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A Direct Measurement of Major Galaxy Mergers at z<~3
Papovich, Casey; Dickinson, Mark; Conselice, Christopher J. +1 more
This paper presents direct evidence for hierarchical galaxy assembly out to redshifts z~3. We identify major mergers using the model-independent CAS (concentration, asymmetry, clumpiness) physical morphological system on galaxies detected, and photometrically selected, in the WFPC2 and NICMOS Hubble Deep Field North. We specifically use the asymme…
The Extremely Metal-poor, Neutron Capture-rich Star CS 22892-052: A Comprehensive Abundance Analysis
Beers, Timothy C.; Truran, James W.; Hill, Vanessa +9 more
High-resolution spectra obtained with three ground-based facilities and the Hubble Space Telescope (HST) have been combined to produce a new abundance analysis of CS 22892-052, an extremely metal-poor giant with large relative enhancements of neutron capture elements. A revised model stellar atmosphere has been derived with the aid of a large numb…
HST Photometry of Dwarf Elliptical Galaxies in Coma, and an Explanation for the Alleged Structural Dichotomy between Dwarf and Bright Elliptical Galaxies
Graham, Alister W.; Guzmán, Rafael
As part of a research program exploring how and why dwarf elliptical (dE) galaxies depart from the fundamental plane defined by luminous elliptical (E) galaxies, we have analyzed archival Hubble Space Telescope F606W images of a sample of 18 dE galaxy candidates in the Coma Cluster. We model the full radial extent of their light profiles by simult…
The Evolution of the Global Stellar Mass Density at 0<z<3
Papovich, Casey; Dickinson, Mark; Ferguson, Henry C. +1 more
The buildup of stellar mass in galaxies is the consequence of their past star formation and merging histories. Here we report measurements of rest-frame optical light and calculations of stellar mass at high redshift based on an infrared-selected sample of galaxies from the Hubble Deep Field-North. The bright envelope of rest-frame B-band galaxy l…
Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I.
Gray, R. O.; Corbally, C. J.; Garrison, R. F. +2 more
We have embarked on a project, under the aegis of the Nearby Stars (NStars)/Space Interferometry Mission Preparatory Science Program, to obtain spectra, spectral types, and, where feasible, basic physical parameters for the 3600 dwarf and giant stars earlier than M0 within 40 pc of the Sun. In this paper, we report on the results of this project f…
Age and metallicity distribution of the Galactic bulge from extensive optical and near-IR stellar photometry
Rejkuba, M.; Greggio, L.; Zoccali, M. +7 more
We present a new determination of the metallicity distribution, age, and luminosity function of the Galactic bulge stellar population. By combining near-IR data from the 2MASS survey, from the SOFI imager at ESO NTT and the NICMOS camera on board HST we were able to construct color-magnitude diagrams (CMD) and luminosity functions (LF) with large …
A high-velocity ionized outflow and XUV photosphere in the narrow emission line quasar PG1211+143
O'Brien, P. T.; King, A. R.; Reeves, J. N. +3 more
We report on the analysis of a ~60-ks XMM-Newton observation of the bright, narrow emission line quasar PG1211+143. Absorption lines are seen in both European Photon Imaging Camera and Reflection Grating Spectrometer spectra corresponding to H- and He-like ions of Fe, S, Mg, Ne, O, N and C. The observed line energies indicate an ionized outflow ve…
JEM-X: The X-ray monitor aboard INTEGRAL
Andersson, H.; Frontera, F.; Costa, E. +52 more
The JEM-X monitor provides X-ray spectra and imaging with arcminute angular resolution in the 3 to 35 keV band. The good angular resolution and the low energy response of JEM-X plays an important role in the identification of gamma ray sources and in the analysis and scientific interpretation of the combined X-ray and gamma ray data. JEM-X is a co…
Axisymmetric Dynamical Models of the Central Regions of Galaxies
Filippenko, Alexei V.; Ho, Luis C.; Gebhardt, Karl +12 more
We present axisymmetric, orbit superposition models for 12 galaxies using data taken with the Hubble Space Telescope (HST) and ground-based observatories. In each galaxy, we detect a central black hole (BH) and measure its mass to accuracies ranging from 10% to 70%. We demonstrate that in most cases the BH detection requires both the HST and groun…
Binarity in Brown Dwarfs: T Dwarf Binaries Discovered with the Hubble Space Telescope Wide Field Planetary Camera 2
Kirkpatrick, J. Davy; Burgasser, Adam J.; Brown, Michael E. +3 more
We present the discovery of two T dwarf binaries, 2MASS 1225-2739AB and 2MASS 1534-2952AB, identified in a sample of 10 T dwarfs imaged with the Hubble Space Telescope (HST) Wide Field Planetary Camera 2. Companionship is established by the uniquely red F814W-F1042M colors of the binary components, caused by heavily pressure-broadened K I absorpti…