Search Publications
In Situ Generation of Transverse Magnetohydrodynamic Waves from Colliding Flows in the Solar Corona
Antolin, Patrick; Pagano, Paolo; Nakariakov, Valery M. +1 more
Transverse magnetohydrodynamic (MHD) waves permeate the solar atmosphere and are a candidate for coronal heating. However, the origin of these waves is still unclear. In this Letter, we analyze coordinated observations from Hinode/Solar Optical Telescope (SOT) and Interface Region Imaging Spectrograph ( IRIS) of a prominence/coronal rain loop-like…
Gaia-ESO Survey: INTRIGOSS—A New Library of High-resolution Synthetic Spectra
Jofré, Paula; Flaccomio, Ettore; Koposov, Sergey E. +19 more
We present a high-resolution synthetic spectral library, INTRIGOSS, designed for studying FGK stars. The library is based on atmosphere models computed with specified individual element abundances via ATLAS12 code. Normalized SPectra (NSPs) and surface Flux SPectra (FSP) in the wavelength range 4830-5400 Å were computed with the SPECTRUM code. INT…
Formation of the UV Spectrum of Molecular Hydrogen in the Sun
Judge, P. G.; Jaeggli, S. A.; Daw, A. N.
Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in part…
Observational Study of an Earth-affecting Problematic ICME from STEREO
Hess, Phillip; Wang, Yuming; Shen, Chenglong +4 more
We present a study of the origin of one interplanetary coronal mass ejection (ICME) that lacked an easily identifiable signature of an associated progenitor coronal mass ejection (CME) near the Sun in the observations of SOHO/LASCO at the L1 point. We consider these kinds of ICMEs as problematic, as they pose the difficulty of understanding the Su…
GD-1: The Relic of an Old Metal-poor Globular Cluster
Yanny, Brian; Wu, Yue; Li, Guang-Wei
Combining data from Gaia DR2, SDSS DR14, and LAMOST DR6, we update the fit to model of the properties of the stellar stream GD-1 and find that it has an age of ∼13 Gyr, [Fe/H] of -2.2 ± 0.12, and a distance from the Sun of ∼8 kpc. We tabulate six-dimensional (6D) phase-space fiducial points along the GD-1 stream orbit over a 90° arc. The fitted or…
Magnetic Field near Venus: Comparison between Solar Cycle 24 and Previous Cycles
Xu, Qi; Zhang, Tielong; Xu, Xiaojun +3 more
Solar Cycle 24 has been proven to be the weakest cycle in solar activity in the last century. So far, most of the evidence has been presented near Earth at 1 au. In this study, we statistically studied the magnetic field of the solar wind near Venus and the induced magnetosphere of Venus using Pioneer Venus Orbiter (PVO) and Venus Express (VEX) ob…
“Red” but Not “Dead”: Actively Star-forming Brightest Cluster Galaxies at Low Redshifts
Yan, Haojing; Runge, James
Brightest cluster galaxies (BCGs) are believed to have assembled most of their stars early in time and therefore should be passively evolving at low redshifts and appear “red-and-dead.” However, there have been reports that a minority of low-redshift BCGs still have ongoing star formation rates (SFRs) of a few to even ∼ 100 {M}⊙ {{yr}}…
Angular Momentum Evolution of Stellar Disks at High Redshifts
Shimasaku, Kazuhiro; Kawamata, Ryota; Okamura, Taku
The stellar disk size of a galaxy depends on the ratio of the disk stellar mass to the halo mass, m ⋆ ≡ M ⋆/M dh, and the fraction of the dark halo angular momentum transferred to the stellar disk, j ⋆ ≡ J ⋆/J dh. Since m ⋆ and j ⋆ are determined by many star f…
X-Ray Reverberation Mapping and Dramatic Variability of Seyfert 1 Galaxy 1H 1934-063
Frederick, Sara; Kara, Erin; Fabian, Andrew +2 more
A fraction of active galactic nuclei (AGN) exhibit dramatic variability, which is observed on timescales down to minutes in the X-ray band. We introduce the case study of 1H 1934-063 (z = 0.0102), a Narrow-line Seyfert 1 among the brightest and most variable AGN ever observed with XMM-Newton. This work includes spectral and temporal analyses of a …
SU Lyn: Diagnosing the Boundary Layer with UV and Hard X-Ray Data
Nelson, T.; Mukai, K.; Sokoloski, J. L. +2 more
Symbiotic stars in which the symbiotic phenomenon is powered solely by accretion, often at an average rate that is higher than in cataclysmic variable stars, provide an important opportunity to diagnose boundary layers around disk-accreting white dwarfs. Here, we investigate SU Lyncis (SU Lyn), a recently discovered example of a purely accretion-p…