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A critique of the Spite Plateau and the astration of primordial lithium
Yong, D.; Norris, J. E.; Frebel, A. +1 more
We investigate the distribution of the lithium abundances, A(Li), of metal-poor dwarf and subgiant stars within the limits 5500 K < Teff < 6700 K, -6.0 < [Fe/H] < -1.5, and log g ≳ 3.5 (a superset of parameters first adopted by Spite and Spite), using literature data for some 200 stars. We address the problem of the several …
Probing the Galactic Diffuse Continuum Emission with COSI
Boggs, Steven E.; Tomsick, John A.; Siegert, Thomas +10 more
In 2016, the Compton Spectrometer and Imager (COSI) had a successful 46 day flight on board NASA's Super Pressure Balloon platform. In this work, we report measurements of the Galactic diffuse continuum emission (GDCE) observed toward the inner Galaxy during the flight, which in the COSI energy band (0.2-5 MeV) is primarily generated from inverse …
Galactic population synthesis of radioactive nucleosynthesis ejecta
Diehl, Roland; Greiner, Jochen; Siegert, Thomas +3 more
Diffuse γ-ray line emission traces freshly produced radioisotopes in the interstellar gas, providing a unique perspective on the entire Galactic cycle of matter from nucleosynthesis in massive stars to their ejection and mixing in the interstellar medium (ISM). We aim to construct a model of nucleosynthesis ejecta on a galactic scale that is speci…
A unified exploration of the chronology of the Galaxy
Stokholm, Amalie; Stello, Dennis; Hon, Marc +2 more
The Milky Way has distinct structural stellar components linked to its formation and subsequent evolution, but disentangling them is non-trivial. With the recent availability of high-quality data for a large numbers of stars in the Milky Way, it is a natural next step for research in the evolution of the Galaxy to perform automated explorations wi…
Analysis of the ionized interstellar medium and orbital dynamics of PSR J1909-3744 using scintillation arcs
Shannon, R. M.; Askew, J.; Reardon, D. J.
Long-term studies of binary millisecond pulsars (MSPs) provide precise tests of strong-field gravity, and can be used to measure neutron-star masses. PSR J1909-3744, a binary MSP has been the subject of several pulsar timing analyses. The edge-on orbit enables measurement of its mass using the Shapiro delay; however, there is degeneracy in the sen…
Geometry and Kinematics of a Dancing Milky Way: Unveiling the Precession and Inclination Variation across the Galactic Plane via Open Clusters
He, Zhihong
This Letter presents a study of the geometry and motion of the Galactic disk using open clusters in the Gaia era. The findings suggest that the inclination θ i of the Galactic disk increases gradually from the inner to the outer disk, with a shift in orientation at the Galactocentric radius of approximately 6 ± 1 kpc. Furthermore, thi…
Binary star population of the Sculptor dwarf galaxy
McConnachie, Alan W.; Tolstoy, Eline; Irwin, Michael J. +3 more
Aims: We aim to compute the binary fraction of "classical" dwarf spheroidal galaxies (dSphs) that are satellites of the Milky Way (MW). This value can offer insights into the binary fraction in environments that are less dense and more metal-poor than our own galaxy. Additionally, knowledge of the binary fraction in dwarf galaxies is importan…
Propeller states in locally supercritical ULXs
Walton, D. J.; Middleton, M.; Gúrpide, A.
An expected signature of the presence of neutron stars in the population of ultraluminous X-ray sources (ULXs) are large scale changes in X-ray luminosity, as systems reach spin equilibrium and a propeller state ensues. We explore the predicted luminosity changes when the disc is locally supercritical, finding that a significant parameter space in…
Early Results from GLASS-JWST. XX. Unveiling a Population of "Red Excess" Galaxies in Abell2744 and in the Coeval Field
Santini, Paola; Calabrò, Antonello; Castellano, Marco +26 more
We combine JWST/NIRCam imaging and MUSE data to characterize the properties of galaxies in different environmental conditions in the cluster Abell2744 (z = 0.3064) and in its immediate surroundings. We investigate how galaxy colors, morphology, and star-forming fractions depend on wavelength and on different parameterizations of environment. Our m…
Tentative detection of titanium oxide in the atmosphere of WASP-69 b with a 4m ground-based telescope
Zhao, Gang; Wang, Wei; Zhao, Fei +6 more
Transiting planets provide unique opportunities for the atmospheric characterization of exoplanets as they can reveal composition and the temperature structures at the day-night terminator regions in planetary atmospheres, and help understand the atmospheric process and formation environments of exoplanets. Here, we present the optical transmissio…