Star formation in the outer disk of spiral galaxies

Download
  1. Get@NRC: Star formation in the outer disk of spiral galaxies (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1088/0004-637X/757/1/64
AuthorSearch for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleThe Astrophysical Journal
ISSN0004-637X
Volume757
Issue1
Article number64
AbstractWe combine new deep and wide field of view Hα imaging of a sample of eight nearby (d 17Mpc) spiral galaxies with new and archival H I and CO imaging to study the star formation and the star formation regulation in the outer disk. We find that, in agreement with previous studies, star formation in the outer disk has low covering fractions, and star formation is typically organized into spiral arms. The star formation in the outer disk is at extremely low levels, with typical star formation rate surface densities of ∼10 -5 to 10 -6 M Oyr -1kpc -2. We find that the ratio of the radial extent of detected H II regions to the radius of the H I disk is typically ≳85%. This implies that in order to further our understanding of the implications of extended star formation, we must further our understanding of the formation of extended H I disks. We measure the gravitational stability of the gas disk, and find that the outer gaseous disk is typically a factor of ∼2times more stable than the inner star-forming disk. We measure the surface density of outer disk H I arms, and find that the disk is closer to gravitational instability along these arms. Therefore, it seems that spiral arms are a necessary, but not sufficient, requirement for star formation in the outer disk. We use an estimation of the flaring of the outer gas disk to illustrate the effect of flaring on the Schmidt power-law index; we find that including flaring increases the agreement between the power-law indices of the inner and outer disks. © 2012. The American Astronomical Society. All rights reserved.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Herzberg Institute of Astrophysics (HIA-IHA)
Peer reviewedYes
NPARC number21269209
Export citationExport as RIS
Report a correctionReport a correction
Record identifierb42028d0-9776-46c8-83bc-26fab4b35e2b
Record created2013-12-12
Record modified2016-07-18
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)