========================================================================= "The nature of the faint radio-source population and a radio study of LIRGs from the GOALS sample" Dr. Eleni Vardoulaki University of Crete, Greece When: Wednesday 9 May 2012 at 1:30pm Where: 2nd Floor Seminar Room Abstract: The first part of this talk is devoted to my research on extragalactic radio-loud radio sources at redshifts 0.5 < z < 4. This study focuses on two independent samples of radio sources, selected at different frequencies. The first sample is the low-frequency radio selected TOOT00 radio sources with flux density limit S_151MHz >~ 100 mJy and a median redshift z ~ 1.25. The second sample is the high-frequency radio selected SXDS radio sources with flux density limit S_1.4GHz >~ 2 mJy and a median redshift z ~ 1.1. Using multi-wavelength data in the optical, infrared and radio, I will present a comparison of their quantities in order to understand the nature of the faint radio-source population. The second part of the talk is my current project on a radio study of Luminous Infrared Galaxies from the GOALS sample. This project is divided in 3 parts, one for each year of the project. The target is: 1) to use VLA radio observations at 2 different frequencies (1.49 & 8.44 GHz) and different VLA resolutions (A, B, C, D configurations) to study these objects and identify the AGN contribution by looking at the radio spectral slope and evidence of radio jets; 2) to compare our radio findings to other mid-IR AGN diagnostics (e.g. BPT diagram), explore the spatially resolved mid-IR/radio and far-IR/radio correlations, and to expand the study of LIRGs to high redshifts; and 3) to examine the spatial variation of the radio emission and compare it to the emission in the mid- & far-IR, and to explore the dependence of radio emission on different nuclear types and stages of interactions. =========================================================================