Stellar populations in the nuclei of late-type spiral galaxies

Details Stellar populations in the nuclei of late-type spiral galaxies Stellar populations in the nuclei of late-type spiral galaxies

2006-04-06

arxiv.org/abs/astro-ph/0604138v1

Astrophys.J.649:692-708,2006

Astronomy and Astrophysics

Astrophysics

ApJ submitted (original submission Oct 19, 2005, present version includes changes based on referee recommendations). 53 pages,

Scientific paper

10.1086/505166

(Abridged) As part of an ongoing effort to study the stellar nuclei of very late-type, bulge-less spirals, we present results from a high-resolution spectroscopic survey of nine such nuclear star clusters, undertaken with VLT/UVES. We fit the spectra with population synthesis models and measure Lick-type indices to determine mean luminosity-weighted ages, which range from 4.1*10^7 to 1.1*10^10 years and are insensitive to assumed metallicity or internal extinction. The average metallicity of nuclear clusters in late-type spirals is slightly sub-solar ( = 0.015) but shows significant scatter. The fits also show that the nuclear cluster spectra are best described by a mix of several generations of stars. This is supported by the fact that only models with composite stellar populations yield mass-to-light ratios that match those obtained from dynamical measurements. The last star formation episode was on average 34 Myr ago, while all clusters experienced some star formation in the last 100 Myr. We thus conclude that the nuclear clusters undergo repeated episodes of star formation. The robustness with respect to possible contamination from the underlying galaxy disk is demonstrated by comparison to spectra obtained with HST/STIS. Combining these results with those from Walcher et al. (2005), we have thus shown that the stellar nuclei of these bulge-less galaxies are massive and dense star clusters that form stars recurrently until the present day. This unique set of properties is likely due to the central location of these clusters in their host galaxies.

Affiliated with

Also associated with

No associations

Rating

Stellar populations in the nuclei of late-type spiral galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Stellar populations in the nuclei of late-type spiral galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stellar populations in the nuclei of late-type spiral galaxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-721058