Search Publications
Resolving a Candidate Dual Active Galactic Nucleus with ∼100 pc Separation in MCG-03-34-64
Turner, T. J.; Kraemer, S. B.; Braito, V. +4 more
We report the serendipitous multiwavelength discovery of a candidate dual black hole system with a separation of ∼100 pc, in the gas-rich luminous infrared galaxy MCG-03-34-64 (z = 0.016). Hubble Space Telescope/Advanced Camera for Surveys observations show three distinct optical centroids in the [O III] narrow-band and F814W images. Subsequent an…
Combined JWST–MUSE Integral Field Spectroscopy of the Most Luminous Quasar in the Local Universe, PDS 456
Veilleux, Sylvain; Zakamska, Nadia L.; Liu, Weizhe +5 more
Fast accreting, extremely luminous quasars contribute heavily to the feedback process within galaxies. While these systems are most common at cosmic noon (z ∼ 2), here we choose to study PDS 456, an extremely luminous (L bol ∼ 1047 erg s‑1) but nearby (z ∼ 0.185) quasar where the physics of feedback can be studied …
Discovery of an Extremely r-process-enhanced Thin-disk Star with [Eu/H] = +0.78
Shi, Jianrong; Beers, Timothy C.; Allende Prieto, Carlos +9 more
Highly r-process-enhanced (RPE) stars are rare and usually metal poor ([Fe/H] < ‑1.0), and they mainly populate the Milky Way halo and dwarf galaxies. This study presents the discovery of a relatively bright (V = 12.72), highly RPE (r-II) star ([Eu/Fe] = +1.32, [Ba/Eu] = ‑0.95), LAMOST J020623.21+494127.9. This star was selected from the Large …
The Missing Symbiotic Stars: A Joint Analysis with Gaia, GALEX, and XMM-Newton Data
Shao, Yong; Li, Xiang-Dong; Xu, Xiao-jie
The existence of a population of low-accretion-rate symbiotic stars (SySts), consisting of a giant star and a compact companion (usually a white dwarf), has been proposed recently. However, their population has not been fully understood. In this work, we present an investigation on SySts candidates consisting of asymptotic giant branch stars (AGBs…
TIC 435850195: The Second Triaxial Tidally Tilted Pulsator
Rappaport, Saul A.; Gagliano, Robert; Jayaraman, Rahul +8 more
The Transiting Exoplanet Survey Satellite (TESS) has enabled the discovery of numerous tidally tilted pulsators (TTPs), which are pulsating stars in close binaries where the presence of a tidal bulge has the effect of tilting the primary star's pulsation axes into the orbital plane. Recently, the modeling framework developed to analyze TTPs has be…
Expanding the Ultracompacts: Gravitational-wave-driven Mass Transfer in the Shortest-period Binaries with Accretion Disks
Kulkarni, S. R.; Rappaport, Saul A.; Riddle, Reed +35 more
We report the discovery of three ultracompact binary white dwarf systems hosting accretion disks, with orbital periods of 7.95, 8.68, and 13.15 minutes. This significantly augments the population of mass-transferring binaries at the shortest periods, and provides the first evidence that accretors in ultracompacts can be dense enough to host accret…
Tests of Disk-locking in T Tauri Stars of the Orion Nebula Cluster
Dixon, Don M.; Stassun, Keivan G.; Johns-Krull, Christopher M. +1 more
We look for specific correlations predicted by magnetospheric accretion models for young stars that assume disk-locking using stellar and accretion parameters derived from low-resolution HST-STIS spectra of 33 T Tauri stars in the Orion Nebula Cluster. Our results provide strong support for the correlation predicted by a model that does not constr…
Analysis of the Full Spitzer Microlensing Sample. I. Dark Remnant Candidates and Gaia Predictions
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk +70 more
In the pursuit of understanding the population of stellar remnants within the Milky Way, we analyze the sample of ∼950 microlensing events observed by the Spitzer Space Telescope between 2014 and 2019. In this study we focus on a subsample of nine microlensing events, selected based on their long timescales, small microlensing parallaxes, and join…
Ba Enrichment in Gaia MS+WD Binaries: Tracing s-process Element Production
Hallakoun, Na'ama; Toonen, Silvia; Rix, Hans-Walter +3 more
A large population of intermediate-separation binaries, consisting of a main-sequence (MS) star and a white dwarf (WD), recently emerged from Gaia's third data release (DR3), posing challenges to current models of binary evolution. Here we examine the s-process element abundances in these systems using data from GALAH DR3. Following refined sample…
Galactic-Seismology Substructures and Streams Hunter with LAMOST and Gaia. I. Methodology and Local Halo Results
Ting, Yuan-Sen; Bland-Hawthorn, Joss; Wang, Hai-Feng +4 more
We present a novel, deep-learning-based method—dubbed Galactic-Seismology Substructures and Streams Hunter, or GS3 Hunter for short—to search for substructures and streams in stellar kinematics data. GS3 Hunter relies on a combined application of Siamese neural networks to transform the phase space information and the K-means…