Search Publications
The Properties of Low Redshift Intergalactic O VI Absorbers Determined from High S/N Observations of 14 QSOs with the Cosmic Origins Spectrograph
Savage, B. D.; Wakker, B. P.; Stocke, J. T. +4 more
We report on the observed properties of the plasma revealed through high signal-to-noise observations of 54 intervening O VI absorption systems containing 85 O VI and 133 H I components in a blind survey of 14 QSOs observed at ~18 km s-1 resolution with the Cosmic Origins Spectrograph over a redshift path of 3.52 at z < 0.5. Simple s…
Improved Ni I log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
Sneden, C.; Wood, M. P.; Lawler, J. E. +1 more
Atomic transition probability measurements for 371 Ni I lines in the UV through near-IR are reported. Branching fractions from data recorded using a Fourier transform spectrometer and a new echelle spectrograph are combined with published radiative lifetimes to determine these transition probabilities. Generally good agreement is found in comparis…
Warm Breeze from the Starboard Bow: a New Population of Neutral Helium in the Heliosphere
Wurz, P.; McComas, D. J.; Fuselier, S. A. +9 more
We investigate the signals from neutral helium atoms observed in situ from Earth orbit in 2010 by the Interstellar Boundary Explorer (IBEX). The full helium signal observed during the 2010 observation season can be explained as a superposition of pristine neutral interstellar He gas and an additional population of neutral helium that we call the W…
The Absolute Calibration of the EUV Imaging Spectrometer on Hinode
Landi, Enrico; Warren, Harry P.; Ugarte-Urra, Ignacio
We investigate the absolute calibration of the EUV Imaging Spectrometer (EIS) on Hinode by comparing EIS full-disk mosaics with irradiance observations from the EUV Variability Experiment on the Solar Dynamics Observatory. We also use extended observations of the quiet corona above the limb combined with a simple differential emission measure mode…
Spectroscopic Redshifts of Galaxies within the Frontier Fields
Ebeling, Harald; Ma, Cheng-Jiun; Barrett, Elizabeth
We present a catalog of 1921 spectroscopic redshifts measured in the fields of the massive galaxy clusters MACSJ0416.1-2403 (z = 0.397), MACSJ0717.5+3745 (z = 0.546), and MACSJ1149.5+2223 (z = 0.544), i.e., three of the four clusters selected by Space Telescope Science Institute as the targets of the Frontier Fields (FFs) initiative for studies of…
Fluctuations and Flares in the Ultraviolet Line Emission of Cool Stars: Implications for Exoplanet Transit Observations
Loyd, R. O. Parke; France, Kevin
Variations in stellar flux can potentially overwhelm the photometric signal of a transiting planet. Such variability has not previously been well-characterized in the ultraviolet lines used to probe the inflated atmospheres surrounding hot Jupiters. Therefore, we surveyed 38 F-M stars for intensity variations in four narrow spectroscopic bands: tw…
Improved V II Log(gf) Values, Hyperfine Structure Constants, and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
Sneden, C.; Wood, M. P.; Lawler, J. E. +2 more
New experimental absolute atomic transition probabilities are reported for 203 lines of V II. Branching fractions are measured from spectra recorded using a Fourier transform spectrometer and an echelle spectrometer. The branching fractions are normalized with radiative lifetime measurements to determine the new transition probabilities. Generally…
A Sensitive Identification of Warm Debris Disks in the Solar Neighborhood through Precise Calibration of Saturated WISE Photometry
Metchev, Stanimir A.; Heinze, Aren; Patel, Rahul I.
We present a sensitive search for WISE W3 (12 µm) and W4 (22 µm) excesses from warm optically thin dust around Hipparcos main sequence stars within 75 pc from the Sun. We use contemporaneously measured photometry from WISE, remove sources of contamination, and derive and apply corrections to saturated fluxes to attain optimal sensitivi…
Infrared Spectra and Photometry Of Complete Samples of Palomar-Green and Two Micron All Sky Survey Quasars
Balog, Z.; Rieke, G. H.; Shi, Yong +2 more
As a step toward a comprehensive overview of the infrared (IR) diagnostics of the central engines and host galaxies of quasars at low redshift, we present Spitzer Space Telescope spectroscopic (5-40 µm) and photometric (24, 70, and 160 µm) measurements of all Palomar-Green (PG) quasars at z < 0.5 and Two Micron All Sky Survey (2MASS…
Periodic and Aperiodic Variability in the Molecular Cloud ρ Ophiuchus
Plavchan, Peter; Parks, J. Robert; White, Russel J. +1 more
Presented are the results of a near-IR photometric survey of 1678 stars in the direction of the ρ Ophiuchus (ρ Oph) star forming region using data from the 2MASS Calibration Database. For each target in this sample, up to 1584 individual J-, H-, and Ks -band photometric measurements with a cadence of ~1 day are obtained over three obser…