To understand the nuclear stellar populations and star formation histories of the nuclei of spiral galaxies, we have obtained K-band nuclear spectra for 41 galaxies and H-band spectra for 20 galaxies in the ISO Atlas of Bright Spiral Galaxies. In the vast majority of the subsample (80%), the near-infrared spectra suggest that evolved red stars completely dominate the nuclear stellar populations...

Models for the formation and evolution of galaxies readily predict physical properties such as the star formation rates, metal enrichment histories, and, increasingly, gas and dust content of synthetic galaxies. Such predictions are frequently compared to the spectral energy distributions of observed galaxies via the stellar population synthesis (SPS) technique. Substantial uncertainties in SPS...

This work presents high S/N spectroscopic observations of a sample of six suspected merger remnants, selected primarily on the basis of Hi tidal debris detections. Single stellar population analysis of these galaxies indicates that their ages, metallicities, and α-enhancement ratios are consistent with those of a representative sample of nearby elliptical galaxies. The expected stellar populati...

the rotation curves of a sample of 46 low- and high-surface brightness galaxies are considered in the context of milgrom's modi_ed dynamics (mond) to test a new interpolating function proposed by zhao et al. (2010) [1] and compare with the results of simple interpolating function. the predicted rotation curves are calculated from the total baryonic matter based on the b-band surface photometry,...

This work presents high S/N spectroscopic observations of a representative sample of nearby elliptical galaxies. These observations provide a strong test of models for the formation of elliptical galaxies and their star formation histories. Combining these data with the Gonzalez (1993) data set, a volume limited sample of 45 galaxies has been defined. Results are in agreement with previous stud...

In this work we have examined the spectroscopic properties of a sample of 19 optically bright, low luminosity Flat Radio Spectrum (LL FRS) sources. Our study focuses on the properties of their host galaxies, namely the nuclear stellar populations and dust content. In the optical — spectral region covered by our data — the objects in the sample are mainly dominated by the host galaxy starlight, ...

If the stellar halos of disk galaxies are built up from the disruption of dwarf galaxies, models predict highly structured variations in the stellar populations within these halos. We test this prediction by studying the ratio of blue horizontal branch stars (BHB stars; more abundant in old, metal-poor populations) to main-sequence turn-off stars (MSTO stars; a feature of all populations) in th...

We study the luminosity functions of high-redshift galaxies in detailed hydrodynamic simulations of cosmic reionization, which are designed to reproduce the evolution of the Lyman-α forest between z ∼ 5 and z ∼ 6. We find that the luminosity functions and total stellar mass densities are in agreement with observations when plausible assumptions about reddenning at z ∼ 6 are made. Our simulation...

Optical and near-IR observations of the halos of disk galaxies and blue compact galaxies have revealed a very red spectral energy distribution which cannot easily be reconciled with a normal, metal-poor stellar population like that in the stellar halo of the Milky Way. Here, spectral evolutionary models are used to explore the consequences of these observations. We demonstrate that a stellar po...