Search Publications
Three-dimensional finite difference time domain modeling of the Schumann resonance parameters on Titan, Venus, and Mars
Yang, Heng; Pasko, Victor P.; Yair, Yoav
The conducting ionosphere and conducting surface of Titan, Venus, and Mars form a concentric resonator, which would support the possibility of the existence of global electromagnetic resonances. On Earth, such resonances are commonly referred to as Schumann resonances and are excited by lightning discharges. The detection of such resonances on oth…
Disentangling the synchrotron and inverse Compton variability in the X-ray emission of the intermediate BL Lacertae object S5 0716+71
Emmanoulopoulos, D.; Wagner, S. J.; Ferrero, E. +1 more
Context: .The possibility to detect simultaneously in the X-ray band the synchrotron and Inverse Compton (IC) emission of intermediate BL Lac objects offers the unique opportunity to study contemporaneously the low- and high-energy tails of the electron distribution in the jets of these sources.
Aims: .We attempted to disentangle the X-ray spe…
The Rate of Emergence of Magnetic Dipoles in Coronal Holes and Adjacent Quiet-Sun Regions
Abramenko, V. I.; Yurchyshyn, V. B.; Fisk, L. A.
Observations from the Michelson Doppler Imager and the EUV Imaging Telescope on the Solar and Heliospheric Observatory are analyzed to determine the rate of emergence of new magnetic flux in coronal holes and in surrounding regions on the quiet Sun. Coronal holes are regions where the open magnetic flux of the Sun, the component that forms the hel…
An XMM-Newton view of the young open cluster NGC 6231. I. The catalogue
Gosset, E.; Rauw, G.; Vreux, J. -M. +2 more
This paper is the first of a series dedicated to the X-ray properties of the young open cluster NGC 6231. Our data set relies on an XMM-Newton campaign of a nominal duration of 180 ks and reveals that NGC 6231 is very rich in the X-ray domain too. Indeed, 610 X-ray sources are detected in the present field of view, centered on the cluster core. Th…
Cluster survey of the mid-altitude cusp: 1. size, location, and dynamics
Escoubet, C. P.; Pitout, F.; Klecker, B. +1 more
We present a statistical study of four years of Cluster crossings of the mid-altitude cusp. In this first part of the study, we start by introducing the method we have used a) to define the cusp properties, b) to sort the interplanetary magnetic field (IMF) conditions or behaviors into classes, c) to determine the proper time delay between the sol…
The DEEP Groth Strip Survey. VI. Spectroscopic, Variability, and X-Ray Detection of Active Galactic Nuclei
Kobulnicky, Henry A.; Gebhardt, Karl; Willmer, Christopher N. A. +8 more
We identify active galactic nuclei (AGNs) in the Groth-Westphal Survey Strip (GSS) using the independent and complementary selection techniques of optical spectroscopy and photometric variability. We discuss the X-ray properties of these AGNs using Chandra/XMM-Newton data for this region. From a sample of 576 galaxies with high-quality spectra we …
Saturn's auroral morphology and activity during quiet magnetospheric conditions
Coates, A. J.; Dougherty, M. K.; Kurth, W. S. +8 more
We report the results of a coordinated Hubble Space Telescope-Cassini campaign that took place between 26 October and 2 November 2005. During this period, Saturn's magnetosphere was in an expanded state and the solar wind was quiet, as indicated by the location of the magnetopause, in situ particle measurements, weak auroral SKR emission, and the …
Analysis and Interpretation of Hard X-Ray Emission from the Bullet Cluster (1ES 0657-558), the Most Distant Cluster of Galaxies Observed by RXTE
Madejski, Greg; Petrosian, Vahé; Luli, Kevin
Evidence for nonthermal activity in clusters of galaxies is well established from radio observations of synchrotron emission by relativistic electrons. New windows in the extreme-ultraviolet and hard X-ray ranges have provided more powerful tools for the investigation of this phenomenon. Detections of hard X-rays in the 20-100 keV range have been …
A Spitzer IRAC Search for Substellar Companions of the Debris Disk Star ɛ Eridani
Stapelfeldt, K. R.; Fazio, G. G.; Marengo, M. +3 more
We have used the Infrared Array Camera (IRAC) on board the Spitzer Space Telescope to search for low-mass companions of the nearby debris disk star ɛ Eri. The star was observed in two epochs 39 days apart, with different focal plane rotation to allow the subtraction of the instrumental point-spread function, achieving a maximum sensitivity of 0.01…
Structural parameters from ground-based observations of newly discovered globular clusters in NGC 5128
Geisler, D.; Gómez, M.; Richtler, T. +3 more
We have investigated a number of globular cluster candidates from a recent wide-field study by Harris et al. (2004a, AJ, 128, 712) of the giant elliptical galaxy