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Gaia EDR3 Proper Motions of Milky Way Dwarfs. II Velocities, Total Energy, and Angular Momentum
Hammer, Francois; Babusiaux, Carine; Bonifacio, Piercarlo +5 more
Here we show that precise Gaia EDR3 proper motions have provided robust estimates of 3D velocities, angular momentum, and total energy for 40 Milky Way dwarfs. The results are statistically robust and are independent of the Milky Way mass profile. Dwarfs do not behave like long-lived satellites of the Milky Way because of their excessively large v…
Forward Modeling of Solar Coronal Magnetic-field Measurements Based on a Magnetic-field-induced Transition in Fe X
Chen, Yajie; Tian, Hui; Deng, Yuanyong +6 more
It was recently proposed that the intensity ratios of several extreme ultraviolet spectral lines from Fe X ions can be used to measure the solar coronal magnetic field based on magnetic-field-induced transition (MIT) theory. To verify the suitability of this method, we performed forward modeling with a three-dimensional radiation magnetohydrodynam…
Ultra-steep-spectrum Radio "Jellyfish" Uncovered in A2877
Johnston-Hollitt, Melanie; Hodgson, Torrance; Bartalucci, Iacopo +3 more
We report on the discovery of a mysterious ultra-steep-spectrum (USS) synchrotron source in the galaxy cluster A2877. We have observed the source with the Murchison Widefield Array at five frequencies across 72-231 MHz and found the source to exhibit strong spectral curvature over this range, as well as the steepest known spectra of a synchrotron …
IGM transmission bias for z ≥ 2.9 Lyman continuum detected galaxies
Ryan-Weber, E. V.; Rafelski, M.; Bassett, R. +4 more
Understanding the relationship between the underlying escape fraction of Lyman continuum (LyC) photons (fesc) emitted by galaxies and measuring the distribution of observed fesc values at high redshift is fundamental to the interpretation of the reionization process. In this paper, we perform a statistical exploration of the …
Asteroid spectral taxonomy using neural networks
Muinonen, K.; Penttilä, A.; Hietala, H.
Aims: We explore the performance of neural networks in automatically classifying asteroids into their taxonomic spectral classes. We particularly focus on what the methodology could offer the ESA Gaia mission.
Methods: We constructed an asteroid dataset that can be limited to simulating Gaia samples. The samples were fed into a custom-de…
Metallicities and ages for 35 star clusters and their surrounding fields in the Small Magellanic Cloud
Piatti, A. E.; Pych, W.; Narloch, W. +13 more
Aims: In this work we study 35 stellar clusters in the Small Magellanic Cloud (SMC) in order to provide their mean metallicities and ages. We also provide mean metallicities of the fields surrounding the clusters.
Methods: We used Strömgren photometry obtained with the 4.1 m SOAR telescope and take advantage of (b − y) and m1 colors for …
NGTS-19b: a high-mass transiting brown dwarf in a 17-d eccentric orbit
Jackman, James A. G.; Wheatley, Peter J.; Bayliss, Daniel +34 more
We present the discovery of NGTS-19b, a high-mass transiting brown dwarf discovered by the Next Generation Transit Survey. We investigate the system using follow-up photometry from the South African Astronomical Observatory, as well as sector 11 Transiting Exoplanet Survey Satellite data, in combination with radial velocity measurements from the C…
Classification of 4XMM-DR9 sources by machine learning
Wu, Xue-Bing; Zhang, Yanxia; Zhao, Yongheng
The ESA's X-ray Multi-mirror Mission (XMM-Newton) created a new high-quality version of the XMM-Newton serendipitous source catalogue, 4XMM-DR9, which provides a wealth of information for observed sources. The 4XMM-DR9 catalogue is correlated with the Sloan Digital Sky Survey (SDSS) DR12 photometric data base and the AllWISE data base; we then get…
A new approach to spectroscopic phase curves. The emission spectrum of WASP-12b observed in quadrature with HST/WFC3
Désert, J. -M.; Stevenson, K. B.; Parmentier, V. +2 more
We analyse emission spectra of WASP-12b from a partial phase curve observed over three epochs with the Hubble Space Telescope, covering eclipse, quadrature, and transit, respectively. As the 1.1-day period phase curve was only partially covered over three epochs, traditional methods to extract the planet flux and instrument systematic errors canno…
Cold Traps of Hypervolatiles in the Protosolar Nebula at the Origin of the Peculiar Composition of Comet C/2016 R2 (PanSTARRS)
Mousis, Olivier; Aguichine, Artyom; Bouquet, Alexis +4 more
Recent observations of the long-period comet C/2016 R2 (PanSTARRS; hereafter R2) indicate an unusually high N2/CO abundance ratio, typically larger than ∼0.05, and at least 2-3 times higher than the one measured in 67P/Churyumov-Gerasimenko. Another striking compositional feature of this comet is its heavy depletion in H2O (H…