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X-ray obscuration and obscured AGN in the local universe
Perola, G. C.; Guainazzi, M.; Matt, G.
We discuss the X-ray properties of 49 local (z<0.035) Seyfert 2 galaxies with HST/WFC2 high-resolution optical coverage. It includes the results of 26 still unpublished Chandra and XMM-Newton observations, which yield 25 (22) new X-ray detections in the 0.5-2 keV (2-10 keV) energy band. Our sample covers a range in the 2-10 keV observed flux, F…
Masses of Star Clusters in the Nuclei of Bulgeless Spiral Galaxies
Ho, L. C.; Rix, H. -W.; Shields, J. C. +6 more
In the last decade star clusters have been found in the centers of spiral galaxies across all Hubble types. We here present a spectroscopic study of the exceptionally bright (106-108 Lsolar) but compact (re~5 pc) nuclear star clusters in very late type spirals with the Ultraviolet and Visual Echelle Spec…
GEMS: The Surface Brightness and Surface Mass Density Evolution of Disk Galaxies
Bell, Eric F.; Somerville, Rachel S.; Wisotzki, Lutz +14 more
We combine HST imaging from the GEMS (Galaxy Evolution from Morphologies and SEDs) survey with photometric redshifts from COMBO-17 to explore the evolution of disk-dominated galaxies since z<~1.1. The sample is composed of all GEMS galaxies with Sérsic indices n<2.5, derived from fits to the galaxy images. We account fully for selection effe…
Fluvial sedimentary deposits on Mars: Ancient deltas in a crater lake in the Nili Fossae region
Head, James W.; Fassett, Caleb I.
New spacecraft observations in the Nili Fossae region of Mars reveal two valley networks (~80 and ~200 km long) that each formed distributary fans as they entered an ancient 40-km diameter impact crater. An outlet channel on the eastern crater rim, lying at an elevation above the fans, suggests these fans formed as subaqueous deltas in a crater la…
The Surprisingly Steep Mass Profile of A1689, from a Lensing Analysis of Subaru Images
Kong, X.; Broadhurst, T.; Umetsu, K. +4 more
Subaru observations of A1689 (z=0.183) are used to derive an accurate, model-independent mass profile for the entire cluster, r<~2 Mpc h-1, by combining magnification bias and distortion measurements. The projected mass profile steepens quickly with increasing radius, falling away to zero at r~1.0 Mpc h-1, well short of th…
The Central Region of Barred Galaxies: Molecular Environment, Starbursts, and Secular Evolution
Scoville, Nick; Jogee, Shardha; Kenney, Jeffrey D. P.
Stellar bars drive gas into the circumnuclear (CN) region of galaxies. To investigate the fate of the CN gas and star formation (SF), we study a sample of barred nonstarbursts and starbursts with high-resolution CO, optical, Hα, radio continuum, Brγ, and HST data, and find the following. (1) The inner kiloparsec of bars differs markedly from the o…
A Jovian-Mass Planet in Microlensing Event OGLE-2005-BLG-071
Bennett, D. P.; Gal-Yam, A.; Soszyński, I. +34 more
We report the discovery of a several-Jupiter-mass planetary companion to the primary lens star in microlensing event OGLE-2005-BLG-071. Precise (<~1%) photometry at the peak of the event yields an extremely high signal-to-noise ratio detection of a deviation from the light curve expected from an isolated lens. The planetary character of this de…
Solar-like Oscillations in α Centauri B
Butler, R. Paul; Bedding, Timothy R.; Marcy, Geoffrey W. +6 more
We have made velocity observations of the star α Centauri B from two sites, allowing us to identify 37 oscillation modes with l=0-3. Fitting to these modes gives the large and small frequency separations as a function of frequency. The mode lifetime, as measured from the scatter of the oscillation frequencies about a smooth trend, is similar to th…
The Luminosity, Stellar Mass, and Number Density Evolution of Field Galaxies of Known Morphology from z = 0.5 to 3
Papovich, Casey; Conselice, Christopher J.; Blackburne, Jeffrey A.
The evolution of rest-frame B-band luminosities, stellar masses, and number densities of field galaxies in the Hubble Deep Fields North and South are studied as a function of rest-frame B-band morphological type out to redshift z~3 using a sample of 1231 I<27 galaxies with spectroscopic and photometric redshifts. We find that the comoving and r…
The structural and scaling properties of nearby galaxy clusters. I. The universal mass profile
Arnaud, M.; Pointecouteau, E.; Pratt, G. W.
We present the integrated mass profiles for a sample of ten nearby (z<~0.15), relaxed galaxy clusters, covering a temperature range of [2-9] keV, observed with XMM-Newton. The mass profiles were derived from the observed gas density and temperature profiles under the hypothesis of spherical symmetry and hydrostatic equilibrium. All ten mass pro…