منابع مشابه
T Dwarfs and the Substellar Mass Function . I . Monte Carlo Simulations
Monte Carlo simulations of the field substellar mass function (MF) are presented, based on the latest brown dwarf evolutionary models from Burrows et al. (1997) and Baraffe et al. (2003). Starting from various representations of the MF below 0.1 M⊙ and the stellar birth rate, luminosity functions (LFs) and Teff distributions are produced for comparison with observed samples. These distributions...
متن کاملThe Substellar Mass Function: A Bayesian Approach
We report our efforts to constrain the form of the low-mass star and brown dwarf mass function via Bayesian inference. Recent surveys of M, L, and T dwarfs in the local solar neighborhood are an essential component of our study. Uncertainties in the age distribution of local field stars make reliable inference complicated. We adopt a wide range of plausible assumptions about the rate of galacti...
متن کاملThe Substellar Mass Function in σ Orionis
We combine results from imaging searches for substellar objects in the σ Orionis cluster and follow-up photometric and spectroscopic observations to derive a census of the brown dwarf population in a region of 847 arcmin 2. We identify 64 very low-mass cluster member candidates in this region. We – 2 – have available three color (IZ and J) photometry for all of them, spectra for 9 objects, and ...
متن کاملGalactic Stellar and Substellar Initial Mass Function
We review recent determinations of the present day mass function (PDMF) and initial mass functions (IMF) in various components of the Galaxy, disk, spheroid, young and globular clusters and in conditions characteristic of early star formation. As a general feature, the IMF is found to depend weakly on the environment and to be well described by a power-law form for m & 1M⊙ and a lognormal form ...
متن کاملConstraints on the Space Density of Methane Dwarfs and the Substellar Mass Function from a Deep Near-Infrared Survey.
We report preliminary results of a deep near-infrared search for methane-absorbing brown dwarfs; almost 5 yr after the discovery of Gl 229b, there are only a few confirmed examples of this type of object. New J-band, wide-field images, combined with preexisting R-band observations, allow efficient identification of candidates by their extreme (R-J) colors. Follow-up measurements with custom fil...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 1999
ISSN: 0004-637X,1538-4357
DOI: 10.1086/307589