Search Publications
Spectroscopic Study on the Atmospheric Parameters of Nearby F--K Dwarfs and Subgiants
Sato, Bun'ei; Kambe, Eiji; Takeda, Yoichi +2 more
Based on a collection of high-dispersion spectra obtained at Okayama Astrophysical Observatory, the atmospheric parameters (Teff, log g, vt, and [Fe/H]) of 160 mid-F through early-K stars were extensively determined by the spectroscopic method using the equivalent widths of Fe I and Fe II lines along with the numerical techni…
Molecular gas in NUclei of GAlaxies (NUGA). IV. Gravitational torques and AGN feeding
Hunt, L. K.; Schinnerer, E.; Combes, F. +2 more
We discuss the efficiency of stellar gravity torques as a mechanism to account for the feeding of the central engines of four low luminosity Active Galactic Nuclei (AGN): NGC 4321 (HII nucleus/LINER), NGC 4826 (HII nucleus/LINER), NGC 4579 (LINER 1.9/Seyfert 1.9) and NGC 6951 (Seyfert 2). These galaxies have been observed as part of the NUclei of …
Properties of Lyα emitters around the radio galaxy MRC 0316 257,
Pentericci, L.; Röttgering, H. J. A.; Miley, G. K. +9 more
Observations of the radio galaxy MRC 0316 257 at z = 3.13 and the surrounding field are presented. Using narrow- and broad-band imaging obtained with the VLT, 77 candidate Lyα emitters with a rest-frame equivalent width of >15 Å were selected in a ∼ 7´ × 7´ field around the radio galaxy. Spectroscopy of 40 candidate emitters resulted in the dis…
The Murmur of the Sleeping Black Hole: Detection of Nuclear Ultraviolet Variability in LINER Galaxies
Maoz, Dan; Nagar, Neil M.; Wilson, Andrew S. +1 more
LINER nuclei, which are present in many nearby galactic bulges, may be the manifestation of low-rate or low-radiative-efficiency accretion onto supermassive central black holes. However, it has been unclear whether the compact UV nuclear sources present in many LINERs are clusters of massive stars, rather than being directly related to the accreti…
On the Polar Caps of the Three Musketeers
Caraveo, P. A.; Bignami, G. F.; Mereghetti, S. +2 more
XMM-Newton EPIC observations of PSR B0656+14, PSR B1055-52, and Geminga have substantially increased the collection of statistics available for these three isolated neutron stars, so apparently similar to deserve the nickname of the Three Musketeers, given to them by Becker & Trümper. Here we take advantage of the EPIC statistics to perform ph…
Cassini Imaging Science: Initial Results on Phoebe and Iapetus
Burns, J. A.; Neukum, G.; Wagner, R. +32 more
The Cassini Imaging Science Subsystem acquired high-resolution imaging data on the outer Saturnian moon, Phoebe, during Cassini's close flyby on 11 June 2004 and on Iapetus during a flyby on 31 December 2004. Phoebe has a heavily cratered and ancient surface, shows evidence of ice near the surface, has distinct layering of different materials, and…
MCG-6-30-15: long time-scale X-ray variability, black hole mass and active galactic nuclei high states
Uttley, P.; Goad, M. R.; McHardy, I. M. +1 more
We present a detailed study of the long time-scale X-ray variability of the Seyfert 1 Galaxy MCG-6-30-15, based on eight years of frequent monitoring observations with the Rossi X-ray Timing Explorer. When combined with the published short-time-scale XMM-Newton observations, we derive the power-spectral density (PSD) covering six decades of freque…
Statistical Constraints for Astrometric Binaries with Nonlinear Motion
Makarov, V. V.; Kaplan, G. H.
Useful constraints on the orbits and mass ratios of astrometric binaries in the Hipparcos catalog are derived from the measured proper motion differences of Hipparcos and Tycho-2 (Δµ), accelerations of proper motions (µ˙), and second derivatives of proper motions (µ̈). It is shown how, in some cases, statistical bounds can be esti…
Complex organic matter in Titan's atmospheric aerosols from in situ pyrolysis and analysis
Steller, M.; Atreya, S. K.; Owen, T. +19 more
Aerosols in Titan's atmosphere play an important role in determining its thermal structure. They also serve as sinks for organic vapours and can act as condensation nuclei for the formation of clouds, where the condensation efficiency will depend on the chemical composition of the aerosols. So far, however, no direct information has been available…
Sub-arcsec imaging of the AB Aur molecular disk and envelope at millimeter wavelengths: a non Keplerian disk
Guilloteau, S.; Dutrey, A.; Piétu, V.
We present sub-arcsecond images of AB Auriga obtained with the IRAM Plateau de Bure interferometer in the isotopologues of CO, and in continuum at 3 and 1.3 mm. These observations allow us to trace the structure of the circumstellar material of