Search Publications
Constraints on patchy reionization from Planck CMB temperature trispectrum
Namikawa, Toshiya
We present constraints on the patchy reionization by measuring the trispectrum of the Planck 2015 cosmic microwave background (CMB) temperature anisotropies. The patchy reionization leads to anisotropies in the CMB optical depth, and the statistics of the observed CMB anisotropies is altered. We estimate the trispectrum of the CMB temperature anis…
On the Existence of Ionospheric Feedback Instability in the Earth's Magnetosphere-Ionosphere System
Mishin, Evgeny V.; Streltsov, Anatoly V.
The ionospheric feedback instability (IFI) has been considered one of the main generation mechanisms for large-amplitude ultralow frequency waves and small-scale field-aligned currents in the auroral and subauroral regions for more than 40 years. Sydorenko and Rankin (2017, https://doi.org/10.1002/201…
VLBA polarimetric monitoring of 3C 111
Gurwell, M.; Wilms, J.; Kadler, M. +17 more
Context. While studies of large samples of jets of active galactic nuclei (AGN) are important in order to establish a global picture, dedicated single-source studies are an invaluable tool for probing crucial processes within jets on parsec scales. These processes involve in particular the formation and geometry of the jet magnetic field as well a…
STREAMFINDER II: A possible fanning structure parallel to the GD-1 stream in Pan-STARRS1
Goldman, Bertrand; Magnier, Eugene; Malhan, Khyati +3 more
STREAMFINDER is a new algorithm that we have built to detect stellar streams in an automated and systematic way in astrophysical datasets that possess any combination of positional and kinematic information. In Paper I, we introduced the methodology and the workings of our algorithm and showed that it is capable of detecting ultra-faint and distan…
Expanding CO Shells in the Orion A Molecular Cloud
Nakamura, Fumitaka; Shimajiri, Yoshito; Kawabe, Ryohei +6 more
We present the discovery of expanding spherical shells around low- to intermediate-mass young stars in the Orion A giant molecular cloud using observations of {}12{CO}(1-0) and {}13{CO}(1-0) from the Nobeyama Radio Observatory 45 m telescope. The shells have radii from 0.05 to 0.85 pc and expand outward at 0.8-5 km s-1
Surface gravities for 15 000 Kepler stars measured from stellar granulation and validated with Gaia DR2 parallaxes
Huber, Daniel; Bedding, Timothy R.; Kjeldsen, Hans +1 more
We have developed a method to estimate surface gravity (log g) from light curves by measuring the granulation background, similar to the `flicker' method by Bastien et al. (2016) but working in the Fourier power spectrum. We calibrated the method using Kepler stars for which asteroseismology has been possible with short-cadence data, demonstrating…
Hard X-ray-selected giant radio galaxies - I. The X-ray properties and radio connection
Bird, A. J.; Fiocchi, M.; Ubertini, P. +6 more
We present the first broad-band X-ray study of the nuclei of 14 hard X-ray-selected giant radio galaxies, based both on the literature and on the analysis of archival X-ray data from NuSTAR, XMM-Newton, Swift, and INTEGRAL. The X-ray properties of the sources are consistent with an accretion-related X-ray emission, likely originating from an X-ray…
Anatomy of the AGN in NGC 5548. IX. Photoionized emission features in the soft X-ray spectra
Kaastra, J. S.; Kriss, G. A.; Bianchi, S. +10 more
The X-ray narrow emission line region (NELR) of the archetypal Seyfert 1 galaxy NGC 5548 has been interpreted as a single-phase photoionized plasma that is absorbed by some of the warm absorber components. This scenario requires those overlaying warm absorber components to have larger distance (to the central engine) than the X-ray NELR, which is …
Galaxy Inclination and the IRX-β Relation: Effects on UV Star Formation Rate Measurements at Intermediate to High Redshifts
Barro, Guillermo; Pérez-González, Pablo G.; Ferguson, Henry C. +11 more
At intermediate and high redshifts, measurements of galaxy star formation rates are usually based on rest-frame ultraviolet (UV) data. A correction for dust attenuation, A UV, is needed for these measurements. This correction is typically inferred from UV spectral slopes (β) using an equation known as “Meurer's Relation.” In this paper,…
Stellar Population Diagnostics of the Massive Star Binary Fraction
Dorn-Wallenstein, Trevor Z.; Levesque, Emily M.
Populations of massive stars are directly reflective of the physics of stellar evolution. Counts of subtypes of massive stars and ratios of massive stars in different evolutionary states have been used ubiquitously as diagnostics of age and metallicity effects. While the binary fraction of massive stars is significant, inferences are often based u…