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TOPIC: Young massive star clusters

Blobrana

L

Posts: 131433

Date: Aug 23 00:32 2012

Massive proto-clusters	Permalink

Title: There are no starless massive proto-clusters in the first quadrant of the Galaxy Authors: A. Ginsburg, E. Bressert, J. Bally, C. Battersby We search the lambda = 1.1 mm Bolocam Galactic Plane Survey for clumps containing sufficient mass to form ~10^4 solar mass star clusters. 18 candidate massive proto-clusters are identified in the first Galactic quadrant outside of the central kiloparsec. This sample is complete to clumps with mass M(clump) > 10^4 M_sun and radius r < 2.5 pc. The overall Galactic massive cluster formation rate is CFR(M_cluster > 10^4) ~ 5 Myr^-1, which is in agreement with the rates inferred from Galactic open clusters and M31 massive clusters. We find that all massive proto-clusters in the first quadrant are actively forming massive stars and place an upper limit of t_starless < 0.5 Myr on the lifetime of the starless phase of massive cluster formation. If massive clusters go through a starless phase with all of their mass in a single clump, the lifetime of this phase is very short. Read more (105kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jun 14 10:28 2007

Young massive star clusters	Permalink

Title: Young massive star clusters in the era of the Hubble Space Telescope Authors: Richard de Grijs (University of Sheffield, UK) The Hubble Space Telescope (HST) has been instrumental in the discovery of large numbers of extragalactic young massive star clusters (YMCs), often assumed to be proto-globular clusters (GCs). As a consequence, the field of YMC formation and evolution is thriving, generating major breakthroughs as well as controversies on annual (or shorter) time-scales. Here, I review the long-term survival chances of YMCs, hallmarks of intense starburst episodes often associated with violent galaxy interactions. In the absence of significant external perturbations, the key factor determining a cluster's long-term survival chances is the shape of its stellar initial mass function (IMF). It is, however, not straightforward to assess the IMF shape in unresolved extragalactic YMCs. I also discuss the latest progress in worldwide efforts to better understand the evolution of entire cluster populations, predominantly based on HST observations, and conclude that there is an increasing body of evidence that GC formation appears to be continuing until today; their long-term evolution crucially depends on their environmental conditions, however. Read more (24kb, PDF) __________________

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