VLT/VIMOS integral field spectroscopy of luminous and ultraluminous infrared galaxies: 2D kinematic properties*

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dc.contributor.author Bellocchi, Enrica
dc.contributor.author Arribas, Santiago
dc.contributor.author Colina, Luis
dc.contributor.author Miralles-Caballero, Daniel
dc.contributor.other UAM. Departamento de Física Teórica es_ES
dc.date.accessioned 2014-11-11T18:24:19Z
dc.date.available 2014-11-11T18:24:19Z
dc.date.issued 2013-09-09
dc.identifier.citation Astronomy and Astrophysics 577 (2013): A59 en_US
dc.identifier.issn 0004-6361(print) es_ES
dc.identifier.issn 1432-0746 (online) es_ES
dc.identifier.uri http://hdl.handle.net/10486/662511
dc.description Astronomy and Astrophysics 577 (2013): A59 reproduced with permission from Astronomy and Astrophysics en_US
dc.description.abstract Context.(Ultra) Luminous infrared galaxies [(U)LIRGs] host the most extreme star-forming events in the present universe and are places where a significant fraction of the past star formation beyond z ~ 1 has occurred. The kinematic characterization of this population is important to constrain the processes that govern such events. Aims. We present and discuss the 2D kinematic properties of the ionized gas (Hα) in sample local (U)LIRGs, for which relatively high linear resolution and signal-to-noise (S/N) ratio can be obtained. Methods. We have obtained Very Large Telescope VIMOS optical integral field spectroscopy (IFS) for 38 local (z < 0.1) (U)LIRGs (31 LIRGs and 7 ULIRGs, 51 individual galaxies). This sample covers well the less studied LIRG luminosity range, and it includes the morphological types corresponding to the different phases along the merging process (i.e., isolated disks, interacting and merging systems). Results. The vast majority of objects have two main kinematically distinct components. One component (i.e., narrow or systemic) extends over the whole line-emitting region and is characterized by small-to-intermediate velocity dispersions (i.e., σ from 30 to 160 km s-1). The second component (broad) has a larger velocity dispersion (up to 320 km s -1); it is mainly found in the inner regions and is generally blueshifted with respect to the systemic component. The largest extensions and extreme kinematic properties are observed in interacting and merging systems, and they are likely associated with nuclear outflows. The systemic component traces the overall velocity field, showing a large variety of kinematic 2D structures, from very regular velocity patterns typical of pure rotating disks (29%) to kinematically perturbed disks (47%) and highly disrupted and complex velocity fields (24%). Thus, most of the objects (76%) are dominated by rotation. We find that rotation is more relevant in LIRGs than in ULIRGs. There is a clear correlation between the different phases of the merging process and the mean kinematic properties inferred from the velocity maps. In particular, isolated disks, interacting galaxies, and merging systems define a sequence of increasing mean velocity dispersion and decreasing velocity field amplitude, characterized by average dynamical ratios (v*shear/ σmean) of 4.7, 3.0 and 1.8, respectively. We also find that the σcentral/σ mean vs. σmean plane is an excellent discriminating plane between disks and interacting/merging systems: disks show a mean ratio a factor of 2 larger than those characterizing the other two classes. The LIRGs classified as isolated disks have similar velocity amplitudes but larger mean velocity dispersions (44 vs. 24 km s-1) than local spirals, implying a larger turbulence and thicker disks. Interacting systems and mergers have values closer to those of low velocity dispersion elliptical/lenticular galaxies (E/SOs). The subclass of (U)LIRGs classified as mergers have kinematical properties similar to those shown by the Lyman break analogs (LBAs), although the dynamical mass of LBAs is five times lower on average. Therefore, despite the difference in mass and dust content, the kinematics of these two local populations appears to have significantly noncircular motions. These motions may be induced by the tidal forces, producing dynamically hot systems. The dynamical masses range from ~0.04 m to 1.4 m (i.e., m = 1.4 × 10 11 M), with ULIRGs being more massive (i.e., ~0.5 ± 0.2 m) than LIRGs by, on average, a factor of about 2. The mass ratio of individual pre-coalescence galaxies is <2.5 for most of the systems, confirming that most (U)LIRG mergers involve sub-m galaxies of similar mass en_US
dc.description.sponsorship This work was funded in part by the Marie Curie Initial Training Network ELIXIR of the European Commission under contract PITNGA- 2008-214227. This work has been supported by the Spanish Ministry of Science and Innovation (MICINN) under grant ESP2007-65475-C02-01 en_US
dc.format.extent 64 pag. es_ES
dc.format.mimetype application/pdf en
dc.language.iso eng en
dc.publisher ESO en_US
dc.relation.ispartof Astronomy and Astrophysics en_US
dc.rights © 2013 ESO. en_US
dc.subject.other Galaxy: evolution es_ES
dc.subject.other Galaxy: kinematics and dynamics es_ES
dc.title VLT/VIMOS integral field spectroscopy of luminous and ultraluminous infrared galaxies: 2D kinematic properties* es_ES
dc.type article es_ES
dc.subject.eciencia Física es_ES
dc.abstract
dc.relation.publisherversion http://dx.doi.org/10.1051/0004-6361/201221019 es_ES
dc.identifier.doi 10.1051/0004-6361/201221019 es_ES
dc.identifier.publicationfirstpage A59 es_ES
dc.identifier.publicationlastpage A59 es_ES
dc.identifier.publicationvolume 557 es_ES
dc.type.version info:eu-repo/semantics/publishedVersion en
dc.rights.accessRights openAccess es_ES


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