Search Publications
Kepler-503b: An Object at the Hydrogen Burning Mass Limit Orbiting a Subgiant Star
Schneider, Donald P.; Mahadevan, Suvrath; Majewski, Steven R. +10 more
Using spectroscopic radial velocities with the Apache Point Observatory Galaxy Evolution Experiment (APOGEE) instrument and Gaia distance estimates, we demonstrate that Kepler-503b, currently considered a validated Kepler planet, is in fact a brown-dwarf/low-mass star in a nearly circular 7.2-day orbit around a subgiant star. Using a mass estimate…
The GeMS/GSAOI Galactic Globular Cluster Survey (G4CS). I. A Pilot Study of the Stellar Populations in NGC 2298 and NGC 3201
Dotter, Aaron; Miller, Bryan W.; Monty, Stephanie +12 more
We present the first results from the GeMS/GSAOI Galactic Globular Cluster Survey (G4CS) of the Milky Way globular clusters NGC 3201 and NGC 2298. Using the Gemini South Adaptive Optics Imager (GSAOI), in tandem with the Gemini Multi-conjugate adaptive optics System (GeMS) on the 8.1 m Gemini-South telescope, we collected deep near-IR observations…
Near-infrared Stellar Populations in the Metal-poor, Dwarf Irregular Galaxies Sextans A and Leo A
Boyer, Martha L.; Meixner, Margaret; McDonald, Iain +3 more
We present JHK s observations of the metal-poor ([Fe/H] < -1.40) dwarf-irregular galaxies, Leo A and Sextans A, obtained with the WIYN High-resolution Infrared Camera at Kitt Peak. Their near-IR stellar populations are characterized by using a combination of color-magnitude diagrams and by identifying long-period variable stars. We…
Multi-spacecraft Observations of the Rotation and Nonradial Motion of a CME Flux Rope Causing an Intense Geomagnetic Storm
Wang, Rui; Liu, Ying D.; Hu, Huidong +2 more
We present an investigation of the rotation and nonradial motion of a coronal mass ejection (CME) from AR 12468 on 2015 December 16 using observations from SDO, SOHO, STEREO A, and Wind. The EUV and HMI observations of the source region show that the associated magnetic flux rope (MFR) axis pointed to the east before the eruption. We use a nonline…
Metal Deficiency in Two Massive Dead Galaxies at z ∼ 2
Vulcani, B.; Treu, T.; Jones, T. +8 more
Local massive early-type galaxies are believed to have completed most of their star formation ∼10 Gyr ago and evolved without having substantial star formation since that time. If so, their progenitors should have roughly solar stellar metallicities (Z *), comparable to their values today. We report the discovery of two lensed massive (…
Obscured Star Formation in the Host Galaxies of Superluminous Supernovae
Morokuma, T.; Matsuda, Y.; Konishi, M. +7 more
We present the results of 3 GHz radio continuum observations of the eight host galaxies of superluminous supernovae (SLSNe) at 0.1 < z < 0.3 by using the Karl G. Jansky Very Large Array. Four host galaxies are detected significantly, and two of them are found to have high star formation rates (SFRs > 20 M ⊙ yr-1) der…
Betatron Cooling of Suprathermal Electrons in the Terrestrial Magnetotail
Xu, Y.; Liu, Y. Y.; Liu, C. M. +1 more
The cigar distribution of suprathermal electrons (40-200 keV), showing electron pitch angles primarily in the parallel and anti-parallel directions, has been frequently observed in the terrestrial magnetotail. The formation of such a distribution is typically attributed to Fermi acceleration, betatron cooling, or a combination of these. To date, F…
The TRENDS High-contrast Imaging Survey. VII. Discovery of a Nearby Sirius-like White Dwarf System (HD 169889)
Stone, Jordan; Ertel, Steve; Spalding, Eckhart +8 more
Monitoring the long-term radial velocity (RV) and acceleration of nearby stars has been proven as an effective method for directly detecting binary and substellar companions. Some fraction of nearby RV trend systems are expected to be comprised of compact objects that likewise induce a systemic Doppler signal. In this paper, we report the discover…
Observational Evidence of Magnetic Reconnection Associated with Magnetic Flux Cancellation
Yang, Bo; Yang, Jiayan; Bi, Yi +4 more
Using high spatial and temporal data from the Solar Dynamics Observatory (SDO) and the Interface Region Imaging Spectrograph (IRIS), several observational signatures of magnetic reconnection in the course of magnetic flux cancellation are presented, including two loop-loop interaction processes, multiple plasma blob ejections, and a sheet-like str…
Chandrasekhar and Sub-Chandrasekhar Models for the X-Ray Emission of Type Ia Supernova Remnants. I. Bulk Properties
Yamaguchi, Hiroya; Auchettl, Katie; Badenes, Carles +9 more
Type Ia supernovae originate from the explosion of carbon-oxygen white dwarfs in binary systems, but the exact nature of their progenitors remains elusive. The bulk properties of Type Ia supernova remnants, such as the radius and the centroid energy of the Fe Kα blend in the X-ray spectrum, are determined by the properties of the supernova ejecta …