Related papers: SONYC - Substellar Objects in Nearby Young Cluster…
We are conducting a survey of several regions of high-mass star formation to assess their content and structure. The observations include Spitzer observations, ground-based optical and near-IR imaging surveys, and optical and IR spectra of…
We present a complete low-resolution (R~100) near-infrared spectrum of the substellar object GY11, member of the rho-Ophiuchi young association. The object is remarkable because of its low estimated mass and age and because it is associated…
We predict near-infrared luminosity functions of young (5 Myr to 1 Gyr) star clusters by combining evolutionary models of very low-mass ($1 M_J$ to $0.15 M_{\odot}$) dwarfs with empirical bolometric corrections. We identify several…
We present near-infrared long slit and multi-slit spectra of low mass brown dwarf candidates in the Orion Nebula Cluster. The long slit data were observed in the H- & K-bands using NIRI on the Gemini North Telescope. The multi-object…
We have used images obtained with the Infrared Array Camera and the Multiband Imaging Photometer onboard the Spitzer Space Telescope to search for low-mass stars and brown dwarfs with circumstellar disks in the Chamaeleon I star-forming…
Measurement of the substellar initial mass function (IMF) in very young clusters is hampered by the possibility of the age spread of cluster members. This is particularly serious for candidate planetary mass objects (PMOs), which have a…
Herbig-Haro objects (HHOs) are caused by outflows from young objects. Since the outflow relies on mass accretion from a circumstellar disk, it indicates ongoing growth. Recent results of infrared observations yielded evidence for disks…
We present the stellar and substellar mass function of the open cluster IC2391, plus its radial dependence, and use this to put constraints on the formation mechanism of brown dwarfs. Our multiband optical and infrared photometric survey…
We have performed a search for planetary-mass brown dwarfs in the Chamaeleon I star-forming region using proper motions and photometry measured from optical and infrared images from the Spitzer Space Telescope, the Hubble Space Telescope,…
We report the results of deep infrared observations of brown dwarf candidates in the Trapezium cluster in Orion. Analysis of the JHK color-color diagram indicates that a large fraction (approx 65% +/- 15%) of the observed sources exhibit…
We present a study of the young (30-100Myr) open cluster IC 4665 with the aim to determine the shape of the mass function well into the brown dwarf regime. We photometrically select 691 low-mass stellar and 94 brown dwarf candidate members…
Since the discovery of the first bona-fide brown dwarfs and extra-solar planets in 1995, the field of low mass stars and substellar objects has considerably progressed, both from theoretical and observational viewpoints.Recent developments…
The mass domain where massive extrasolar planets and brown dwarfs lay is still poorly understood. Indeed, not even a clear dividing line between massive planets and brown dwarfs has been established yet. This is partly due to the paucity of…
We explore the possibility that, in the vicinity of an OB star, a prestellar core which would otherwise have formed an intermediate or low-mass star may form a free-floating brown dwarf or planetary-mass object, because the outer layers of…
Age-benchmark brown dwarfs' and planetary-mass objects' spectroscopy is key to characterize substellar evolution. In this paper we present the JHK medium resolution (R~3000) spectra of 25 7-75 M_Jup (spectral types L3.0-M6.0) brown dwarfs…
We have completed an optical spectroscopic survey of an unbiased, extinction-limited sample of candidate young stars covering 1.3 square degrees of the Rho Ophiuchi star forming region. While infrared, X-ray, and optical surveys of the…
Low mass star formation inside massive clusters is crucial to understand the effect of cluster environment on processes like circumstellar disk evolution, planet and brown dwarf formation. The young massive association of Cygnus OB2, with a…
We summarize the main results of a mid-IR photometric survey with ISO for a few nearby embedded clusters. The sensitivity and spatial resolution of ISOCAM provided a wonderful tool for studies of the youngest stellar clusters, which are…
We present near-infrared (1.0-2.4 micron) spectra confirming the youth and cool effective temperatures of 6 brown dwarfs and low mass stars with circumstellar disks toward the Chamaeleon II and Ophiuchus star forming regions. The spectrum…
We have completed a systematic survey for disks around young brown dwarfs and very low mass stars. By choosing a well-defined sample and by obtaining sensitive thermal IR observations, we can make an unbiased measurement of the disk…