Search Publications
Current Population Statistics Do Not Favor Photoevaporation over Core-powered Mass Loss as the Dominant Cause of the Exoplanet Radius Gap
Loyd, R. O. Parke; Peacock, Sarah; Richey-Yowell, Tyler +4 more
We search for evidence of the cause of the exoplanet radius gap, I.e., the dearth of planets with radii near 1.8 R⊕. If the cause were photoevaporation, the radius gap should trend with proxies for the early-life high-energy emission of the planet-hosting stars. If, alternatively, the cause were core-powered mass loss, no such trends sh…
Chasing Accreted Structures within Gaia DR2 Using Deep Learning
Lisanti, Mariangela; Necib, Lina; Cohen, Timothy +3 more
In previous work, we developed a deep neural network classifier that only relies on phase-space information to obtain a catalog of accreted stars based on the second data release of Gaia (DR2). In this paper, we apply two clustering algorithms to identify velocity substructure within this catalog. We focus on the subset of stars with line-of-sight…
Gaia 18dvy: A New FUor in the Cygnus OB3 Association
Gromadzki, M.; Szabados, L.; Mugrauer, M. +60 more
We present optical-infrared photometric and spectroscopic observations of Gaia 18dvy, located in the Cygnus OB3 association at a distance of 1.88 kpc. Gaia 18dvy was noted by the Gaia alerts system when its light curve exhibited a ≳4 mag rise in 2018-2019. The brightening was also observable at mid-infared wavelengths. The infrared colors of Gaia …
The Cepheid Distance to the Seyfert 1 Galaxy NGC 4151
Ferrarese, L.; Vestergaard, M.; Peterson, B. M. +15 more
We derive a distance of 15.8 ± 0.4 Mpc to the archetypal Seyfert 1 galaxy NGC 4151 based on the near-infrared Cepheid period-luminosity relation and new Hubble Space Telescope multiband imaging. This distance determination, based on measurements of 35 long-period (P > 25 days) Cepheids, will support the absolute calibration of the supermassive …
Properties of M Dwarf Flares at Millimeter Wavelengths
Hughes, A. Meredith; Osten, Rachel A.; MacGregor, A. Meredith
We report on two millimeter flares detected by the Atacama Large Millimeter/submillimeter Array at 220 GHz from AU Mic, a nearby M dwarf. The larger flare had a duration of only ∼35 s, with peak LR = 2 × 1015 erg s-1 Hz-1, and lower limit on linear polarization of | Q/I| > 0.12 ± 0.04. We examine the …
Resolving the FU Orionis System with ALMA: Interacting Twin Disks?
Liu, Hauyu Baobab; Williams, Jonathan; Zhu, Zhaohuan +7 more
FU Orionis objects are low-mass pre-main sequence stars characterized by dramatic outbursts several magnitudes in brightness. These outbursts are linked to episodic accretion events in which stars gain a significant portion of their mass. The physical processes behind these accretion events are not yet well understood. The archetypal FU Ori system…
Multiwavelength Follow-up of the Hyperluminous Intermediate-mass Black Hole Candidate 3XMM J215022.4-055108
Romanowsky, Aaron J.; Remillard, Ronald A.; Strader, Jay +6 more
We recently discovered the X-ray/optical outbursting source 3XMM J215022.4-055108. It was best explained as the tidal disruption of a star by an intermediate-mass black hole of mass of a few tens of thousand solar masses in a massive star cluster at the outskirts of a large barred lenticular galaxy at DL = 247 Mpc. However, we could not…
Exploring the Stellar Age Distribution of the Milky Way Bulge Using APOGEE
Cohen, Roger E.; Cunha, Katia; Smith, Verne V. +20 more
We present stellar age distributions of the Milky Way bulge region using ages for ∼6000 high-luminosity ( $\mathrm{log}(g)\lt 2.0$ ), metal-rich ([Fe/H] ≥ -0.5) bulge stars observed by the Apache Point Observatory Galactic Evolution Experiment. Ages are derived using The Cannon label-transfer method, trained on a sample of nearby luminous giants w…
Expanding the Y Dwarf Census with Spitzer Follow-up of the Coldest CatWISE Solar Neighborhood Discoveries
Meisner, Aaron M.; Cushing, Michael C.; Kirkpatrick, J. Davy +11 more
We present Spitzer 3.6 and 4.5 µm follow-up of 170 candidate extremely cool brown dwarfs newly discovered via the combination of Wide-field Infrared Survey Explorer (WISE) and NEOWISE imaging at 3-5 µm. CatWISE, a joint analysis of archival WISE and NEOWISE data, has improved upon the motion measurements of AllWISE by leveraging a >…
Magnetic Flux of Active Regions Determining the Eruptive Character of Large Solar Flares
Veronig, Astrid M.; Hou, Yijun; Li, Ting +3 more
We establish the largest eruptive/confined flare database to date and analyze 322 flares of Geostationary Operational Environmental Satellite class M1.0 and larger that occurred during 2010-2019, i.e., almost spanning all of solar cycle 24. We find that the total unsigned magnetic flux ( ${{\rm{\Phi }}}_{\mathrm{AR}}$ ) of active regions (ARs) is …