Related papers: Better age estimations using UV-optical colours: b…
We present an empirical assessment of the use of broadband optical colours as age indicators for unresolved extragalactic clusters and investigate stochastic sampling effects on integrated colours. We use the integrated properties of…
The precision of cluster parameter determination has significantly improved with the availability of homogeneous photometric Gaia data, however, challenges such as age-metallicity degeneracy and lack of spectroscopic observations remain. In…
Using Monte Carlo simulations of globular clusters we developed a method separating metallicity effects from age effects on observed integrated ugriz colors. We demonstrate that these colors do not evolve with time significantly after an…
Number Counts of galaxies in two GALEX bands (FUV: 1530A and NUV: 2310A, both in AB magnitudes) are reported. They provide for the first time in the literature homogeneously calibrated number counts of UV galaxies covering continuously a…
High resolution, ultraviolet imaging is often unavailable across the sky, even in heavily studied fields such as the Chandra Deep Field - South. The Habitable Worlds Observatory is one of two upcoming missions with the possibility of…
Interstellar extinction in ultraviolet is the most severe in comparison with optical and infrared wavebands and a precise determination plays an important role in correctly recovering the ultraviolet brightness and colors of objects. By…
With the coming generation of instruments and telescopes capable of spectroscopy of high redshift galaxies, the spectral synthesis technique in the rest-frame UV and Far-UV range will become one of a few number of tools remaining to study…
The GALEX (Galaxy Evolution Explorer) Nearby Galaxies Survey is providing deep far-UV and near-UV imaging for a representative sample of galaxies in the local universe. We present early results for M51 and M101, from GALEX UV imaging and…
The high-redshift galaxy UV luminosity function (UVLF) has become essential for understanding the formation and evolution of the first galaxies. Yet, UVLFs only measure galaxy abundances, giving rise to a degeneracy between the mean galaxy…
We combine GALEX (ultra-violet; UV) and SDSS (optical) photometry to study the recent star formation histories of ~100 field galaxies on the optical red sequence, a large fraction of which exhibit widespread signs of disturbed morphologies…
We have studied ~2100 early-type galaxies in the SDSS DR3 which have been detected by the GALEX Medium Imaging Survey (MIS), in the redshift range 0 < z < 0.11. Combining GALEX UV photometry with corollary optical data from the SDSS, we…
I will show that photometry -- if extending over a reasonable choice of passbands -- can give fairly precise information about young star clusters and their evolutionary state. Optical colors alone are known to leave severe ambiguities due…
We describe a new method to identify young, late-type stars within ~150 pc of the Earth that employs visual or near-infrared data and the GALEX GR4/5 database. For spectral types later than K5, we demonstrate that the ratio of GALEX…
Conventionally, CMD analyses of nearby star clusters are based on observations in 2 passbands. They are plagued by considerable degeneracies between age, metallicity, distance (and extinction) that can largely be resolved by including…
We present the results of combined optical and near-infrared photometry for the globular cluster systems of the giant ellipticals IC 4051 and NGC 3311. We use the reduced age-metallicity degeneracy in (V-I) vs.(V-H) color-color diagrams to…
We derive new spectral H_gamma index definitions which are robust age indicators for old and relatively old stellar populations and thus have great potential for solving the age-metallicity degeneracy of galaxy spectra. To study H_gamma as…
We investigate the effects of abundance and age on the mid-UV spectra and Mg_{2} strengths of stellar populations using simple population synthesis models. These models are used to constrain the star formation history of four nearby…
We present the first photometric results in J, H, and K_s from 2MASS imaging of 10 classical globular clusters in the far outer regions of M31. Combined with the V and I photometric data from previous literature, we constructed the…
We have constrained the age of the globular cluster S312 in the Andromeda galaxy (M31) by comparing its multicolor photometry with theoretical stellar population synthesis models. This is both a check on the age of this globular cluster, as…
In the last decades we witnessed an increase in studies of open clusters of the Galaxy, especially because of the good determination for a wide range of values of parameters such as age, distance, reddening, and proper motion. The reliable…