Search Publications
Mixed Modes and Asteroseismic Surface Effects. II. Subgiant Systematics
Bieryla, Allyson; Latham, David W.; Basu, Sarbani +3 more
Models of solar-like oscillators yield acoustic modes at different frequencies than would be seen in actual stars possessing identical interior structure, due to modeling error near the surface. This asteroseismic "surface term" must be corrected when mode frequencies are used to infer stellar structure. Subgiants exhibit oscillations of mixed aco…
A Distance-deviation Consistency and Model-independent Method to Test the Cosmic Distance-Duality Relation
Fang, Guanwen; Zhou, Chichun; Hu, Jian +2 more
A distance-deviation consistency and model-independent method to test the cosmic distance-duality relation (CDDR) is provided. This method is worthy of attention for two reasons. First, a distance-deviation consistency method is used to pair subsamples: instead of pairing subsamples with redshift deviations smaller than a value of, say, $\left|{\r…
Kinetic Alfvén Waves in Space Plasma Environment with κ-electrons
Lakhina, G. S.; Singh, S. V.; Barik, K. C.
A resonant instability of kinetic Alfvén waves (KAWs) driven by ion beam is discussed through a theoretical model encompassing Maxwellian background ions and beam ions and non-Maxwellian κ-electrons. The ion beam velocity alone as a source is able to excite the KAWs up to a significant growth. The non-Maxwellian parameter κ impedes the growth of K…
Resolved Nuclear Kinematics Link the Formation and Growth of Nuclear Star Clusters with the Evolution of Their Early- and Late-type Hosts
Böker, Torsten; Neumayer, Nadine; Emsellem, Eric +7 more
We present parsec-scale kinematics of 11 nearby galactic nuclei, derived from adaptive-optics assisted integral-field spectroscopy at (near-infrared) CO band-head wavelengths. We focus our analysis on the balance between ordered rotation and random motions, which can provide insights into the dominant formation mechanism of nuclear star clusters (…
Electron Densities in the Solar Corona Measured Simultaneously in the Extreme Ultraviolet and Infrared
Del Zanna, Giulio; Dudík, Jaroslav; Dzifčáková, Elena +5 more
Accurate measurements of electron density are critical for determination of the plasma properties in the solar corona. We compare the electron densities diagnosed from Fe XIII lines observed by the Extreme-Ultraviolet Imaging Spectrometer (EIS) onboard the Hinode mission with the near-infrared (NIR) measurements provided by the ground-based Corona…
The Center of Expansion and Age of the Oxygen-rich Supernova Remnant 1E 0102.2-7219
Drout, Maria R.; Blair, William P.; Margutti, Raffaella +8 more
We present new proper-motion measurements of optically emitting oxygen-rich knots of supernova remnant 1E 0102.2-7219 (E0102), which are used to estimate the remnant's center of expansion and age. Four epochs of high-resolution Hubble Space Telescope images spanning 19 yr were retrieved and analyzed. We found a robust center of expansion of α = 1<…
Analysis of the Unconcentrated Background of the EPIC pn Camera on Board XMM-Newton
Esposito, Paolo; Tiengo, Andrea; De Luca, Andrea +8 more
Our understanding of the background of the EPIC/pn camera on board XMM-Newton is incomplete. This affects the study of extended sources and can influence the predictions of the expected background of future X-ray missions, such as the Advanced Telescope for High Energy Astrophysics (ATHENA). Here we provide new results based on the analysis of the…
Acceleration of Ring Current Protons Driven by Magnetosonic Waves: Comparisons of Test Particle Simulations with Quasilinear Calculations
Fu, Song; Ge, Yasong
Wave-particle interactions play important roles in local acceleration and pitch angle scattering loss of charged particle dynamics in astrophysics and space physics, and energy transfer between plasma waves and particles is a key problem in plasma physics. Using full relativistic test particle simulations, we quantitatively evaluate the magnetoson…
Star Formation Histories from Spectral Energy Distributions and Color-magnitude Diagrams Agree: Evidence for Synchronized Star Formation in Local Volume Dwarf Galaxies over the Past 3 Gyr
McQuinn, Kristen B. W.; Johnson, Benjamin D.; Gawiser, Eric +6 more
Star formation histories (SFHs) reveal physical processes that influence how galaxies form their stellar mass. We compare the SFHs of a sample of 36 nearby (D ⪅ 4 Mpc) dwarf galaxies from the ACS Nearby Galaxy Survey Treasury (ANGST), inferred from the color-magnitude diagrams (CMDs) of individually resolved stars in these galaxies, with those rec…
Blow-away in the Extreme Low-mass Starburst Galaxy Pox 186
Scarlata, Claudia; Jaskot, Anne; Skillman, Evan +1 more
Pox 186 is an exceptionally small dwarf starburst galaxy hosting a stellar mass of ∼105 M⊙. Undetected in H I (M < 106 M⊙) from deep 21 cm observations and with an [O III]/[O II] (5007/3727) ratio of 18.3 ± 0.11, Pox 186 is a promising candidate Lyman continuum emitter. It may be a possible analog of …