Related papers: How Galaxies Disguise Their Ages
We suggest a model for star formation function and a model for dissipation of the turbulent energy of interstellar medium. Star formation function takes into account the effect of turbulization of the ISM. It is shown that application of…
Nine presently known "young" Galactic globular clusters, which have ages / 3 Gyr smaller than the oldest clusters of similar metallicity, all have RGC > 15 kpc. Furthermore these young globulars are found to have below-average luminosities.…
Determining the sequence of events in the formation of stars and planetary systems and their time-scales is essential for understanding those processes, yet establishing ages is fundamentally difficult because we lack direct indicators. In…
Recent studies based on line indices of nearby early-type galaxies suggest that stars in the galaxies' inner part may be younger and more metal rich than stars in the outer part. If confirmed, the finding has a profound implication for the…
New observations over the next few years of the emission of distant objects will help unfold the chapter in cosmic history around the era of the first galaxies. These observations will use the neutral hydrogen emission or absorption at a…
We have acquired intermediate resolution spectra in the 3700-7000 A wavelength range for a sample of 65 early-type galaxies predominantly located in low density environments, a large fraction of which show emission lines. The spectral…
Context. Absorption line indices are widely used to determine the stellar population parameters such as age and metallicity of galaxies, but it is not easy to obtain the line indices of some distant galaxies that have colours available.…
The influence of both major and minor mergers is expected to significantly affect gradients of stellar ages and metallicities in the outskirts of galaxies. Measurements of observed gradients are beginning to reach large radii in galaxies,…
We report preliminary results of the characterization of bulge and inner disk stellar populations for 8 nearby spiral galaxies using Gemini/GMOS. The long-slit spectra extend out to 1-2 disk scale lengths with S/N/Ang > 50. Two different…
We identify the nature of high redshift long Gamma-Ray Bursts (LGRBs) host galaxies by comparing the observed abundance ratios in the interstellar medium with detailed chemical evolution models accounting for the presence of dust. We…
The degree of influence that environment and mass have on the stellar populations of early-type galaxies is uncertain. In this paper we present the results of a spectroscopic analysis of the stellar populations of early-type galaxies aimed…
We discuss recent developments on the age and metallicity distribution for early type galaxies in different environments.
Dating the ages and weighting the stellar populations in galaxies are essential steps when studying galaxy formation through cosmic times. Evolutionary population synthesis models with different input physics are used for this purpose.…
The details of bulge formation via collapse, mergers, secular processes or their interplay remain unresolved. To start answering this question and quantify the importance of distinct mechanisms, we mapped a sample of three galactic bulges…
We measure the ages, stellar masses, and star formation histories of z~6 galaxies, observed within 1Gyr of the Big Bang. We use imaging from HST and Spitzer from the public "Great Observatories Origins Deep Survey", coupled with…
Using the Mid-Infrared Spectrometer (MIRS) on board the Infrared Telescope in Space (IRTS) we obtained the 4.5 to 11.7 micron spectra of the stellar populations and diffuse interstellar medium in the Galactic bulge (l = 8.7 degree, b = 2.9,…
We study the variation of the stellar population properties as a function of distance from the nucleus for a sample of 35 Seyfert 2 galaxies using the technique of stellar population synthesis. We sample regions at the galaxies with…
We present deep Keck/LRIS spectroscopy and HST/WFC3 imaging in the rest-frame optical for a sample of eight galaxies at z~1.5 with high photometrically-determined stellar masses. The data are combined with VLT/XShooter spectra of five…
Integrated spectroscopy is the method of choice for deriving the ages of unresolved stellar systems. However, hot stellar evolutionary stages, such as hot horizontal branch stars and blue straggler stars (BSSs), can affect the integrated…
In integrated-light, some color-color diagrams that use optical and near-infrared photometry show surprisingly orthogonal grids as age and metallicity are varied, and they are coming into common usage for estimating the average age and…