Science-advisor
REGISTER info/FAQ
Login
username
password
     
forgot password?
register here
 
Research articles
  search articles
  reviews guidelines
  reviews
  articles index
My Pages
my alerts
  my messages
  my reviews
  my favorites
 
 
Stat
Members: 3667
Articles: 2'599'751
Articles rated: 2609

07 February 2025
 
  » arxiv » astro-ph/0412069

 Article overview



The Fundamental Building Blocks of Galaxies
Pavel Kroupa ;
Date 2 Dec 2004
Subject astro-ph
AffiliationUniBonn
AbstractMost stars form in compact, dense embedded clusters with memberships ranging from a dozen stars to many millions of stars. Embedded clusters containing more than a few hundred stars also contain O stars that disrupt the nebula abruptly. There are observational indications that the expulsion of gas from such clusters may occur within, or even quicker than, a stellar crossing-time scale. Because the star-formation efficiency is empirically deduced to be typically lower than 40 per cent, such clusters are left severely out of dynamical equilibrium with a super-virial velocity dispersion when they are exposed. As a consequence, they expand drastically. The velocity dispersion of expanding star-burst clusters may achieve values of a few tens km/s, which would have a significant impact on the stellar velocity distribution function and therefore the morphology of a galaxy. An application of these ideas to the vertical structure of the Milky Way (MW) disk suggests that such popping star clusters may constitute the missing heat source for understanding the age-velocity-dispersion relation. If the early MW disk experienced a vigorous epoch of star formation then perhaps even the thick disk may have formed from popping clusters. Thus we have an alternative hypothesis to understanding thick disks which does not rely on, or may act in addition to, sinking galaxy satellites or sinking cosmological sub-structures. The GAIA mission will test this hypothesis by allowing the kinematical fields around young clusters to be mapped to exquisite precision.
Source arXiv, astro-ph/0412069
Services Forum | Review | PDF | Favorites   
 
Visitor rating: did you like this article? no 1   2   3   4   5   yes

No review found.
 Did you like this article?

This article or document is ...
important:
of broad interest:
readable:
new:
correct:
Global appreciation:

  Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.






ScienXe.org
» my Online CV
» Free

home  |  contact  |  terms of use  |  sitemap
Copyright © 2005-2025 - Scimetrica