Search Publications
Revealing the Evolution of Non-thermal Electrons in Solar Flares Using 3D Modeling
Fleishman, Gregory D.; Nita, Gelu M.; Kuroda, Natsuha +4 more
Understanding non-thermal particle generation, transport, and escape in solar flares requires detailed quantification of the particle evolution in the realistic 3D domain where the flare takes place. Rather surprisingly, apart from the standard flare scenario and integral characteristics of non-thermal electrons, not much is known about the actual…
Properties of a Small-scale Short-duration Solar Eruption with a Driven Shock
Feng, Li; Lu, Lei; Gan, Weiqun +5 more
Large-scale solar eruptions have been extensively explored over many years. However, the properties of small-scale events with associated shocks have rarely been investigated. We present analyses of a small-scale, short-duration event originating from a small region. The impulsive phase of the M1.9-class flare lasted only four minutes. The kinemat…
Detection of [O III] at z ∼ 3: A Galaxy Above the Main Sequence, Rapidly Assembling Its Stellar Mass
Menten, Karl M.; Güsten, Rolf; Weiss, Axel +8 more
We detect bright emission in the far-infrared (far-IR) fine structure [O III] 88 µm line from a strong lensing candidate galaxy, H-ATLAS J113526.3-014605, hereafter G12v2.43, at z = 3.127, using the second-generation Redshift (z) and Early Universe Spectrometer (ZEUS-2) at the Atacama Pathfinder Experiment Telescope (APEX). This is only the …
Magnetic Helicity Reversal in the Corona at Small Plasma Beta
Brandenburg, Axel; Bourdin, Philippe; Singh, Nishant K.
Solar and stellar dynamos shed small-scale and large-scale magnetic helicity of opposite signs. However, solar wind observations and simulations have shown that some distance above the dynamo both the small-scale and large-scale magnetic helicities have reversed signs. With realistic simulations of the solar corona above an active region now being…
Velocity-resolved [{\rm{C}}\,{\rm{II}}] Emission from Cold Diffuse Clouds in the Interstellar Medium
Neufeld, David A.; Wolfire, Mark G.; Simon, Robert +3 more
We have combined emission from the 158 µm fine structure transition of C+ observed with the GREAT and upGREAT instruments on SOFIA with 21 cm absorption spectra and visual extinction to characterize the diffuse interstellar clouds found along the lines of sight. The weak [C II] emission is consistent in velocity and line width wit…
Solar Coronal Modeling by Path-conservative HLLEM Riemann Solver
Feng, Xueshang; Wei, Fengsi; Li, Caixia +3 more
In this paper, we employ a path-conservative HLLEM finite-volume method (FVM) to solve the solar wind magnetohydrodynamics (MHD) systems of extended generalized Lagrange multiplier (EGLM) formulation with Galilean invariance (G-EGLM MHD equations). The governing equations of single-fluid solar wind plasma MHD are advanced by using a one-step MUSCL…
Nonlinear Effects in Three-minute Oscillations of the Solar Chromosphere. II. Measurement of Nonlinearity Parameters at Different Atmospheric Levels
Chae, Jongchul; Cho, Kyuhyoun; Song, Donguk +1 more
Recent theoretical studies suggest that the nonlinearity of three-minute velocity oscillations at each atmospheric level can be quantified by the two independent parameters—the steepening parameter and the velocity amplitude parameter. For the first time, we measured these two parameters at different atmospheric levels by analyzing a set of spectr…
The Strong Gravitationally Lensed Herschel Galaxy HLock01: Optical Spectroscopy Reveals a Close Galaxy Merger with Evidence of Inflowing Gas
Marques-Chaves, Rui; Clements, David L.; Cabrera-Lavers, Antonio +15 more
The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z = 2.9574 ± 0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total a…
Current Sheets in the Wake of an Eruption of Two Crossing Filaments
Zhang, Jun; Yang, Jiayan; Li, Leping +1 more
Employing Solar Dynamic Observatory/Atmospheric Imaging Assembly (AIA) multi-wavelength images, we study an eruption of two crossing filaments, and report for the first time the current sheets (CSs) connecting the lower flare ribbons and the upper erupting filaments. On 2014 July 8, two crossing filaments are observed in the NOAA active region 121…
High-resolution Spectroscopic Abundances of Red Giant Branch Stars in NGC 6584 and NGC 7099
Chaboyer, Brian; O'Malley, Erin M.
We obtain high-resolution spectra of red giant branch stars in NGC 6584 and NGC 7099 to perform a detailed abundance analysis. We confirm cluster membership for these stars based on consistent radial velocities measured in this study and small pixel offsets between the observations of Sarajedini et al. and Piotto et al. We find mean metallicities …