Search Publications
The White Dwarf Age of NGC 2477
van Dyk, David A.; von Hippel, Ted; Jeffery, Elizabeth J. +3 more
We present deep photometric observations of the open cluster NGC 2477 using HST/WFPC2. By identifying seven cluster white dwarf candidates, we present an analysis of the white dwarf age of this cluster, using both the traditional method of fitting isochrones to the white dwarf cooling sequence, and by employing a new Bayesian statistical technique…
Erratum: "Comprehensive Analysis of Coronal Mass Ejection Mass and Energy Properties Over a Full Solar Cycle" (2010, ApJ, 722, 1522)
Howard, R. A.; Patsourakos, S.; Michalek, G. +3 more
Variability and Multiwavelength-detected Active Galactic Nuclei in the Goods Fields
Koo, David C.; Laird, Elise S.; Sarajedini, Vicki L. +3 more
We identify 85 variable galaxies in the GOODS North and South fields using five epochs of Hubble Space Telescope Advance Camera for Survey V-band (F606W) images spanning 6 months. The variables are identified through significant flux changes in the galaxy's nucleus and represent ~2% of the survey galaxies. With the aim of studying the active galax…
A Reconnection-driven Rarefaction Wave Model for Coronal Outflows
Aulanier, G.; Del Zanna, G.; Bradshaw, S. J.
We conduct numerical experiments to determine whether interchange reconnection at high altitude coronal null points can explain the outflows observed as blueshifts in coronal emission lines at the boundaries between open and closed magnetic field regions. In this scenario, a strong, post-reconnection pressure gradient forms in the field-aligned di…
The ACS Fornax Cluster Survey. IV. Deprojection of the Surface Brightness Profiles of Early-type Galaxies in the Virgo and Fornax Clusters: Investigating the "Core/Power-law Dichotomy"
Jordán, Andrés; Infante, Leopoldo; Tonry, John L. +8 more
Although early observations with the Hubble Space Telescope (HST) pointed to a sharp dichotomy among early-type galaxies in terms of the logarithmic slope γ' of their central surface brightness profiles, several studies in the past few years have called this finding into question. In particular, recent imaging surveys of 143 early-type galaxies be…
The Binary Fraction in the Globular Cluster M10 (NGC 6254): Comparing Core and Outer Regions
Dalessandro, E.; Beccari, G.; Ferraro, F. R. +3 more
We study the binary fraction of the globular cluster M10 (NGC 6254) as a function of the radius from the cluster core to the outskirts, by means of a quantitative analysis of the color distribution of stars relative to the fiducial main sequence. By taking advantage of two data sets, acquired with the Advanced Camera for Survey and the Wide Field …
H II Region Luminosity Function of the Interacting Galaxy M51
Hwang, Narae; Lee, Myung Gyoon; Lee, Jong Hwan
We present a study of H II regions in M51 using the Hubble Space Telescope Advanced Camera for Surveys images taken as part of the Hubble Heritage Program. We have cataloged about 19,600 H II regions in M51 with Hα luminosity in the range of L = 1035.5-1039.0 erg s-1. The Hα luminosity function of H II regions (H I…
Hubble Space Telescope/Advanced Camera for Surveys Observations of Europa's Atmospheric Ultraviolet Emission at Eastern Elongation
Nimmo, Francis; Saur, Joachim; Roth, Lorenz +7 more
We report results of a Hubble Space Telescope (HST) campaign with the Advanced Camera for Surveys to observe Europa at eastern elongation, i.e., Europa's leading side, on 2008 June 29. With five consecutive HST orbits, we constrain Europa's atmospheric O I 1304 Å and O I 1356 Å emissions using the prism PR130L. The total emissions of both oxygen m…
Identification of Super- and Subcritical Regions in Shocks Driven by Coronal Mass Ejections
Bemporad, A.; Mancuso, S.
In this work, we focus on the analysis of a coronal mass ejection (CME) driven shock observed by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph Experiment. We show that white-light coronagraphic images can be employed to estimate the compression ratio X = ρ d /ρ u all along the front of CME-…
Obscured GOODS Active Galactic Nuclei and Their Host Galaxies at z < 1.25: The Slow Black Hole Growth Phase
Treister, E.; Koekemoer, A. M.; Grogin, N. A. +4 more
We compute black hole masses and bolometric luminosities for 87 obscured active galactic nuclei (AGNs) in the redshift range 0.25 <= z <= 1.25, selected from the GOODS deep multi-wavelength survey fields via their X-ray emission. We fit the optical images and obtain morphological parameters for the host galaxy, separating the galaxy from its…