Search Publications
A transition mass in the local Tully-Fisher relation
Weiner, Benjamin J.; Heckman, Timothy M.; Lotz, Jennifer M. +5 more
We study the stellar mass Tully-Fisher relation (TFR; stellar mass versus rotation velocity) for a morphologically blind selection of emission line galaxies in the field at redshifts 0.1 < z < 0.375. Kinematics (σg, Vrot) are measured from emission lines in Keck/DEIMOS spectra and quantitative morphology is measured fro…
Detection of Callisto's oxygen atmosphere with the Hubble Space Telescope
France, Kevin; Feldman, Paul D.; Strobel, Darrell F. +3 more
We report the result of a search for evidence of an O2-dominated atmosphere on Callisto, using the high far-ultraviolet sensitivity of the Hubble Space Telescope Cosmic Origins Spectrograph (COS). Observations of Callisto's leading/Jupiter-facing hemisphere show, for the first time, variable-strength atomic oxygen (O I) emissions with b…
Comet 67P/Churyumov-Gerasimenko: Constraints on its origin from OSIRIS observations
Jorda, L.; Lara, L. M.; Bertaux, J. -L. +38 more
Context. One of the main aims of the ESA Rosetta mission is to study the origin of the solar system by exploring comet 67P/Churyumov-Gerasimenko at close range.
Aims: In this paper we discuss the origin and evolution of comet 67P/Churyumov-Gerasimenko in relation to that of comets in general and in the framework of current solar system format…
Bicep2 III: Instrumental Systematics
Ade, P. A. R.; Bock, J. J.; Hildebrandt, S. R. +42 more
In a companion paper, we have reported a >5σ detection of degree scale B-mode polarization at 150 GHz by the Bicep2 experiment. Here we provide a detailed study of potential instrumental systematic contamination to that measurement. We focus extensively on spurious polarization that can potentially arise from beam imperfections. We present a he…
Radiative heating and cooling in the middle and lower atmosphere of Venus and responses to atmospheric and spectroscopic parameter variations
Kappel, D.; Arnold, G.; Haus, R.
A sophisticated radiative transfer model that considers absorption, emission, and multiple scattering by gaseous and particulate constituents over the broad spectral range 0.125-1000 µm is applied to calculate radiative fluxes and temperature change rates in the middle and lower atmosphere of Venus (0-100 km). Responses of these quantities t…
Radial Distributions of Sub-Populations in the Globular Cluster M15: A More Centrally Concentrated Primordial Population
Brodie, Jean P.; Strader, Jay; Larsen, Søren S. +3 more
We examine the radial distributions of stellar populations in the globular cluster (GC) M15, using Hubble Space Telescope/Wide Field Camera 3 (WFC3) photometry of red giants in the nitrogen-sensitive F343N-F555W color. Surprisingly, we find that giants with “primordial” composition (i.e., N abundances similar to those in field stars) are the most …
Suzaku broad-band spectrum of 4U 1705-44: probing the reflection component in the hard state
Robba, N. R.; Egron, E.; Papitto, A. +7 more
Iron emission lines at 6.4-6.97 keV, identified with Kα radiative transitions, are among the strongest discrete features in the X-ray band. These are one of the most powerful probes to infer the properties of the plasma in the innermost part of the accretion disc around a compact object. In this paper, we present a recent Suzaku observation, 100-k…
Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares (Invited Review)
Milligan, Ryan O.
The extreme ultra-violet (EUV) portion of the solar spectrum contains a wealth of diagnostic tools for probing the lower solar atmosphere in response to an injection of energy, particularly during the impulsive phase of solar flares. These include temperature- and density-sensitive line ratios, Doppler-shifted emission lines, nonthermal broadening…
Suprathermal electron environment of comet 67P/Churyumov-Gerasimenko: Observations from the Rosetta Ion and Electron Sensor
Frahm, R. A.; Goldstein, R.; Mokashi, P. +9 more
Context. The Rosetta spacecraft is currently escorting comet 67P/Churyumov-Gerasimenko until its perihelion approach at 1.2 AU. This mission has provided unprecedented views into the interaction of the solar wind and the comet as a function of heliocentric distance.
Aims: We study the interaction of the solar wind and comet at large heliocent…
Control of the topside Martian ionosphere by crustal magnetic fields
Gurnett, D. A.; Edberg, N. J. T.; Němec, F. +4 more
We present observations from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument onboard Mars Express of the thermal electron plasma density of the Martian ionosphere and investigate the extent to which it is influenced by the presence of Mars's remnant crustal magnetic fields. We use locally measured electron densi…