Search Publications
The Density and Masses of Obscured Black Holes
Comastri, Andrea; Fiore, Fabrizio
Recent Chandra and XMM-Newton surveys have uncovered a large fraction of the obscured AGN responsible of the hard X-ray background. One of the most intriguing results of extensive programs of follow-up observations concerns the optical and near-infrared properties of the hard X-ray sources counterparts. More specifically, for a significant fractio…
Cassini Plasma Spectrometer electron measurements close to the magnetopause of Jupiter
Coates, A. J.; Linder, D. R.; Young, D. T. +2 more
During late 2000 and early 2001 the Cassini satellite made a flyby of Jupiter en route to Saturn. The flyby speed was about 20 km/s, and the trajectory brought the spacecraft through the magnetosheath on the afternoonside. The Cassini Plasma Spectrometer (CAPS) instrument, consisting of two ion sensors and an electron spectrometer, was thus able t…
Source characteristics and radiation mechanism of Jovian anomalous continuum
Misawa, H.; Tsuchiya, F.; Morioka, A. +2 more
We investigate the characteristics of the Jovian anomalous continuum (JAC) in interplanetary space and in the magnetosheath, using Ulysses observations. Some new source characteristics of JAC were obtained in addition to those found by previous authors [e.g., , 1998]. JAC tends to occur when the solar wind dynamic pressure decreases after a rapid …
Characterization of Intensity Variations Along Fe XIV Coronal Loops - A Case Study
Stenborg, Guillermo; Costa, Andrea
We discuss a method, and corresponding results, to analyze the dynamics of localized small-scale coronal (post-flare) loops observed with the MICA (Mirror Coronagraph for Argentina) telescope in the well-known green coronal line at 530.3 nm. In particular, we designed a procedure to measure intensity variations along the structure of a loop, both …
Calibration of Hubble Space Telescope Advanced Camera for Surveys Emission-Line Filters
O'Dell, C. R.
The most commonly used narrowband filters of the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope do not allow the clear delineation of individual emission lines as done with the more narrow field-of-view Wide Field and Planetary Camera. However, we have determined the calibration characteristics that allow separation of the Hα and …
Resolving X-Ray Sources from B Stars Spectroscopically: The Example of µ Leporis
Güdel, Manuel; Kahn, Steven M.; Behar, Ehud +4 more
We present high-resolution X-ray observations of the chemically peculiar late-type B star µ Lep. However, we find spectroscopic and astrometric evidence, which shows that the X-rays are not traced back to the B star itself but rather to a previously unresolved companion, µ Lep-B, whose X-ray spectrum resembles that of a coronally activ…
Hubble Space Telescope Astrometric Observations and Orbital Mean Motion Corrections for the Inner Satellites of Neptune
Pascu, Dan; Rohde, James R.; Seidelmann, P. Kenneth +6 more
Six small inner satellites of Neptune were imaged in 1989 with Voyager 2. In 1997, we recovered the four outermost with the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 for astrometric, dynamical, and photometric studies. The ring arcs were not detected in our images. Thirteen exposures were taken in each of three HST orbits: two orb…
Discovery of a Peculiar Pulsar in the Small Magellanic Cloud
Ueno, Masaru; Yamaguchi, Hiroya; Takagi, Shin-Ichiro +2 more
We report on a peculiar X-ray binary pulsar, IKT 1 = RX J0047.3 - 7312, observed with XMM-Newton in 2000 October. The X-ray spectrum is described by a two-component spectrum. The hard component has a broken power-law with respective photon indices of 0.2 and 1.8, below and above the break energy at 5.8keV. The soft component can be modeled by a bl…
An XMM-Newton and Chandra View of Massive Clusters of Galaxies to z = 1
Gondoin, P.; Maughan, B. J.; Mason, K. O. +7 more
The X-ray properties of a sample of high redshift (z>0.6), massive clusters observed with XMM-Newton and Chandra are described, including two exceptional systems. One, at z = 0.89, has an X-ray temperature of T = 11.5+1.1-0.9 keV (the highest temperature of any cluster known at z>0.6), an estimated mass of ≅(1.4±0.2)x10…
Laboratory experiments on cometary materials
Brucato, J. R.; Colangeli, L.; Bar-Nun, A. +2 more
Laboratory experiments to simulate cometary materials and their processing contribute to the investigation of the properties and evolution of comets. Experimental methods can produce both refractory materials and frozen volatiles with chemical, structural, and morphological characteristics that reproduce those of materials observed and/or expected…