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Ultraluminous high-redshift quasars from SkyMapper - II. New quasars and the bright end of the luminosity function
Fan, Xiaohui; Wolf, Christian; Lai, Samuel +5 more
We search for ultraluminous Quasi-Stellar Objects (QSOs) at high redshift using photometry from the SkyMapper Southern Survey Data Release 3 (DR3), in combination with 2MASS, VHS DR6, VIKING DR5, AllWISE, and CatWISE2020, as well as parallaxes and proper motions from Gaia DR2 and eDR3. We report 142 newly discovered Southern QSOs at 3.8 < z <…
The R-Process Alliance: Abundance Universality among Some Elements at and between the First and Second R-Process Peaks
Beers, Timothy C.; Placco, Vinicius M.; Holmbeck, Erika M. +11 more
We present new observational benchmarks of rapid neutron-capture process (r-process) nucleosynthesis for elements at and between the first (A ~ 80) and second (A ~ 130) peaks. Our analysis is based on archival ultraviolet and optical spectroscopy of eight metal-poor stars with Se (Z = 34) or Te (Z = 52) detections, whose r-process enhancement vari…
Hubble Asteroid Hunter. II. Identifying strong gravitational lenses in HST images with crowdsourcing
Bhatawdekar, Rachana; Merín, Bruno; Kruk, Sandor +3 more
Context. The Hubble Space Telescope (HST) archives constitute a rich dataset of high-resolution images to mine for strong gravitational lenses. While many HST programmes specifically target strong lenses, they can also be present by coincidence in other HST observations.
Aims: Our aim is to identify non-targeted strong gravitational lenses, w…
Interpretable Machine Learning to Forecast SEP Events for Solar Cycle 23
Chen, Yang; Gombosi, Tamas; Zhao, Lulu +3 more
We use machine learning methods to predict whether an active region (AR) which produces flares will lead to a solar energetic particle (SEP) event using Space-Weather Michelson Doppler Imager (MDI) Active Region Patches (SMARPs). This new data product is derived from maps of the solar surface magnetic field taken by the MDI aboard the Solar and He…
In Situ Observations of Interstellar Pickup Ions from 1 au to the Outer Heliosphere
McComas, D. J.; Möbius, E.; Pogorelov, N. V. +5 more
Interstellar pickup ions are an ubiquitous and thermodynamically important component of the solar wind plasma in the heliosphere. These PUIs are born from the ionization of the interstellar neutral gas, consisting of hydrogen, helium, and trace amounts of heavier elements, in the solar wind as the heliosphere moves through the local interstellar m…
A Transiting, Temperate Mini-Neptune Orbiting the M Dwarf TOI-1759 Unveiled by TESS
Trifonov, Trifon; Stock, Stephan; Henning, Thomas +66 more
We report the discovery and characterization of TOI-1759 b, a temperate (400 K) sub-Neptune-sized exoplanet orbiting the M dwarf TOI-1759 (TIC 408636441). TOI-1759 b was observed by TESS to transit in Sectors 16, 17, and 24, with only one transit observed per sector, creating an ambiguity regarding the orbital period of the planet candidate. Groun…
V1298 Tau with TESS: Updated Ephemerides, Radii, and Period Constraints from a Second Transit of V1298 Tau e
Foreman-Mackey, Daniel; Livingston, John H.; Montet, Benjamin T. +3 more
V1298 Tau is a young (20-30 Myr) solar-mass K star hosting four transiting exoplanets with sizes between 0.5 and 0.9 R J. Given the system's youth, it provides a unique opportunity to understand the evolution of planetary radii at different separations in the same stellar environment. V1298 Tau was originally observed 6 yr ago during K2…
A comprehensive search for the radio counterpart of GW190814 with the Australian Square Kilometre Array Pathfinder
Gromadzki, M.; Wang, Z.; Buckley, D. A. H. +13 more
We present results from a search for the radio counterpart to the possible neutron star-black hole merger GW190814 with the Australian Square Kilometre Array Pathfinder. We have carried out 10 epochs of observation spanning 2-655 d post-merger at a frequency of 944 MHz. Each observation covered 30 deg2, corresponding to 87 per cent of t…
A Census of the Low Accretors. I. The Catalog
Calvet, Nuria; Briceño, César; Hernández, Jesús +2 more
Observations have shown that the disk frequency and the fraction of accreting pre-main-sequence stars decrease with the age of the population and that some stars appear to have disks while their accretion has stopped. Still, it is unclear how disk-bearing stars stop their accretion. To provide insight into the last stages of accretion in low-mass …
The earliest O-type eclipsing binary in the Small Magellanic Cloud, AzV 476: A comprehensive analysis reveals surprisingly low stellar masses
Hamann, W. -R.; Oskinova, L. M.; Sander, A. A. C. +7 more
Context. Massive stars at low metallicity are among the main feedback agents in the early Universe and in present-day star forming galaxies. When in binaries, these stars are potential progenitors of gravitational-wave events. Knowledge of stellar masses is a prerequisite to understanding evolution and feedback of low-metallicity massive stars.