Galaxy Evolution in dense environments observed by the IFS MUSE, a kinematic approach
Creators: name: Abril-Melgarejo, Valentina
Publisher: name: Zenodo
Year: 2020
Subjects: Galaxy Evolution, Galaxy Dynamics, Ionized gas, Intermediate redshift, IFS samples, morpho-kinematics analysis

description: Galaxies form and evolve in different environments, arranged at large scales, in structures shaped by the distribution of dark matter halos, like filaments, walls, clusters, cosmic voids. The evolution of galaxies in low-density environment significantly differs from those embedded in large crowded structures like groups or clusters of galaxies, where environmental drivers reduce the gas content and consequently quench their star-forming capacity earlier than their isolated counterparts. The goal of this work is to study the Tully-Fisher relation (TFR) for galaxies at intermediate redshift (z~0.7) in groups of galaxies. The TFR links the maximum rotation velocity of galaxies - a proxy of dark matter halo mass distribution - to their stellar and/or baryonic mass content. This relation provides key information on the dynamical support, and on formation and evolutionary state of galaxies. The advent of powerful Integral Field Spectroscopy instruments like MUSE, allows to reach a resolution high enough to perform spatially resolved studies at intermediate redshifts and recover essential physical parameters. This research is based on the exploitation of an unique sample of 12 dense galaxy groups selected in the COSMOS field, from the Guaranteed Time Observations MUSE gAlaxy Groups In Cosmos (MAGIC) Survey, spanning the redshift range 0.3&lt;z&lt;0.8. I performed a morpho-kinematics analysis on a total of ~350 galaxies in those groups, from which ~70 are distributed in 4 structures at lower redshift (z&lt;0.4). My analysis was centered on the sub-sample of 8 groups at 0.5&lt;z&lt;0.8, containing ~280 galaxies, for which the kinematics was extracted using the [OII] λλ3726,3729 Å doublet. A bulge-disk decomposition was applied on high resolution ACS-HST FW814 images, in order to retrieve the projection parameters, an accurate global size and the light contribution of the bulge and disk components. A 2D kinematic modeling was applied to recover the maximum rotation velocity at 2.2 Rd (disk scale-length radius), the intrinsic velocity dispersion and the dynamical mass. In order to get robust kinematic measurements, I performed a rigorous sample selection in setting limits on the spatial resolution and on the signal-to-noise ratio. This selection is not based on a posteriori assumption, like it is typically done when the velocity-to-dispersion ratio is used. The effects of selection criteria were carefully evaluated on the TFR: I found the selected galaxies are mostly rotation dominated disk systems and are besides enough resolved in order to retrieve reliable dynamical parameters. I compared my results with previous studies in similar dense environments (e.g. ORELSE) and in lower density environments (e.g. KMOS3D, KROSS) for which the selection criteria were less restrictive, pointing out the advantages of our method which considerably reduces the number of dispersion-dominated outliers in the TFR. I analyzed the stellar and baryon mass fractions within stellar disks and found they both increase with stellar mass. I found a clear offset of the TFR zero-point between galaxies in low- and high-density environments implying that at fixed stellar or baryonic mass, galaxies in dense environments rotate faster than in low-density environments. The evolution of the TFR in dense environments could be due to a combination of quenching of star-formation and of contraction of the baryonic content, depending on the mass regime. These hypotheses are supported by evidences presented by previous environmental studies in literature.