Search Publications
Identifying Coronal Mass Ejection Active Region Sources: An Automated Approach
Green, Lucie M.; Hernandez Camero, Julio; Piñel Neparidze, Alex
Identifying the source regions of coronal mass ejections (CMEs) is crucial for understanding their origins and improving space weather forecasting. We present an automated algorithm for matching CMEs detected by the Large Angle Spectrometric Coronagraph with their source active regions, specifically Space Weather HMI Active Region Patches (SHARPs)…
Hidden in Plain Sight: Searching for Dark Companions to Bright Stars with the Large Binocular Telescope and SHARK-VIS
Kochanek, C. S.; Testa, V.; Antoniucci, S. +15 more
We report the results from a pilot study to search for black holes and other dark companions in binary systems using direct imaging with SHARK-VIS and the iLocater pathfinder "Lili" on the Large Binocular Telescope. Starting from known single-lined spectroscopic binaries, we select systems with high mass functions that could host dark companions a…
The Disk Wind Contribution to the Gamma-Ray Emission from the Nearby Seyfert Galaxy GRS 1734‑292
Fukazawa, Yasushi; Inoue, Yoshiyuki; Yamada, Tomoya +4 more
Radio-quiet Seyfert galaxies have been detected in GeV gamma rays by the Fermi Large Area Telescope (LAT), but the origin of much of this emission is unclear. We consider the nearby example GRS 1734‑292, which exhibits weak starburst and jet activities that are insufficient to explain the observed gamma-ray flux. With the first detailed multiwavel…
Nonthermal Velocities in a Solar Active Region Observed by SERTS
Brosius, Jeffrey W.
We present measurements of coronal nonthermal Doppler velocities in NOAA Active Region 7870 observed by the Solar EUV Research Telescope and Spectrograph during its 1995 sounding rocket flight (SERTS-95). The instrument included a multilayer-coated toroidal diffraction grating that enhanced its sensitivity in second order at wavelengths between ab…
A Magnetohydrodynamics Simulation of Coronal Mass Ejections in the Upper Corona at 2.5R⊙ ≤ r ≤ 19R⊙
Hayashi, Keiji; Wu, Chin-Chun; Liou, Kan
The methodology of a new magnetohydrodynamics simulation model of the propagation of coronal mass ejections (CMEs) in the near-Sun solar wind region at 2.5R⊙ ≥ r ≥ 19R⊙ is presented. The simulation model first determines the steady state of the transonic/Alfvénic solar wind with the characteristic-based inner boundary treatme…
Extending the ALMA Census of Circumstellar Disks in the Upper Scorpius OB Association
Andrews, Sean M.; Mamajek, Eric E.; Carpenter, John M. +2 more
We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 7 continuum (340 GHz) and carbon monoxide (CO) J = 3–2 observations for an extended sample of disks in the Upper Scorpius OB Association (Upper Sco, age ∼10 Myr). The targets were selected from previous studies that identified new members of Upper Sco using photometry and astromet…
A Simplified Theory of External Occulters for Solar Coronagraphs
Osterman, Steven N.; DeForest, Craig. E.; Erickson, Nicholas F. +3 more
We present a first-principles analytic treatment of modern multivane occulters in circular (coronagraph) and linear (heliospheric imager) geometry, develop a simplified theory that is useful for designing and predicting their performance, explain certain visual artifacts, and explore the performance limits of multivane occulters. Multivane occulte…
A Nonstop Aurora? The Intriguing Radio Emission from the Rapidly Rotating Magnetic Massive Star HR 5907
Wade, Gregg A.; Biswas, Ayan; Das, Barnali +2 more
HR 5907 (HD 142184) stands out among magnetic OB stars for its rapid rotation, exceptionally hard X-ray emission, and strong magnetic field. High-frequency (>5 GHz) radio emission from the star exhibits an approximately flat spectrum that can be attributed to gyrosynchrotron emission from a dense centrifugal magnetosphere. In a survey of radio …
Ubiquitous Small-scale Extreme-ultraviolet Upflow-like Events above Network Regions Observed by the Solar Orbiter/Extreme Ultraviolet Imager
Shen, Yuandeng; Hou, Zhenyong; Duan, Yadan +2 more
Universal small-scale solar activity in the quiet region is suggested to be a potential source of solar wind and the upper solar atmosphere. Here, with the high-resolution 174 Å imaging observations from the Solar Orbiter/Extreme Ultraviolet Imager, we investigate 59 EUV upflow-like events observed in the quiet Sun. Their average apparent (plane-o…
Luminosity Distance and Extinction by Submicrometer-sized Grains
Siebenmorgen, R.; Chini, R.; Heymann, Frank
The distance to the stars is a fundamental parameter, which is determined via two primary methods—parallax and luminosity. While the parallax is a direct trigonometric method, the luminosity distance is usually influenced by interstellar extinction. As long as the optical properties of dust grains are wavelength-dependent this contamination can be…