Related papers: A Census of Compact Elliptical Galaxies in the Com…
We report on a study of young star cluster complexes in the spiral galaxy M51. Recent studies have confirmed that star clusters do not form in isolation, but instead tend to form in larger groupings or complexes. We use {\it HST} broad and…
Using a sample of 91 galaxies distributed over 27 Compact Groups of Galaxies (CGs), we define an index that allows us to quantify their level of activity, be it AGN or star formation. By combining the mean activity index with the mean…
Besides its major objective tuned to the detection of the stellar galactic population the Gaia mission experiment will also observe a large number of galaxies. In this work we intend to evaluate the number and the characteristics of the…
We investigate the properties of 12 ultra-massive passively evolving early type galaxies (ETGs) at z_phot>1.4 in the COSMOS 2 deg^2 field. These 12 ETGs were selected as pBzKs, have accurate 1.4<= z_phot <=1.7,high Sersic index profiles…
We present optical VLT spectroscopy of 16 dwarf elliptical galaxies (or dEs) comparable in mass to NGC 205, and belonging to the Fornax cluster and to nearby groups of galaxies. Using ULySS and STECKMAP, we derive radial profiles of the…
It has been widely remarked that compact, massive, elliptical-like galaxies are abundant at high redshifts but exceedingly rare in the Universe today, implying significant evolution such that their sizes at z ~ 2+/-0.6 have increased by…
The James Webb Space Telescope has found an unexpected population of high-mass galaxies ($\log (M^\star / {\rm M} _\odot) \gtrsim 10$) with extremely small effective radii ($\sim 100\,\rm pc$) at $z \gtrsim 6$. Also, the existence of an…
The long-slit spectra obtained along the minor axis, offset major axis and diagonal axis are presented for 12 E and S0 galaxies of the Coma cluster drawn from a magnitude-limited sample studied before. The rotation curves, velocity…
We report the discovery of 854 ultra diffuse galaxies (UDGs) in the Coma cluster using deep R band images, with partial B, i, and Halpha band coverage, obtained with the Subaru telescope. Many of them (332) are Milky Way-sized with very…
High sensitivity 21-cm HI line observations, with an rms noise level of \sim 0.5 mJy, were made of 35 spiral galaxies in the Coma Supercluster, using the refurbished Arecibo telescope, which resulted in the detection of 25 objects. These…
We report the discovery of 652 star clusters, stellar groups and candidates in the Milky Way with WISE. Most of the objects are projected close to Galactic Plane and are embedded clusters. The present sample complements a similar study…
A homogeneous sample of galaxy redshifts in the core regions (R < 0.5 h$^{-1}$ Mpc) of 12 clusters is used to measure the frequency of substructure with different tests. In 50 % of the cases substructure is detected, a frequency which…
We report the results of a high quality spectral study of early-type galaxies within the Coma Cluster core. Stellar population analysis using Lick/IDS indices to break the age/metallicity degeneracy are presented, probing their formation…
Due to observational constraints, dark matter determinations in nearby clusters based on weak lensing are still extremely rare, in spite of their importance for the determination of cluster properties independent of other methods. We…
Elliptical and S0 galaxies dominate the galaxy population in nearby rich clusters such as Coma. Studies of the evolution of the colors, M/L ratios, and line indices of early-type galaxies indicate that they have been a highly homogeneous,…
We have used ISO to observe at 12$\mu$m seven E+A galaxies plus an additional emission line galaxy, all in the Coma cluster. E+A galaxies lacking narrow emission lines have 2.2$\mu$m to 12$\mu$m flux density ratios or limits similar to old…
Dwarf elliptical (dE) galaxies, with blue absolute magnitudes typically fainter than $M_B = -16$, are the most numerous type of galaxy in the nearby universe. Tremendous advances have been made over the past several years in delineating the…
Ellipticals in very low density environments are extremely rare but hold important clues about galaxy formation and evolution. In this paper we continue our study of isolated elliptical galaxies, presenting results on the radial stellar…
In spite of the promise of new techniques for constraining the mass distribution in galaxy clusters, much remains to be learned from galaxy orbital velocities. This article reviews the theory of potential estimation in hot dynamical systems…
What is the origin of the numerous population of diffuse elliptical galaxies (dE) in clusters? These galaxies formed their stars several billion years ago and lost their gas. Though the stellar winds resulting from star formation and the…