Search Publications
Effect of Enceladus's rapid synchronous spin on interpretation of Cassini gravity
McKinnon, William B.
Enceladus's degree 2 gravity, determined by Cassini, is nominally nonhydrostatic to 3σ (J2/C22 = 3.38-3.63, as opposed to 10/3). Iess et al. (2014) interpret this in terms of a hydrostatic interior (core) and isostatic (not hydrostatic) floating ice shell. Enceladus's rapid (1.37 d) synchronous spin and tide distorts its shap…
Subsurface properties and early activity of comet 67P/Churyumov-Gerasimenko
Hartogh, Paul; Lellouch, Emmanuel; Ip, Wing-Huen +21 more
Heat transport and ice sublimation in comets are interrelated processes reflecting properties acquired at the time of formation and during subsequent evolution. The Microwave Instrument on the Rosetta Orbiter (MIRO) acquired maps of the subsurface temperature of comet 67P/Churyumov-Gerasimenko, at 1.6 mm and 0.5 mm wavelengths, and spectra of wate…
Observations of discrete harmonics emerging from equatorial noise
Dandouras, Iannis; Walker, Simon N.; Balikhin, Michael A. +7 more
A number of modes of oscillations of particles and fields can exist in space plasmas. Since the early 1970s, space missions have observed noise-like plasma waves near the geomagnetic equator known as `equatorial noise'. Several theories were suggested, but clear observational evidence supported by realistic modelling has not been provided. Here we…
The Relation between Solar Eruption Topologies and Observed Flare Features. I. Flare Ribbons
Pariat, E.; DeLuca, E. E.; McKillop, S. +5 more
In this paper we present a topological magnetic field investigation of seven two-ribbon flares in sigmoidal active regions observed with Hinode, STEREO, and Solar Dynamics Observatory. We first derive the 3D coronal magnetic field structure of all regions using marginally unstable 3D coronal magnetic field models created with the flux rope inserti…
Diagnosing the accretion flow in ultraluminous X-ray sources using soft X-ray atomic features
Middleton, Matthew J.; Roberts, Timothy P.; Walton, Dominic J. +5 more
The lack of unambiguous detections of atomic features in the X-ray spectra of ultraluminous X-ray sources (ULXs) has proven a hindrance in diagnosing the nature of the accretion flow. The possible association of spectral residuals at soft energies with atomic features seen in absorption and/or emission and potentially broadened by velocity dispers…
Beyond six parameters: Extending Λ CDM
Di Valentino, Eleonora; Melchiorri, Alessandro; Silk, Joseph
Cosmological constraints are usually derived under the assumption of a six-parameter Λ CDM theoretical framework or simple one-parameter extensions. In this paper we present, for the first time, cosmological constraints in a significantly extended scenario, varying up to 12 cosmological parameters simultaneously, including the sum of neutrino mass…
On the role played by magnetic expansion factor in the prediction of solar wind speed
Riley, Pete; Linker, Jon A.; Arge, C. Nick
Over the last two decades, the Wang-Sheeley-Arge (WSA) model has evolved significantly. Beginning as a simple observed correlation between the expansion factor of coronal magnetic field lines and the measured speed of the solar wind at 1 AU (the Wang-Sheeley (WS) model), the WSA model now drives NOAA's first operational space weather model, provid…
The Dust and Gas Content of the Crab Nebula
Barlow, M. J.; Owen, P. J.
We have constructed mocassin photoionization plus dust radiative transfer models for the Crab Nebula core-collapse supernova (CCSN) remnant, using either smooth or clumped mass distributions, in order to determine the chemical composition and masses of the nebular gas and dust. We computed models for several different geometries suggested for the …
Delensing the CMB with the cosmic infrared background
Sherwin, Blake D.; Schmittfull, Marcel
As confusion with lensing B modes begins to limit experiments that search for primordial B-mode polarization, robust methods for delensing the cosmic microwave background (CMB) polarization sky are becoming increasingly important. We investigate in detail the possibility of delensing the CMB with the cosmic infrared background (CIB), emission from…
Photometric properties of comet 67P/Churyumov-Gerasimenko from VIRTIS-M onboard Rosetta
Bellucci, G.; Mottola, S.; Fornasier, S. +17 more
Aims: We investigate the nucleus photometric properties of the comet 67P/Churyumov-Gerasimenko as observed by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) onboard the Rosetta spacecraft. Both full-disk and disk-resolved images of the comet have been analyzed, deriving light and phase curves as well as a photometric reduction…