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Elevation distribution of Titan's craters suggests extensive wetlands
Lorenz, R. D.; Neish, C. D.
Using a new global topographic map of Titan, we find that craters on Titan preferentially lie at higher than average elevations. We explore several explanations for this observed behavior, and judge the most reasonable explanation to be the presence of widespread wetlands of liquid hydrocarbons at low elevations over much of geologic time. Impacts…
Outflow of hot and cold molecular gas from the obscured secondary nucleus of NGC 3256: closing in on feedback physics
Colina, L.; Villar-Martín, M.; Arribas, S. +5 more
The nuclei of merging galaxies are often deeply buried in dense layers of gas and dust. In these regions, gas outflows driven by starburst and active galactic nuclear activity are believed to play a crucial role in the evolution of these galaxies. However, to fully understand this process it is essential to resolve the morphology and kinematics of…
Tracing the Outer Halo in a Giant Elliptical to 25 R eff
Rejkuba, M.; Greggio, L.; Jerjen, H. +3 more
We have used the Advanced Camera for Surveys and Wide Field Camera 3 cameras on board the Hubble Space Telescope to resolve stars in the halo of the nearest giant elliptical (gE) galaxy NGC 5128 out to a projected distance of 140 kpc (25 effective radii, R eff) along the major axis and 90 kpc (16 R eff) along the minor axis. …
On the local variation of the Hubble constant
Hannestad, Steen; Odderskov, Io; Haugbølle, Troels
We have carefully studied how local measurements of the Hubble constant, H0, can be influenced by a variety of different parameters related to survey depth, size, and fraction of the sky observed, as well as observer position in space. Our study is based on N-body simulations of structure in the standard ΛCDM model and our conclusion is…
Search for Gravitational Waves Associated with γ-ray Bursts Detected by the Interplanetary Network
Lee, H. M.; Cline, T.; Hurley, K. +899 more
We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significan…
Expectations for the Hard X-Ray Continuum and Gamma-Ray Line Fluxes from the Type Ia Supernova SN 2014J in M82
Burrows, Adam; The, Lih-Sin
The hard X-ray continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the 56Ni yield and spatial distribution, its kinetic energy and expansion speed, and the mechanism of explosion. Such signatures and their time behavior "X-ray" the …
SDSS J143244.91+301435.3: a link between radio-loud narrow-line Seyfert 1 galaxies and compact steep-spectrum radio sources?
Ballo, L.; Dallacasa, D.; Foschini, L. +12 more
We present SDSS J143244.91+301435.3, a new case of a radio-loud narrow-line Seyfert 1 (RL NLS1) with a relatively high radio power (P1.4 GHz = 2.1 × 1025 W Hz-1) and large radio-loudness parameter (R1.4 = 600 ± 100). The radio source is compact with a linear size below ∼1.4 kpc but, in contrast to most o…
Tracking Solar Active Region Outflow Plasma from Its Source to the Near-Earth Environment
Mandrini, C. H.; van Driel-Gesztelyi, L.; Culhane, J. L. +6 more
Seeking to establish whether active-region upflow material contributes to the slow solar wind, we examine in detail the plasma upflows from Active Region (AR) 10978, which crossed the Sun's disc in the interval 8 to 16 December 2007 during Carrington rotation (CR) 2064. In previous work, using data from the Hinode/EUV Imaging Spectrometer, upflow …
HZ Her: Stellar Radius from X-Ray Eclipse Observations, Evolutionary State, and a New Distance
Leahy, D. A.; Abdallah, M. H.
Observations of HZ Her/Her X-1 by the Rossi X-Ray Timing Explorer (RXTE) covering high state eclipses of the neutron star are analyzed here. Models of the eclipse are used to measure the radius and atmospheric scale height of HZ Her, the stellar companion to the neutron star. The radius is 2.58-3.01 × 1011 cm, depending on system inclin…
Valles Marineris dune fields as compared with other martian populations: Diversity of dune compositions, morphologies, and thermophysical properties
Chojnacki, Matthew; Moersch, Jeffrey E.; Burr, Devon M.
Planetary dune field properties and their bulk bedform morphologies relate to regional wind patterns, sediment supply, climate, and topography. On Mars, major occurrences of spatially contiguous low-albedo sand dunes are primarily found in three major topographic settings: impact craters, high-latitude basins, and linear troughs or valleys, the la…