Search Publications
Spitzer/IRAC and ISOCAM/CVF insights on the origin of the near to mid-IR Galactic diffuse emission
Boulanger, F.; Reach, W. T.; Flagey, N. +3 more
Spitzer/IRAC images of extended emission provide a new insight on the nature of small dust particles in the Galactic diffuse interstellar medium. We measure IRAC colors of extended emission in several fields covering a range of Galactic latitudes and longitudes outside of star forming regions. We determine the nature of the Galactic diffuse emissi…
A Radio Study of the Seyfert Galaxy Markarian 6: Implications for Seyfert Life Cycles
O'Dea, C. P.; Xu, C.; Baum, S. A. +2 more
We have carried out an extensive radio study with the Very Large Array on the Seyfert 1.5 galaxy Mrk 6 and imaged a spectacular radio structure in the source. The radio emission occurs on three different spatial scales: ~7.5 kpc bubbles, ~1.5 kpc bubbles lying nearly orthogonal to them, and a ~1 kpc radio jet lying orthogonal to the kiloparsec-sca…
Plasma Acceleration Above Martian Magnetic Anomalies
Coates, A. J.; Kallio, E.; Fedorov, A. +20 more
Auroras are caused by accelerated charged particles precipitating along magnetic field lines into a planetary atmosphere, the auroral brightness being roughly proportional to the precipitating particle energy flux. The Analyzer of Space Plasma and Energetic Atoms experiment on the Mars Express spacecraft has made a detailed study of acceleration p…
Abundance studies of sdB stars using UV echelle HST/STIS spectroscopy
Heber, U.; O'Toole, S. J.
Aims.We test the hypothesis that the pulsations in sdB stars are correlated with the surface abundances of iron-group elements. Any correlation might explain why, when given two spectroscopically similar stars, one will pulsate while the other will not.
Methods: .We have obtained high-resolution ultraviolet spectra two pulsating and three non-…
Latitudinal variations of HCN, HC 3N, and C 2N 2 in Titan's stratosphere derived from Cassini CIRS data
Fletcher, L.; Irwin, P. G. J.; Teanby, N. A. +9 more
Mid- and far-infrared spectra from the Composite InfraRed Spectrometer (CIRS) have been used to determine volume mixing ratios of nitriles in Titan's atmosphere. HCN, HC 3N, C 2H 2, and temperature were derived from 2.5 cm -1 spectral resolution mid-IR mapping sequences taken during three flybys, which p…
The Eclipsing Binary V1061 Cygni: Confronting Stellar Evolution Models for Active and Inactive Solar-Type Stars
Torres, Guillermo; Lacy, Claud H.; Marschall, Laurence A. +2 more
We present spectroscopic and photometric observations of the eclipsing system V1061 Cyg (P=2.35 days). A third star is visible in the spectrum, and the system is a hierarchical triple. We combine the radial velocities for the three stars, times of eclipse, and intermediate astrometric data from the Hipparcos mission (abscissa residuals) to establi…
Hierarchical Star Formation in the Spiral Galaxy NGC 628
Chandar, Rupali; Elmegreen, Bruce G.; Whitmore, Brad +2 more
The distributions of size and luminosity for star-forming regions in the nearby spiral galaxy NGC 628 are studied over a wide range of scales using progressively blurred versions of an image from the Hubble Space Telescope Advanced Camera for Surveys. Four optical filters are considered for the central region, including Hα. Two filters are used fo…
Alfvén vortex filaments observed in magnetosheath downstream of a quasi-perpendicular bow shock
André, M.; Maksimovic, M.; Alexandrova, O. +3 more
Magnetic field fluctuations in the frequency range [0.02-12.5] Hz are studied with the four Cluster satellites in the Earth magnetosheath downstream of a quasi-perpendicular bow shock. The turbulent spectrum presents a spectral break accompanied by a broad maximum usually interpreted as due to Alfvén ion cyclotron waves. In this paper we establish…
A 70 Kiloparsec X-Ray Tail in the Cluster A3627
Forman, W.; Sun, M.; Nulsen, P. E. J. +3 more
We present the discovery of a 70 kpc X-ray tail behind the small late-type galaxy ESO 137-001, in the nearby, hot (T=6.5 keV) merging cluster A3627, from both Chandra and XMM-Newton observations. The tail has a length-to-width ratio of ~10. It is luminous (L0.5-2keV~1041 ergs s-1), with a temperature of ~0.7 keV an…
Evolution of magnetic fields in stars across the upper main sequence: I. Catalogue of magnetic field measurements with FORS 1 at the VLT
Hubrig, S.; North, P.; Schöller, M. +1 more
To properly understand the physics of Ap and Bp stars it is particularly important to identify the origin of their magnetic fields. For that, an accurate knowledge of the evolutionary state of stars that have a measured magnetic field is an important diagnostic. Previous results based on a small and possibly biased sample suggest that the distribu…