Search Publications
Constraints on the Variation of the Fine-structure Constant at 3 < z < 10 with JWST Emission-line Galaxies
Jiang, Linhua; Cai, Zheng; Bosman, Sarah E. I. +7 more
We present constraints on the spacetime variation of the fine-structure constant α at redshifts 2.5 ≤ z < 9.5 using JWST emission-line galaxies (ELGs). The galaxy sample consists of 621 high-quality spectra with strong and narrow [O III] λλ4959,5007 doublet emission lines from 578 galaxies, including 232 spectra at z > 5. The [O III] doublet…
Episodic X-Ray Outflows from the Tidal Disruption Event ASASSN-14li
Steiner, James F.; Tombesi, Francesco; Pasham, Dheeraj R. +4 more
ASASSN-14li is a low-redshift (z = 0.0206) tidal disruption event (TDE) that has been studied extensively across the entire electromagnetic spectrum and has provided one of the most sensitive measurements of a TDE to date. Its X-ray spectrum is soft and thermal (kT ∼ 0.05 keV) and shows a residual broad absorption feature between 0.6 and 0.8 keV, …
Data-driven Dynamics with Orbital Torus Imaging: A Flexible Model of the Vertical Phase Space of the Galaxy
Hogg, David W.; Price-Whelan, Adrian M.; Horta, Danny +4 more
The vertical kinematics of stars near the Sun can be used to measure the total mass distribution near the Galactic disk and to study out-of-equilibrium dynamics. With contemporary stellar surveys, the tracers of vertical dynamics are so numerous and so well measured that the shapes of underlying orbits are almost directly visible in the data throu…
Hydrogen Column Density Variability in a Sample of Local Compton-thin AGN II
Buchner, J.; Ajello, M.; Marchesi, S. +7 more
We present the multiepoch analysis of 13 variable, nearby (z ≲ 0.1), and Compton-thin (1022 < NH < 1.5 × 1024 cm‑2) active galactic nuclei (AGN) selected from the 105-month BAT catalog. Analyzing all available archival soft and hard X-ray observations, we investigate the line-of-sight hydrogen colu…
The NuSTAR Local AGN N H Distribution Survey (NuLANDS). I. Toward a Truly Representative Column Density Distribution in the Local Universe
Brandt, William N.; Gandhi, Poshak; Ueda, Yoshihiro +33 more
Hard X-ray-selected samples of active galactic nuclei (AGN) provide one of the cleanest views of supermassive black hole accretion but are biased against objects obscured by Compton-thick gas column densities of N H > 1024 cm‑2. To tackle this issue, we present the NuSTAR Local AGN N H Distribution Su…
On the Formation of Planets in the Milky Way's Thick Disk
Lee, Eve J.; Hallatt, Tim
Exoplanet demographic surveys have revealed that close-in (≲1 au) small planets orbiting stars in the Milky Way's thick disk are ∼50% less abundant than those orbiting stars in the Galactic thin disk. One key difference between the two stellar populations is the time at which they emerged: thick-disk stars are the likely product of cosmic noon (re…
Testing the Breakdown of the Asteroseismic Scaling Relations in Luminous Red Giants
Pinsonneault, Marc H.; Vrard, Mathieu; Zinn, Joel C. +1 more
Nearly all cool, evolved stars are solar-like oscillators, and fundamental stellar properties can be inferred from these oscillations with asteroseismology. Scaling relations are commonly used to relate global asteroseismic properties—the frequency of maximum power
Characterization of a Peculiar Einstein Probe Transient EP240408a: An Exotic Gamma-Ray Burst or an Abnormal Jetted Tidal Disruption Event?
Buckley, David; Cenko, S. Bradley; Klingler, Noel +30 more
We present the results of our multiwavelength (X-ray to radio) follow-up campaign of the Einstein Probe transient EP240408a. The initial 10 s trigger displayed bright soft X-ray (0.5–4 keV) radiation with peak luminosity LX ≳ 1049 (1050) erg s‑1 for an assumed redshift z ≳ 0.5 (2.0). The Neil Gehrels Swi…
The Discovery and Characterization of Minimoon 2024 PT5
Chiboucas, Kristin; Lemaux, Brian C.; Bolin, Bryce T. +4 more
Minimoons are asteroids that become temporarily captured by the Earth–Moon system. We present the discovery of 2024 PT5, a minimoon discovered by the Asteroid Terrestrial-impact Last Alert System Sutherland telescope on 2024 August 7. The minimoon with heliocentric semimajor axis, a ~ 1.01 au, and perihelion, q ~ 0.99 au, became capture…
On Finding Black Holes in Photometric Microlensing Surveys
Lu, Jessica R.; McGill, Peter; Dawson, William A. +5 more
There are expected to be millions of isolated black holes in the galaxy resulting from the deaths of massive stars. Measuring the abundance and properties of this remnant population would shed light on the end stages of stellar evolution and the evolution paths of black hole systems. Detecting isolated black holes is currently only possible via gr…