New near-infrared surface brightness fluctuation models
Abstract
We present new theoretical models for surface brightness fluctuations (SBFs) in the near-infrared (near-IR). We show the time evolution of near-IR brightness fluctuation properties over large age and metallicity ranges, i.e. from 12 Myr to 16 Gyr and from Z/Zsolar= 1/50 to 2.5, for single age, single metallicity stellar populations. All the stellar models are followed from the zero-age main-sequence to the central carbon ignition for massive stars, or to the end of the thermally pulsing regime of the asymptotic giant branch (AGB) phase for low- and intermediate-mass stars.
The new models are compared with observed near-IR fluctuation absolute magnitudes and colours for a sample of Magellanic Cloud (MC) star clusters and Fornax cluster galaxies. For star clusters younger than ~3Gyr, the predicted near-IR fluctuation properties are in satisfactory agreement with observed ones over a wide range of stellar population metallicities. However, for older star clusters, the agreement between the observed and predicted near-IR brightness fluctuations depends on how the surface brightness absolute magnitudes are estimated. The computed set of models are not able to match the observed near-IR fluctuation absolute magnitudes and colours simultaneously. We argue that the observed discrepancies between the predicted and observed properties of old MC superclusters are more likely due to observational reasons.- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2005
- DOI:
- 10.1111/j.1365-2966.2005.09387.x
- arXiv:
- arXiv:astro-ph/0511823
- Bibcode:
- 2005MNRAS.362.1208M
- Keywords:
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- stars: AGB and post-AGB;
- galaxies: star clusters;
- galaxies: stellar content;
- infrared: galaxies;
- Astrophysics
- E-Print:
- MNRAS, 2005, 362, 1208 (12 pages, 7 figures)