2D kinematic characterization of a representative sample of local (U)LIRGs: A «kinemetry» analysis based on VIMOS/VTL Integral Field Spectroscopy

Enrica Bellocchi

Departamento de Astrofísica

Año 2014

Luminous and ultraluminous infrared galaxies (i.e., LIRGs, LIR = [8-1000 μm] = 1011 – 1012 L⊙, and ULIRGs, LIR > 1012 L⊙, respectively) host the most extreme star-forming events in the present universe. Although they are rare in the local universe, they are much more numerous at high-z and are relevant contributors to the whole past star formation beyond z ∼ 1. Local (U)LIRGs were initially assumed to be the local counterpart of high-z (U)LIRGs similar to those discovered by Spitzer and the more luminous sub-mm galaxies (SMGs). More recently, several authors have found that in the local universe (U)LIRGs cover a similar star formation rate (SFR) range than high-z normal star-forming galaxies (SFGs). Therefore, low-z (U)LIRGs offer a unique opportunity to study, at high linear resolution and signal-to-noise ratio (S/N), extreme SF events and compare them with those observed at high-z. Furthermore, their analysis would allow the methods and techniques applied to high-z galaxies to be tested. One particular relevant and interesting topic is the kinematics characterization of high-z galaxies in order to better understand how galaxies assembled and evolved at early epochs. In the context of the proposed evolutionary scenarios, there is a strong interest in kinematically characterizing galaxies as disks and mergers, as their relative fraction is a key observational input to constrain different evolutionary scenarios.

This thesis is focused on the 2D kinematic characterization of a unique sample observed with VIMOS/VLT integral field unit (IFU) consisting of 38 local (U)LIRG systems (51 individual galaxies). This sample significantly enlarges previous samples both in number and characteristics, showing a large variety of dynamical phases: from mostly isolated disks for low-luminosity LIRGs to a majority of merger remnants for ULIRGs. It shows the first attempt to obtain a statistically significant study of the 2D kinematic properties of these systems as a function of the infrared luminosity, morphology (i.e., interaction phase) and dynamical status. The majority of the sources (i.e., 31/38) covers the less studied LIRG luminosity range: this is relevant because they fill the gap between the extreme cases and the general population of local SFGs, complementing previous studies which are mainly focused on ULIRGs. Then, the luminosity range covered by the sample is particularly relevant for the high-z comparison since local (U)LIRGs cover a SFR range similar to that of high-z normal SFGs. In order to expand the luminosity range we have also included a subsample formed by ULIRGs (i.e., 25 objects) observed with INTEGRAL/WHT. […]

Datos de interés

Supervisores: Santiago Arribas Mocoroa (CAB), Ángeles Isabel Díaz Beltrán
Universidad: UAM. Departamento de Física Teórica; Centro de Astrobiología (CAB)
Fecha de lectura: 02/06/2014