相关论文: Spatial distribution of stars and brown dwarfs in …

VLT/FORS spectroscopy and 2MASS near-infrared photometry, together with previously known data, have been used to establish the membership and the properties of a sample of low-mass candidate members of the sigma Orionis cluster with masses…

We report on a high-spatial-resolution survey for binary stars in the periphery of the Orion Nebula Cluster, at 5 - 15 arcmin (0.65 - 2 pc) from the cluster center. We observed 228 stars with adaptive optics systems, in order to find…

New observations in the $VI$ bands along with archival data from the 2MASS and $WISE$ surveys have been used to generate a catalog of young stellar objects (YSOs) covering an area of about $6^\circ\times6^\circ$ in the Auriga region…

Low-mass stars and sub-stellar objects are essential in tracing the initial mass function (IMF). We study the nearby young $\sigma$ Orionis cluster (d$\sim$408 pc; age$\sim$1.8 Myr) using deep NIR photometric data in J, W and H-bands from…

The recent detection by direct imaging of three giant planets at wide separation (50-250 AU) from their primaries has raised the question about the ``true isolation'' of planetary-mass objects in clusters. Our goal was to test the…

We present a study of the radial distribution of dust species in young brown dwarf disks. Our work is based on a compositional analysis of the 10 and 20 micron silicate emission features for brown dwarfs in the Taurus-Auriga star-forming…

We use the 2MASS Second Incremental Release Point Source Catalog to investigate the spatial distribution of young stars in the Perseus, Orion A, Orion B, and MonR2 molecular clouds. After subtracting a semi-empirical model of the field star…

Aims.We study the photometric and structural properties of the star cluster system in the late type Sc spiral NGC 3370. Methods. BVI observations from the Advanced Camera for Surveys on board of HST are used to analyse in detail the…

Young stellar clusters are predominantly the hub of star formation and hence, ideal to perform comprehensive studies over the least explored sub-stellar regime. Various unanswered questions like the mass distribution in brown dwarf regime…

We present a synthesis of recent photometric and kinematic data for several of the most dark-matter dominated galaxies. There is a bimodal distribution in half-light radii, with stable star clusters always being smaller than $\sim30$pc,…

Forty new low mass members with spectral types ranging from M4-M9 have been confirmed in the Orion Molecular Cloud 2/3 region. Through deep, I, z', J, H, K photometry of a 20' x 20' field in OMC 2/3, we selected brown dwarf candidates for…

The distribution of member stars in the surroundings of an Open Cluster (OC) can shed light on the process of its formation, evolution and dissolution. The analysis of structural parameters of OCs as a function of their age and position in…

In this paper we present strong evidence for a core in the density distribution of the dark halo around a (dwarf) galaxy. DDO 47 has a rotation curve that increases linearly from the first data point, at 300 pc, up to to the last one, at 5…

I review the up-to-date status on the properties of the Dark Matter density distribution around Galaxies. The rotation curves of spirals all conform to a same Universal profile which can be uniquely decomposed as the sum of an exponential…

The Galactic centre hosts a crowded, dense nuclear star cluster with a half-light radius of 4 pc. Most of the stars in the Galactic centre are cool late-type stars, but there are also >100 hot early-type stars in the central parsec of the…

We present results from an 850-$\mu$m survey of the $\sim$ 5 Myr old $\lambda$ Orionis star-forming region. We used the SCUBA-2 camera on the James Clerk Maxwell Telescope to survey a $\sim$0.5-diameter circular region containing 36 (out of…

We have retrieved multicolor WFPC2/HST data from the STScI archive for 27 nearby Massive (>= 3x10^4 M_Sun) Young (< 20 Myr) star Clusters (MYCs). The data represents the most-complete-to-date sample of clearly resolved MYCs. We have…

We have obtained low resolution optical spectra of 15 isolated planetary mass objects (IPMOs) in the sigma Orionis cluster, and derived spectral types by comparison with nearby M and L dwarfs. The spectral types are in the range late M -…

We present results from 1351 high resolution spectra of 1215 stars in the Orion Nebula Cluster (ONC) and the surrounding Orion 1c association, obtained with the Hectochelle multiobject echelle spectrograph on the 6.5m MMT. We confirmed 1111…

An overall analysis of the structure and stellar content of M11 is presented, thanks to the wide-angle 2MASS spatial coverage. We derive photometric and structural parameters and discuss the spatial dependance of the luminosity and mass…