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Full-Text Articles in Astrophysics and Astronomy
Spitzer Observations Of Star Formation In The Extreme Outer Disk Of M83 (Ngc5236), H Dong, D Calzetti, M Regan, D Thilker, L Bianchi, Gr Meurer, F Walter
Spitzer Observations Of Star Formation In The Extreme Outer Disk Of M83 (Ngc5236), H Dong, D Calzetti, M Regan, D Thilker, L Bianchi, Gr Meurer, F Walter
Astronomy Department Faculty Publication Series
Spitzer Infrared Array Camera (IRAC) observations of two fields in the extended UV disk (XUV-disk) of M83 have been recently obtained, ~3 R HII away from the center of the galaxy (R HII = 6.6 kpc). Galaxy Evolution Explorer (GALEX) UV images have shown the two fields to host in situ recent star formation. The IRAC images are used in conjunction with GALEX data and new H I imaging from The H I Nearby Galaxy Survey (THINGS) to constrain stellar masses and ages of the UV clumps in the fields, and to relate the local recent star formation to the …
On The Evolutionary History Of Stars And Their Fossil Mass And Light, Ma Fardal, N Katz, Dh Weinberg, R Dave
On The Evolutionary History Of Stars And Their Fossil Mass And Light, Ma Fardal, N Katz, Dh Weinberg, R Dave
Astronomy Department Faculty Publication Series
The total extragalactic background radiation can be an important test of the global star formation history (SFH). Using direct observational estimates of the SFH, along with standard assumptions about the initial mass function (IMF), we calculate the total extragalactic background radiation and the observed stellar density today. We show that plausible SFHs allow a significant range in each quantity, but that their ratio is very tightly constrained. Current estimates of the stellar mass and extragalactic background are difficult to reconcile, as long as the IMF is fixed to the Salpeter slope above 1 M⊙. The joint confidence interval …
The Optical And Near-Infrared Properties Of Galaxies. I. Luminosity And Stellar Mass Functions, Ef Bell, Dh Mcintosh, N Katz, Md Weinberg
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
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
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 …
Structure Of The Large Magellanic Cloud From 2mass, Md Weinberg, S Nikolaev
Structure Of The Large Magellanic Cloud From 2mass, Md Weinberg, S Nikolaev
Astronomy Department Faculty Publication Series
We derive structural parameters and evidence for extended tidal debris from star count and preliminary standard candle analyses of the Large Magellanic Cloud based on Two-Micron All-Sky Survey (2MASS) data. The full-sky coverage and low extinction in Ks present an ideal sample for structural analysis of the LMC. The star count surface densities and deprojected inclination for both young and older populations are generally consistent with previous work. We fit the projected density with an exponential disk or spherical power-law model with an optional two-dimensional elliptical bar. The derived disk scale length is R = 1.42 ± 0.01 kpc for …