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Physical Sciences and Mathematics Commons

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University of Massachusetts Amherst

2003

Galaxies : stellar content

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

The Optical And Near-Infrared Properties Of Galaxies. I. Luminosity And Stellar Mass Functions, Ef Bell, Dh Mcintosh, N Katz, Md Weinberg Jan 2003

The Optical And Near-Infrared Properties Of Galaxies. I. Luminosity And Stellar Mass Functions, Ef Bell, Dh Mcintosh, N Katz, Md Weinberg

Astronomy Department Faculty Publication Series

We use a large sample of galaxies from the Two Micron All Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS) to calculate galaxy luminosity and stellar mass functions in the local universe. We estimate corrections for passband shifting and galaxy evolution, as well as present-day stellar mass-to-light (M/L) ratios, by fitting the optical-near-infrared galaxy data with simple models. Accounting for the 8% galaxy overdensity in the SDSS early data release region, the optical and near-infrared luminosity functions we construct for this sample agree with most recent literature optical and near-infrared determinations within the uncertainties. We argue that 2MASS …


A Two Micron All Sky Survey View Of The Sagittarius Dwarf Galaxy. I. Morphology Of The Sagittarius Core And Tidal Arms, Sr Majewski, Mf Skrutskie, Md Weinberg, Jc Ostheimer Jan 2003

A Two Micron All Sky Survey View Of The Sagittarius Dwarf Galaxy. I. Morphology Of The Sagittarius Core And Tidal Arms, Sr Majewski, Mf Skrutskie, Md Weinberg, Jc Ostheimer

Astronomy Department Faculty Publication Series

We present the first all-sky view of the Sagittarius (Sgr) dwarf galaxy mapped by M-giant star tracers detected in the complete Two Micron All Sky Survey (2MASS). Near-infrared photometry of Sgr's prominent M-giant population permits an unprecedentedly clear view of the center of Sgr. The main body is fitted with a King profile of limiting major-axis radius 30°—substantially larger than previously found or assumed—beyond which is a prominent break in the density profile from stars in the Sgr tidal tails; thus the Sgr radial profile resembles that of Galactic dwarf speroidal (dSph) satellites. Adopting traditional methods for analyzing dSph light …


A First Estimate Of The Baryonic Mass Function Of Galaxies, Ef Bell, Dh Mcintosh, N Katz, Md Weinberg Jan 2003

A First Estimate Of The Baryonic Mass Function Of Galaxies, Ef Bell, Dh Mcintosh, N Katz, Md Weinberg

Astronomy Department Faculty Publication Series

We estimate the baryonic (stellar+cold gas) mass function of galaxies in the local universe by assigning a complete sample of Two Micron All Sky Survey and Sloan Digital Sky Survey galaxies a gas fraction based on a statistical sample of the entire population, under the assumption of a universally applicable stellar initial mass function. The baryonic mass function is similar to the stellar mass function at the high-mass end and has a reasonably steep faint-end slope owing to the typically high cold gas fractions and low stellar mass-to-light ratios characteristic of low-mass galaxies. The Schechter function fit parameters are phi*h-3 …