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The chemical diversity of the metal-poor Milky Way
Hawkins, Keith; Jofré, Paula; Yates, Robert M. +2 more
We present a detailed study of the chemical diversity of the metal-poor Milky Way using data from the GALAH DR3 survey. Considering 17 chemical abundances relative to iron ([X/Fe]) for 9923 stars, we employ principal component analysis (PCA) and extreme deconvolution (XD) to identify 10 distinct stellar groups. This approach, free from chemical or…
Undersampling effects on observed periods of coronal oscillations
Gao, Yuhang; Van Doorsselaere, Tom; Lim, Daye +3 more
Context. Recent observations of decayless transverse oscillations have revealed two branches in the relationship between period and loop length. One is a linear relationship, interpreted as a standing mode, while the other shows almost no correlation and has not yet been interpreted conclusively. Aims. We investigated the undersampling effect on o…
The Polstar UV spectropolarimetry mission
Ignace, R.; Scowen, P.
The Polstar small explorer concept is for an ultraviolet (UV) spectropolarimetry space telescope mission with a focus on massive star astrophysics. The instrument waveband will be from 115 nm to 286 nm for spectroscopy, and from 122 nm to 286 nm for polarimetry. All four Stokes parameters, I, Q, U, and V , will be measured at a resolving power of …
Deep Entry of Low-Energy Ions Into Mercury's Magnetosphere: BepiColombo Mio's Third Flyby Observations
Persson, Moa; Saito, Yoshifumi; Delcourt, Dominique +15 more
Although solar wind-driven convection is expected to dominate magnetospheric circulation at Mercury, its exact pattern remains poorly characterized by observations. Here we present BepiColombo Mio observations during the third Mercury flyby indicative of convection-driven transport of low-energy dense ions into the deep magnetosphere. During the f…
Planet-star interactions with precise transit timing: IV. Probing the regime of dynamical tides for GK host stars
Casanova, V.; Fernández, M.; Maciejewski, G. +3 more
Context. Giant exoplanets on 1-3 day orbits, known as ultra-hot Jupiters, induce detectable tides in their host stars. The energy of those tides dissipates at a rate related to the properties of the stellar interior. At the same time, a planet loses its orbital angular momentum and spirals into the host star. The decrease in the orbital period is …
Nonparametric Bayesian reconstruction of Galactic magnetic fields using information field theory: The inclusion of line-of-sight information in ultrahigh-energy cosmic-ray backtracing
Enßlin, Torsten; Edenhofer, Gordian; Pavlidou, Vasiliki +4 more
Context. Ultrahigh-energy cosmic rays (UHECRs) are charged particles with energies surpassing 1018 eV. Their sources remain elusive because they are obscured by deflections caused by the Galactic magnetic field (GMF). This challenge is further complicated by our limited understanding of the 3D structure of the GMF because current GMF ob…
The Plane Quasar Survey: First Data Release
Tchernyshyov, Kirill; Zheng, Yong; Werk, Jessica +4 more
We present a sample of 305 QSO candidates having ∣b∣ < 30°, the majority with GALEX magnitudes near-UV < 18.75. To generate this sample, we apply UV–IR color selection criteria to photometric data from the Ultraviolet Galactic Plane Survey as part of GALEX-CAUSE, the Million Quasars Catalog, Gaia DR2, and Pan-STARRS DR1. 165 of these 305 can…
Chemical evolution models: the role of type Ia supernovae in the α-elements over iron relative abundances and their variations in time and space
Galbany, L.; Monteiro, H.; Mollá, M. +6 more
The role of type Ia supernovae (SN Ia), mainly the delay time distributions (DTDs) determined by the binary systems, and the yields of elements created by different explosion mechanisms, are studied by using the MULCHEM chemical evolution model applied to our Galaxy. We explored 15 DTDs and 12 tables of elemental yields produced by different SN Ia…
Accretion properties of a low-mass active galactic nucleus: UGC 6728
Safi-Harb, Samar; Naik, Sachindra; Chatterjee, Arka +4 more
We present a comprehensive analysis of approximately 15 years (2006-2021) of X-ray observations of UGC 6728, a low-mass bare AGN, for the first time. Our study encompasses both spectral and temporal aspects of this source. The spectral properties of this source are studied using various phenomenological and physical models. We conclude that (a) th…
The interaction of a large-scale nuclear wind with the high-velocity H II region G0.17+0.15
Yusef-Zadeh, F.; Wardle, M.; Rudnick, L. +4 more
We investigate the nature of a Galactic Centre source, G0.17+0.15, lying along the northern extension of the radio arc near l ~ 0.2°. G0.17+0.15 is an H II region located towards the eastern edge of the radio bubble, embedded within the highly polarized Galactic Centre eastern lobe where a number of radio filaments appear to cross through the H II…