Search Publications
A Comparison of Flare Forecasting Methods. III. Systematic Behaviors of Operational Solar Flare Forecasting Systems
Leka, K. D.; Gallagher, Peter T.; Murray, Sophie A. +21 more
A workshop was recently held at Nagoya University (2017 October 31-November 2), sponsored by the Center for International Collaborative Research, at the Institute for Space-Earth Environmental Research, Nagoya University, Japan, to quantitatively compare the performance of today’s operational solar flare forecasting facilities. Building upon Paper…
Relationship between the Metallicity of the Circumgalactic Medium and Galaxy Orientation
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +4 more
We investigate the geometric distribution of gas metallicities in the circumgalactic medium (CGM) around 47, z < 0.7 galaxies from the “Multiphase Galaxy Halos” Survey. Using a combination of quasar spectra from Hubble Space Telescope (HST)/COS and from Keck/HIRES or Very Large Telescope/UVES, we measure column densities of, or determine limits…
Far-infrared Properties of the Bright, Gravitationally Lensed Quasar J0439+1634 at z = 6.5
Fan, Xiaohui; Keeton, Charles R.; Walter, Fabian +11 more
We present IRAM NOrthern Extended Millimeter Array, James Clerk Maxwell Telescope/Submillimetre Common-User Bolometer Array-2 and Very Large Array (VLA) observations of the most distant known gravitationally lensed quasar, J0439+1634 at z = 6.5. We detect strong dust emission, [C II] 158 µm, [C I] 369 µm, [O I] 146 µm, CO(6-5), C…
The Mass of Stirring Bodies in the AU Mic Debris Disk Inferred from Resolved Vertical Structure
Hughes, A. Meredith; Carpenter, John; Wilner, David +9 more
The vertical distribution of dust in debris disks is sensitive to the number and size of large planetesimals dynamically stirring the disk, and is therefore well-suited for constraining the prevalence of otherwise unobservable Uranus and Neptune analogs. Information regarding stirring bodies has previously been inferred from infrared and optical o…
Kepler-730: A Hot Jupiter System with a Close-in, Transiting, Earth-sized Planet
Schneider, Donald P.; Mahadevan, Suvrath; Majewski, Steven R. +9 more
Kepler-730 is a planetary system hosting a statistically validated hot Jupiter in a 6.49 day orbit and an additional transiting candidate in a 2.85 day orbit. We use spectroscopic radial velocities from the APOGEE-2N instrument, Robo-AO contrast curves, and Gaia distance estimates to statistically validate the planetary nature of the additional Ea…
Searches after Gravitational Waves Using ARizona Observatories (SAGUARO): System Overview and First Results from Advanced LIGO/Virgo’s Third Observing Run
Gabor, P.; Palazzi, E.; Smith, N. +54 more
We present Searches After Gravitational-waves Using ARizona Observatories (SAGUARO), a comprehensive effort dedicated to the discovery and characterization of optical counterparts to gravitational-wave (GW) events. SAGUARO utilizes ground-based facilities ranging from 1.5 to 10 m in diameter, located primarily in the Northern Hemisphere. We provid…
NuSTAR Observations of the Accreting Atolls GX 3+1, 4U 1702-429, 4U 0614+091, and 4U 1746-371
Harrison, F. A.; Degenaar, N.; Miller, J. M. +7 more
Atoll sources are accreting neutron star (NS) low-mass X-ray binaries. We present a spectral analysis of four persistent atoll sources (GX 3+1, 4U 1702-429, 4U 0614+091, and 4U 1746-371) observed for ∼20 ks each with NuSTAR to determine the extent of the inner accretion disk. These sources range from an apparent luminosity of 0.006-0.11 of the Edd…
Flame-like Ellerman Bombs and Their Connection to Solar Ultraviolet Bursts
Chen, Yajie; Cao, Wenda; Wang, Haimin +6 more
Ellerman bombs (EBs) are small-scale intense brightenings in Hα wing images, which are generally believed to be signatures of magnetic reconnection around the temperature minimum region of the solar atmosphere. They have a flame-like morphology when observed near the solar limb. Recent observations from the Interface Region Imaging Spectrograph (I…
The Evolution of the He II-ionizing Background at Redshifts 2.3 < z < 3.8 Inferred from a Statistical Sample of 24 HST/COS He II Lyα Absorption Spectra
Hennawi, Joseph F.; Worseck, Gábor; Prochaska, J. Xavier +1 more
We present measurements of the large-scale (≈40 comoving Mpc) effective optical depth of He II Lyα absorption, {τ }eff}, at 2.54 < z < 3.86 toward 16 He II-transparent quasars observed with the Cosmic Origins Spectrograph on the Hubble Space Telescope, to characterize the ionization state of helium in the intergalactic medium (IGM…
New Constraints on the Nuclear Equation of State from the Thermal Emission of Neutron Stars in Quiescent Low-mass X-Ray Binaries
Guillot, Sebastien; Webb, Natalie; Reisenegger, Andreas +3 more
This paper presents a new analysis of the thermal emission from the neutron star (NS) surface to constrain the dense matter equation of state. We employ an empirical parameterization of the equation of state with a Markov Chain Monte Carlo approach to consistently fit the spectra of quiescent low-mass X-ray binaries in globular clusters with well-…