Search Publications
Particle Energization during Solar Maximum: Diffusive Shock Acceleration at Multiple Shocks
Zank, G. P.; Neergaard Parker, L.
We present a model for the acceleration of particles at multiple shocks using an approach related to box models. A distribution of particles is diffusively accelerated inside the box while simultaneously experiencing decompression through adiabatic expansion and losses from the convection and diffusion of particles out of the box by either the met…
X-ray time delays from the Seyfert 2 galaxy IRAS 18325-5926
Vaughan, S.; Alston, W. N.; Lobban, A. P.
Using new XMM-Newton observations we detect hard X-ray time lags in the rapid variability of the Compton-thin Seyfert 2 galaxy IRAS 18325-5926. The higher-energy X-ray variations lag behind correlated lower-energy variations by up to ∼3 ks and the magnitude of the lag increases clearly with energy separation between the energy bands. We find that …
Near-infrared Hubble Space Telescope polarimetry of a complete sample of narrow-line radio galaxies
Tadhunter, C. N.; Ramírez, E. A.; Axon, D. +5 more
We present an analysis of 2.05 µm Hubble Space Telescope polarimetric data for a sample of 13 nearby Fanaroff-Riley type II (FRII) 3CR radio sources (0.03 < z < 0.11) that are classified as narrow-line radio galaxies (NLRG) at optical wavelengths. We find that the compact cores of the NLRG in our sample are intrinsically highly polariz…
Large tensor-to-scalar ratio from composite inflation
Channuie, Phongpichit; Karwan, Khamphee
The claimed detection of the BICEP2 experiment on the primordial B-mode of cosmic microwave background polarization suggests that cosmic inflation possibly takes place at the energy around the grand unified theory scale given a constraint on the tensor-to-scalar ratio, i.e., r≃0.20. In this report, we revisit single-field (slow-roll) composite inf…
Comparative Analysis of a Transition Region Bright Point with a Blinker and Coronal Bright Point Using Multiple EIS Emission Lines
Orange, N. Brice; Oluseyi, Hakeem M.; Chesny, David L. +5 more
Since their discovery 20 year ago, transition region bright points have never been observed spectroscopically. Bright point properties have not been compared with similar transition region and coronal structures. In this work we have investigated three transient quiet Sun brightenings including a transition region bright point (TR BP), a coronal b…
Star Clusters in a Nuclear Star Forming Ring: The Disappearing String of Pearls
Barway, Sudhanshu; Väisänen, Petri; Randriamanakoto, Zara
An analysis of the star cluster population in a low-luminosity early-type galaxy, NGC 2328, is presented. The clusters are found in a tight star forming nuclear spiral/ring pattern and we also identify a bar from structural two-dimensional decomposition. These massive clusters are forming very efficiently in the circumnuclear environment and they …
Non-uniform global methane distribution in Titan’s troposphere evidenced by Cassini radio occultations
Tokano, Tetsuya
The global distribution of atmospheric pressure retrieved from Cassini radio occultations is reanalyzed and interpreted in a meteorological context. The retrieval of Titan's atmospheric pressure profile from radio occultations is ambiguous because it depends on the methane mole fraction, which is not precisely known in the troposphere beyond the e…
The Global Morphology of the Solar Wind Interaction with Comet Churyumov-Gerasimenko
Mendis, D. A.; Horányi, M.
The forthcoming Rosetta-Philae mission to comet 67P/Churyumov-Gerasimenko provides a novel opportunity to observe the variable nature of the solar wind interaction with a comet over an extended range of heliocentric distance. We use a simple analytical one-dimensional MHD model to estimate the sizes of the two most prominent features in the global…
The Flow-chart Loop: Temperature, Density, and Cooling Observables Supporting Nanoflare Coronal Heating Models
Schmelz, J. T.; Pathak, S.; Christian, G. M. +2 more
We have tested three controversial properties for a target loop observed with the Atmospheric Imaging Assembly: (1) overdense loops; (2) long-lifetime loops; and (3) multithermal loops. Our loop is overdense by a factor of about 10 compared to results expected from steady uniform heating models. If this were the only inconsistency, our loop could …
The Disk around the Brown Dwarf KPNO Tau 3
Duchêne, Gaspard; Chrysostomou, Antonio; Di Francesco, James +4 more
We present submillimeter observations of the young brown dwarfs KPNO Tau 1, KPNO Tau 3, and KPNO Tau 6 at 450 µm and 850 µm taken with the Submillimetre Common-User Bolometer Array on the James Clerk Maxwell Telescope. KPNO Tau 3 and KPNO Tau 6 have been previously identified as Class II objects hosting accretion disks, whereas KPNO Ta…