Search Publications
Observations of Outward-propagating and Mirroring of the Same Energetic Electrons by Wind
Zhao, L.; Li, G.; Yao, S. +1 more
We report an energetic electron event observed by the Wind spacecraft in which electrons were first detected to propagate away from the Sun, and subsequently detected to propagate back toward the Sun. Using the recently developed fractional velocity dispersion analysis (FVDA), the path lengths corresponding to these two sequential electron signals…
Comparison of Kinematics of Solar Eruptive Prominences and Spatial Distribution of the Magnetic Decay Index
Myshyakov, Ivan; Tsvetkov, Tsvetan
Theoretical studies of electric current instability explaining solar prominence eruptions show that the loss of equilibrium may develop in a case when the surrounding magnetic field decreases sufficiently rapidly with height. The magnetic decay index, a parameter indicating whether the external magnetic field has a configuration that may lead to a…
Testing ΛCDM with Dwarf Galaxy Morphology
Xu, Weishuang Linda; Randall, Lisa
The leading tensions to the collisionless cold dark matter (CDM) paradigm are the "small-scale controversies," discrepancies between observations at the dwarf-galactic scale, and their simulational counterparts. In this work we consider methods to infer 3D morphological information on Local Group dwarf spheroidals and test the fitness of CDM+hydro…
Relationship between Current Filaments and Turbulence During a Turbulent Reconnection
Yu, Y.; Chen, Z. Z.; Chen, F. +1 more
Both magnetic reconnection and turbulence can play crucial roles in space plasmas. The current layers, developing during magnetic reconnection, can collapse into various small-scale coherent structures, such as current filaments. These current filaments can significantly modulate the kinetic-scale turbulence. However, the quantitative correlation …
Spatially Resolved C III] λ1909 Emission in Haro 11
Hayes, Matthew; Inoue, Akio K.; Östlin, Göran +7 more
The C III] 1909 (hereafter C III]) line is the strongest ultraviolet emission line after Lyα and is therefore of interest to high-redshift studies of star-forming (SF) galaxies near the epoch of reionization. It is thought that C III] emission is strongest in galaxies with subsolar metallicity and low mass; however, spectral observations of numero…
Long-term Near-infrared Brightening of Nonvariable OH/IR Stars
Mito, Hiroyuki; Nakada, Yoshikazu; Ita, Yoshifusa +8 more
Nonvariable OH/IR stars are thought to have just left the asymptotic giant branch (AGB) phase. In this conventional picture, they must still show strong circumstellar extinction caused by the dust ejected during the AGB phase, and the extinction is expected to decrease over time because of the dispersal of the circumstellar dust after the cessatio…
Herschel 158 µm [{C} {II}}] Observations of "CO-dark" Gas in the Perseus Giant Molecular Cloud
Stanimirović, Snežana; Lee, Min-Young; Wolfire, Mark +2 more
We present observations of velocity-resolved [C II] 158 µm emission from both a dense and a more diffuse photodissociation region (PDR) in the Perseus giant molecular cloud using the Heterodyne Instrument for the Far-Infrared on board the Herschel Space Telescope. We detect [C II] emission from 80% of the total positions, with a 95% detectio…
Velocity-inverted Three-dimensional Distribution of the Gas Clouds in the Type 2 AGN NGC 1068
Kishimoto, Makoto; Miyauchi, Ryuji
Spatially resolved velocity maps at high resolutions of 1-10 pc are becoming available for many nearby active galactic nuclei (AGNs) in both optical/infrared atomic emission lines and submillimeter molecular lines. For the former, it is known that a linear relationship appears to exist between the velocity of the ionized gas clouds and the distanc…
Two Substructures in the nearby Stellar Halo Found in Gaia and RAVE
Shi, Jianrong; Ma, Jun; Du, Cuihua +4 more
We use the second Gaia data release (Gaia DR2), combined with Radial Velocity Experiment spectroscopic surveys, to identify the substructures in the nearby stellar halo. We select 3845 halo stars kinematically and chemically and determine their density distribution in energy and angular momentum space. To select the substructures from overdensitie…
Axial Asymmetry Studies in Gaia Data Release 2 Yield the Pattern Speed of the Galactic Bar
Yanny, Brian; Gardner, Susan; Hinkel, Austin
Our recent studies of axial-symmetry breaking in the nearby (d < 3 kpc) star counts are sensitive to the distortions of stellar orbits perpendicular and parallel to the orientation of the bar just within and beyond the outer Lindblad resonance (OLR) radius. Using the location of the sign flip in the left-right asymmetry in stars counts about th…