Search Publications
The Lack of Diffuse, Non-thermal Hard X-ray Emission in the Coma Cluster: The Swift Burst Alert Telescope's Eye View
Sarazin, Craig L.; Okajima, Takashi; Wik, Daniel R. +5 more
The Coma Cluster of galaxies hosts the brightest radio halo known and has therefore been the target of numerous searches for associated inverse Compton (IC) emission, particularly at hard X-ray energies where the IC signal must eventually dominate over thermal emission. The most recent search with the Suzaku Hard X-ray Detector failed to confirm p…
Three-dimensional Structure of a Solar Active Region from Spatially and Spectrally Resolved Microwave Observations
Gary, Dale E.; Georgoulis, Manolis K.; Tun, Samuel D.
We report on the structure of the solar atmosphere above active region (AR) 10923, observed on 2006 November 10, as deduced from multi-wavelength studies including combined microwave observations from the Very Large Array (VLA) and the Owens Valley Solar Array (OVSA). The VLA observations provide excellent image quality at a few widely spaced freq…
GSC 07396-00759 = V4046 Sgr C[D]: A Wide-separation Companion to the Close T Tauri Binary System V4046 Sgr AB
Donati, J. -F.; Audard, M.; Güdel, M. +13 more
We explore the possibility that GSC 07396-00759 (spectral type M1e) is a widely separated (~2farcm82, or projected separation ~12,350 AU) companion to the "old" (age ~12 Myr) classical T Tauri binary system V4046 Sgr AB, as suggested by the proximity and similar space motions of the two systems. If the two systems are equidistant and coeval, then …
How the effects of resonant absorption on black hole reflection spectra can mimic high-velocity outflows
Fabian, A. C.; Gallo, L. C.
Narrow absorption lines seen in the 2-10 keV spectra of active galaxies and Galactic black holes are normally attributed to iron in high-velocity outflows or inflows. We consider the possibility that such features could arise naturally in the accretion disc. Resonant absorption by highly ionized iron (e.g. Fe XXVI and Fe XXV) in an optically thin …
The EUV spectrum of the Sun: SOHO CDS NIS irradiances from 1998 until 2010
Andretta, V.; Del Zanna, G.
We present extreme-ultraviolet (EUV) irradiances of the Sun taken during the 1998-2010 period from the Solar and Heliospheric Observatory (SoHO) Coronal Diagnostic Spectrometer (CDS) Normal Incidence Spectrograph (NIS). They were obtained from NIS full-Sun radiance observations, and represent the first set of EUV spectral observations spanning a s…
IGR J17354-3255 as a candidate intermediate supergiant fast X-ray transient possibly associated with the transient MeV AGL J1734-3310
Bird, A. J.; Ubertini, P.; Landi, R. +3 more
We present spectral and temporal results from INTEGRAL long-term monitoring of the unidentified X-ray source IGR J17354-3255. We show that it is a weak persistent hard X-ray source spending a major fraction of the time in an out-of-outburst state with an average of 18-60 keV X-ray flux of ∼1.1 milliCrab, occasionally interspersed with fast X-ray f…
Structure and Dynamics of the 2010 July 11 Eclipse White-light Corona
Seaton, D. B.; Golub, L.; Lucas, R. +8 more
The white-light corona (WLC) during the total solar eclipse on 2010 July 11 was observed by several teams in the Moon's shadow stretching across the Pacific Ocean and a number of isolated islands. We present a comparison of the WLC as observed by eclipse teams located on the Tatakoto Atoll in French Polynesia and on Easter Island, 83 minutes later…
Differential Emission Measure Analysis of a Polar Coronal Hole during the Solar Minimum in 2007
Hahn, M.; Savin, D. W.; Landi, E.
We have performed a differential emission measure (DEM) analysis for a polar coronal hole observed during solar minimum in 2007. Five observations are analyzed spanning the coronal hole from the central meridian to the boundary with the quiet-Sun corona. The observed heights ranged from 1.05 to 1.20 R sun. The analysis shows that the pl…
The evolution of early-type galaxies in clusters from z∼ 0.8 to z ∼ 0: the ellipticity distribution and the morphological mix
Cava, Antonio; Dressler, Alan; Vulcani, Benedetta +10 more
We present the ellipticity distribution and its evolution for early-type galaxies in clusters from z∼ 0.8 to the current epoch, based on the WIde-field Nearby Galaxy-cluster Survey (0.04 ≤z≤ 0.07) and the ESO Distant Cluster Survey (0.4 ≤z≤ 0.8). We first investigate a mass-limited sample and we find that above a fixed mass limit (M*≥ 1…
The atmospheric influence, size and possible asteroidal nature of the July 2009 Jupiter impactor
Baines, K. H.; Momary, T. W.; Hueso, R. +24 more
Near-infrared and mid-infrared observations of the site of the 2009 July 19 impact of an unknown object with Jupiter were obtained within days of the event. The observations were used to assess the properties of a particulate debris field, elevated temperatures, and the extent of ammonia gas redistributed from the troposphere into Jupiter's strato…