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Gravity Field, Shape, and Moment of Inertia of Titan
Stevenson, David J.; Iess, Luciano; Jacobson, Robert A. +5 more
Precise radio tracking of the spacecraft Cassini has provided a determination of Titan’s mass and gravity harmonics to degree 3. The quadrupole field is consistent with a hydrostatically relaxed body shaped by tidal and rotational effects. The inferred moment of inertia factor is about 0.34, implying incomplete differentiation, either in the sense…
Spin-Down Measurement of PSR J1852+0040 in Kesteven 79: Central Compact Objects as Anti-Magnetars
Gotthelf, E. V.; Halpern, J. P.
Using XMM-Newton and Chandra, we achieved phase-connected timing of the 105 ms X-ray pulsar PSR J1852+0040 that provides the first measurement of the spin-down rate of a member of the class of central compact objects (CCOs) in supernova remnants. We measure \dot{P} = (8.68 ± 0.09) × 10^{-18}, and find no evidence for timing noise or variations in …
The Palermo Swift-BAT hard X-ray catalogue. III. Results after 54 months of sky survey
Tagliaferri, G.; Cusumano, G.; Sbarufatti, B. +10 more
Aims: We present the Second Palermo Swift-BAT hard X-ray catalogue obtained by analysing data acquired in the first 54 months of the Swift mission.
Methods: Using our software dedicated to the analysis of data from coded mask telescopes, we analysed the BAT survey data in three energy bands (15-30 keV, 15-70 keV, 15-150 keV), obtaining a…
Three-dimensional Solar WIND Modeling from the Sun to Earth by a SIP-CESE MHD Model with a Six-component Grid
Wu, S. T.; Feng, Xueshang; Xiang, Changqing +3 more
The objective of this paper is to explore the application of a six-component overset grid to solar wind simulation with a three-dimensional (3D) Solar-InterPlanetary Conservation Element/Solution Element MHD model. The essential focus of our numerical model is devoted to dealing with: (1) the singularity and mesh convergence near the poles via the…
A Bayesian test for periodic signals in red noise
Vaughan, S.
Many astrophysical sources, especially compact accreting sources, show strong, random brightness fluctuations with broad power spectra in addition to periodic or quasi-periodic oscillations (QPOs) that have narrower spectra. The random nature of the dominant source of variance greatly complicates the process of searching for possible weak periodic…
Fermi Large Area Telescope View of the Core of the Radio Galaxy Centaurus A
Ozaki, M.; Caraveo, P. A.; Frailis, M. +195 more
We present γ-ray observations with the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope of the nearby radio galaxy Centaurus A (Cen A). The previous EGRET detection is confirmed, and the localization is improved using data from the first 10 months of Fermi science operation. In previous work, we presented the detection of th…
Reconnection Outflows and Current Sheet Observed with Hinode/XRT in the 2008 April 9 "Cartwheel CME" Flare
Reeves, Katharine K.; Longcope, Dana W.; Savage, Sabrina L. +2 more
Supra-arcade downflows (SADs) have been observed with Yohkoh/SXT (soft X-rays (SXR)), TRACE (extreme ultraviolet (EUV)), SOHO/LASCO (white light), SOHO/SUMER (EUV spectra), and Hinode/XRT (SXR). Characteristics such as low emissivity and trajectories, which slow as they reach the top of the arcade, are consistent with post-reconnection magnetic fl…
Deep imaging survey of young, nearby austral stars . VLT/NACO near-infrared Lyot-coronographic observations
Zuckerman, B.; Lagrange, A. -M.; Desidera, S. +10 more
Context. High contrast and high angular resolution imaging is the optimal search technique for substellar companions to nearby stars at physical separations larger than typically 10 AU. Two distinct populations of substellar companions, brown dwarfs and planets, can be probed and characterized. As a result, fossile traces of processes of formation…
The halos of satellite galaxies: the companion of the massive elliptical lens SL2S J08544-0121
Halkola, A.; Suyu, S. H.
Strong gravitational lensing by groups or clusters of galaxies provides a powerful technique to measure the dark matter properties of individual lens galaxies. We study in detail the mass distribution of the satellite lens galaxy in the group-scale lens SL2S J08544-0121 by modelling simultaneously the spatially extended surface brightness distribu…
Depth of the Martian cryosphere: Revised estimates and implications for the existence and detection of subpermafrost groundwater
Heggy, Essam; Clifford, Stephen M.; Lasue, Jeremie +3 more
The Martian cryosphere is defined as that region of the crust where the temperature remains continuously below the freezing point of water. Previous estimates of its present thickness have ranged from ∼2.3-4.7 km at the equator to ∼6.5-12.5 km at the poles. Here we revisit these calculations, review some of the assumptions on which they were based…