Search Publications
22Ne Phase Separation as a Solution to the Ultramassive White Dwarf Cooling Anomaly
Blouin, Simon; Saumon, Didier; Daligault, Jérôme
The precise astrometric measurements of the Gaia Data Release 2 have opened the door to detailed tests of the predictions of white dwarf cooling models. Significant discrepancies between theory and observations have been identified, the most striking affecting ultramassive white dwarfs. Cheng et al. found that a small fraction of white dwarfs on t…
3D Morphology of Open Clusters in the Solar Neighborhood with Gaia EDR 3: Its Relation to Cluster Dynamics
Tang, Shih-Yun; Pang, Xiaoying; Kroupa, Pavel +5 more
We analyze the 3D morphology and kinematics of 13 open clusters (OCs) located within 500 pc of the Sun, using Gaia EDR 3 and kinematic data from the literature. Members of OCs are identified using the unsupervised machine-learning method StarGO, using five parameters (X, Y, Z, ${\mu }_{\alpha }\cos \delta ,{\mu }_{\delta }$ ). The OC sample covers…
Luminosity Functions and Host-to-host Scatter of Dwarf Satellite Systems in the Local Volume
Greene, Jenny E.; Beaton, Rachael L.; Peter, Annika H. G. +2 more
Low-mass satellites around Milky Way (MW)-like galaxies are important probes of small-scale structure and galaxy formation. However, confirmation of satellite candidates with distance measurements remains a key barrier to fast progress in the Local Volume (LV). We measure the surface brightness fluctuation distances to recently cataloged candidate…
Turbulent Generation of Magnetic Switchbacks in the Alfvénic Solar Wind
Cranmer, Steven R.; Shoda, Munehito; Chandran, Benjamin D. G.
One of the most important early results from the Parker Solar Probe (PSP) is the ubiquitous presence of magnetic switchbacks, whose origin is under debate. Using a three-dimensional direct numerical simulation of the equations of compressible magnetohydrodynamics from the corona to 40 solar radii, we investigate whether magnetic switchbacks emerge…
UV/Optical Disk Thermal Reverberation in Active Galactic Nuclei: An In-depth Study with an Analytic Prescription for Time-lag Spectra
Papadakis, I. E.; Dovčiak, M.; Karas, V. +2 more
Several active galactic nuclei show correlated variations in the UV/optical range, with time delays increasing at longer wavelengths. Thermal reprocessing of the X-rays illuminating the accretion disk has been proposed as a viable explanation. In this scenario, the variable X-ray flux irradiating the accretion disk is partially reflected in X-rays…
Illuminating the Dark Side of Cosmic Star Formation Two Billion Years after the Big Bang
Le Fèvre, Olivier; Faisst, Andreas; Cimatti, Andrea +5 more
How and when did galaxies form and assemble their stars and stellar mass? The answer to these questions, so crucial to astrophysics and cosmology, requires the full reconstruction of the so-called cosmic star formation rate density (SFRD), i.e., the evolution of the average star formation rate per unit volume of the universe. While the SFRD has be…
Space Telescope and Optical Reverberation Mapping Project. IX. Velocity-Delay Maps for Broad Emission Lines in NGC 5548
Im, M.; Fox, O. D.; Malkan, M. A. +152 more
In this contribution, we achieve the primary goal of the active galactic nucleus (AGN) STORM campaign by recovering velocity-delay maps for the prominent broad emission lines (Lyα, C IV, He II, and Hβ) in the spectrum of NGC 5548. These are the most detailed velocity-delay maps ever obtained for an AGN, providing unprecedented information on the g…
CLEAR: The Gas-phase Metallicity Gradients of Star-forming Galaxies at 0.6 < z < 2.6
Papovich, Casey; Finkelstein, Steven L.; Cleri, Nikko J. +11 more
We report on the gas-phase metallicity gradients of a sample of 238 star-forming galaxies at 0.6 < z < 2.6, measured through deep near-infrared Hubble Space Telescope slitless spectroscopy. The observations include 12 orbit depth Hubble/WFC3 G102 grism spectra taken as a part of the CANDELS Lyα Emission at Reionization (CLEAR) survey, and ar…
Evolution of Stellar Feedback in H II Regions
Bolatto, Alberto D.; Reiter, Megan; Lopez, Laura A. +4 more
Stellar feedback is needed to produce realistic giant molecular clouds and galaxies in simulations, but due to limited numerical resolution, feedback must be implemented using sub-grid models. Observational work is an important means to test and anchor these models, but limited studies have assessed the relative dynamical role of multiple feedback…
Improving Damped Random Walk Parameters for SDSS Stripe 82 Quasars with Pan-STARRS1
Ivezić, Željko; MacLeod, Chelsea; Suberlak, Krzysztof L.
We use the Panoramic Survey Telescope and Rapid Response System 1 Survey (Pan-STARRS1, PS1) data to extend the Sloan Digital Sky Survey (SDSS) Stripe 82 quasar light curves. Combining PS1 and SDSS light curves provides a 15 yr baseline for 9248 quasars—5 yr longer than prior studies that used only SDSS. We fit the light curves with the damped rand…