相关论文: A revisit to agglomerates of early-type Hipparcos …
(abridged) Our project endeavors to obtain a robust view of multiplicity among embedded Class I and Flat Spectrum protostars in a wide array of nearby molecular clouds to disentangle ``universal'' from cloud-dependent processes. We have…
Aims: According to some estimations, there are as many as 100000 open clusters in the Galaxy, but less than 2000 of them have been discovered, measured, and cataloged. We plan to undertake data mining of multiwavelength surveys to find new…
We present the first results of a comprehensive census of the stellar content of the nearby OB associations based on Hipparcos positions, proper motions and parallaxes for 12842 candidate member stars distributed over 21 fields on the sky.…
A comprehensive census of the stellar content of the nearby OB associations is presented, based on Hipparcos positions, proper motions, and parallaxes. Moving groups are identified by combining de Bruijne's refurbished convergent point…
We present deep 3.8 micron observations of the Trapezium cluster in Orion obtained with the ESO VLT. We use these data to search for infrared excess emission and evidence for protoplanetary disks associated with the faint, substellar…
In this work we investigate the nature of 50 overdensities from the catalogue of Froebrich, Scholz, and Raftery (FSR) projected towards the Galactic anticentre, in the sector 160{\deg} \leq \ell \leq 200{\deg}. The sample contains…
We have carried out a study of the early type stars in nearby OB associations spanning an age range of $\sim$ 3 to 16 Myr, with the aim of determining the fraction of stars which belong to the Herbig Ae/Be class. We studied the B, A, and F…
This paper presents the detailed results obtained in the search of density- velocity inhomogeneities in a volume limited and absolute magnitude limited sample of A-F type dwarfs within 125 parsecs of the Sun. A 3-D wavelet analysis is used…
We have used a star-count algorithm based the Panoramic Survey Telescope And Rapid Response System 3$\pi$ survey data aim to identify and characterize uncharted open clusters (OCs). With limiting magnitudes of about 22 mag in \gps, \rps,…
The clusters of young stars in massive star-forming regions show a wide range of sizes, morphologies, and numbers of stars. Their highly subclustered structures are revealed by the MYStIX project's sample of 31,754 young stars in nearby…
(Abridged). We have conducted deep photometric searches for substellar members of the Praesepe (0.5-1 Gyr) and sigma Orionis (3 Myr) star clusters using the Sloan i' and z' filters, the 3.5-m and the 5-m Hale telescopes on the Calar Alto…
We review the current knowledge of the population of `older' stars in the Orion OB1 association, specifically those in subgroups 1a and 1b. We briefly outline the history of the subject and then continue with a summary of the present state…
New and archival HST images of the globular cluster systems of 17 relatively nearby galaxies and 6 more distant galaxies have been used to establish the characteristics of GC subpopulations over a range of host galaxy morphological type…
We perform a search for faint, common proper motion companions of Hipparcos stars using the recently published LSPM-north catalog of stars with proper motion mu>0.15 arcsec/yr. Our survey uncovers a total of 521 systems with angular…
Young stellar populations provide a powerful record that traces millions of years of star formation history in the solar neighborhood. Using a revised form of the SPYGLASS young star identification methodology, we produce an expanded census…
We performed a systematic search for strong gravitational lenses using Hyper Suprime-Cam (HSC) data, focusing on galaxy-scale lenses combined with an environment analysis resulting in the identification of lensing clusters. To identify…
The sample of known star clusters, the fundamental building blocks of galaxies, in the Milky Way is still extremely incomplete for objects beyond a distance of 1-2kpc. Many of the more distant and young clusters are compact and hidden…
We have developed a star-counting algorithm and tested it on the 2MASS star catalog to search for density enhancements significantly above the field in Galactic latitude $|b|<50^{\circ}$. Nearly 500 open clusters are "rediscovered", along…
The multiplicity of early-type stars is still not well established. The derived binary fraction is different for individual star forming regions, suggesting a connection with the age and the environment conditions. The few studies that have…
Deep optical imaging is used to study time-domain properties of young brown dwarfs in sigma Orionis over typical rotational time-scales and to search for new substellar and planetary-mass cluster members. We used VIMOS at the VLT to monitor…