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Lensing in the Blue. II. Estimating the Sensitivity of Stratospheric Balloons to Weak Gravitational Lensing
Jauzac, Mathilde; Benton, Steven J.; Clark, Paul +23 more
The Superpressure Balloon-borne Imaging Telescope (SUPERBIT) is a diffraction-limited, wide-field, 0.5 m, near-infrared to near-ultraviolet observatory designed to exploit the stratosphere's space-like conditions. SUPERBIT's 2023 science flight will deliver deep, blue imaging of galaxy clusters for gravitational lensing analysis. In preparation, w…
Dynamics in the outskirts of four Milky Way globular clusters: it's the tides that dominate
Lewis, Geraint F.; de Boer, Thomas; van der Marel, Roeland P. +17 more
We present the results of a spectroscopic survey of the outskirts of four globular - 1261, NGC 4590, NGC 1904, and NGC 1851 - covering targets within 1° from the cluster centres, with 2dF/AAOmega on the Anglo-Australian Telescope (AAT) and FLAMES on the very large telescope (VLT). We extracted chemo-dynamical information for individual stars, from…
X-ray properties of the white dwarf pulsar eRASSU J191213.9−441044
Marsh, T. R.; Schwope, A.; Pelisoli, I. +5 more
We report X-ray observations of the newly discovered pulsating white dwarf eRASSU J191213.9−441044 with Spectrum Roentgen Gamma and eROSITA (SRG/eROSITA) and XMM-Newton. The new source was discovered during the first eROSITA all-sky survey at a flux level of fX(0.2 − 2.3 keV) = 3.3 × 10−13 erg cm−2 s−1 a…
Inhomogeneous Galactic chemical evolution: modelling ultra-faint dwarf galaxies of the Large Magellanic Cloud
Jordan, C. J.; Vincenzo, F.; Ji, A. P. +3 more
Ultra-faint dwarf galaxies (UFDs) are among the oldest and most metal-poor galaxies in the cosmos, observed to contain no gas and a high dark matter mass fraction. Understanding the chemical abundance dispersion in such extreme environments could shed light on the very first generations of stars. We present a novel inhomogeneous chemical evolution…
RR Lyrae stars as probes of the outer Galactic halo: chemical and kinematic analysis of a pilot sample
Grebel, Eva K.; Vivas, A. Katherina; Carlin, Jeffrey L. +4 more
We report the spectroscopic analysis of 20 halo ab-type RR Lyrae stars with heliocentric distances between 15 and 165 kpc, conducted using medium-resolution spectra from the Magellan Inamori Kyocera Echelle (MIKE) spectrograph. We obtain the systemic line-of-sight velocities of our targets with typical uncertainties of 5-10 km s-1 and c…
The First Survey of Quiet Sun Features Observed in Hard X-Rays with NuSTAR
Krucker, Säm; White, Stephen M.; Grefenstette, Brian W. +5 more
We present the first survey of quiet Sun features observed in hard X-rays (HXRs), using the Nuclear Spectroscopic Telescope ARray (NuSTAR), a HXR focusing optics telescope. The recent solar minimum, combined with NuSTAR's high sensitivity, has presented a unique opportunity to perform the first HXR imaging spectroscopy on a range of features in th…
Comparing Globular Cluster System Properties with Host Galaxy Environment
Ma, Chung-Pei; Greene, Jenny E.; Blakeslee, John P. +2 more
We present Hubble Space Telescope photometry in the optical (F475X) and near-infrared (F110W) bands of the globular cluster (GC) systems of the inner halos of a sample of 15 massive elliptical galaxies. The targets are selected from the volume-limited MASSIVE survey, and chosen to sample a range of environments from sparsely populated groups to th…
The extremely X-ray luminous radio-loud quasar CFHQS J142952 + 544717 at z = 6.18 under Chandra high-angular resolution lens
Cheung, C. C.; Stawarz, Ł.; Siemiginowska, A. +6 more
We present the first X-ray observation at sub-arcsecond resolution of the high-redshift (z = 6.18) radio-loud quasar CFHQS J142952 + 544717 (J1429). The ~100 net-count 0.3-7 keV spectrum obtained from ~30 ks Chandra exposure is best fit by a single power-law model with a photon index Γ = 2.0 ± 0.2 and no indication of an intrinsic absorber, implyi…
Distillation of 56Fe in Ultramassive O-Ne White Dwarfs
Blouin, Simon; Caplan, Matthew E.; Freeman, Ian F.
When white dwarfs freeze, the plasma mixtures inside them undergo separation processes that can produce radical changes in the composition profile of the star. The abundance of neutron-rich elements, such as 22Ne or 56Fe, determines whether or not the first crystals are more or less dense than the surrounding fluid and thus w…
Physical Properties of 5000 Cool Large Magellanic Cloud Supergiants with Gaia XP Spectra: A Detailed Portrait of the Upper H-R Diagram Hints at Missing Supernova Progenitors
Dorn-Wallenstein, Trevor Z.; Levesque, Emily M.; Neugent, Kathryn F.
Characterizing the physical properties of cool supergiants allows us to probe the final stages of a massive star's evolution before it undergoes core collapse. Despite their importance, the fundamental properties of these stars- $\mathrm{log}{T}_{\mathrm{eff}}$ and $\mathrm{log}L/{L}_{\odot }$ -are only known for a limited number of objects. The t…