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Vertical and meridional distribution of ethane, acetylene and propane in Saturn’s stratosphere from CIRS/Cassini limb observations
Bézard, Bruno; Guerlet, Sandrine; Fouchet, Thierry +2 more
Measuring the spatial distribution of chemical compounds in Saturn's stratosphere is critical to better understand the planet's photochemistry and dynamics. Here we present an analysis of infrared spectra in the range 600-1400 cm -1 acquired in limb geometry by the Cassini spacecraft between March 2005 and January 2008. We first determi…
Plasma in Saturn's nightside magnetosphere and the implications for global circulation
Coates, A. J.; Dougherty, M. K.; Thomsen, M. F. +8 more
We present a bulk ion flow map from the nightside, equatorial region of Saturn's magnetosphere derived from the Cassini CAPS ion mass spectrometer data. The map clearly demonstrates the dominance of corotation flow over radial flow and suggests that the flux tubes sampled are still closed and attached to the planet up to distances of 50 RS
Upper Limits on the Masses of 105 Supermassive Black Holes from Hubble Space Telescope/Space Telescope Imaging Spectrograph Archival Data
Beifiori, A.; Dalla Bontà, E.; Corsini, E. M. +4 more
Based on the modeling of the central emission-line width measured over subarcsecond apertures with the Hubble Space Telescope, we present stringent upper bounds on the mass of the central supermassive black hole, M •, for a sample of 105 nearby galaxies (D < 100 Mpc) spanning a wide range of Hubble types (E-Sc) and values of the cent…
Evidence for Quasi-Isotropic Magnetic Fields from Hinode Quiet-Sun Observations
Asensio Ramos, A.
Some recent investigations of spectropolarimetric observations of the Zeeman effect in the Fe I lines at 630 nm carried out with the Hinode solar space telescope have concluded that the strength of the magnetic field vector in the internetwork regions of the quiet Sun is in the hG regime and that its inclination is predominantly horizontal. We cri…
Quiescent current sheets in the solar wind and origins of slow wind
Ko, Y. -K.; Moore, R. L.; von Steiger, R. +1 more
Solar wind near the heliospheric current sheet is investigated using Ulysses and ACE data in a superposed epoch analysis for several days on either side of the current sheets. Only data near sunspot minima are used, minimizing the influence of transients. New results are shown for composition and ionization state. Existing results showing a ∼2 day…
XMM-Newton observations of Seyfert galaxies from the Palomar spectroscopic survey: the X-ray absorption distribution
Georgantopoulos, I.; Akylas, A.
We present XMM-Newton spectral analysis of all 38 Seyfert galaxies from the Palomar spectroscopic sample of galaxies. These are found at distances of up to 67 Mpc and cover the absorbed 2-10 keV luminosity range ~1038-1043 erg s-1. Our aim is to determine the distribution of the X-ray absorption in the local Univer…
Star Formation in Luminous H II Regions in M33
Relaño, Mónica; Kennicutt, Robert C., Jr.
We present a multiwavelength (ultraviolet, infrared, optical, and CO) study of a set of luminous H II regions in M33: NGC 604, NGC 595, NGC 592, NGC 588, and IC131. We study the emission distribution in the interiors of the H II regions to investigate the relation between the dust emission at 8 µm and 24 µm and the location of the mass…
Plausible parent bodies for enstatite chondrites and mesosiderites: Implications for Lutetia's fly-by
Fulchignoni, M.; Vernazza, P.; Strazzulla, G. +4 more
We present new irradiation experiments performed on the enstatite chondrite Eagle (EL6) and the mesosiderite Vaca Muerta. These experiments were performed with the aims of (a) quantifying the spectral effect of the solar wind on their parent asteroid surfaces and (b) identifying their parent bodies within the asteroid belt. For Vaca Muerta we obse…
Lithium abundances of halo dwarfs based on excitation temperature. I. Local thermodynamic equilibrium
García Pérez, A. E.; Norris, J. E.; Ryan, S. G. +2 more
Context: The discovery of the Spite plateau in the abundances of 7Li for metal-poor stars led to the determination of an observationally deduced primordial lithium abundance. However, after the success of the Wilkinson Microwave Anisotropy Probe (WMAP) in determining the baryon density, Ω_Bh2, there was a discrepancy between …
A Stellar Dynamical Measurement of the Black Hole Mass in the Maser Galaxy NGC 4258
Filippenko, Alexei V.; Ho, Luis C.; Gebhardt, Karl +13 more
We determine the mass of the black hole at the center of the spiral galaxy NGC 4258 by constructing axisymmetric dynamical models of the galaxy. These models are constrained by high spatial resolution imaging and long-slit spectroscopy of the nuclear region obtained with the Hubble Space Telescope, complemented by ground-based observations extendi…