Search Publications
A Direct Empirical Proof of the Existence of Dark Matter
Bradač, Maruša; Jones, Christine; Gonzalez, Anthony H. +4 more
We present new weak-lensing observations of 1E 0657-558 (z=0.296), a unique cluster merger, that enable a direct detection of dark matter, independent of assumptions regarding the nature of the gravitational force law. Due to the collision of two clusters, the dissipationless stellar component and the fluid-like X-ray-emitting plasma are spatially…
Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships
Peterson, Bradley M.; Vestergaard, Marianne
We present four improved empirical relationships useful for estimating the central black hole mass in nearby AGNs and distant luminous quasars alike using either optical or UV single-epoch spectroscopy. These mass scaling relationships between line widths and luminosity are based on recently improved empirical relationships between the broad-line …
The Sloan Lens ACS Survey. III. The Structure and Formation of Early-Type Galaxies and Their Evolution since z ~ 1
Treu, Tommaso; Koopmans, Léon V. E.; Bolton, Adam S. +2 more
We present a joint gravitational lensing and stellar-dynamical analysis of 15 massive field early-type galaxies selected from the Sloan Lens ACS (SLACS) Survey. The following numerical results are found: (1) A joint likelihood gives an average logarithmic density slope for the total mass density of <γ'>=2.01+0.02-0…
High-Resolution Millimeter Imaging of Submillimeter Galaxies
Smail, I.; Genzel, R.; Tacconi, L. J. +8 more
We present ~0.6" resolution IRAM PdBI interferometry of eight submillimeter galaxies at z~2-3.4, where we detect continuum at 1 mm and/or CO lines at 3 and 1 mm. The CO 3-2/4-3 line profiles in five of the sources are double-peaked, indicative of orbital motion either in a single rotating disk or of a merger of two galaxies. The millimeter line an…
The Size Evolution of Galaxies since z~3: Combining SDSS, GEMS, and FIRES
van Dokkum, Pieter G.; Franx, Marijn; Labbé, Ivo +15 more
We present the evolution of the luminosity-size and stellar mass-size relations of luminous (LV>~3.4×1010 h-270 Lsolar) and massive (M*>~3×1010 h-270 Msolar) galaxies in the last ~11 Gyr. We use very deep near-infrared images of the …
Constraining Black Hole Spin via X-Ray Spectroscopy
Brenneman, Laura W.; Reynolds, Christopher S.
We present an analysis of the observed broad iron line feature and putative warm absorber in the long 2001 XMM-Newton observation of the Seyfert 1.2 galaxy MCG -06-30-15. The new kerrdisk model we have designed for simulating line emission from accretion disk systems allows black hole spin to be a free parameter in the fit, enabling the user to fo…
Modeling of Flux Rope Coronal Mass Ejections
Howard, R. A.; Vourlidas, A.; Thernisien, A. F. R.
We present a forward-modeling technique for flux rope-like CMEs using an empirically defined model of a flux rope, the graduated cylindrical shell (GCS). To compare it with white-light coronagraph observations, we assume an electron distribution through the GCS and derive synthetic images in total and polarized brightness for various projections o…
The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample of Massive Early-Type Lens Galaxies
Treu, Tommaso; Koopmans, Léon V. E.; Bolton, Adam S. +2 more
The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple nebular emission lines at a redshift significant…
Damped Lyα Systems at z<1.65: The Expanded Sloan Digital Sky Survey Hubble Space Telescope Sample
Turnshek, David A.; Rao, Sandhya M.; Nestor, Daniel B.
We present results of our Hubble Space Telescope Cycle 11 survey for low-redshift (z<1.65) damped Lyα (DLA) systems in the UV spectra of quasars selected from the Sloan Digital Sky Survey (SDSS) Early Data Release. These quasars have strong intervening Mg II-Fe II systems that are known signatures of high column density neutral gas. In total, i…
The ACS Virgo Cluster Survey. IX. The Color Distributions of Globular Cluster Systems in Early-Type Galaxies
Jordán, Andrés; Tonry, John L.; Côté, Patrick +7 more
We present the color distributions of globular cluster (GC) systems for 100 early-type galaxies observed in the ACS Virgo Cluster Survey, the deepest and most homogeneous survey of this kind to date. On average, galaxies at all luminosities in our study (-22<MB<-15) appear to have bimodal or asymmetric GC color distributions. Almo…