相关论文: Beyond 31 mag/arcsec^2: the low surface brightness…
We present measurements of the extended dark halo profiles of bright early type galaxies at redshifts 0.1 to 0.9 obtained via galaxy-galaxy lensing analysis of images taken at the CFHT using the UH8K CCD mosaic camera. Six half degree…
We report on the detection of a stellar halo around NGC 1560, a 10^9 Mo spiral galaxy member of the Maffei group. We obtained deep images in the r and i bands using the 10.4m Gran Telescopio Canarias in a field centered at ~ 3.7 arcmin…
The extragalactic background light at far-infrared wavelengths originates from optically-faint, dusty, star-forming galaxies in the universe with star-formation rates at the level of a few hundred solar masses per year. Due to the…
Compact dark matter has been efficiently constrained in the M <~ 10 M_sun mass range by null searches for microlensing of stars in nearby galaxies. Here we propose to probe the mass range M >~ 10 M_sun by seeking echoes in gamma-ray-burst…
A high optical depth to gravitational microlensing towards the galactic bulge is consistent with current models of the galactic bar. The low optical depth towards the LMC can probably be accounted for by the ordinary stars in our galaxy and…
We detail how microlensing internal to M31 could be used to test whether a large fraction of the matter in spiral galaxy haloes is composed of dark objects with masses comparable to those of stars, and in the process show how the…
First galaxies formed within halos of mass M=E7.5-E9 Msun at z=30-40 in the standard cold dark matter (CDM) universe may each display an extended hydrogen 21-cm absorption halo against the cosmic microwave background with a brightness…
MAGIC is a system of two Cherenkov telescopes located in the Canary island of La Palma. A key part of MAGIC Fundamental Physics program is the search for indirect signals of Dark Matter (DM) from different sources. In the Milky Way, DM…
Images of the Hubble Deep Field at 3.2 um, taken with the 10-m Keck Telescope, are presented. The images cover a total area of ~2.5 arcmin^2. To a 5-sigma limit of [3.2](total)=17.5 mag (Vega-relative), 11 sources are detected, 9 of which…
We report a significant detection of weak, tangential distortion of the images of cosmologically distant, faint galaxies due to gravitational lensing by foreground galaxies. A mean image polarisation of $<p>=0.011\pm 0.006$ is measured for…
We describe a deep, systematic imaging study of satellites in the outer halo of the Milky Way. Our sample consists of 58 stellar overdensities --- i.e., substructures classified as either globular clusters, classical dwarf galaxies, or…
Detection and photometry of sources in the U_n, G, R, and K_s bands in a 9x9 arcmin^2 region of the sky, centered on the Hubble Deep Field, are described. The data permit construction of complete photometric catalogs to roughly U_n=25,…
Deep fields are unique probes of the Galactic halo. With a limiting magnitude of, e.g., I = 30 mag, all stars down to the hydrogen-burning limit are detected out to distances of 10 kpc, while stars with 0.5 solar masses could be traced out…
We present HST/ACS imaging of twenty-three very low surface brightness ($\mu_{e,V}$=25-27.5) galaxies detected in the fields of four nearby galaxy groups. These objects were selected from deep optical imaging obtained with the Dragonfly…
The Andromeda Galaxy (M31) is the closest large galaxy to the Milky Way, thus it is an important laboratory for studying massive dark objects in galactic halos (MACHOs) by gravitational microlensing. Such studies strongly complement the…
In this Letter we present calibrated observations of the average mass of galaxies with 22< I < 25 in the Hubble Deep Field. We measure the mean mass profile using the statistical gravitational lens distortion of faint blue background…
We present an overview of the LIGHTS (LBT Imaging of Galactic Halos and Tidal Structures) survey, which currently includes 25 nearby galaxies that are on average $\sim$ 1 mag fainter than the Milky Way, and a catalog of 54 low central…
We present the first results of the LBT Imaging of Galaxy Haloes and Tidal Structures (LIGHTS) survey. LIGHTS is an ongoing observational campaign with the 2x8.4m Large Binocular Telescope (LBT) aiming to explore the stellar haloes and the…
We examine the possibility of observing gravitational lensing in the weak deflection regime by the supermassive black hole in the center of the galaxy M31. This black hole is significantly more massive than the black hole in the center of…
Various theoretical models predict the existence of extended $\gamma$-ray halo around normal galaxies that could be produced by interactions of cosmic rays with the circumgalactic medium or by annihilation or decay of hypothetical dark…