Related papers: Population Effects on the Metallicity Distribution…

The capability of reconstructing the past star formation history of dwarf elliptical galaxies out of the Local Volume relies on modelling bright stellar populations currently evolving through the red giant branch (RGB) and the asymptotic…

Over the last few years, many studies have found an empirical relationship between the abundance of a star and its age. Here we estimate spectroscopic stellar ages for 178 825 red-giant stars observed by the APOGEE survey with a median…

We present wide field near-infrared photometry of 12 Galactic globular clusters, typically extending from the tip of the cluster red giant branch (RGB) to the main sequence turnoff. Using recent homogenous values of cluster distance,…

We present a new empirical framework modeling the metallicity and star-formation history (SFH) dependence of X-ray luminous ($L > 10^{36}$ ergs s$^{-1}$) point-source population luminosity functions (XLFs) in normal galaxies. We expect the…

We present the time evolution of the stellar metallicity for SDSS galaxies, a sample that spans five orders of magnitude in stellar mass (10^7 - 10^{12} Msun). Assuming the BC03 stellar population models, we find that more massive galaxies…

We introduce a new parameter {\Delta}{\xi} - the difference in magnitude between the red giant branch (RGB) bump and a point on the main sequence (MS) at the same color as the bump, the "benchmark" - to estimate the helium content in old…

Evolutionary synthesis models for star clusters of various metallicities including gaseous emission during the lifetime of the ionising stars are used to model star cluster systems comprising two populations: an old metal-poor globular…

We present the broadest and most precise empirical investigation of red giant branch bump (RGBB) brightness and number counts ever conducted. We implement a new method and use data from two \textit{Hubble Space Telescope (HST)} globular…

We report the results of an extensive VLT high-resolution imaging campaign of the central region of the giant globular cluster omega Centauri. More than 100,000 stars have been measured in the inner 9'x 9' region of the cluster. On the…

We use a sample of 43,690 galaxies selected from the Sloan Digital Sky Survey Data Release 4 to study the systematic effects of specific star formation rate (SSFR) and galaxy size (as measured by the half light radius, r_h) on the…

Standard stellar evolution theory poorly predicts the surface abundances of chemical species in low-mass, red giant branch (RGB) stars. Observations show an enhancement of p-p chain and CNO cycle products in red giant envelopes, which…

We use archival JWST/NIRCam images in the F115W, F150W, and F200W filters to measure the Tip of the Red Giant Branch (TRGB) magnitudes across the disk of the late-type spiral galaxy NGC 628. In this exploratory study, we demonstrate how the…

We present a deep color-magnitude diagram for individual stars in the halo of the nearby spiral galaxy M81, at a projected distance of 19 kpc, based on data taken with the Advanced Camera for Surveys on the Hubble Space Telescope (HST). The…

We present a new technique to determine age and metallicity of old stellar populations (globular clusters and elliptical galaxies) using an iterative principal component analysis on narrow band (Str\"omgren) colors. Our technique is capable…

Over much of the initial mass function, stars are destined to become luminous and cool red giants. They may then be able to produce dust in an atmosphere which has been elevated by strong radial pulsations, and hence drive a wind. The…

In this letter, we calculate the redshift distribution of gamma-ray bursts assuming that they trace (i) the globally averaged star formation rate or (ii) the average metallicity in the Universe. While at redshifts 5 and below, both the star…

We present a V-I color-magnitude diagram for a region 1'-2' from the center of M32 based on Hubble Space Telescope WFPC2 images. The broad color-luminosity distribution of red giants shows that the stellar population comprises stars with a…

The redshift dependence of the luminosity density in certain wavebands (e.g. UV and H-alpha) can be used to infer the history of star formation in the populations of galaxies producing this luminosity. This history is a useful datum in…

Aims. We use the spectra of more than 30,000 red giant branch (RGB) stars in 25 globular clusters (GC), obtained within the MUSE survey of Galactic globular clusters, to calibrate the Ca II triplet (CaT) metallicity relation and derive…

The spectra of emission-line galaxies (ELGs) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digit Sky Survey (SDSS) are used to study the mass-metallicity relation (MZR) at $z\sim0.8$. The selected sample…