Search Publications
A systematic look at the very high and low/hard state of GX339-4: constraining the black hole spin with a new reflection model
Fabian, A. C.; Miller, J. M.; Miniutti, G. +3 more
We present a systematic study of GX 339-4 in both its very high and low hard states from simultaneous observations made with XMM-Newton and RXTE in 2002 and 2004. The X-ray spectra of both these extreme states exhibit strong reflection signatures, with a broad, skewed Fe Kα line clearly visible above the continuum. Using a newly developed, self-co…
Dynamical Centers and Noncircular Motions in THINGS Galaxies: Implications for Dark Matter Halos
Walter, F.; Brinks, E.; de Blok, W. J. G. +2 more
We present harmonic decompositions of the velocity fields of 19 galaxies from The H I Nearby Galaxy Survey (THINGS) which quantify the magnitude of the noncircular motions in these galaxies and yield observational estimates of the elongations of the dark matter halo potentials. Additionally, we present accurate dynamical center positions for these…
Magnetic Field Overlying Solar Eruption Regions and Kink and Torus Instabilities
Liu, Y.
Using a potential field source surface (PFSS) model, we study a magnetic field overlying erupted filaments in solar active regions. The filaments studied here were reported to experience a kink instability or a torus instability. The torus instability leads to a full eruption, while the kink instability leads to a full eruption or a failed eruptio…
An Integrated Picture of Star Formation, Metallicity Evolution, and Galactic Stellar Mass Assembly
Barger, A. J.; Cowie, L. L.
We present an integrated study of star formation and galactic stellar mass assembly from z = 0.05 to 1.5 and galactic metallicity evolution from z = 0.05 to 0.9 using a very large and highly spectroscopically complete sample selected by rest-frame NIR bolometric flux in the GOODS-N. We assume a Salpeter IMF and fit Bruzual & Charlot models to …
Warping of Saturn's magnetospheric and magnetotail current sheets
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +5 more
The magnetotails of Jupiter and Earth are known to be hinged so that their orientation is controlled by the magnetic field of the planet at small distances and asymptotically approach the direction of the flow of the solar wind at large distances. In this paper we present Cassini observations showing that Saturn's magnetosphere is also similarly h…
Formation and distribution of benzene on Titan
Yelle, R. V.; Vuitton, V.; Cui, J.
We present a study of the formation and distribution of benzene (C6H6) on Titan. Analysis of the Cassini Mass Spectrometer (INMS) measurements of benzene densities on 12 Titan passes shows that the benzene signal exhibits an unusual time dependence, peaking ~20 s after closest approach, rather than at closest approach. We sho…
Study of Nonthermal Emission from SNR RX J1713.7-3946 with Suzaku
Petre, Robert; Kokubun, Motohide; Nakazawa, Kazuhiro +11 more
We present results obtained from a series of observations of the supernova remnant RX J1713.7-3946 by Suzaku. Hard X-rays have been detected up to ~40 keV. The hard X-ray spectra are described by a power law with photon indices of ~3.0, which is larger than those below 10 keV. The combination of the spatially integrated XIS and HXD spectra clearly…
Variation of the Martian ionospheric electron density from Mars Express radar soundings
Gurnett, D. A.; Morgan, D. D.; Plaut, J. J. +3 more
The Mars Advanced Radar for Subsurface and Ionospheric Sounding aboard Mars Express has been in operation for over 2 years. Between 14 August 2005 and 31 July 2007, we obtain 34,492 ionospheric traces, of which 14,060 yield electron density profiles and 12,291 yield acceptable fits to the Chapman ionospheric model. These results are used to study …
The luminosities and distance scales of type II Cepheid and RR Lyrae variables
van Leeuwen, Floor; Whitelock, Patricia A.; Feast, Michael W. +2 more
Infrared and optical absolute magnitudes are derived for the type II Cepheids κ Pav and VY Pyx using revised Hipparcos parallaxes and for κ Pav, V553 Cen and SW Tau from pulsational parallaxes. Revised Hipparcos and HST parallaxes for RR Lyrae agree satisfactorily and are combined in deriving absolute magnitudes. Phase-corrected J, H and Ks
X-ray hiccups from Sagittarius A* observed by XMM-Newton. The second brightest flare and three moderate flares caught in half a day
Genzel, R.; Hasinger, G.; Grosso, N. +13 more
Context: Our Galaxy hosts at its dynamical center Sgr A*, the closest supermassive black hole. Surprisingly, its luminosity is several orders of magnitude lower than the Eddington luminosity. However, the recent observations of occasional rapid X-ray flares from Sgr A* provide constraints on the accretion and radiation mechanisms at work close to …