other query modes : |
Identifier query |
Coordinate query |
Criteria query |
Reference query |
Basic query |
Script submission |
TAP |
Output options |
Object types |
Help |
1999AJ....117.2398M - Astron. J., 117, 2398-2427 (1999/May-0)
The efficiency of globular cluster formation.
McLAUGHLIN D.E.
Abstract (from CDS):
This claim is checked and confirmed in each of M87, M49, and NGC 1399, all of which have been thought to suffer from one or the other of these SN problems. Existing data are combined to construct GCS surface density profiles that extend over nearly the whole extents of these three galaxies, and a nonparametric, geometrical deprojection algorithm is developed to afford a direct comparison between the volume density profiles of their GCSs, stars, and gas. It is found, in each case, that ρcl∝(ρgas+ρstars) at radii beyond roughly a stellar effective radius, inside of which dynamical evolution may have depleted the initial GCSs. The constant of proportionality is the same in all three galaxies: εcl=0.0026±0.0005. Taken together, these results suggest that GCSs generally should be more spatially extended than stellar halos only in gas-rich galaxies that also have a high global specific frequency.
The implication that εcl might have had a universal value is supported by global GCS data for a sample of 97 giant ellipticals, brightest cluster galaxies, and faint dwarfs. The total globular cluster populations in all of these early-type systems are in excellent agreement with the predictions of a constant εcl at the level observed directly in M87, M49, and NGC 1399; all systematic variations in GCS specific frequency between galaxies are shown to result entirely from different relations, in different magnitude ranges, between Minitgas and the present-day LV,gal. An identical εcl is also calculated for the Population II spheroid of the Milky Way and is indicated (although less conclusively) for the ongoing formation of open clusters. The inferred universal cluster formation efficiency, of ≃0.25% by mass, should serve as a strong constraint on general theories of star and cluster formation. The associated inference of a nonuniversal formation efficiency for unclustered stars is considered, particularly in terms of the suggestion that this might result, both in dwarf galaxies and at large galactocentric radii in the brightest ellipticals, from feedback and galactic winds. Implications for a merger-formation model of early-type GCSs, and for the proposed existence of intergalactic globulars in clusters of galaxies, are briefly discussed.
Abstract Copyright: ∼
Journal keyword(s): Galaxies: Elliptical and Lenticular, cD - galaxies: individual (M87, M49, NGC 1399) - Galaxies: Star Clusters - Galaxy: Globular Clusters: General - Stars: Formation
Simbad objects: 10
To bookmark this query, right click on this link: simbad:1999AJ....117.2398M and select 'bookmark this link' or equivalent in the popup menu