galaxies in the Hercules cluster, as are accurate positions (::::: 5"), revised types, apparent diameters, and luminosity classes for the brighter spirals. The distance of the cluster is found to be about 90 megaparsecs, and its dimensions are 2.7 Mpc by 1.3 Mpc. Key word: clusters of galaxies
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TL;DR: Using the mean ratio of mass to 10-O.4M (luminosity) as mentioned in this paper allows determination of the mean cosmic density from galaxy counts and galaxy masses alone, without the need for luminosity flinctions.
Abstract: Use of the mean ratio of mass to 10-O.6M, where M is the absolute magnitude, instead of the ratio of mass to 10-O.4M (luminosity) allows determination of the mean cosmic density from galaxy counts and galaxy masses alone, without the need for luminosity flinctions. Available data indicate a mean density of 2 to 5 X 10- 1 g , for a Hubble constant of 100 km Mpc 1, to a distance of order 102 Mpc. The greatest uncertainty comes from galaxy masses and galaxy counts, rather than galactic absorption or abundances of galaxy types. Key words: cosmic density - mass-luminosity ratio - galaxy counts
TL;DR: In this article, the authors conjecture that the highly obscured galaxy IC342 might be associated with Maffei 1 and Mafei 2 (refs. 1 and 2) and show that IC342 is the fourth largest (after M31, M33 and M101) spiral galaxy known.
Abstract: I SUGGEST in this report that the highly obscured galaxy IC342 might be associated with Maffei 1 and Maffei 2 (refs. 1 and 2). IC342 is the fourth largest (after M31, M33 and M101) spiral galaxy known. It is separated from Maffei 1 by less than 12° which, at a distance of 2 M parsec (Mpc), would correspond to a projected separation of only 0.4 Mpc. Available data on Maffei 1 and on IC342 are compared in Table 1.
TL;DR: In this paper, data on 48 galaxies of peculiar, or otherwise interesting, structure are tabulated, and seventeen peculiar galaxies are briefly described; see Section 5.1.1 for a survey.
Abstract: Data on 48 galaxies of peculiar, or otherwise interesting, structure are tabulated. Seventeen peculiar galaxies are briefly described. Key words: galaxies - peculiar galaxies
Journal Article•
TL;DR: In this article, the optical positions of the 82l galaxies of the Reference Catalogue of Bright Galaxies, in the declination zone 26 deg to 90 deg, are given with an accuracy of a few seconds of arc, together with two small nearby reference stars, for each galaxy, to locate the chosen center.
Abstract: The optical positions of the 82l galaxies of the Reference Catalogue of Bright Galaxies by G. and A. de Vaucouleurs, in the declination zone 26 deg to 90 deg , are given with an accuracy of a few seconds of arc, together with two small nearby reference stars, for each galaxy, to locate the chosen center. (auth)
TL;DR: X-RAY measurements and limits on the Coma and Virgo clusters of galaxies have been said to limit the mass of hot gas in them to 2% of the amount required for stabilization according to the virial theorem, but this conclusion is strongly dependent on the value of the Hubble constant H 0.
Abstract: X-RAY measurements and limits on the Coma and Virgo clusters of galaxies have been said to limit the mass of hot gas in them to 2% of the amount required for stabilization according to the virial theorem1. Such a conclusion is strongly dependent on the value of the Hubble constant H0. The linear diameter of the cluster D and the cluster mass M, estimated by the virial theorem, each vary as H0−1. Therefore, the density ρ has the dependence ρ∼H02. The predicted X-ray flux F from this gas is ∼ρM/R2, where R is the distance to the cluster. R varies as H0−1. We therefore have the relation Meekins et al.1 appear to have used the value H0 = 95 km s−1 Mpc−1 found by van den Bergh2, because they took R= 70 Mpc. If Abell's value3H0 = 47 is used, the predicted flux is reduced by a factor of 0.12. A reduction of H0 to a value as low as 20 is not inconceivable. Although clumpiness increases F/M2, the presence of helium as a mass fraction f reduces F for fixed M in the ratio (1–½f).
TL;DR: In this paper, an attempt is made to take into account the difference in richness between the clusters withz<0.1 and the ones with 0.1
Abstract: Because of a suspicion that a positive correlation exists between the luminosity of the first-class galaxies and the richness of the clusters, an attempt is made of taking into account the difference in richness (and presumably in total population) between the clusters withz<0.1 and the ones with 0.1
TL;DR: The mean ratio R of mass to total 10-O.6M for clusters of galaxies (particularly the Coma cluster) is derived and used to obtain the mean cosmic density based on the assumption that field galaxies have the same mean R as cluster galaxies as discussed by the authors.
Abstract: The mean ratio R of mass to total 10-O.6M, where M is absolute magnitude, for clusters of galaxies (particularly the Coma cluster) is derived and used to obtain the mean cosmic density based on the assumption that field galaxies have the same mean R as cluster galaxies (including the "unseen" mass). The result is p = (5 2) >c 10-30 g for H = . Key words: cosmic density - galaxies - clusters of galaxies
TL;DR: In this article, the average mass-to-luminosity ratio of compact galaxies was found to be (9'(/L) 50 '0IL0, which is similar to that for normal galaxies.
Abstract: Published observations on compact galaxies indicate that their mass distribution is similar to that for normal galaxies. The average mass-to-luminosity ratio is (9)'(/L) 50 '0IL0 Key words: galaxies - compact galaxies