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…
Comparing jet-shaped point symmetry in cluster cooling flows and supernovae
Soker, Noam
I point out similarities between point-symmetric X-ray morphologies in cooling flow groups and clusters of galaxies, which are observed to be shaped by jets, and point-symmetric morphologies of eight core-collapse supernova (CCSN) remnants. I identify these similarities by qualitative eye inspection of multiwavelength images. I use these similarit…
Spectroscopic Confirmation of an Ultra-Massive Galaxy in a Protocluster at z ∼ 4.9
Cooper, M. C.; Urbano Stawinski, Stephanie M.; Muzzin, Adam +8 more
We present spectroscopic confirmation of an ultra-massive galaxy (UMG) with log(M⋆/M⊙)=10.98±0.07 at zspec=4.8947 in the Extended Groth Strip (EGS), based on deep observations of Ly α emission with Keck/DEIMOS. The ultra-massive galaxy (UMG-28740) is the most massive member in one of the most significant overdensities in the EGS, with four additio…
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…
The Millions of Optical-Radio/X-ray Associations (MORX) Catalogue, v2
Flesch, Eric Wim
Announcing the release v2 of the MORX (Millions of Optical-Radio/X-ray Associations) catalogue which presents probable (40%-100% likelihood) radio/X-ray associations, including double radio lobes, to optical objects over the whole sky. Detections from all the largest radio/X-ray surveys to June 2023 are evaluated, those surveys being VLASS, LoTSS,…
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,…