A Young Stellar Cluster in the Nucleus of NGC 4449
arXiv:astro-ph/0010542 · doi:10.1086/319415
Abstract
We have obtained 1-2 A resolution optical Echellette spectra of the nuclear star cluster in the nearby starburst galaxy NGC 4449. The light is clearly dominated by a very young (6-10 Myr) population of stars. For our age dating, we have used recent population synthesis models to interpret the observed equivalent width of stellar absorption features such as the HI Balmer series and the CaII triplet around 8500 A. We also compare the observed spectrum of the nuclear cluster to synthesized spectra of simple stellar populations of varying ages. All these approaches yield a consistent cluster age. Metallicity estimates based on the relative intensities of various ionization lines yield no evidence for significant enrichment in the center of this low mass galaxy: the metallicity of the nuclear cluster is about one fourth of the solar value, in agreement with independent estimates for the disk material of NGC 4449.
arXiv comment24 pages (incl. 7 figures), accepted by AJ, March 2001 issue revised version with minor changes and additions, one additional figure
References in corpus (21)
- Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
- Starburst99: Synthesis Models for Galaxies with Active Star Formation
- A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
- Reddening and Star Formation in Starburst Galaxies
- On Measuring Chemical Abundances in Distant Galaxies Using Global Emission Line Spectra
- Dust-to-gas Ratio and Metal Abundance in Dwarf Galaxies
- Improving Predictions for Helium Emission Lines
- Spiral galaxies with WFPC2: II. The Nuclear Properties of 40 objects
- M32+/-1
- A Catalog of Digital Images of 113 Nearby Galaxies
- Synthetic spectra of H Balmer and HeI absorption lines. II: Evolutionary synthesis models for starburst and post-starburst galaxies
- The NICMOS Snapshot Survey of nearby Galaxies
- WFPC2 Observations of Compact Star Cluster Nuclei in Low Luminosity Spiral Galaxies
- CO-bandhead spectroscopy of IC 342: mass and age of the nuclear star cluster
- HST Optical-NIR Colors of Nearby and Exponential Bulges
- Evolutionary synthesis modeling of red supergiant features in the near-infrared
- Calibration of Nebular Emission-line Diagnostics: II. Abundances
- The Star Clusters in the Irregular Galaxy NGC 4449
- Calcium Triplet Synthesis
- Ultraviolet Imaging of the Irregular Galaxy NGC 4449 with UIT: Photometry and Recent Star-Formation History
- A PRELIMINARY CLASSIFICATION SCHEME FOR THE CENTRAL REGIONS OF LATE-TYPE GALAXIES