Search Publications
They Might Be Giants: An Efficient Color-based Selection of Red Giant Stars
Conroy, Charlie; Dotter, Aaron; Johnson, Benjamin D. +4 more
We present a color-based method for identifying red giants based on the Pan-STARRS grz and WISE W1 and W2 photometry. We utilize a subsample of bright stars with precise parallaxes from Gaia’s second data release (DR2) to verify that the color-based selection reliably separates dwarfs from giants. The selection is conservative in the sense that co…
Angular Sizes and Effective Temperatures of O-type Stars from Optical Interferometry with the CHARA Array
Gies, Douglas R.; Schaefer, Gail H.; Hillier, D. John +3 more
We present interferometric observations of six O-type stars that were made with the Precision Astronomical Visible Observations beam combiner at the Center for High Angular Resolution Astronomy (CHARA) Array. The observations include multiple brackets for three targets, λ Ori A, ζ Oph, and 10 Lac, but there are only preliminary, single observation…
Synthesis of Molecular Oxygen via Irradiation of Ice Grains in the Protosolar Nebula
Wurz, P.; Lunine, J. I.; Danger, G. +4 more
Molecular oxygen has been detected in the coma of comet 67P/Churyumov-Gerasimenko with a mean abundance of 3.80 ± 0.85% by the ROSINA mass spectrometer on board the Rosetta spacecraft. To account for the presence of this species in comet 67P/Churyumov-Gerasimenko, it has been shown that the radiolysis of ice grain precursors of comets is a viable …
Hα Emitting Galaxies at z ∼ 0.6 in the Deep And Wide Narrow-band Survey
Mobasher, Bahram; Zheng, Zhen-Ya; Veilleux, Sylvain +14 more
We present new measurements of the Hα luminosity function (LF) and star formation rate (SFR) volume density for galaxies at z ∼ 0.62 in the COSMOS field. Our results are part of the Deep And Wide Narrow-band Survey (DAWN), a unique infrared imaging program with large areal coverage (∼1.1 deg2 over five fields) and sensitivity (9.9× {10}…
Properties of Decaying Plasma Turbulence at Subproton Scales
Servidio, Sergio; Lapenta, Giovanni; Primavera, Leonardo +2 more
We study the properties of plasma turbulence at subproton scales using kinetic electromagnetic three-dimensional simulations with nonidentical initial conditions. Particle-in-cell modeling of the Taylor-Green vortex has been performed, starting from three different magnetic field configurations. All simulations expose very similar energy evolution…
Plasma Interactions with the Space Environment in the Acceleration Region: Indications of CME-trailing Reconnection Regions
Vilas, Faith; Heiles, Carl; Kepley, Amanda A. +6 more
Coronal mass ejections (CMEs) are sources of major geomagnetic disturbances. On 2013 May 10, a CME crossed the signal path between the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft and Earth. Using the MESSENGER signal, characteristics of the density, velocity, and magnetic field properties of the crossing pl…
An Extreme-ultraviolet Wave Generating Upward Secondary Waves in a Streamer-like Solar Structure
Chen, Yao; Feng, Shiwei; Zheng, Ruisheng +2 more
Extreme-ultraviolet (EUV) waves, spectacular horizontally propagating disturbances in the low solar corona, always trigger horizontal secondary waves (SWs) when they encounter the ambient coronal structure. We present the first example of upward SWs in a streamer-like structure after the passing of an EUV wave. This event occurred on 2017 June 1. …
Optical Observations of the Young Type Ic Supernova SN 2014L in M99
Zhang, Yu; Wang, Lifan; Wheeler, J. Craig +22 more
We present optical spectroscopic and photometric observations of the nearby type Ic supernova (SN Ic) SN 2014L. This SN was discovered by the Tsinghua-NAOC Transient Survey (TNTS) in the nearby type-Sc spiral galaxy M99 (NGC 4254). Fitting to the early-time light curve indicates that SN 2014L was detected at only a few hours after the shock breako…
Toward the Measurement of the Mass of Isolated Neutron Stars: Prediction of Future Astrometric Microlensing Events by Pulsars
Ofek, Eran O.
The mass of single neutron stars (NSs) can be measured using astrometric microlensing events. In such events, the center-of-light motion of a star lensed by an NS will deviate from the expected nonlensed motion and this deviation can be used to measure the mass of the NS. I search for future conjunctions between pulsars, with measured proper motio…
Observations of Upward Propagating Waves in the Transition Region and Corona above Sunspots
Fu, Hui; Li, Bo; Xia, Lidong +2 more
We present observations of persistent oscillations of some bright features in the upper-chromosphere/transition region above sunspots taken by IRIS SJ 1400 Å and upward propagating quasi-periodic disturbances along coronal loops rooted in the same region taken by the AIA 171 Å passband. The oscillations of the features are cyclic oscillatory motio…