Related papers: DDO 187: Do dwarf galaxies have extended halos?
There appears to exist a conflict between the standard structure formation theory and the existence of the faint dwarf spheroidal galaxies in the Local Group. Theoretical considerations suggest that a cold dark matter universe has been a…
Dark matter (DM) halos of Sc-Im galaxies satisfy scaling laws analogous to the fundamental plane relations for elliptical galaxies. Halos in less luminous galaxies have smaller core radii, higher central densities, and smaller central…
We test the hypothesis that the classical and ultra-faint dwarf spheroidal satellites of the our Galaxy have been the building blocks of the Galactic halo by comparing their [O/Fe] and [Ba/Fe] vs. [Fe/H] patterns with the ones observed in…
We report the discovery of a significant old population in the dwarf spheroidal (dSph) galaxy Leo I as a result of a wide-area search with the ESO New Technology Telescope. Studies of the stellar content of Local Group dwarf galaxies have…
In order to recognize environmental effects on the evolution of dwarf galaxies in clusters of galaxies, it is first necessary to quantify the properties of objects which have evolved in relative isolation. With oxygen abundance as the gauge…
We study the chemical and kinematic properties of the first galaxies which formed at a high redshift, using high resolution cosmological numerical simulations, and compared them with the recent observational results for the Sculptor dwarf…
The dwarf spheroidal galaxies (dSphs) in the Local Group are excellent systems on which we can test theories of galaxy formation and evolution. Color-magnitude diagrams (CMDs) containing many thousands of stars from the asymptotic giant…
Dwarf galaxies are valuable laboratories for dynamical studies related to dark matter and galaxy evolution, yet it is currently unknown just how physically extended their stellar components are. Satellites orbiting the Galaxy's potential…
On the scale of dwarf galaxies, several tensions between observations and the theory of structure formation have been identified in the Local Group of galaxies. One of them, the plane-of-satellite problem describes the distribution and…
The properties of gas in the halos of galaxies constrain global models of the interstellar medium. Kinematical information is of particular interest since it is a clue to the origin of the gas. Until now mostly massive galaxies have been…
Understanding galaxy formation involves look-back and fossil-record studies of distant and nearby galaxies, respectively. Debris trails in our Galaxy's spheroidal halo of old stars provide evidence of "bottom-up" formation via tidal…
It has been recently claimed that the confined structure of the debris from the Sagittarius dwarf implies that the dark-matter halo of our Galaxy should be nearly spherical, in strong contrast with predictions from cold dark-matter (CDM)…
We present narrowband H-alpha imaging data of a small survey of nearby edge-on spiral galaxies, aiming at the detection of `extraplanar' diffuse ionized gas (DIG). A few of our studied edge-on spirals show signs of disk-halo interaction…
The origin of dwarf spheroidal galaxies (dSphs) is investigated in a global cosmological context by simultaneously following the evolution of the Milky Way Galaxy and its dwarf satellites. This approach enable to study the formation of…
The results of UBV and H alpha imaging of a large sample of isolated dwarf irregular galaxies are interpreted in the context of composite stellar population models. The observed optical colors are best fit by composite stellar populations…
Dwarf spheroidal galaxies are regarded as the basic building blocks in the formation of larger galaxies and are believed to be the most dark matter dominated systems known in the Universe. There are several models that attempt to explain…
The concordance cosmological model based on cold dark matter makes definitive predictions for the growth of galaxies in the Universe, which are being actively studied using numerical simulations. These predictions appear to contradict the…
Two surveys for intrinsically faint galaxies towards nearby voids have been conducted at the MPI f\"ur Astronomie, Heidelberg. One selected targets from a new diameter limited ($\Phi \ge 5''$) catalog with morphological criteria while the…
We present a project on study of groups composed of dwarf galaxies only. We selected such structures using HyperLEDA and NED databases with visual inspection on SDSS images and on digital copy of POSS. The groups are characterized by size…
The stellar halos of dwarf galaxies are becoming an object of interest in the extragalactic community due to their detection in some recent observations. Additionally, new cosmological simulations of very high resolution were performed,…