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Near-Earth Sub-Alfvénic Solar Winds: Interplanetary Origins and Geomagnetic Impacts
Hajra, Rajkumar; Tsurutani, Bruce T.
The near-Earth solar wind is in general super-Alfvénic and supermagnetosonic. Using all available near-Earth solar wind measurements between 1973 and 2020, we identified 30 intervals with sub-Alfvénic solar winds. The majority (83%) of the events occurred within interplanetary coronal mass ejection magnetic clouds (MCs)/driver gases. These MC sub-…
Deep learning-based super-resolution and de-noising for XMM-newton images
Valtchanov, Ivan; Verdugo, Eva; Lieu, Maggie +6 more
The field of artificial intelligence based image enhancement has been rapidly evolving over the last few years and is able to produce impressive results on non-astronomical images. In this work, we present the first application of Machine Learning based super-resolution (SR) and de-noising (DN) to enhance X-ray images from the European Space Agenc…
Quasi-periodic Accelerations of Energetic Particles during a Solar Flare
Chen, Wei; Li, Dong
We report the observation of nonstationary quasi-periodic pulsations (QPPs) in high-energy particles during the impulsive phase of an X4.8 flare on 2002 July 23 (SOL2002-07-23T00:35). The X4.8 flare was simultaneously measured by the Reuven Ramaty High Energy Solar Spectroscopic Imager, Nobeyama Radio Polarimeters, and Nobeyama Radioheliograph. Th…
zELDA: fitting Lyman alpha line profiles using deep learning
Gronke, Max; Saito, Shun; Bonoli, Silvia +2 more
We present zELDA (redshift Estimator for Line profiles of Distant Lyman Alpha emitters), an open source code to fit Lyman α (Ly α) line profiles. The main motivation is to provide the community with an easy to use and fast tool to analyse Ly α line profiles uniformly to improve the understating of Ly α emitting galaxies. zELDA is based on line pro…
Future constraints on primordial black holes from XGIS-THESEUS
Ghosh, Diptimoy; Sachdeva, Divya; Singh, Praniti
Current observations allow primordial black holes (PBHs) in asteroid mass range 1017- 1022 g to constitute the entire dark matter energy density (barring a small mass range constrained by 21-cm observations). In this work, we explore the possibility of probing PBHs with masses 1017- 1019 g via the upcomi…
Dark and luminous mass components of Omega Centauri from stellar kinematics
Zivick, Paul; Strigari, Louis E.; Evans, Addy J.
We combine proper motion data from Gaia EDR3 and HST with line-of-sight velocity data to study the stellar kinematics of the ω Cen globular cluster. Using a steady-state, axisymmetric dynamical model, we measure the distribution of both the dark and luminous mass components. Assuming both Gaussian and Navarro-Frenk-White mass profiles, depending o…
Chemodynamical Signatures of Bar Resonances in the Galactic Disk: Current Data and Future Prospects
Fragkoudi, Francesca; Wheeler, Adam; Ness, Melissa +2 more
The Galactic disk exhibits complex chemical and dynamical substructure thought to be induced by the bar, spiral arms, and satellites. Here, we explore the chemical signatures of bar resonances in action and velocity space, and characterize the differences between the signatures of corotation (CR) and higher-order resonances using test particle sim…
From ridges to manifolds: 3D characterization of the moving groups in the Milky Way disc
Antoja, T.; Bernet, M.; Monari, G. +4 more
Context. The details of the effect of the bar and spiral arms on the disc dynamics of the Milky Way are still unknown. The stellar velocity distribution in the solar neighbourhood displays kinematic substructures, which are possibly signatures of these processes and of previous accretion events. With the Gaia mission, more details of these signatu…
Dynamically Tagged Groups of Metal-poor Stars. II. The Radial Velocity Experiment Data Release 6
Huang, Yang; Beers, Timothy C.; Placco, Vinicius M. +2 more
Orbital characteristics based on Gaia Early Data Release 3 astrometric parameters are analyzed for ~8000 metal-poor stars ([Fe/H] ≤ -0.8) compiled from the Radial Velocity Experiment (RAVE) Data Release 6. Selected as metal-poor candidates based on broadband photometry, RAVE collected moderate-resolution (R ~ 7500) spectra in the region of the Ca …
Quasars with large proper motions: A selection from the LQAC-5 catalogue combined with Gaia EDR3. Focusing on astrometric and photometric properties
Zacharias, N.; Barache, C.; Lambert, S. +5 more
Context. Thanks to the cross-identification between the Gaia EDR3 (E-Data Release 3) catalogue and the quasars' compiled catalogue LQAC-5 (Large Quasar Astrometric Catalogue-5), accurate astrometric parameters as well as photometric measurements were available for a set of 416 113 quasars.
Aims: After analysing the astrometric and photometric…