Search Publications
Saturn’s Great Storm of 2010-2011: Evidence for ammonia and water ices from analysis of VIMS spectra
Baines, K. H.; Sromovsky, L. A.; Fry, P. M.
Our analysis of Cassini/VIMS near-infrared spectra of Saturn’s Great Storm of 2010-2011 reveals a multi-component aerosol composition comprised primarily of ammonia ice, with a significant component of water ice. The most likely third component is ammonium hydrosulfide or some weakly absorbing material similar to what dominates visible clouds outs…
The UV/optical spectra of the Type Ia supernova SN 2010jn: a bright supernova with outer layers rich in iron-group elements
Gal-Yam, A.; Kulkarni, S. R.; Sullivan, M. +19 more
Radiative transfer studies of Type Ia supernovae (SNe Ia) hold the promise of constraining both the density profile of the SN ejecta and its stratification by element abundance which, in turn, may discriminate between different explosion mechanisms and progenitor classes. Here we analyse the Type Ia SN 2010jn (PTF10ygu) in detail, presenting and e…
Young Stars near Earth: The Octans-Near Association and Castor Moving Group
Zuckerman, B.; Song, Inseok; Schneider, Adam +1 more
All cataloged stellar moving groups and associations with ages <=100 Myr and within 100 pc of Earth have Galactic space motions (UVW) situated in a "good box" with dimensions ~20 km s-1 on a side. Torres et al. defined the Octans Association as a group of 15 stars with age "20 Myr?" and located ~140 pc from Earth, but with average V …
Helioseismology of Pre-emerging Active Regions. II. Average Emergence Properties
Leka, K. D.; Barnes, G.; Birch, A. C. +2 more
We report on average subsurface properties of pre-emerging active regions as compared to areas where no active region emergence was detected. Helioseismic holography is applied to samples of the two populations (pre-emergence and without emergence), each sample having over 100 members, which were selected to minimize systematic bias, as described …
Properties of outflow-driven sawtooth substorms
Lyon, J. G.; Rogers, B. N.; Ouellette, J. E. +2 more
The mechanisms by which ionospheric O+ stretches the plasma sheet causing variations in polar cap flux during magnetospheric sawtooth substorms are investigated using the multi-fluid Lyon-Fedder-Mobarry simulation code. O+ outflow is induced in the simulation by Alfvénic Poynting flux flowing to low altitude during the sawtoo…
Nonlinear electron acceleration by oblique whistler waves: Landau resonance vs. cyclotron resonance
Artemyev, A. V.; Agapitov, O. V.; Krasnoselskikh, V. V. +2 more
This paper is devoted to the study of the nonlinear interaction of relativistic electrons and high amplitude strongly oblique whistler waves in the Earth's radiation belts. We consider electron trapping into Landau and fundamental cyclotron resonances in a simplified model of dipolar magnetic field. Trapping into the Landau resonance corresponds t…
The unbiased measurement of ultraviolet spectral slopes in low-luminosity galaxies at z ≈ 7
McLure, R. J.; Dunlop, J. S.; Rogers, A. B.
The ultraviolet (UV) continuum slope β, typically observed at z ≈ 7 in Hubble Space Telescope (HST) WFC3/IR bands via the J - H colour, is a useful indicator of the age, metallicity and dust content of high-redshift stellar populations. Recent studies have shown that the redward evolution of β with cosmic time from redshift 7 to 4 can be largely e…
Environmental Effects in the Interaction and Merging of Galaxies in zCOSMOS
Kneib, J. -P.; Cimatti, A.; Sargent, M. T. +56 more
We analyze the environments and galactic properties (morphologies and star formation histories) of a sample of 153 close kinematic pairs in the redshift range 0.2 < z < 1 identified in the zCOSMOS-bright 10 k spectroscopic sample of galaxies. Correcting for projection effects, the fraction of close kinematic pairs is three times higher in th…
Concurrent Supermassive Black Hole and Galaxy Growth: Linking Environment and Nuclear Activity in z = 2.23 Hα Emitters
Lehmer, B. D.; Hornschemeier, A. E.; Smail, Ian +9 more
We present results from a ≈100 ks Chandra observation of the 2QZ Cluster 1004+00 structure at z = 2.23 (hereafter 2QZ Clus). 2QZ Clus was originally identified as an overdensity of four optically-selected QSOs at z = 2.23 within a 15 × 15 arcmin2 region. Narrow-band imaging in the near-IR (within the K band) revealed that the structure …
Fomalhaut b: Independent Analysis of the Hubble Space Telescope Public Archive Data
Macintosh, Bruce; Zuckerman, B.; Marois, Christian +1 more
The nature and even the existence of a putative planet-mass companion ("Fomalhaut b") to Fomalhaut has been debated since 2008. In the present paper, we reanalyze the multi-epoch ACS/STIS/WFC3 Hubble Space Telescope (HST) optical/near-infrared images on which the discovery and some other claims were based. We confirm that the HST images do reveal …