Search Publications
Wide Post-common Envelope Binaries from Gaia: Orbit Validation and Formation Models
El-Badry, Kareem; Mazeh, Tsevi; Yamaguchi, Natsuko +3 more
Astrometry from Gaia DR3 has enabled the discovery of a sample of 3000+ binaries containing white dwarfs (WD) and main-sequence (MS) stars in relatively wide orbits, with orbital periods P orb = (100–1000) days. This population was not predicted by binary population synthesis models before Gaia and—if the Gaia orbits are robust—likely r…
High-precision Astrometry and Photometry with the JWST/MIRI Imager
Law, David R.; Hines, Dean C.; Álvarez-Márquez, Javier +8 more
Astrometry is one of the main pillars of astronomy, and one of its oldest branches. Over the years, an increasing number of astrometric works by means of Hubble Space Telescope (HST) data have revolutionized our understanding of various phenomena. With the launch of JWST, it becomes almost instinctive to want to replicate or improve these results …
Global Parameters of Eight W UMa-type Binary Systems
Poro, Atila; Paki, Ehsan; Michel, Raul +1 more
Multiband photometric investigations for eight binary systems of the W Ursae Majoris-type are presented. Six systems are presented for the first time to analyze their light curves. All the analyzed systems have a temperature below 5000 K and an orbital period of less than 0.28 days. We extracted primary and secondary minima from the ground-based o…
ESPRESSO Observations of Gaia BH1: High-precision Orbital Constraints and no Evidence for an Inner Binary
Triaud, Amaury H. M. J.; Bieryla, Allyson; Rix, Hans-Walter +9 more
We present high-precision radial velocity observations of Gaia BH1, the nearest known black hole (BH). The system contains a solar-type G star orbiting a massive dark companion, which could be either a single BH or an inner BH + BH binary. A BH + BH binary is expected in some models where Gaia BH1 formed as a hierarchical triple, which is attracti…
The BlackGEM Telescope Array. I. Overview
Gal-Yam, A.; Geier, S.; Vreeswijk, P. M. +76 more
The main science aim of the BlackGEM array is to detect optical counterparts to gravitational wave mergers. Additionally, the array will perform a set of synoptic surveys to detect Local Universe transients and short timescale variability in stars and binaries, as well as a six-filter all-sky survey down to ∼22nd mag. The BlackGEM Phase-I array co…
The Symbiotic X-Ray Binary IGR J16194-2810: A Window on the Future Evolution of Wide Neutron Star Binaries From Gaia
El-Badry, Kareem; Nagarajan, Pranav; Reggiani, Henrique +1 more
We present optical follow-up of IGR J16194-2810, a hard X-ray source discovered by the INTEGRAL mission. The optical counterpart is a ∼500 L ⊙ red giant at a distance of 2.1 kpc. We measured 17 radial velocities (RVs) of the giant over a period of 271 days. Fitting these RVs with a Keplerian model, we find an orbital period of P or…
No Longer Impossible: The Self-lensing Binary KIC 8145411 is a Triple
Bieryla, Allyson; Latham, David W.; El-Badry, Kareem +5 more
Five self-lensing binaries (SLBs) have been discovered with data from the Kepler mission. One of these systems is KIC 8145411, which was reported to host an extremely low mass (ELM; 0.2 M ⊙) white dwarf (WD) in a 456 days orbit with a solar-type companion. The system has been dubbed "impossible," because evolutionary models predict that…
From Active Stars to Black Holes: A Discovery Tool for Galactic X-Ray Sources
Rodriguez, Antonio C.
Galactic X-ray sources are diverse, ranging from active M dwarfs to compact object binaries, and everything in between. The X-ray landscape of today is rich, with point source catalogs such as those from XMM-Newton, Chandra, and Swift, each with ≳105 sources and growing. Furthermore, X-ray astronomy is on the verge of being transformed …
A Quick Guide to Nearby Young Associations
Gagné, Jonathan
Nearby associations of stars which are coeval are important benchmark laboratories because they provide robust measurements of stellar ages. The study of such coeval groups makes it possible to better understand star formation by studying the initial mass function, the binary fraction or the circumstellar disks of stars, to determine how the initi…
An Infrared Census of R Coronae Borealis Stars II—Spectroscopic Classifications and Implications for the Rate of Low-mass White Dwarf Mergers
Soria, Roberto; Clayton, Geoffrey C.; De, Kishalay +18 more
We present results from a systematic infrared (IR) census of R Coronae Borealis (RCB) stars in the Milky Way, using data from the Palomar Gattini IR (PGIR) survey. RCB stars are dusty, erratic variable stars presumably formed from the merger of a He-core and a CO-core white dwarf (WD). PGIR is a 30 cm J-band telescope with a 25 deg2 cam…