Search Publications
The ELM Survey South. II. Two Dozen New Low-mass White Dwarf Binaries
Gianninas, A.; Kupfer, Thomas; Kilic, Mukremin +5 more
We present the results from our ongoing spectroscopic survey targeting low-mass white dwarf binaries, focusing on the southern sky. We used a Gaia DR2- and eDR3-based selection and identified 28 new binaries, including 19 new extremely low-mass (ELM) white dwarfs, one short period, likely eclipsing, DABZ, and two potential LISA binaries. We presen…
Multipole expansion of the local expansion rate
Kalbouneh, Basheer; Marinoni, Christian; Bel, Julien
We design a new observable, the expansion rate fluctuation η , to characterize deviations from the linear relation between redshift and distance in the local universe. We also show how to compress the resulting signal into spherical harmonic coefficients in order to better decipher the structure and symmetries of the anisotropies in the local expa…
A comparative analysis of the chemical compositions of Gaia-Enceladus/Sausage and Milky Way satellites using APOGEE
Horta, Danny; Minniti, Dante; Beaton, Rachael L. +11 more
We use data from the 17th data release of the Apache Point Observatory Galactic Evolution Experiment (APOGEE 2) to contrast the chemical composition of the recently discovered Gaia Enceladus/Sausage system (GE/S) to those of 10 Milky Way (MW) dwarf satellite galaxies: LMC, SMC, Boötes I, Carina, Draco, Fornax, Sagittarius, Sculptor, Sextans, and U…
Observational constraints on the origin of the elements. V. NLTE abundance ratios of [Ni/Fe] in Galactic stars and enrichment by sub-Chandrasekhar mass supernovae
Ruiter, A. J.; Seitenzahl, I. R.; Bergemann, M. +4 more
Aims: We constrain the role of different Type Ia supernova (SN Ia) channels in the chemical enrichment of the Galaxy by studying the abundances of nickel in Galactic stars. We investigated four different SN Ia sub-classes, including the classical single-degenerate near-Chandrasekhar mass (Mch) SN Ia, the fainter SN Iax systems asso…
The period-luminosity relation for Mira variables in the Milky Way using Gaia DR3: a further distance anchor for H0
Sanders, Jason L.
Gaia DR3 parallaxes are used to calibrate preliminary period-luminosity relations of O-rich Mira variables in the 2MASS J, H, and Ks bands using a probabilistic model accounting for variations in the parallax zero-point and underestimation of the parallax uncertainties. The derived relations are compared to those measured for the Large …
SPLUS J142445.34-254247.1: An r-process-enhanced, Actinide-boost, Extremely Metal-poor Star Observed with GHOST
Jones, David O.; Simpson, Chris; Placco, Vinicius M. +33 more
We report on a chemo-dynamical analysis of SPLUS J142445.34-254247.1 (SPLUS J1424-2542), an extremely metal-poor halo star enhanced in elements formed by the rapid neutron-capture process (r-process). This star was first selected as a metal-poor candidate from its narrowband S-PLUS photometry and followed up spectroscopically in medium resolution …
Discovery of the Magellanic Stellar Stream Out to 100 kpc
Conroy, Charlie; Ting, Yuan-Sen; Cargile, Phillip A. +7 more
The Magellanic Stream (MS)-an enormous ribbon of gas spanning 140° of the southern sky trailing the Magellanic Clouds-has been exquisitely mapped in the five decades since its discovery. However, despite concerted efforts, no stellar counterpart to the MS has been conclusively identified. This stellar stream would reveal the distance and 6D kinema…
A Photometric Survey of Globular Cluster Systems in Brightest Cluster Galaxies
Harris, William E.
Hubble Space Telescope imaging for 26 giant early-type galaxies, all drawn from the MAST archive, is used to carry out photometry of their surrounding globular cluster (GC) systems. Most of these targets are Brightest Cluster Galaxies and their distances range from 24-210 Mpc. The catalogs of photometry, completed with DOLPHOT, are publicly availa…
The Solar Neighborhood in the Age of Gaia
Alves, J.; Meingast, S.; Zucker, C. +2 more
Most of what we know about the formation of stars, and essentially everything we know about the formation of planets, comes from observations of our solar neighborhood within 2 kpc of the Sun. Before 2018, accurate distance measurements needed to turn the 2D Sky into a faithful 3D physical picture of the distribution of stars, and the interstellar…
The Thermosphere Is a Drag: The 2022 Starlink Incident and the Threat of Geomagnetic Storms to Low Earth Orbit Space Operations
Berger, T. E.; Dominique, M.; Thiemann, E. +6 more
On 03 February 2022, SpaceX launched 49 Starlink satellites, 38 of which re-entered the atmosphere on or about 07 February 2022 due to unexpectedly high atmospheric drag. We use empirical model (NRLMSIS, JB08, and HASDM) outputs as well as solar extreme ultraviolet occultation and high-fidelity accelerometer data to show that thermospheric density…