Search Publications
A New Survey for Giant Arcs
Hennawi, Joseph F.; Strauss, Michael A.; Schneider, Donald P. +11 more
We report on the first results of an imaging survey to detect strong gravitational lensing targeting the richest clusters selected from the photometric data of the Sloan Digital Sky Survey (SDSS) with follow-up deep imaging observations from the Wisconsin-Indiana-Yale NOAO (WIYN) 3.5 m telescope and the University of Hawaii 88 inch telescope (UH88…
Multidimensional modelling of X-ray spectra for AGN accretion disc outflows
Turner, T. J.; Long, K. S.; Sim, S. A. +1 more
We use a multidimensional Monte Carlo code to compute X-ray spectra for a variety of active galactic nucleus (AGN) disc-wind outflow geometries. We focus on the formation of blueshifted absorption features in the Fe K band and show that line features similar to those which have been reported in observations are often produced for lines of sight th…
The cosmological properties of AGN in the XMM-Newton Hard Bright Survey
Page, M. J.; Carrera, F. J.; Caccianiga, A. +7 more
Aims: We investigate here the X-ray luminosity function (XLF) of absorbed (NH between 4 × 1021 and 1024 cm-2) and unabsorbed (NH < 4 × 1021 cm-2) AGN, the fraction of absorbed AGN as a function of LX (and z), the intrinsic NH distribution of the A…
Near-infrared mapping and physical properties of the dwarf-planet Ceres
Berthier, J.; Carry, B.; Hestroffer, D. +5 more
Aims:We study the physical characteristics (shape, dimensions, spin axis direction, albedo maps, mineralogy) of the dwarf-planet Ceres based on high angular-resolution near-infrared observations.
Methods: We analyze adaptive optics J/H/K imaging observations of Ceres performed at Keck II Observatory in September 2002 with an equivalent spatial…
Energetic ion precipitation at Titan
Krimigis, S. M.; Waite, J. H.; Cravens, T. E. +3 more
Energetic protons and oxygen ions have been observed in Saturn's outer magnetosphere and can precipitate into Titan's atmosphere where they deposit energy, ionize, and drive ionospheric chemistry. Ion production rates caused by this precipitation are calculated using fluxes of incident 27 keV to 4 MeV protons measured by the Cassini MIMI instrumen…
Detailed high-energy characteristics of AXP 4U 0142+61. Multi-year observations with INTEGRAL, RXTE, XMM-Newton, and ASCA
Knödlseder, J.; Kuiper, L.; Hermsen, W. +4 more
4U 0142+61 is one of the Anomalous X-ray Pulsars exhibiting hard X-ray emission above 10 keV discovered with INTEGRAL. In this paper we present detailed spectral and temporal characteristics both in the hard X-ray (>10 keV) and soft X-ray (<10 keV) domains obtained using data from INTEGRAL, XMM-Newton, ASCA and RXTE. Accumulating data collec…
Evaluating the Performance of Solar Flare Forecasting Methods
Leka, K. D.; Barnes, G.
The number of published approaches to solar flare forecasting using photospheric magnetic field observations has proliferated recently, with widely varying claims about how well each works. As different analysis techniques and data sets were used, it is essentially impossible to directly compare the results. A systematic comparison is presented he…
Cosmological parameters from strong gravitational lensing and stellar dynamics in elliptical galaxies
Grillo, C.; Lombardi, M.; Bertin, G.
Context: Observations of the cosmic microwave background, light element abundances, large-scale distribution of galaxies, and distant supernovae are the primary tools for determining the cosmological parameters that define the global structure of the Universe.
Aims: Here we illustrate how the combination of observations related to strong gravi…
PAH Emission from Herbig Ae/Be Stars
Watson, D. M.; Chen, C. H.; Sargent, B. +10 more
We present spectra of a sample of Herbig Ae and Be (HAeBe) stars obtained with the Infrared Spectrograph on Spitzer. All but one of the Herbig stars show emission from PAHs, and seven of the spectra show PAH emission, but no silicate emission at 10 µm. The central wavelengths of the 6.2, 7.7-8.2, and 11.3 µm emission features decrease …
Discovery of the Radio and X-Ray Counterpart of TeV γ-Ray Source HESS J1731-347
Leahy, D. A.; Jiang, B.; Haverkorn, M. +1 more
We discover a faint shell-type radio and X-ray source, G353.6-0.7, associated with HESS J1731-347. G353.6-0.7 is likely an old supernova remnant (SNR), based on radio (0.8, 1.4, and 5 GHz), infrared (8 µm from the GLIMPSE Legacy Project and 21 µm from the Midcourse Space Experiment), and X-ray (0.1-2.4 keV from the ROSAT survey and 5-2…