Search Publications
A New Catalog of 100,000 Variable TESS A-F Stars Reveals a Correlation between δ Scuti Pulsator Fraction and Stellar Rotation
Huber, Daniel; Bedding, Timothy R.; Murphy, Simon J. +3 more
δ Scuti variables are found at the intersection of the classical instability strip and the main sequence on the Hertzsprung–Russell diagram. With space-based photometry providing millions of light curves of A-F type stars, we can now probe the occurrence rate of δ Scuti pulsations in detail. Using the 30 minutes cadence light curves from NASA's Tr…
Measuring the Mass–Radius Relation of White Dwarfs Using Wide Binaries
Brownstein, Joel R.; Hermes, J. J.; Stassun, Keivan G. +10 more
Measuring the mass–radius relation of individual white dwarfs is an empirically challenging task that has been performed for only a few dozen stars. We measure the white dwarf mass–radius relation using the gravitational redshifts and radii of 135 white dwarfs in wide binaries with main-sequence companions. We obtain the radial velocities of these…
A 350 MHz Green Bank Telescope Survey of Unassociated Fermi LAT Sources: Discovery and Timing of 10 Millisecond Pulsars
Camilo, F.; Guillemot, L.; Johnson, T. J. +18 more
We have searched for radio pulsations toward 49 Fermi Large Area Telescope (LAT) 1FGL Catalog γ-ray sources using the Green Bank Telescope at 350 MHz. We detected 18 millisecond pulsars (MSPs) in blind searches of the data; 10 of these were discoveries unique to our survey. 16 are binaries, with eight having short orbital periods P B …
Black Hole Mass and Eddington Ratio Distribution of Hot Dust-obscured Galaxies
Tsai, Chao-Wei; Jun, Hyunsung D.; Eisenhardt, Peter R. M. +8 more
Hot dust-obscured galaxies (Hot DOGs) are a rare population of hyperluminous infrared galaxies discovered by the Wide-field Infrared Survey Explorer mission. Despite the significant obscuration of the active galactic nucleus (AGN) by dust in these systems, pronounced broad and blueshifted emission lines are often observed. Previous work has shown …
A Buddy for Betelgeuse: Binarity as the Origin of the Long Secondary Period in α Orionis
Joyce, Meridith; Molnár, László; Goldberg, Jared A.
We predict the existence of α Ori B, a low-mass companion orbiting Betelgeuse. This is motivated by the presence of a 2170 day long secondary period (LSP) in Betelgeuse's lightcurve, a periodicity that is ≈5 times longer than the star's 416 day fundamental radial pulsation mode. While binarity is currently the leading hypothesis for LSPs in genera…
The Cause of the Difference in the Propagation Distances between Compact and Transient Jets in Black Hole X-Ray Binaries
Zdziarski, Andrzej A.; Heinz, Sebastian
Accreting black hole binaries change their properties during evolution, passing through two main luminous states, dominated by either hard or soft X-rays. In the hard state, steady compact jets emitting multiwavelength radiation are present. Those jets are usually observed in radio, and when resolved, their extent is ≲1015 cm. Then, dur…
Upstream Plasma Waves and Downstream Magnetic Reconnection at a Reforming Quasi-parallel Shock
Yang, Zhongwei; Lu, Quanming; Gao, Xinliang +4 more
With the help of a two-dimensional particle-in-cell simulation model, we investigate the long-time evolution (near $100{{\rm{\Omega }}}_{i0}^{-1}$ , where Ω i0 is the ion gyrofrequency in the upstream) of a quasi-parallel shock. Some of the upstream ions are reflected by the shock front, and their interactions with the incident ions exc…
Identifying Jittering Jet-shaped Ejecta in the Cygnus Loop Supernova Remnant
Soker, Noam; Shishkin, Dmitry; Kaye, Roy
Analyzing images of the Cygnus Loop, a core-collapse supernova (CCSN) remnant, in different emission bands, we identify a point-symmetrical morphology composed of three symmetry axes that we attribute to shaping by three pairs of jets. The main jet axis has an elongated S shape, appearing as a faint narrow zone in visible and UV. We term it the S-…
The Thickness of Galaxy Disks from z = 5 to 0 Probed by JWST
Lian, Jianhui; Luo, Li
Although a thick disk is a structure prevalent in local disk galaxies and also present in our home Galaxy, its formation and evolution are still unclear. Whether the thick disk is born thick and/or gradually heated to be thick after formation is under debate. To disentangle these two scenarios, one effective approach is to inspect the thickness of…
JWST/MIRI Detection of a Carbon-rich Chemistry in the Disk of a Solar Nebula Analog
Pascucci, Ilaria; Banzatti, Andrea; Bergin, Edwin A. +16 more
It has been proposed, and confirmed by multiple observations, that disks around low-mass stars display a molecule-rich emission and carbon-rich disk chemistry as compared to their hotter, more massive solar counterparts. In this work, we present JWST Disk Infrared Spectral Chemistry Survey MIRI-MRS observations of the solar-mass star DoAr 33, a lo…