Search Publications
The Merging of a Coronal Dimming and the Southern Polar Coronal Hole
Long, David M.; Baker, Deborah; Green, Lucie M. +4 more
We report on the merging between the southern polar coronal hole and an adjacent coronal dimming induced by a coronal mass ejection on 2022 March 18, resulting in the merged region persisting for at least 72 hr. We use remote sensing data from multiple co-observing spacecraft to understand the physical processes during this merging event. The evol…
Search for Extremely Metal-poor Stars with Gemini-N/Graces. I. Chemical-abundance Analysis
Koo, Jae-Rim; Beers, Timothy C.; Lee, Young Sun +5 more
We present stellar parameters and abundances of 13 elements for 18 very metal-poor (VMP; [Fe/H] < –2.0) stars, selected as extremely metal-poor (EMP; [Fe/H] < –3.0) candidates from the Sloan Digital Sky Survey and Large sky Area Multi-Object Fiber Spectroscopic Telescope survey. High-resolution spectroscopic observations were performed using…
VLTI/GRAVITY Observations and Characterization of the Brown Dwarf Companion HD 72946 B
Lutz, D.; Genzel, R.; Sturm, E. +97 more
Tension remains between the observed and modeled properties of substellar objects, but objects in binary orbits, with known dynamical masses, can provide a way forward. HD 72946 B is a recently imaged brown dwarf companion to a nearby, solar-type star. We achieve ~100 µas relative astrometry of HD 72946 B in the K band using VLTI/GRAVITY, un…
Joint Modelling of Dust Scattering and Thermal Emission: The Spider Complex
van Dokkum, Pieter; Abraham, Roberto; Merritt, Allison +4 more
Observations across the electromagnetic spectrum of radiative processes involving interstellar dust-emission, absorption, and scattering-are used to constrain the parameters of dust models and more directly to aid in foreground removal of dust for extragalactic and cosmological observations. Dust models can benefit from more independent constraint…
On the Hunt for the Origins of the Orphan-Chenab Stream: Detailed Element Abundances with APOGEE and Gaia
Laporte, Chervin F. P.; Price-Whelan, Adrian M.; Erkal, Denis +8 more
Stellar streams in the Galactic halo are useful probes of the assembly of galaxies like the Milky Way. Many tidal stellar streams that have been found in recent years are accompanied by a known progenitor globular cluster or dwarf galaxy. However, the Orphan-Chenab (OC) stream is one case where a relatively narrow stream of stars has been found wi…
An SMA Survey of Chemistry in Disks Around Herbig AeBe Stars
Wilner, David J.; Andrews, Sean M.; Huang, Jane +6 more
Protoplanetary disks around Herbig AeBe stars are exciting targets for studying the chemical environments where giant planets form. Save for a few disks, however, much of Herbig AeBe disk chemistry is an open frontier. We present a Submillimeter Array ~213-268 GHz pilot survey of millimeter continuum CO isotopologs and other small molecules in dis…
Mapping NGC 7027 in New Light: CO+ and HCO+ Emission Reveal Its Photon- and X-Ray-dominated Regions
Wilner, David J.; Montez, Rodolfo; Kastner, Joel H. +7 more
The young and well-studied planetary nebula (PN) NGC 7027 harbors significant molecular gas that is irradiated by luminous, pointlike UV (central star) and diffuse (shocked nebular) X-ray emission. This nebula represents an excellent subject to investigate the molecular chemistry and physical conditions within photon- and X-ray-dominated regions (…
The Luminosity Phase Space of Galactic and Extragalactic X-Ray Transients Out to Intermediate Redshifts
Esposito, Paolo; Auchettl, Katie; Vasilopoulos, Georgios +8 more
We present a detailed compilation and analysis of the X-ray phase space of low- to intermediate-redshift (0 ≤ z ≤ 1) transients that consolidates observed light curves (and theory where necessary) for a large variety of classes of transient/variable phenomena in the 0.3-10 keV energy band. We include gamma-ray burst afterglows, supernovae, superno…
Reconnection-generated Plasma Flows in the Quasi-separatrix Layer in Localized Solar Corona
Srivastava, Abhishek K.; Kayshap, Pradeep; Pontin, David I. +8 more
Multiwavelength observations of the propagating disturbances (PDs), discovered by Atmospheric Imaging Assembly (AIA) on board Solar Dynamics Observatory (SDO), are analyzed to determine their driving mechanism and physical nature. Two magnetic strands in the localized corona are observed to approach and merge with each other, followed by the gener…
Chemodynamical Analysis of Metal-rich High-eccentricity Stars in the Milky Way's Disk
Beers, Timothy C.; Lee, Young Sun; An, Deokkeun +2 more
We present a chemodynamical analysis of 11,562 metal-rich, high-eccentricity halo-like main-sequence stars, which have been referred to as the Splash or Splashed Disk, selected from the Sloan Digital Sky Survey and Large Sky Area Multi-Object Fiber Spectroscopic Telescope. When divided into two groups, a low-[α/Fe] population (LAP) and a high-[α/F…