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Restoration of T80-S telescope's images using neural networks
Roth, Martin M.; Bernardi, Rafael L.; Berdja, Amokrane +2 more
Convolutional neural networks (CNNs) have been used for a wide range of applications in astronomy, including for the restoration of degraded images using a spatially invariant point spread function (PSF) across the field of view. Most existing development techniques use a single PSF in the deconvolution process, which is unrealistic when spatially…
Updated Elements of Variable Stars in Sagittarius
Lemke, W.
High-precision Mg abundances in the metal-rich Galactic disc: chemodynamical relations and comparison with chemical evolution models
Recio-Blanco, A.; Kordopatis, G.; Palla, M. +2 more
The [Mg/Fe] abundance ratios are a fundamental fossil signature in Galactic archaeology for tracing the chemical evolution of disc stellar populations. High-precision chemical abundances, accurate stellar ages, distances, and dynamical data, together with their direct comparison with theoretical models, are crucial to infer the Milky Way formation…
A Comparison of Co-temporal Vector Magnetograms Obtained with HMI/SDO and SP/Hinode
Zhang, Mei; Zhang, Haocheng; Jiang, Chengqing
Accurate measurement of magnetic fields is very important for understanding the formation and evolution of solar magnetic fields. Currently, there are two types of solar magnetic field measurement instruments: filter-based magnetographs and Stokes polarimeters. The former gives high temporal resolution magnetograms and the latter provides more acc…
Model-independent periodogram for scanning astrometry
Zucker, S.; Binnenfeld, A.; Shahaf, S.
We present a new periodogram for the periodicity detection in one-dimensional time-series data from scanning astrometry space missions such as HIPPARCOS or Gaia. The periodogram is non-parametric and does not rely on a full or approximate orbital solution. Since no specific properties of the periodic signal are assumed, the method is expected to b…
Photometric calibration of M-dwarf metallicity using Bayesian inference
Caballero, J. A.; Montes, D.; Duque-Arribas, C. +3 more
Metallicity has remained as a challenging parameter when characterizing M-type dwarf stars due to difficulties in the analysis of their spectra, dominated by molecular features, but it is required in multiple areas of astrophysics, for example to constrain theoretical stellar models or guide exoplanet searches. In order to estimate the metallicity…
Multifilter Time-series Observations of Eleven Blue Short-period ATLAS Variable Stars
Kniazev, A.; Schaffenroth, V.; Koen, C.
Eleven periodic variable stars were observed photometrically through two to four filters from the set UBVR C I C . Phase-folded data for each star cover full cycles of variation. Spectral energy distributions, based on absolute photometry extracted from the literature, are used to inform models of the stars. The stars incl…
HIP 67506 C: MagAO-X confirmation of a new low-mass stellar companion to HIP 67506 A
Weinberger, Alycia J.; Guyon, Olivier; Close, Laird M. +17 more
We report the confirmation of HIP 67506 C, a new stellar companion to HIP 67506 A. We previously reported a candidate signal at 2λ/D (240 mas) in L' in MagAO/Clio imaging using the binary differential imaging technique. Several additional indirect signals showed that the candidate signal merited follow-up: significant astrometric accele…
Search strategies for supermassive stars in young clusters and application to nearby galaxies
Schaerer, D.; Marques-Chaves, R.; Usher, C. +4 more
Context. Supermassive stars (SMSs) with masses M ≳ 103 − 104 M⊙ formed by runaway collisions in young, massive, and dense star clusters have been invoked as a possible solution to the problem of the presence of multiple stellar populations and peculiar abundance patterns observed in globular clusters (GCs). However…
Langmuir waves associated with magnetic holes in the solar wind
André, M.; Maksimovic, M.; Souček, J. +6 more
Context. Langmuir waves (electrostatic waves near the electron plasma frequency) are often observed in the solar wind and may play a role in the energy dissipation of electrons. The largest amplitude Langmuir waves are typically associated with type II and III solar radio bursts and planetary foreshocks. In addition, Langmuir waves not related to …