Search Publications
Missions
Journals
Publication Years
Modeling Extragalactic Foregrounds and Secondaries for Unbiased Estimation of Cosmological Parameters from Primary Cosmic Microwave Background Anisotropy
Doré, O.; Dudley, J.; Knox, L. +5 more
Using the latest physical modeling and constrained by the most recent data, we develop a phenomenological parameterized model of the contributions to intensity and polarization maps at millimeter wavelengths from external galaxies and Sunyaev-Zeldovich effects. We find such modeling to be necessary for estimation of cosmological parameters from Pl…
The Orbit of Charon is Circular
Buie, Marc W.; Grundy, William M.; Tholen, David J.
We present a detailed analysis of the orbit of Charon where we show its orbit to be circular. This analysis explores the effects of surface albedo variations on the astrometry and the resulting errors in the orbital elements. We present two new epochs of data from the Hubble Space Telescope taken in 2008 and 2010 and combine that with a re-analysi…
Locations of thin liquid water layers on present-day Mars
Kereszturi, Akos; Rivera-Valentin, Edgard G.
CRISM indicates the presence of water ice patches in Richardson crater, located on Mars’ southern polar region at the area of the seasonal ice cap. Numerical simulations suggest that the maximum daytime temperature of the ice at these locations is between 195 and 220 K during local spring. Previous studies suggest that at these temperatures liquid…
Characterizing CO Fourth Positive Emission in Young Circumstellar Disks
Herczeg, Gregory J.; Valenti, Jeff A.; Brown, Alexander +5 more
Carbon monoxide is a commonly used IR/submillimeter tracer of gas in protoplanetary disks. We present an analysis of ultraviolet CO emission in Hubble Space Telescope Cosmic Origins Spectrograph spectra for 12 Classical T Tauri stars (CTTSs). Several ro-vibrational bands of the CO A 1Π-X 1Σ+ (Fourth Positive) elect…
Cosmic Origins Spectrograph Observations of Warm Intervening Gas at z ~ 0.325 toward 3C 263
Savage, Blair D.; Wakker, Bart P.; Narayanan, Anand
We present HST/COS high-S/N observations of the z = 0.32566 multiphase absorber toward 3C 263. The Cosmic Origins Spectrograph (COS) data show absorption from H I (Lyα to Lyθ), O VI, C III, N III, Si III, and C II. The Ne VIII in this absorber is detected in the FUSE spectrum along with O III, O IV, and N IV. The low and intermediate ions are kine…
Rheologies and ages of lava flows on Elysium Mons, Mars
Reiss, Dennis; Hiesinger, Harald; Pasckert, Jan Hendrik
We present results of our study of the rheologies and ages of lava flows in the Elysium Mons region of Mars. Previous studies have shown that the geometric dimensions of lava flows reflect rheological properties such as yield strength, effusion rate and viscosity. In this study the rheological properties of lava flows in the Elysium Mons region we…
Revisiting the Chlorine Abundance in Diffuse Interstellar Clouds from Measurements with the Copernicus Satellite
Federman, S. R.; Sheffer, Y.; Moomey, Daniel
We reanalyzed interstellar Cl I and Cl II spectra acquired with the Copernicus satellite. The directions for this study come from those of Crenny & Federman and sample the transition from atomic to molecular-rich clouds where the unique chemistry leading to molecules containing chlorine is initiated. Our profile syntheses relied on up-to-date …
A Lighthouse Effect in Eta Carinae
Madura, Thomas I.; Groh, Jose H.
We present a new model for the behavior of scattered time-dependent, asymmetric near-UV emission from the nearby ejecta of η Car. Using a three-dimensional (3D) hydrodynamical simulation of η Car's binary colliding winds, we show that the 3D binary orientation derived by Madura et al. in 2012 is capable of explaining the asymmetric near-UV variabi…
AGN Activity and the Misaligned Hot ISM in the Compact Radio Elliptical NGC 4278
Trinchieri, Ginevra; Zezas, Andreas; Gallagher, John S. +5 more
The analysis of a deep (579 ks) Chandra ACIS pointing of the elliptical galaxy NGC 4278, which hosts a low-luminosity active galactic nucleus (AGN) and compact radio emission, allowed us to detect extended emission from hot gas out to a radius of ~5 kpc, with 0.5-8 keV luminosity of 2.4 × 1039 erg s-1. The emission is elongat…
Production of neutral species in Titan's ionosphere through dissociative recombination of ions
Carrasco, Nathalie; Plessis, Sylvain; Dobrijevic, Michel +1 more
The production rates of neutral species by dissociative recombination (DR) of molecular ions with electrons in the ionosphere of Titan are quantified by a new model, including, for the first time, all the available kinetic data on this process. The calculation is based on the ion densities measured by the INMS instrument on Cassini orbiter during …