Related papers: The Extended Optical Disk of M101
HST-WFPC2 F555W and F814W photometry were obtained for 16 fields of the luminous nearby spiral galaxy M31, sampling the stellar content of the disk and the halo at different distances from the center, from ~ 20 to ~ 150 arcmin (i.e. ~ 4.5…
We present a study of the density profile of the remote M31 globular cluster B514, obtained from HST/ACS observations. Coupling the analysis of the distribution of the integrated light with star counts we can reliably follow the profile of…
The Andromeda (M31) galaxy subtends nearly 100 sq. deg. on the sky, with severe contamination from the Milky Way halo stars whose surface density displays a steep gradient across the entire M31 field-of-view. Planetary Nebulae (PNe) are a…
We present a structural analysis of NGC891, an edge-on galaxy that has long been considered to be an analogue of the Milky Way. Using starcounts derived from deep HST/ACS images, we detect the presence of a thick disk component in this…
By using images from the HST/WFPC2/ACS archive, we have analyzed the spatial distribution of the AGB and RGB stars along the galactocentric radius of nearby spiral galaxies M~81, NGC 300 and NGC 55. Using color-magnitude diagrams and…
We present new HI observations of the nearby dwarf galaxy NGC 3741. This galaxy has an extremely extended HI disk, which allows us to trace the rotation curve out to unprecedented distances in terms of the optical disk: we reach 42 B-band…
We present photometry from Hubble Space Telescope (HST)/Wide Field Planetary Camera 2 parallel imagery of a remote M31 field at a projected distance of about 34 kpc from the nucleus near the SW major axis. This field is near the globular…
The disk surface density of the nearby spiral galaxy M33 is estimated assuming that it is marginally stable against gravitational perturbations. For this purpose we used the radial profile of line-of-sight velocity dispersion of the disk…
Our proximity and external vantage point make M31 an ideal testbed for understanding the structure of spiral galaxies. The Andromeda Optical and Infrared Disk Survey (ANDROIDS) has mapped M31's bulge and disk out to R=40 kpc in $ugriJK_s$…
M32, the compact elliptical-galaxy companion to the Andromeda spiral galaxy has been imaged by the Galaxy Evolution Explorer (GALEX) in two ultraviolet bands, centered at ~1500 (FUV) and 2300 Angstroms (NUV). The imaging data have been…
Debris disks are usually detected through the infrared excess over the photospheric level of their host star. The most favorable stars for disk detection are those with spectral types between A and K, while the statistics for debris disks…
We present optical and IR surface photometry of M51 (NGC~5194) at B~V~R~I~J~K and CO$(2.3\mu )$. These data are used to establish whether K-band ($2.2\mu$) images of spiral galaxies provide reliable maps of stellar surface mass density…
We present surface photometry of a very faint, giant arc feature in the halo of the nearby spiral galaxy NGC 5055 (M63) that is consistent with being a part of a stellar stream resulting from the disruption of a dwarf satellite galaxy. This…
Stellar photometry of about one million stars in the system of the interacting galaxies M51 (NGC5194/NGC5195) has been carried out on the basis of the ACS/WFC images of the Hubble Space telescope. The distance to the system has been…
The fine details of the large-scale structure in the local universe provide important empirical benchmarks for testing cosmological models of structure formation. Dwarf galaxies are key object for such studies. Enlarge the sample of known…
We use deep Hubble Space Telescope imaging to study stellar populations in the outer halo of the spiral galaxy M96, located in the dynamically active Leo I galaxy group. Our imaging targets two fields at a projected distance of 50 kpc from…
We report the discovery of a nearly edge-on disk about the A0 star HD 32297 seen in light scattered by the disk grains revealed in NICMOS PSF-subtracted coronagraphic images. The disk extends to a distance of at least 400 AU (3.3") along…
The optical depth to microlensing toward M31 due to known stars in the disk of M31 itself is $\tau\sim 2\times 10^{-7}e^{-r/d}$ where $d$ is the disk scale length and $r$ is the distance along the major axis. Thus, there can be significant…
Crescent-like asymmetric dust structures discovered in protoplanetary disks indicate dust aggregations. Thus, the research on them helps us understand the planet formation process. Here we analyze the ALMA data of the protoplanetary disk…
We use deep surface photometry of the giant elliptical M49 (NGC 4472), obtained as part of our survey for diffuse light in the Virgo Cluster, to study the stellar populations in its outer halo. Our data trace M49's stellar halo out to ~ 100…