Search Publications
Precise and Accurate Mass and Radius Measurements of Fifteen Galactic Red Giants in Detached Eclipsing Binaries
Lu, Jessica R.; Fulton, Benjamin J.; Kochanek, Christopher S. +9 more
Precise and accurate mass and radius measurements of evolved stars are crucial to calibrating stellar models. Stars in detached eclipsing binaries (EBs) are excellent potential calibrators because their stellar parameters can be measured with fractional uncertainties of a few percent, independent of stellar models. The All-Sky Automated Survey for…
A halo model approach for mock catalogs of time-variable strong gravitational lenses
Marshall, Philip J.; Oguri, Masamune; Birrer, Simon +5 more
Time delays in both galaxy- and cluster-scale strong gravitational lenses have recently attracted a lot of attention in the context of the Hubble tension. Future wide-field cadenced surveys, such as the LSST, are anticipated to discover strong lenses across various scales. We generate mock catalogs of strongly lensed QSOs and SNe on galaxy-, group…
Dark Energy Survey Year 6 Results: Point-Spread Function Modeling
Bechtol, K.; Smith, M.; Davis, T. M. +57 more
We present the point-spread function (PSF) modeling for weak lensing shear measurement using the full six years of the Dark Energy Survey (DES Y6) data. We review the PSF estimation procedure using the PIFF (PSFs In the Full FOV) software package and describe the key improvements made to PIFF and modeling diagnostics since the DES year three (Y3) …
Untangling Magellanic Streams
Conroy, Charlie; Cargile, Phillip A.; Naidu, Rohan P. +3 more
The Magellanic Stream (MS) is known to contain multiple H<small>I</small> strands and corresponding stellar populations are being discovered. Combining a sample of 17 stars from the H3 ("Hectochelle in the Halo at High Resolution") survey with 891 stars drawn from the Gaia DR3 catalog, we trace stars along a sub-dominant strand of the …
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…