Star forming regions in a sample of HST spiral galaxies

Aims. The presence of small- and large-scale star formation structures in a sample of six spiral Hubble Space Telescope (HST) galaxies is investigated to identify small structures of young stars known as OB associations and to tell whether they are formed inside larger scale star forming stellar str...

Full description

Saved in:
Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2013-05, Vol.553, p.1-11
Main Authors: Drazinos, P., Kontizas, E., Karampelas, A., Kontizas, M., Dapergolas, A.
Format: Article
Language:English
Subjects:
Aggregates
Algorithms
Astronomy
Color
Galaxies
galaxies: structure
methods: statistical
Star formation
Stars
Stellar structure
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Aims. The presence of small- and large-scale star formation structures in a sample of six spiral Hubble Space Telescope (HST) galaxies is investigated to identify small structures of young stars known as OB associations and to tell whether they are formed inside larger scale star forming stellar structures in a hierarchical form. Methods. This process was based on a friend-of-friend (FOF) algorithm applied to the bright, early type stars above a certain color cutoff limit in order to ensure that we include main sequence stars. A size criterion was introduced in order to apply the same algorithm to different types of stellar structures. Depending on their size, the structures were divided into the four categories of associations, aggregates, complexes, and supercomplexes. Results. Star forming structures of the four types mentioned above are found in all six galaxies of our sample. The majority of the associations and aggregates (the smaller structures) found are lying inside larger structures like complexes and supercomplexes, indicating a hierarchical star formation mechanism.
ISSN:0004-6361
1432-0746
DOI:10.1051/0004-6361/201220648