Search Publications
High-contrast Imaging of Intermediate-mass Giants with Long-term Radial Velocity Trends
Henning, Thomas; Terada, Hiroshi; Usuda, Tomonori +62 more
A radial velocity (RV) survey for intermediate-mass giants has been in operation for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey has revealed that some giants show long-term linear RV accelerations (RV trends), indicating the presence of outer companions. Direct-imaging observations can help clarify what objects genera…
Quantifying the Interstellar Medium and Cosmic Rays in the MBM 53, 54, and 55 Molecular Clouds and the Pegasus Loop Using Fermi-LAT Gamma-ray Observations
Mizuno, T.; Okumura, A.; Fukui, Y. +4 more
A study of the interstellar medium (ISM) and cosmic rays (CRs) using Fermi Large Area Telescope (LAT) data, in a region encompassing the nearby molecular clouds MBM 53, 54, and 55 and a far-infrared loop-like structure in Pegasus, is reported. By comparing the Planck dust thermal emission model with Fermi-LAT γ-ray data, it was found that neither …
Comparison of CME/Shock Propagation Models with Heliospheric Imaging and In Situ Observations
Lu, Lei; Feng, Xueshang; Liu, Ying D. +3 more
The prediction of the arrival time for fast coronal mass ejections (CMEs) and their associated shocks is highly desirable in space weather studies. In this paper, we use two shock propagation models, I.e., Data Guided Shock Time Of Arrival (DGSTOA) and Data Guided Shock Propagation Model (DGSPM), to predict the kinematical evolution of interplanet…
Properties of Interstellar Medium In Infrared-bright QSOs Probed by [O I] 63 um and [C II] 158 um Emission Lines
Tsai, Chao-Wei; Zhao, Yinghe; Yan, Lin
We present a study of the interstellar medium (ISM) in the host galaxies of nine QSOs at 0.1 < z < 0.2 with black hole masses of 3× {10}7 {M}⊙ to 3× {10}9 {M}⊙ based on the far-IR spectroscopy taken with Herschel Space Observatory. We detect the [O I] 63 µm ([C II] 158 µm) emission in…
Search for Gamma-Ray Emission from AE Aquarii with Seven Years of Fermi-LAT Observations
Rea, Nanda; Torres, Diego F.; Li, Jian +4 more
AE Aquarii (AE Aqr) is a cataclysmic binary hosting one of the fastest rotating ({P}{spin} = 33.08 s) white dwarfs (WDs) known. Based on seven years of Fermi Large Area Telescope (LAT) Pass 8 data, we report on a deep search for gamma-ray emission from AE Aqr. Using X-ray observations from ASCA, XMM-Newton, Chandra, Swift, Suzaku, and N…
The ACS LCID Project. XI. On the Early Time Resolution of SFHs of Local Group Dwarf Galaxies: Comparing the Effects of Reionization in Models with Observations
Dolphin, Andrew; Skillman, Evan; Monelli, Matteo +10 more
The analysis of the early star formation history (SFH) of nearby galaxies, obtained from their resolved stellar populations, is relevant as a test for cosmological models. However, the early time resolution of observationally derived SFHs is limited by several factors. Thus, direct comparison of observationally derived SFHs with those derived from…
Cosmological Parameters from CMB Maps without Likelihood Approximation
Eriksen, H. K.; Wehus, I. K.; Racine, B. +1 more
We propose an efficient Bayesian Markov chain Monte Carlo (MCMC) algorithm for estimating cosmological parameters from cosmic microwave background (CMB) data without the use of likelihood approximations. It builds on a previously developed Gibbs sampling framework that allows for exploration of the joint CMB sky signal and power spectrum posterior…
Relaxation Processes within Flux Ropes in Solar Wind
Perri, S.; Bruno, R.; Carbone, V. +3 more
Flux ropes are localized structures in space plasma whose tube-like organized magnetic configuration can be well approximated by a force-free field model. Both numerical simulations and simple models suggest that the ideal magnetohydrodynamics (MHD) can relax toward a minimum energy state, where magnetic helicity is conserved, characterized by for…
Detection of a Dearth of Stars with Zero Angular Momentum in the Solar Neighborhood
Bovy, Jo; Hunt, Jason A. S.; Carlberg, Raymond G.
We report on the detection in the combined Gaia-DR1/RAVE data of a lack of disk stars in the solar neighborhood with velocities close to zero angular momentum. We propose that this may be caused by the scattering of stars with very low angular momentum onto chaotic, halo-type orbits when they pass through the Galactic nucleus. We model the effect …
Projection Effects in Coronal Dimmings and Associated EUV Wave Event
Magdalenić, J.; Temmer, M.; Veronig, A. M. +2 more
We investigate the high-speed (v > 1000 km s-1) extreme-ultraviolet (EUV) wave associated with an X1.2 flare and coronal mass ejection (CME) from NOAA active region 11283 on 2011 September 6 (SOL2011-09-06T22:12). This EUV wave features peculiar on-disk signatures in particular, we observe an intermittent “disappearance” of the front…