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Discovery of New δ Scuti Stars
Kιrmιzιtaş, Ö.; Çavuş, S.; Aliçavuş, F. Kahraman
—Pulsating stars are remarkable objects for stellar astrophysics. Their pulsation frequencies allow us to probe the internal structure of stars. One of the most known groups of pulsating stars is
Bayesian Inference of Globular Cluster Properties Using Distribution Functions
Webb, Jeremy J.; Eadie, Gwendolyn M.; Rosenthal, Jeffrey S.
We present a Bayesian inference approach to estimating the cumulative mass profile and mean-squared velocity profile of a globular cluster (GC) given the spatial and kinematic information of its stars. Mock GCs with a range of sizes and concentrations are generated from lowered-isothermal dynamical models, from which we test the reliability of the…
Dissipation of hydromagnetic waves in the viscous polytropic zone of the solar wind including FLR corrections, ohmic diffusion, and the Hall effect
Fok, Mei-Ching; Desta, Ephrem Tesfaye; Prajapati, Ram Prasad +1 more
In the polytropic zone of the solar wind, we have used the generalized polytrope pressure laws to investigate the dissipation of hydromagnetic waves and pressure-anisotropy-driven fluid instabilities in magnetized viscous plasmas, including finite Larmor radius (FLR) corrections and non-ideal magnetohydrodynamic (MHD) effects. The modified dispers…
Spatio-temporal bands of coronal bright points and their relation to solar torsional oscillations
Tsinamdzgvrishvili, Tamar; Chargeishvili, B. B.; Shergelashvili, Bidzina M. +1 more
Using automatic processing of daily FITS files from SOHO_EIT, we studied the temporal evolution of the latitudinal distribution of bright coronal points from 1995 to 2020. The study revealed homogeneous and inhomogeneous components of the latitudinal distribution. The homogeneous component has cyclical variations with a significant phase shift com…
X-Ray Redshifts of Obscured Chandra Source Catalog Active Galactic Nuclei
Buchner, Johannes; Peca, Alessandro; Cappelluti, Nico +2 more
We have computed obscured active galactic nuclei (AGN) redshifts using the XZ method, adopting a broad treatment in which we employed a wide-ranging data set and worked primarily at the XZ counts sensitivity threshold, culminating with a redshift catalog containing 121 sources that lack documented redshifts. We considered 363 obscured AGN from the…
The Open Cluster Chemical Abundances and Mapping Survey. V. Chemical Abundances of CTIO/Hydra Clusters Using The Cannon
Donor, John; Frinchaboy, Peter M.; Chojnowski, S. D. +2 more
Open clusters are key chemical and age tracers of Milky Way evolution. While open clusters provide significant constraints on galaxy evolution, their use has been limited due to discrepancies in measuring abundances from different studies. We analyze medium-resolution (R ~ 19,000) Cerro Tololo Inter-American Observatory/Hydra spectra of giant star…
Rings and arcs around evolved stars - III. Physical conditions of the ring-like structures in the planetary nebula IC 4406 revealed by MUSE
Guerrero, M. A.; Toalá, J. A.; Ramos-Larios, G. +2 more
We present the analysis of Very Large Telescope Multi Unit Spectroscopic Explorer (MUSE) observations of the planetary nebula (PN) IC 4406. MUSE images in key emission lines are used to unveil the presence of at least five ring-like structures north and south of the main nebula of IC 4406. MUSE spectra are extracted from the rings to unambiguously…
Hybrid Simulations of the Cusp and Dayside Magnetosheath Dynamics Under Quasi-Radial Interplanetary Magnetic Fields
Lavraud, B.; Zou, Y.; Chen, L. -J. +2 more
Under quasi-radial interplanetary magnetic fields (IMF), foreshock turbulence can have an impact on the magnetosheath and cusps depending on the location of the quasi-parallel shock. We perform three-dimensional simulations of Earth's dayside magnetosphere using the hybrid code HYPERS, and compare northward and southward quasi-radial IMF configura…
Reconciling Observational Challenges to the Impulsive-Piston Shock-Excitation Scenario. I. Kinematic Challenges
Grechnev, V. V.; Kiselev, V. I.; Uralov, A. M.
Until now, there is no consensus on the origin of coronal shock waves. Questions also remain about the patterns that govern the propagation of the presumably related disturbances observed in the extreme ultraviolet (EUV waves). We present arguments in favor of the initial excitation of the waves by the impulsive acceleration of erupting structures…
A low-frequency pilot survey of southern H II regions in the vela constellation
Bourke, Tyler L.; Dickey, John M.; Wong, O. Ivy +3 more
Atomic ionized regions with strong continuum emission are often associated with regions of high-mass star formation and low-frequency (<2 GHz) observations of these regions are needed to help build star formation models. The region toward the Vela Supernova Remnant is particularly interesting as it is a complex structure of recent supernova exp…