Populações estelares em galáxias com formação estelar

Abstract

When studying galaxies it is common to group them into groups defined by types or classifications and observe how their properties may be related. An important existing relationship is between the Star Formation Rate (SFR) and the mass of these objects, which when observed in a group of galaxies exhibits a clear growing trend that can be recognized as the main sequence of star-forming galaxies. However, within a group of galaxies there may be objects that distance themselves from that main sequence. The stellar populations constituting these galaxies can be observed so that possible existing relationships are obtained from their properties. For this, measurements of the properties of the stellar populations from a sample of 40 galaxies with a redshift upper limit of approximately 0.05 where acquired. The data used were obtained from the Sloan Digital Sky Survey (SDSS) spectrophotometric survey. These data are available online and for free. The physical properties of these objects were obtained by adjusting SED using the stellar population synthesis method. This technique allows to reproduce the observed spectrum of the object from individual spectra of simple stellar populations (SSPs), making it possible to obtain parameters of age, metallicity and kinematics for these objects. For this we used the STARLIGHT code associated with the Bruzual and Charlot (2003) SSP models. By means of this technique the integrated properties obtained of each galaxy and relations were established using all the objects of the sample. It is observed that galaxies with high stellar formation present young populations being typically starbursts or spirals.