Search Publications
Evidence for Solar-Wind Charge-Exchange X-Ray Emission from the Earth's Magnetosheath
Yamaguchi, Hiroya; Mitsuda, Kazuhisa; Fujimoto, Ryuichi +7 more
We report an apparent detection of the C VI 4p to 1s transition line at 459eV, during a long-term enhancement (LTE) in the Suzaku north ecliptic pole observation of 2005 September 2. The observed line intensity is comparable to that of the C VI 2p to 1s line at 367eV. This is strong evidence for the charge-exchange process. In addition, O VII , O …
The CFHTLS strong lensing legacy survey. I. Survey overview and T0002 release sample
Alard, C.; Gavazzi, R.; Fort, B. +10 more
Aims:We present data from the CFHTLS Strong Lensing Legacy Survey (SL2S). Due to the unsurpassed combined depth, area and image quality of the Canada-France-Hawaii Legacy Survey it is becoming possible to uncover a large, statistically well-defined sample of strong gravitational lenses which spans the dark halo mass spectrum predicted by the conco…
X-ray observations of ultraluminous X-ray sources
Roberts, Timothy P.
Ultraluminous X-ray sources (ULXs) are amongst the most intriguing of X-ray source classes. Their extreme luminosities—greater than 1039 erg s‑1 in the 0.3–10 keV band alone—suggest either the presence of black holes larger than those regularly encountered in our own Galaxy (the Galactic centre excepted), or sources apparentl…
New Distant Companions to Known Nearby Stars. II. Faint Companions of Hipparcos Stars and the Frequency of Wide Binary Systems
Lépine, Sébastien; Bongiorno, Bethany
We perform a search for faint, common proper motion companions of Hipparcos stars using the recently published Lépine-Shara Proper Motion-North catalog of stars with proper motion µ>0.15'' yr-1. Our survey uncovers a total of 521 systems with angular separations 3''<Δθ<1500'', with 15 trip…
Probing the Dark Matter and Gas Fraction in Relaxed Galaxy Groups with X-Ray Observations from Chandra and XMM-Newton
Humphrey, Philip J.; Buote, David A.; Brighenti, Fabrizio +4 more
We present radial mass profiles within ~0.3rvir for 16 relaxed galaxy groups-poor clusters (kT range 1-3 keV) selected for optimal mass constraints from the Chandra and XMM-Newton data archives. After accounting for the mass of hot gas, the resulting mass profiles are described well by a two-component model consisting of dark matter, re…
Discovery of a Ringlike Dark Matter Structure in the Core of the Galaxy Cluster Cl 0024+17
Ford, H. C.; Demarco, R.; van der Wel, A. +13 more
We present a comprehensive mass reconstruction of the rich galaxy cluster Cl 0024+17 at z~=0.4 from ACS data, unifying both strong- and weak-lensing constraints. The weak-lensing signal from a dense distribution of background galaxies (~120 arcmin-2) across the cluster enables the derivation of a high-resolution parameter-free mass map.…
Six new candidate ultracompact X-ray binaries
in't Zand, J. J. M.; Jonker, P. G.; Markwardt, C. B.
Ultracompact X-ray binaries (UCXBs) appear able to sustain accretion onto the compact accretor at rates lower than in wider X-ray binaries. This may be understood by the smaller accretion disks in UCXBs: a lower X-ray luminosity suffices to keep a disk completely ionized through irradiation and, thus, keep the viscosity at a sufficiently high leve…
Ultralow frequency modulation of energetic particles in the dayside magnetosphere
Balogh, A.; Zong, Q. -G.; Baker, D. N. +8 more
Energetic electron and ion (electrons: 30 keV to 500 keV, protons: 30 keV to 1.5 MeV) flux variations associated with ultralow frequency (ULF) waves in the dayside magnetosphere were observed during the CLUSTER's perigee pass near 0900 MLT on Oct. 31, 2003. The ULF modulation terminated where higher frequency fluctuations appeared, as the CLUSTER …
Small-Scale Jetlike Features in Penumbral Chromospheres
Lites, B. W.; Ichimoto, K.; Tsuneta, S. +8 more
We observed fine-scale jetlike features, referred to as penumbral microjets, in chromospheres of sunspot penumbrae. The microjets were identified in image sequences of a sunspot taken through a Ca II H-line filter on the Solar Optical Telescope on board the Japanese solar physics satellite Hinode. The microjets’ small width of 400 kilometers and s…
Martian gullies in the southern mid-latitudes of Mars: Evidence for climate-controlled formation of young fluvial features based upon local and global topography
Head, James W.; Kreslavsky, Mikhail; Dickson, James L.
A new survey of Mars Orbiter Camera (MOC) narrow-angle images of gullies in the 30°-45° S latitude band includes their distribution, morphology, local topographic setting, orientation, elevation, and slopes. These new data show that gully formation is favored over a specific range of conditions: elevation (-5000 to +3000 m), slope (>10°), and o…