Related papers: The M101 group complex: new dwarf galaxy candidate…
The intrinsically faint M dwarfs are the most numerous stars in the Galaxy, have main-sequence lifetimes longer than the Hubble time, and host some of the most interesting planetary systems known to date. Their identification and…
(Abridged) The spatial distribution of the Galactic satellite system plays an important role in Galactic dynamics and cosmology, where its successful reproduction is a key test of simulations of galaxy halo formation. Here, we examine its…
The Virgo cluster is one of the closest clusters to us where we can further study the evolution of galaxies, with several infalling substructures and several filaments around it have been reported. Therefore, it makes this cluster and its…
We have assembled a spectroscopic sample of low-mass dwarfs observed as part of the Sloan Digital Sky Survey along one Galactic sightline, designed to investigate the observable properties of the thin and thick disks. This sample of ~7400 K…
Using the bright galaxy counts from the 2 Micron All Sky Survey (2MASS) second incremental release, two techniques for probing large-scale structure at distances of ~150 h-1 Mpc are investigated. First, we study the counts from two sets of…
Supernova remnant (SNR) candidates in the giant spiral galaxy M101 have been previously identified from ground-based H-alpha and [SII] images. We have used archival Hubble Space Telescope (HST) H-alpha and broad-band images as well as…
Understanding faint dwarf galaxies is fundamental to the development of a robust theory of galaxy formation on small scales. Since the discovery of a population of ultra diffuse galaxies (UDGs) rich in globular clusters (GCs) in Coma, an…
We present the results of an all-sky, deep optical survey for faint Local Group dwarf galaxies. Candidate objects were selected from the second Palomar survey (POSS-II) and ESO/SRC survey plates and follow-up observations performed to…
The M33 galaxy is a nearby, relatively metal-poor, late-type spiral. Its proximity and almost face-on inclination means that it projects over a large area on the sky, making it an ideal candidate for wide-field CCD mosaic imaging.…
XMM-Newton and Chandra have ushered in a new era for the study of dwarf galaxies in the Local Group. We provide an overview of the opportunities, challenges, and some early results. The large number of background sources relative to galaxy…
We analyse the properties of the early-type dwarf galaxy population in the Hydra I cluster. We investigate the galaxy luminosity function (LF), the colour-magnitude relation (CMR), and the magnitude-surface brightness relation down to…
Motivated by the recent, serendipitous discovery of the densest known galaxy, M60-UCD1, we present two initial findings from a follow-up search, using the Sloan Digital Sky Survey, Subaru/Suprime-Cam and Hubble Space Telescope imaging, and…
Sloan Digital Sky Survey (SDSS) DR5 photometric data with $120^{\circ} < \alpha < 270^{\circ}$, $25^{\circ} < \delta < 70^{\circ}$ are searched for new Milky Way companions or substructures in the Galactic halo. Five candidates are…
We report on our search for distant clusters of galaxies based on optical and X-ray follow up observations of X-ray candidates from the SHARC survey. Based on the assumption that the absence of bright optical or radio counterparts to…
The Millennium N-body simulation and the Sloan Digital Sky Survey seventh data release (SDSS DR7) galaxy and galaxy group catalogues are compared to study the properties of galaxy groups and the distribution of galaxies in groups. We…
A number of mechanisms have been proposed to connect star-forming dwarf irregular galaxies with the formation of non-star-forming dwarf spheroidal galaxies, but distinguishing between these mechanisms has been difficult. We use the Via…
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…
The Local Group offers an excellent laboratory for near-field cosmology by permitting us to use the resolved stellar content of its constituent galaxies as probes of galaxy formation and evolution, which in turn is an important means for…
Using a combination of ground-based and HST imaging, we have constructed a catalog of 179 supernova remnants (SNRs) and SNR candidates in the nearby spiral galaxy M51. Follow-up spectroscopy of 66 of the candidates confirms 61 of these as…
The confinement of most satellite galaxies in the Local Group to thin planes presents a challenge to the theory of hierarchical galaxy clustering. The PAndAS collaboration has identified a particularly thin configuration with kinematic…