相关论文: Population Effects on the Metallicity Distribution…

The stellar populations of intermediate-redshift galaxies can shed light onto the growth of massive galaxies in the last 8 billion years. We perform deep, multi-object rest-frame optical spectroscopy with IMACS/Magellan of ~70 galaxies in…

We present a metallicity distribution based on photometry and spectra for 442 omega Cen cluster members that lie at the main sequence turnoff region of the color-magnitude diagram. This distribution is similar to that found for the red…

Using the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on board the Hubble Space Telescope, we have obtained F110W (J-band) and F160W (H-band) images of three fields in NGC3379, a nearby normal giant elliptical galaxy. These…

Using new narrowband color observations of early-type galaxies in clusters, we reconstruct the color-magnitude relation (CMR) with a higher degree of accuracy than previous work. We then use the spectroscopically determined ages and…

It has been known for a long time that stellar metallicity plays a significant role in the determination of the ages of the different Galactic stellar populations, when main sequence evolutionary tracks are employed. Here we analyze the…

Globular cluster (GC) systems around galaxies of a vast mass range show remarkably simple scaling relations. The combined mass of all GCs is a constant fraction of the total galaxy mass and the mean metallicity and metallicity dispersion of…

In a 1$^{\rm st}$ step I present results from our new set of evolutionary synthesis models for Simple (= single burst) Stellar Populations ({\bf SSP}s) of various metallicities, and in a 2$^{\rm nd}$ step I combine these results with the…

The effect of metallicity on the granulation activity in stars is still poorly understood. Available spectroscopic parameters from the updated APOGEE-\textit{Kepler} catalog, coupled with high-precision photometric observations from NASA's…

A small but significant radial gradient in the mean periods of LMC RR Lyrae variables is established from the OGLEIII survey data. This is interpreted as a metallicity gradient but other possibilities are discussed. Data on the ratio of…

The principal goal of this paper is to use attempts at reconciling the Swift long gamma-ray bursts (LGRBs) with the star formation history (SFH) to compare the predictions of $\Lambda$CDM with those in the $R_{\rm h}=ct$ Universe. In the…

We present a morphological analysis of the feature-rich 2MASS LMC color-magnitude diagram, identifying Galactic and LMC populations and estimating the density of LMC populations alone. We also present the projected spatial distributions of…

The connection between mass loss on the red giant branch (RGB) and horizontal branch (HB) morphology in globular clusters (GCs) has long been acknowledged but the mechanisms governing mass loss remains poorly understood from a theoretical…

We describe a new method for robustly testing theoretical predictions of red giant evolution near the tip of the giant branch. When theoretical cumulative luminosity functions are shifted to align the tip in I-band and normalized at a…

Theoretical predictions of Red Giant Branch stars' effective temperatures, colors, luminosities and surface chemical abundances are a necessary tool for the astrophysical interpretation of the visible--near infrared integrated light from…

There is a well known correlation between the mass and metallicity of star-forming galaxies. Because mass is correlated with luminosity, this relation is often exploited, when spectroscopy is not available, to estimate galaxy metallicities…

We analyse the evolutionary history of galaxies formed in a hierarchical scenario consistent with the concordance $\Lambda$-CDM model focusing on the study of the relation between their chemical and dynamical properties. Our simulations…

We present an improved calibration of photometric metallicity indicators, derived from the new metallicity scale for Globular Clusters presented by Carretta & Gratton (1997) and based on direct high resolution spectroscopy of 160 stars in…

We use population synthesis to construct distributions of gamma-ray bursts (GRBs) for different proposed progenitor models. We use a description of star formation that takes into account the evolution of metallicity with redshift and galaxy…

We performed a detailed study of the evolution of the luminosity of He-ignition stage and of the red giant branch bump luminosity during the red giant branch phase transition for various metallicities. To this purpose we calculated a grid…

Multiple generations of stars are routinely encountered in globular clusters but no convincing evidence has been found in Galactic open clusters to date. In this paper we use new photometric and spectroscopic data to search for multiple…