Search Publications
The Widespread Occurrence of Water Vapor in the Circumstellar Envelopes of Carbon-rich Asymptotic Giant Branch Stars: First Results from a Survey with Herschel/HIFI
Waters, L. B. F. M.; Olofsson, H.; Marston, A. P. +16 more
We report the preliminary results of a survey for water vapor in a sample of eight C stars with large mid-IR continuum fluxes: V384 Per, CIT 6, V Hya, Y CVn, IRAS 15194-5115, V Cyg, S Cep, and IRC+40540. This survey, performed using the HIFI instrument on board the Herschel Space Observatory, entailed observations of the lowest transitions of both…
Modeling the Oxygen K Absorption in the Interstellar Medium: An XMM-Newton View of Sco X-1
Quinet, P.; García, J.; Kallman, T. R. +5 more
We investigate the X-ray absorption structure of oxygen in the interstellar medium by analyzing XMM - Newton observations of the low-mass X-ray binary Sco X-1. Simple models based on the O I atomic photoabsorption cross section from different sources are used to fit the data and evaluate the impact of the atomic data on the interpretation of the o…
Observation of Diffuse Cosmic and Atmospheric Gamma Rays at Balloon Altitudes with an Electron-tracking Compton Camera
Okada, Yoko; Hattori, Kaori; Nagayoshi, Tsutomu +13 more
We observed diffuse cosmic and atmospheric gamma rays at balloon altitudes with the Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I (SMILE-I) as the first step toward a future all-sky survey with a high sensitivity. SMILE-I employed an electron-tracking Compton camera comprised of a gaseous electron tracker as a Compton-scattering target …
A Study of Gravitational Lens Chromaticity with the Hubble Space Telescope
Kochanek, C. S.; Muñoz, J. A.; Falco, E. E. +2 more
We report Hubble Space Telescope observations of six gravitational lenses with the Advanced Camera for Surveys. We measured the flux ratios between the lensed images in seven filters from 8140 Å to 2200 Å. In three of the systems, HE0512-3329, B1600+434, and H1413+117, we were able to construct UV extinction curves partially overlapping the 2175 Å…
HST-COS Observations of Hydrogen, Helium, Carbon, and Nitrogen Emission from the SN 1987A Reverse Shock
Smith, Nathan; Pun, Chun S. J.; France, Kevin +18 more
We present the most sensitive ultraviolet observations of Supernova 1987A to date. Imaging spectroscopy from the Hubble Space Telescope-Cosmic Origins Spectrograph shows many narrow (Δv ~ 300 km s-1) emission lines from the circumstellar ring, broad (Δv ~ 10-20 × 103 km s-1) emission lines from the reverse shock, a…
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…