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Identification of a new outflow channel on Mars in Syrtis Major Planum using HRSC/MEx data
Mangold, N.; Neukum, G.; Hiesinger, H. +6 more
Syrtis Major Planum is a volcanic plain dominated by lava flows. High resolution stereo camera (HRSC) images of the northern Syrtis Major region display erosional features such as grooves, teardrop-shaped islands and valleys. These landforms are characteristics of outflow channels seen on Mars, therefore implying that a flood event took place in t…
Hubble Space Telescope Near-infrared Snapshot Survey of 3CR Radio Source Counterparts. II. An Atlas and Inventory of the Host Galaxies, Mergers, and Companions
O'Dea, Christopher P.; Baum, Stefi; Chiaberge, Marco +10 more
We present the second part of an H-band (1.6 µm) "atlas" of z < 0.3 3CR radio galaxies, using the Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrometer (HST NICMOS2). We present new imaging for 21 recently acquired sources and host galaxy modeling for the full sample of 101 (including 11 archival)—an 87% completion rat…
A nanoflare model for active region radiance: application of artificial neural networks
Solanki, S. K.; Innes, D. E.; Safari, H. +2 more
Context: Nanoflares are small impulsive bursts of energy that blend with and possibly make up much of the solar background emission. Determining their frequency and energy input is central to understanding the heating of the solar corona. One method is to extrapolate the energy frequency distribution of larger individually observed flares to lower…
Thermal observations of Saturn's main rings by Cassini CIRS: Phase, emission and solar elevation dependence
Altobelli, Nicolas; Spilker, Linda J.; Leyrat, Cedric +1 more
Two and a half years after Saturn orbit insertion (SOI) the Cassini composite infrared spectrometer (CIRS) has acquired an extensive set of thermal measurements (including physical temperature and filling factor) of Saturn's main rings for a number of different viewing geometries, most of which are not available from Earth. Thermal mapping of both…
Effect of a northward turning of the interplanetary magnetic field on cusp precipitation as observed by Cluster
Berchem, J.; Escoubet, C. P.; Pitout, F. +10 more
The immediate effect of the rotation of the interplanetary magnetic field (IMF) from southward to northward on cusp precipitation has been rarely observed by a polar orbiting satellite in the past. The four Cluster spacecraft observed such an event on 23 September 2004 as they were crossing the polar cusp within 2-16 min from each other. Between t…
DN Bootis: A low mass-ratio W UMa-type contact binary
Selam, S. O.; Özavcı, İ.; Nelson, R. H. +2 more
New photoelectric BVR light curves and radial velocity curves were obtained for the HIPPARCOS discovery DN Boo at the TÜBİTAK National Observatory of Turkey (TUG) and Dominion Astrophysical Observatory (DAO), respectively, to determine physical nature of the variable. The character of the obtained light curves and double-lined spectroscopic struct…
Suzaku Observation of the TeV Blazar 1ES 1218+304: Clues on Particle Acceleration in an Extreme TeV Blazar
Kataoka, J.; Madejski, G. M.; Sato, R. +3 more
We observed the TeV blazar 1ES 1218+304 with the X-ray astronomy satellite Suzaku in 2006 May. At the beginning of the 2 day continuous observation, we detected a large flare in which the 5-10 keV flux changed by a factor of ~2 on a timescale of 5 × 104 s. During the flare, the increase in the hard X-ray flux clearly lagged behind that …
Positron astronomy with SPI/INTEGRAL
Knödlseder, J.; Schanne, S.; Cordier, B. +7 more
We provide an overview of positron astronomy results that have been obtained using the INTEGRAL spectrometer SPI, and discuss their implications for the still mysterious origin of positrons in our Galaxy. It has long been known that the 511 keV positron annihilation emission is strongest from the central region of our Galaxy. Recently, it has been…
Survey of ELF-VLF plasma waves in outer radiation belt observed by Cluster STAFF-SA experiment
Cornilleau-Wehrlin, N.; Pokhotelov, D.; Lefeuvre, F. +1 more
Various types of plasma waves have profound effects on acceleration and scattering of radiation belt particles. For the purposes of radiation belt modeling it is necessary to know statistical distributions of plasma wave parameters. This paper analyzes four years of plasma wave observations in the Earth's outer radiation belt obtained by the STAFF…
Neon and oxygen in low activity stars: towards a coronal unification with the Sun
Schmitt, J. H. M. M.; Robrade, J.; Favata, F.
Aims: The disagreement between helioseismology and a recent downward revision of solar abundances has resulted in a controversy about the true neon abundance of the Sun and other stars. We study the coronal Ne/O abundance ratios of nearby stars with modest activity levels and investigate a possible peculiarity of the Sun among the stellar populati…