T Dwarfs and the Substellar Mass Function. I. Monte Carlo Simulations

Details T Dwarfs and the Substellar Mass Function. I. Monte Carlo Simulations T Dwarfs and the Substellar Mass Function. I. Monte Carlo Simulations

2004-07-30

arxiv.org/abs/astro-ph/0407624v2

Astrophys.J.Suppl.155:191-207,2004

Astronomy and Astrophysics

Astrophysics

36 pages, 22 figures, accepted for ApJS 1 September 2004 issue

Scientific paper

10.1086/424386

Monte Carlo simulations of the field substellar mass function (MF) are presented. Starting from various representations of the MF below 0.1 M$_{\sun}$ and the stellar birth rate, luminosity functions (LFs) and T$_{eff}$ distributions are produced for comparison with observed samples. These distributions exhibit distinct minima in the mid-type L dwarf regime followed by a rise in number density for fainter/cooler brown dwarfs, predicting many more T-type and cooler brown dwarfs in the field even for relatively shallow mass functions. Deuterium-burning brown dwarfs dominate field objects with 400 $\leq$ T$_{eff}$ $\leq$ 2000 K, while non-fusing brown dwarfs make up a substantial proportion of field dwarfs with T$_{eff}$ $\leq$ 500 K. The shape of the substellar LF is fairly consistent for various assumptions of the Galactic birth rate, choice of evolutionary model, and adopted age and mass ranges, particularly for field T dwarfs, which as a population provide the best constraints for the field substellar MF. Exceptions include a depletion of objects with 1200 $\leq$ T$_{eff}$ $\leq$ 2000 K in ``halo'' systems. Unresolved multiple systems tend to enhance features in the observed LF and may contribute significantly to the space density of very cool brown dwarfs. However, these effects are small ($<$ 10% for T$_{eff} \lesssim 300$ K) for binary fractions typical for brown dwarf systems (10--20%). An analytic approximation to correct the observed space density for unresolved multiple systems in a magnitude-limited survey is derived. [ABRIDGED]

Affiliated with

Also associated with

No associations

Rating

T Dwarfs and the Substellar Mass Function. I. Monte Carlo Simulations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with T Dwarfs and the Substellar Mass Function. I. Monte Carlo Simulations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and T Dwarfs and the Substellar Mass Function. I. Monte Carlo Simulations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-503301