Search Publications
Fast Differential Emission Measure Inversion of Solar Coronal Data
Plowman, Joseph; Kankelborg, Charles; Martens, Petrus
We present a fast method for reconstructing differential emission measures (DEMs) using solar coronal data. The method consists of a fast, simple regularized inversion in conjunction with an iteration scheme for removal of residual negative emission measure. On average, it computes over 1000 DEMs s-1 for a sample active region observed …
A global multispecies single-fluid MHD study of the plasma interaction around Venus
Russell, C. T.; Wei, H. Y.; Toth, G. +3 more
This paper reports a new global multispecies single-fluid MHD model that was recently developed for Venus. This model is similar to the numerical model that has been successfully applied to Mars. Mass densities of proton and three important ionospheric ion species (O+, O2+, and CO2+) are self-…
Growth of brightest cluster galaxies via mergers since z=1
Collins, Chris A.; Burke, Claire
Hierarchical assembly within clusters of galaxies is tied directly to the evolution of the brightest cluster galaxies (BCGs), which dominate the stellar light in the centres of rich clusters. In this paper, we investigate the number of mergers on to BCGs in 14 X-ray-selected clusters over the redshift range 0.8 < z < 1.4 using HST imaging da…
A high Eddington-ratio, true Seyfert 2 galaxy candidate: implications for broad-line region models
Read, A. M.; Esquej, P.; Rodríguez-Pascual, P. M. +5 more
A bright, soft X-ray source was detected on 2010 July 14 during an XMM-Newton slew at a position consistent with the galaxy GSN 069 (z = 0.018). Previous ROSAT observations failed to detect the source and imply that GSN 069 is now ≥240 times brighter than it was in 1994 in the soft X-ray band. Optical spectra (from 2001 to 2003) are dominated by u…
An HST/WFC3-UVIS View of the Starburst in the Cool Core of the Phoenix Cluster
Veilleux, Sylvain; Bautz, Marshall W.; Reichardt, Christian L. +2 more
We present Hubble Space Telescope Wide Field Camera 3 observations of the core of the Phoenix cluster (SPT-CLJ2344-4243) in five broadband filters spanning rest-frame 1000-5500 Å. These observations reveal complex, filamentary blue emission, extending for >40 kpc from the brightest cluster galaxy. We observe an underlying, diffuse population of…
Detection of a High Brightness Temperature Radio Core in the Active-galactic-nucleus-driven Molecular Outflow Candidate NGC 1266
Morganti, Raffaella; Davis, Timothy A.; Nyland, Kristina +6 more
We present new high spatial resolution Karl G. Jansky Very Large Array (VLA) H I absorption and Very Long Baseline Array (VLBA) continuum observations of the active-galactic-nucleus-(AGN-)driven molecular outflow candidate NGC 1266. Although other well-known systems with molecular outflows may be driven by star formation (SF) in a central molecula…
Numerical Simulations of Coronal Mass Ejection on 2011 March 7: One-temperature and Two-temperature Model Comparison
Liu, Y.; Gombosi, T. I.; Toth, G. +6 more
During Carrington rotation (CR) 2107, a fast coronal mass ejection (CME; >2000 km s-1) occurred in active region NOAA 11164. This event is also associated with a solar energetic particle event. In this study, we present simulations of this CME with one-temperature (1T) and two-temperature (2T: coupled thermodynamics of the electron a…
The degeneracy between dust colour temperature and spectral index. Comparison of methods for estimating the β(T) relation
Juvela, M.; Ysard, N.; Montillaud, J. +1 more
Context. Submillimetre dust emission provides information on the physics of interstellar clouds and dust. However, noise can produce a spurious anticorrelation between the colour temperature TC and the spectral index β. These artefacts must be separated from the intrinsic β(T) relation of dust emission.
Aims: We compare methods tha…
Sizes of main-belt asteroids by combining shape models and Keck adaptive optics observations
Hanuš, J.; Marchis, F.; Ďurech, J.
We select 50 main-belt asteroids with a diameter between 20 and 400 km for which we have (i) shape models derived by the lightcurve inversion method and (ii) resolved observations of good quality collected with the Keck II adaptive optics (AO) system in the near-infrared. We derive the size of these asteroids by minimizing the difference between t…
Kelvin-Helmholtz Instabilities at the Sloshing Cold Fronts in the Virgo Cluster as a Measure for the Effective Intracluster Medium Viscosity
Churazov, E.; Forman, W. R.; Nulsen, P. E. J. +2 more
Sloshing cold fronts (CFs) arise from minor merger triggered gas sloshing. Their detailed structure depends on the properties of the intracluster medium (ICM): hydrodynamical simulations predict the CFs to be distorted by Kelvin-Helmholtz instabilities (KHIs), but aligned magnetic fields, viscosity, or thermal conduction can suppress the KHIs. Thu…