Search Publications
Testing physical models for dipolar asymmetry: From temperature to k space to lensing
Contreras, D.; Zibin, J. P.
One of the most intriguing hints of a departure from the standard cosmological model is a large-scale dipolar power asymmetry in the cosmic microwave background (CMB). If not a statistical fluke, its origins must lie in the modulation of the position-space fluctuations via a physical mechanism, which requires the observation of new modes to confir…
On the Orbital Inclination of Proxima Centauri b
Kane, Stephen R.; Gelino, Dawn M.; Turnbull, Margaret C.
The field of exoplanetary science has seen discovery rates increase dramatically over recent years, due largely to the data from the Kepler mission. Even so, individual discoveries of planets orbiting nearby stars are very important for studies of characterization and near-term follow-up prospects. The recent discovery of a terrestrial planet cand…
Tracing the origin of the AGN fuelling reservoir in MCG-6-30-15
Fabian, A. C.; Gandhi, P.; Celotti, A. +3 more
The active galaxy MCG-6-30-15 has a 400 pc diameter stellar kinematically distinct core, counter-rotating with respect to the main body of the galaxy. Our previous high spatial resolution (0.1 arcsec) H-band observations of this galaxy mapped the stellar kinematics and [Fe II] 1.64 µm gas dynamics though mainly restricted to the spatial regi…
Automated Spatiotemporal Analysis of Fibrils and Coronal Rain Using the Rolling Hough Transform
Schad, Thomas
A technique is presented that automates the direction characterization of curvilinear features in multidimensional solar imaging datasets. It is an extension of the Rolling Hough Transform (RHT) technique presented by Clark, Peek, and Putman (Astrophys. J.789, 82, 2014), and it excels at rapid quantification of spatial and spatiotemporal feature o…
Models of the Hydrodynamic Histories of Post-AGB Stars. I. Multiflow Shaping of OH 231.8+04.2
Frank, Adam; Balick, Bruce; Liu, Baowei +1 more
We present a detailed hydrodynamic model that matches the present structure of the well-observed preplanetary nebula (“pPN”) OH 231.8+04.2 (“OH231”). The purpose of the model is to present a physically justified and coherent picture of its evolutionary history from about 100 years from the start of the formation of its complex outer structures to …
Probing the primordial universe with gravitational waves detectors
Liu, Zhi-Guo; Piao, Yun-Song; Wang, Yu-Tong +1 more
The spectrum of primordial gravitational waves (GWs), especially its tilt nT, carries significant information about the primordial universe. Combining recent aLIGO and Planck2015+BK14 data, we find that the current limit is nT=0.016+0.614-0.989 at 95% C.L. We also estimate the impacts of Einstein Telesco…
Variable Stars in Local Group Galaxies. III. And VII, NGC 147, and NGC 185: Insight into the Building Blocks of the M31 Halo
Stetson, P. B.; Bono, G.; Fiorentino, G. +5 more
We present the discovery of 1568 RR Lyrae stars in three of the most luminous M31 satellites: And VII (573), NGC 147 (177), and NGC 185 (818). We use their properties to study the formation history of Local Group spiral haloes, and in particular, to infer about the nature of their possible building blocks by comparison with available data for RR L…
The substorm cycle as reproduced by global MHD models
Gordeev, E.; Sergeev, V.; Tsyganenko, N. +7 more
Recently, Gordeev et al. (2015) suggested a method to test global MHD models against statistical empirical data. They showed that four community-available global MHD models supported by the Community Coordinated Modeling Center (CCMC) produce a reasonable agreement with reality for those key parameters (the magnetospheric size, magnetic field, and…
Ejection of large particles from cometary nuclei in the shape of prolate ellipsoids
Wesołowski, M.; Gronkowski, P.
The ejection of cometary grains from comets is examined. It is assumed that cometary grains are chunks of ice-dust material. We focus on cometary nuclei in the shape of prolate ellipsoids. Two mechanisms are considered. The first one is the drag acting on the motionless grains lying on the surface of a comet's nucleus. It is a consequence of the c…
Comparison of acoustic travel-time measurements of solar meridional circulation from SDO/HMI and SOHO/MDI
Gizon, Laurent; Liang, Zhi-Chao; Birch, Aaron C. +2 more
Context. Time-distance helioseismology is one of the primary tools for studying the solar meridional circulation, especially in the lower convection zone. However, travel-time measurements of the subsurface meridional flow suffer from a variety of systematic errors, such as a center-to-limb variation and an offset due to the position angle (P-angl…