Found 5 talks width keyword Virgo cluster

Thursday November 12, 2020
Dr. Gianluca Castignani


Galaxy clusters are the most massive gravitationally bound structures in the Universe. They are the sites where exceptional morphological transformations of galaxies occur, driven by their interactions within the complex cosmic web. Clusters are thus excellent laboratories to study galaxy evolution in extreme regimes. I will present the results of a large campaign based on IRAM facilities (30m and NOEMA) and targeting in mm different samples of galaxies in and around clusters. The final goal of the project is to evaluate the role of dense mega-parsec scale environments in processing cold gas of galaxies. The following samples of galaxies will be discussed. i) The largest sample of distant ~30 brightest cluster galaxies observed in CO, over a broad range of redshift (z~0.2-2.6). They are drawn from CLASH, COSMOS, SpARCS, and DES deep fields. ii) The largest sample of distant, intermediate redshift z~0.2-0.5, cluster LIRGs (luminous infrared galaxies), which have been observed in CO with the NOEMA interferometer and are drawn from the Herschel Lensing Survey (HLS) and the Local Cluster Substructure Survey (LoCuSS).  iii) I will also present ongoing results of a large campaign with the aim to evaluate the pre-processing of atomic (HI) and molecular (CO) gas of galaxies before they fall into the cluster core. The sample comprises 245 galaxies in cosmological filaments, up to 7 virial radii around Virgo, the benchmark cluster in the local Universe. The outlined studies reveal a complex scenario, where large-scale structures have a different impact in regulating the star formation fueling and mass assembly of the considered galaxies, depending on their morphological type, location with respect to the cluster core, and redshift.


Thursday May 23, 2019
Patricia Sánchez Blázquez
Universidad Autónoma de Madrid


The Time Inference with MUSE in Extragalactic Rings, TIMER, is a project dedicated to study the central regions
of 24 nearby galaxies with the integral field spectrograph MUSE. The spatial resolution of this instruments
allows the detailed study of the different structural components in these galaxies and, therefore, disentangle
their star formation histories, kinematics and dynamics of both, the gaseous and the stellar constituents.
In this talk, I will give an overview of the project as well as some details on  how the  dataset can be used for a plethora of scientific applications, like
understanding the stellar and AGN feedback, the role of primary and secondary bars, the dynamics of nuclear
spiral arms, barlenses, box/peanuts and bulges.

Monday June 29, 2015
Dr. Nathalie Ouellette
Queen's University


Major tests of cosmological and galaxy formation models can be constructed through dynamical and structural parameters of galaxies. Towards this end, we present the SHIVir (Spectroscopic and H-band Imaging of Virgo cluster galaxies) survey, which provides dynamical information and stellar population diagnostics for hundreds of galaxies. We construct scaling relations and dynamical profiles within the optical radius of most galaxies, paying close attention to the baryon-to-dark matter transition region and selected metrics which reduce scatter in fundamental scaling relations. Salient results include bimodal mass and surface brightness distributions for Virgo galaxies, a possible bifurcation in the stellar-to-halo mass relation for low-mass galaxies, and the need for deep velocity dispersions to extract meaningful science. Once complete, ours should be the most extensive mass catalogue ever assembled for a galaxy cluster.

Tuesday January 29, 2013
Dr. Jairo Méndez Abreu


The effects that environment produce on galaxy disks and how they modify the subsequent formation of bars need to be distinguished to fully understand the relationship between bars and environment. To shed light on this issue, we derive the bar fraction in three different environments ranging from the field to Virgo and Coma Clusters, covering an unprecedentedly large range of galaxy luminosities (or, equivalently, stellar masses). We confirm that the fraction of barred galaxies strongly depends on galaxy luminosity. We also show that the difference between the bar fraction distributions as a function of galaxy luminosity (and mass) in the field and Coma Cluster is statistically significant, with Virgo being an intermediate case. We interpret this result as a variation of the effect of environment on bar formation depending on galaxy luminosity. We speculate that brighter disk galaxies are stable enough against interactions to keep their cold structure, thus, the interactions are able to trigger bar formation. For fainter galaxies, the interactions become strong enough to heat up the disks inhibiting bar formation and even destroying the disks. Finally, we point out that the controversy regarding whether the bar fraction depends on environment could be resolved by taking into account the different luminosity ranges probed by the galaxy samples studied so far.

Tuesday January 11, 2011
Dr. Rubén Sánchez-Janssen
European Southern Observatory, Chile


Early-type dwarfs (dEs) are by far the most abundant galaxy population in nearby clusters. Whether these objects are primordial, or recent end-products of the different physical mechanisms that can transform galaxies once they enter these high-density environments, is still a matter of debate. Here we present a novel approach to test the latter scenario by comparing the properties of the globular cluster systems of dEs and their potential progenitors with simple predictions from gravitational and hydrodynamical interactions. Current data in the literature do not favour violent mechanisms, but gentle processes with long timescales or that took place at the early stages of their formation.

« Newer Older »

Upcoming talks

More upcoming talks

Recent Colloquia

Recent Talks