Search Publications
Estimating Stellar Atmospheric Parameters and [α/Fe] for LAMOST O-M-type Stars Using a Spectral Emulator
Luo, A. -Li; Li, Yin-Bi; Kong, Xiao +7 more
In this paper, we developed a spectral emulator based on the Mapping Nearby Galaxies at Apache Point Observatory Stellar Library (MaStar) and a grouping optimization strategy to estimate effective temperature (T eff), surface gravity (log g), metallicity ([Fe/H]), and the abundance of alpha elements with respect to iron ([α/Fe]) for O-M…
Mass segregation and velocity dispersion as evidence for a dark star cluster
Kroupa, Pavel; Pflamm-Altenburg, Jan; Wu, Wenjie
A dark star cluster (DSC) is a system in which the cluster potential is dominated by stellar remnants, such as black holes and neutron stars having larger masses than the long-lived low-mass stars. Due to mass segregation, these remnants are located in the central region of the cluster and form a dark core. We expect that at a few kpc from the Gal…
Alpha Element Populations Among Local Halo Stars
Laird, John B.; Reinhard, Michael V.
Previous studies have shown that the halo of the Milky Way galaxy is made up of two distinct stellar populations, one from dissipative collapse and the other accreted. Elemental abundances with small relative uncertainties along with kinematics are determined for 20 local halo stars in the metallicity range -2.2 ≤ [Fe/H] ≤-1.2. Stars with metallic…
Magnetic field of the roAp star KIC 10685175: Observations versus theory
Zhang, Huawei; Cang, Tianqi; Fu, Jianning +5 more
Context. KIC 10685175 is a roAp star whose polar magnetic field is predicted to be 6 kG through a nonadiabatic axisymmetric pulsation theoretical model. Aims. In this work, we aim to measure the magnetic field strength of KIC 10685175 using high-resolution spectropolarimetric observations, and compare it with the one predicted by the theoretical m…
The Thermal Structure and Composition of Jupiter's Great Red Spot From JWST/MIRI
de Pater, Imke; Wong, Michael H.; Fletcher, Leigh N. +15 more
Jupiter's Great Red Spot (GRS) was mapped by the James Webb Space Telescope (JWST)/Mid-Infrared Instrument (4.9-27.9 µm) in July and August 2022. These observations took place alongside a suite of visual and infrared observations from; Hubble, JWST/NIRCam, Very Large Telescope/VISIR and amateur observers which provided both spatial and tempo…
Investigating the Impact of Atomic Data Uncertainties on the Measured Physical Parameters of the Perseus Galaxy Cluster
Raymond, John; Foster, Adam R.; Smith, Randall +4 more
Accurate atomic data and plasma models are essential for interpreting the upcoming high-quality spectra from missions like XRISM and Athena. Estimating physical quantities, like temperature, abundance, turbulence, and the resonance scattering factor, is highly dependent on the underlying atomic data. We use the AtomDB tool variableapec to estimate…
New Herbig-Haro objects associated with embedded sources
Movsessian, T. A.; Andreasyan, H. R.; Magakian, T. Yu +1 more
We continue to present the results of the Byurakan Narrow Band Imaging Survey (BNBIS). The main goal of this survey is to search for Herbig-Haro (HH) objects and jets in Galactic dark clouds. In this work we present the results of the search in the vicinity of infrared sources that are bright in the WISE survey and embedded in the dark clouds. The…
On the Response of Protons to Dynamical Reconfigurations of Mercury's Magnetosphere
Hadid, L. Z.; Aizawa, S.; Delcourt, D.
We examine the dynamics of protons during tail-like to dipole-like reconfigurations of Mercury's magnetosphere. Such reconfigurations that frequently occur in the highly dynamical Hermean environment are accompanied by induced electric fields leading to short-lived convection enhancements. Using test particle calculations, we show that, under the …
Complex K: Supernova Origin of Anomalous-velocity H I Structure
Jorissen, A.; Verschuur, G. L.; Schmelz, J. T. +1 more
We address one of the lingering mysteries of high-velocity clouds: If the anomalous negative velocities are the result of the approaching gas from old supernovae, then where are the receding counterparts of the expanding shells? Data from the λ-21 cm Galactic neutral hydrogen EBHIS survey (Winkel et al.) show multiple signatures of the expanding s…
Revisiting the Velocity Dispersion–Size Relation in Molecular Cloud Structures
Chen, Zhiwei; Zhang, Shiyu; Su, Yang +10 more
Structures in molecular ISM are observed to follow a power-law relation between the velocity dispersion and spatial size, known as Larson's first relation, which is often attributed to the turbulent nature of molecular ISM and imprints the dynamics of molecular cloud structures. Using the 13CO (J = 1–0) data from the Milky Way Imaging S…