相关论文: The abundance of brown dwarfs

We present a luminosity function (LF) for lower main sequence stars in the Galactic bulge near (l,b)=(0,-6) to J=24, corresponding to M_J~9.3. This LF is derived from HST + NICMOS observations with the F110W and F160W filters. The main…

We present an observational mass function ranging from galaxies to massive galaxy clusters, derived from direct dynamical mass estimates. Our mass function shows, in the low-mass range of galaxies and groups, a behaviour in agreement with…

We combine Spitzer $3.6\mu$ observations of a sample of disk galaxies spanning over 10 magnitudes in luminosity with optical luminosities and colors to test population synthesis prescriptions for computing stellar mass. Many commonly…

Following an old idea of Fritz Zwicky, we make an attempt to establish a universal mass function for astronomical objects on all scales. The object classes considered are: solar system planets and small bodies, exoplanets, brown dwarfs,…

We combine the available astrometric and photometric data for the 1993 microlensing event MACHO-LMC-5 to measure the mass of the lens, M=0.097 +/- 0.016 Msun. This is the most precise direct mass measurement of a single star other than the…

The 2dFGRS is used in conjunction with the 2MASSXSC to study the near-IR light and stellar mass content of the local Universe. Mock galaxy catalogues, constructed from cosmological N-body simulations and semi-analytical galaxy formation…

We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of magnitude larger than previous redshift…

We present a study of M dwarfs discovered in a large area, multicolor survey. We employ a combination of morphological and color criteria to select M dwarfs to a limiting magnitude in V of 22, the deepest such ground-based survey for M…

The search for a luminosity function for galaxies both alternative or companion to a Schechter function is a key problem in the reduction of data from catalogs of galaxies. Two luminosity functions for galaxies can be built starting from…

Star clusters in 6 nearby spiral galaxies are examined using archive images from HST/WFPC2. The galaxies have previously been studied from the ground and some of them are known to possess rich populations of "young massive clusters" (YMCs).…

A Bayesian statistical formalism is developed to quantify the level at which the mass function slope (alpha) and the projected cumulative mass fraction (f) of (CDM) substructure in strong gravitational-lens galaxies, with arcs or Einstein…

A new method is presented to obtain a non-parametric maximum likelihood estimate of the luminosity function and the selection function of a flux limited redshift survey. The method parameterizes the selection function as a series of…

Low-mass stars (M<0.4Msun) are thought to comprise the bulk of the stellar mass of galaxies but they constitute only of order a percent of the bolometric luminosity of an old stellar population. Directly estimating the number of low-mass…

Mass functions for samples of white dwarf stars and for a large heterogeneous sample of nearby stars appear to have unexplained deficits in the range of 0.70 to 0.75 Solar Masses. The existence, or non-existence, of this anomaly constitutes…

We present a Mass-Luminosity Relation (MLR) for red dwarfs spanning a range of masses from 0.62 Msun to the end of the stellar main sequence at 0.08 Msun. The relation is based on 47 stars for which dynamical masses have been determined,…

We perform a Bayesian analysis of the mass distribution of stellar-mass black holes using the observed masses of 15 low-mass X-ray binary systems undergoing Roche lobe overflow and five high-mass, wind-fed X-ray binary systems. Using Markov…

Our knowledge of the birth mass function of neutron stars and black holes is based on observations of binary systems but the binary evolution likely affects the final mass of the compact object. Gravitational microlensing allows us to…

We present a non-parametric, empirically based, model for associating galaxy luminosities with halo/subhalo masses, based on a self-consistent treatment of subhalo mass loss and the subhalo mass function. We find that, at high mass, the…

There is accumulating evidence that the faint end of the galaxy luminosity function might be very different in different locations. The luminosity function might be sharply rising in rich clusters and flat or declining in regions of low…

X-ray luminosity function derived from observations of X-ray sources in galactic bulges can be explained by prinicipal evolutionary relations for mass accretion rate onto the compact object. The observed mean distribution of individual…