Search Publications
Observational Signatures of Simulated Reconnection Events in the Solar Chromosphere and Transition Region
De Pontieu, B.; Hansteen, V. H.; Heggland, L.
We present the results of numerical simulations of wave-induced magnetic reconnection in a model of the solar atmosphere. In the magnetic field geometry we study in this paper, the waves, driven by a monochromatic piston and a driver taken from Hinode observations, induce periodic reconnection of the magnetic field, and this reconnection appears t…
X-Ray and Ultraviolet Spectroscopy of Galactic Diffuse Hot Gas Along the Large Magellanic Cloud X-3 Sight Line
Yao, Y.; Mitsuda, K.; Wang, Q. D. +3 more
We present Suzaku spectra of X-ray emission in the fields just off the LMC X-3 sight line. O VII, O VIII, and Ne IX emission lines are clearly detected, suggesting the presence of an optically thin thermal plasma with an average temperature of 2.4 × 106 K. This temperature is significantly higher than that inferred from existing X-ray a…
Subsurface Circulations within Active Regions
Toomre, Juri; Hindman, Bradley W.; Haber, Deborah A.
Using high-resolution ring analysis, we deduce subsurface flows within magnetic active regions and within the quiet Sun. With this procedure, we are capable of measuring flows with a horizontal spatial resolution of 2° in heliographic angle (or roughly 20 Mm). From the resulting flow fields we deduce mean inflow rates into active regions, mean cir…
Thin embedded current sheets: Cluster observations of ion kinetic structure and analytical models
Malova, H. V.; Petrukovich, A. A.; Zelenyi, L. M. +3 more
Kinetic structure of embedded thin horizontal current sheets is investigated. Current density estimated by curlometer technique is in general agreement with a sum of electron and proton currents. Embedding of observed thin current sheets in the much wider plasma sheet is apparent in the current density profiles. Ion velocity distributions consist …
A refined chronology of catastrophic outflow events in Ares Vallis, Mars
Muller, Jan-Peter; Gupta, Sanjeev; Kim, Jung-Rack +2 more
We investigate the geomorphology and chronology of catastrophic flooding in a major martian outflow channel, Ares Vallis. We use recently acquired stereo and colour images and derived topographic data with grid-spacing of 50 m from the High Resolution Stereo Camera (HRSC) onboard Mars Express to constrain the detailed flood geomorphology of proxim…
An X-Ray/Optical Study of the Complex Dynamics of the Core of the Massive Intermediate-Redshift Cluster MACSJ0717.5+3745
Ebeling, Harald; Ma, Cheng-Jiun; Barrett, Elizabeth
Using CHANDRA, we investigate the spatial temperature distribution of the intracluster medium (ICM) within 700 kpc of the center of the massive merging cluster MACSJ0717.5+3745 at z = 0.55. Combining the X-ray evidence with information about the distribution and velocities of the cluster galaxies near the core provides us with a snapshot of the th…
The evolution of the red sequence slope in massive galaxy clusters
Smith, G. P.; Wardlow, J. L.; Edge, A. C. +2 more
We investigate the evolution of the optical and near-infrared colour-magnitude relation in an homogeneous sample of massive clusters from z = 1 to the present epoch. By comparing deep Hubble Space Telescope Advanced Camera for Surveys imaging of X-ray selected MAssive Cluster Survey (MACS) clusters at z ~ 0.5 to the similarly selected Las Campanas…
Star Formation History in the Small Magellanic Cloud: The Case of NGC 602
Degl'Innocenti, S.; Cignoni, M.; Tosi, M. +9 more
Deep Hubble Space Telescope/Advanced Camera for Surveys photometry of the young cluster NGC 602, located in the remote low-density "wing" of the Small Magellanic Cloud (SMC), reveals numerous pre-main-sequence (PMS) stars as well as young stars on the main sequence. The resolved stellar content thus provides a basis for studying the star formation…
Galaxy Size Problem at z = 3: Simulated Galaxies are too Small
Bryan, Greg L.; Cen, Renyue; Joung, M. Ryan
Using state-of-the-art adaptive mesh refinement cosmological hydrodynamic simulations with a spatial resolution of proper 0.21h -1 73 kpc in refined subregions embedded within a comoving cosmological volume (27.4h -1 73 Mpc)3, we investigate the sizes of galaxies at z = 3 in the standard cold …
The accretion disc in the quasar SDSS J0924+0219
Bate, N. F.; Floyd, David J. E.; Webster, R. L.
We present single-epoch multiwavelength optical-near-infrared observations of the `anomalous' lensed quasar SDSS J0924+0219, made using the Magellan 6.5-m Baade Telescope at Las Campanas Observatory, Chile. The data clearly resolve the anomalous bright image pair in the lensed system, and exhibit a strong decrease in the anomalous flux ratio with …