As part of the Megamaser Cosmology Project, here we present a new geometric distance measurement to the megamaser galaxy NGC 5765b. Through a series of very long baseline interferometry observations, we have confirmed the water masers trace a thin, sub-parsec Keplerian disk around the nucleus, implying an enclosed mass of 4.55 ± 0.40 × 107 M⊙. Meanwhile, from single-dish monitoring of the maser spectra over two years, we measured the secular drifts of maser features near the systemic velocity of the galaxy with rates between 0.5 and 1.2 km s−1 yr−1. Fitting a warped, thin-disk model to these measurements, we determine a Hubble Constant H0 of 66.0 ± 6.0 km s−1 Mpc−1 with an angular-diameter distance to NGC 5765b of 126.3 ± 11.6 Mpc. Apart from the distance measurement, we also investigate some physical properties related to the maser disk in NGC 5765b. The high-velocity features are spatially distributed into several clumps, which may indicate the existence of a spiral density wave associated with the accretion disk. For the redshifted features, the envelope defined by the peak maser intensities increases with radius. The profile of the systemic masers in NGC 5765b is smooth and shows almost no structural changes over the two years of monitoring time, which differs from the more variable case of NGC 4258.

[1] Thermal remote sensing methods for mapping evapotranspiration (ET) exploit the physical interconnection that exists between land-surface temperature (LST) and evaporative cooling, employing principles of surface energy balance (SEB). Unfortunately, while many applications in water resource management require ET information at daily and field spatial scales, current satellite-based thermal sensors are characterized by either low spatial resolution and high repeatability or by moderate/high spatial resolution and low frequency. Here we introduce a novel approach to ET mapping that fuses characteristics of both classes of sensors to provide optimal spatiotemporal coverage. In this approach, coarse resolution daily ET maps generated with a SEB model using geostationary satellite data are spatially disaggregated using daily MODIS (MODerate resolution Imaging Spectroradiometer) 1 km and biweekly Landsat LST imagery sharpened to 30 m. These ET fields are then fused to obtain daily ET maps at 30 m spatial resolution. The accuracy of the fused Landsat-MODIS daily ET maps was evaluated over Iowa using observations collected at eight flux towers sited in corn and soybean fields during the Soil Moisture Experiment of 2002, as well as in comparison with a Landsat-only retrieval. A significant improvement in ET accuracy (reducing errors from 0.75 to 0.58 mm d−1 on average) was obtained by fusing MODIS and Landsat data in comparison with the Landsat-only case, with most notable improvements when a rainfall event occurred between two successive Landsat acquisitions. The improvements are further evident at the seasonal timescale, where a 3% error is obtained using Landsat-MODIS fusion versus a 9% Landsat-only systematic underestimation.

In this work, thermodynamic assessments of the Sb-La and Sb-Tb binary systems have been carried out by using the CALPHAD method on the basis of the experimental data including thermodynamic properties and phase equilibria. The Gibbs free energies of the solution phases (liquid, fcc, bcc, hcp, and dhcp) were described by the subregular solution model with the Redlich-Kister equation. The intermetallic compounds, La 2Sb, La 3Sb 2, LaSb, and LaSb 2 in the Sb-La system and Sb 2Tb, alpha-SbTb, beta-SbTb, alpha-Sb 3Tb 4, beta-Sb 3Tb 4, and Sb 3Tb 5 in the Sb-Tb system, were treated as stoichiometric phases. A consistent set of thermodynamic parameters has been derived for describing the Gibbs free energy of each solution phase and intermetallic compound in the Sb-La and Sb-Tb systems. A good agreement between the calculated results including phase diagrams and thermodynamic properties and the experimental data in the Sb-La and Sb-Tb systems is obtained. [All rights reserved Elsevier].

The recent progress in the use of large-scale ab initio molecular dynamics (AIMD) to investigate low energy recoil events and determine threshold displacement energies, Ed, in ceramics is reviewed. In general, Ed shows a significant dependence on recoil direction and atom. In 3C–SiC, the minimum Ed for both C and Si atoms is found along the 1 0 0 direction, with a value of 20 and 49 eV, respectively. The results demonstrate that significant charge transfer occurs during the dynamics process, and defects can enhance charge transfer to surrounding atoms, which provides important insights into the formation of charged defects. It is found that the C vacancy is a positively charged defect, whereas the Si vacancy is in its neutral state. The minimum Ed in GaN is determined to be 17 and 39 eV for N and Ga atoms, respectively, both along the direction. The average Ed for N atoms (32.4 eV) is smaller than that for Ga atoms (73.2 eV). It is of interest to note that the N defects created along different crystallographic directions have a similar configuration (a N–N dumbbell configuration), but various configurations for Ga defects are formed. In Y2Ti2O7 prochlore, the minimum Ed for Y atoms is determined to be 27 eV for a recoil along the 1 0 0 direction, 31.5 eV for Ti atoms along the 1 0 0 direction, 14.5 eV for O48f atoms along the 1 1 0 direction and 13 eV for O8b atoms along the 1 1 1 direction. The average Ed values determined are 32.7, 34.2, 14.2 and 16.1 eV for yttrium, titanium, O48f and O8b atoms, respectively.

The recent progress in the use of large-scale ab initio molecular dynamics (AIMD) to investigate low energy recoil events and determine threshold displacement energies, Ed, in ceramics is reviewed. In general, Ed shows a significant dependence on recoil direction and atom. In 3C–SiC, the minimum Ed for both C and Si atoms is found along the 1 0 0 direction, with a value of 20 and 49 eV, respectively. The results demonstrate that significant charge transfer occurs during the dynamics process, and defects can enhance charge transfer to surrounding atoms, which provides important insights into the formation of charged defects. It is found that the C vacancy is a positively charged defect, whereas the Si vacancy is in its neutral state. The minimum Ed in GaN is determined to be 17 and 39 eV for N and Ga atoms, respectively, both along the direction. The average Ed for N atoms (32.4 eV) is smaller than that for Ga atoms (73.2 eV). It is of interest to note that the N defects created along different crystallographic directions have a similar configuration (a N–N dumbbell configuration), but various configurations for Ga defects are formed. In Y2Ti2O7 prochlore, the minimum Ed for Y atoms is determined to be 27 eV for a recoil along the 1 0 0 direction, 31.5 eV for Ti atoms along the 1 0 0 direction, 14.5 eV for O48f atoms along the 1 1 0 direction and 13 eV for O8b atoms along the 1 1 1 direction. The average Ed values determined are 32.7, 34.2, 14.2 and 16.1 eV for yttrium, titanium, O48f and O8b atoms, respectively.