Search Publications
A 1.9 solar-mass neutron star candidate in a 2-year orbit
Bieryla, Allyson; Latham, David W.; Rix, Hans-Walter +10 more
We report discovery and characterization of a main-sequence G star orbiting a dark object with mass 1.90±0.04M⊙. The system was discovered via Gaia astrometry and has an orbital period of 731 days. We obtained multi-epoch RV follow-up over a period of 639 days, allowing us to refine the Gaia orbital solution and precisely constrain the masses of b…
A population of neutron star candidates in wide orbits from Gaia astrometry
Bieryla, Allyson; Latham, David W.; Rix, Hans-Walter +10 more
We report discovery and spectroscopic follow-up of 21 astrometric binaries containing solar-type stars and dark companions with masses near 1.4 M⊙. The simplest interpretation is that the companions are dormant neutron stars (NSs), though ultramassive white dwarfs (WDs) and tight WD+WD binaries cannot be fully excluded. We selected targets from Ga…
On the formation of a 33 solar-mass black hole in a low-metallicity binary
El-Badry, Kareem
A 33M⊙ black hole (BH) was recently discovered in an 11.6-year binary only 590 pc from the Sun. The system, Gaia BH3, contains a 0.8M⊙ low-metallicity giant () that is a member of the ED-2 stellar stream. This paper investigates whether the system could have formed via isolated binary evolution. I construct evolutionary models for metal-poor massi…
Galaxy assembly revealed by globular clusters
Chen, Yingtian; Gnedin, Oleg Y.
Many observable properties of globular clusters (GCs) provide valuable insights for unveiling the hierarchical assembly of their host galaxy. For the Milky Way (MW) in particular, GCs from different accreted satellite galaxies show distinct chemical, spatial, kinematic, and age distributions. Here we examine such clustering features for model GC p…
High mass function ellipsoidal variables in the Gaia Focused Product Release: searching for black hole candidates in the binary zoo
Kochanek, Christopher S.; Thompson, Todd A.; Jayasinghe, Tharindu +2 more
The recent Gaia Focused Product Release contains radial velocity time-series for more than 9,000 Gaia long-period photometric variables. Here we search for binary systems with large radial velocity amplitudes to identify candidates with massive, unseen companions. Eight targets have binary mass function f(M)>1M⊙, three of which are eclipsing bi…
LAMOST J1010+2358 is not a Pair-Instability Supernova Relic
Cerny, William; Simon, Joshua D.; Ji, Alexander P. +2 more
The discovery of a star formed out of pair-instability supernova ejecta would have massive implications for the Population III star initial mass function and the existence of stars over 100 Msun, but none have yet been found. Recently, the star LAMOST J1010+2358 was claimed to be a star that formed out of gas enriched by a pair-instability superno…
The extraordinary frequency pattern variation in δ Scuti stars
Balona, Luis A.
Inspection of the periodograms of TESS delta Scuti stars indicates that there is little, if any, similarity between the frequencies of stars in the same region of the H-R diagram. This is difficult to understand because pulsation models predict that stars with similar physical parameters should have similar frequencies. To investigate the problem,…
Compact Binary Formation in Open Star Clusters II: Difficulty of Gaia NS formation in low-mass star clusters
Wang, Long; Fujii, Michiko S.; Tanikawa, Ataru
Gaia mission offers opportunities to search for compact binaries not involved in binary interactions (hereafter inert compact binaries), and results in the discoveries of binaries containing one black hole (BH) or one neutron star (NS), called "Gaia BHs'' and"Gaia NSs'', respectively. We have assessed if Gaia BHs and NSs can be formed in open clus…
A generative model for Gaia astrometric orbit catalogs: selection functions for binary stars, giant planets, and compact object companions
Rix, Hans-Walter; El-Badry, Kareem; Mazeh, Tsevi +4 more
Astrometry from {} DR3 has produced a sample of $$170,000 Keplerian orbital solutions, with many more anticipated in the next few years. These data have enormous potential to constrain the population of binary stars, giant planets, and compact objects in the Solar neighborhood. But in order to use the published orbit catalogs for statistical infer…
Can we constrain structure growth from galaxy proper motions?
Alonso, David; Slosar, Anže; Storey-Fisher, Kate +1 more
Galaxy peculiar velocities can be used to trace the growth of structure on cosmological scales. In the radial direction, peculiar velocities cause redshift space distortions, an established cosmological probe, and can be measured individually in the presence of an independent distance indicator. In the transverse direction, peculiar velocities cau…