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Simulating Deep Hubble Images with Semi-empirical Models of Galaxy Formation
White, Richard L.; Fall, S. Michael; Szalay, Alexander S. +1 more
We simulate deep images from the Hubble Space Telescope (HST) using semi-empirical models of galaxy formation with only a few basic assumptions and parameters. We project our simulations all the way to the observational domain, adding cosmological and instrumental effects to the images, and analyze them in the same way as real HST images ("forward…
A Multiwavelength Study of Three Hybrid Blazars
Marshall, H. L.; Kharb, P.; Lister, M. L. +3 more
We present multiwavelength imaging observations of PKS 1045-188, 8C 1849+670, and PKS 2216-038, three radio-loud active galactic nuclei from the MOJAVE-Chandra Sample that straddle the Fanaroff-Riley (FR) boundary between low- and high-power jets. These hybrid sources provide an excellent opportunity to study jet emission mechanisms and the influe…
The naked nuclei of low ionization nuclear emission line regions
Capetti, Alessandro; Balmaverde, Barbara
We analyze HST spectra and Chandra observations of a sample of 21 low ionization nuclear emission line regions (LINERs), at least 18 of which genuine active galactic nuclei. We find a correlation between the X-rays and emission lines luminosities, extending over three orders of magnitude and with a dispersion of 0.36 dex; no differences emerge bet…
The Herschel view of the nebula around the luminous blue variable star AG Carinae
Nazé, Y.; Rauw, G.; Groenewegen, M. A. T. +5 more
Far-infrared Herschel PACS imaging and spectroscopic observations of the nebula around the luminous blue variable (LBV) star AG Car have been obtained along with optical imaging in the Hα+[ N ii ] filter. In the infrared light, the nebula appears as a clumpy ring shell that extends up to 1.2 pc with an inner radius of 0.4 pc. It coincides with the…
Optical Detection of the Pictor A Jet and Tidal Tail: Evidence against an IC/CMB jet
Perlman, Eric S.; Urry, C. Megan; Lenc, Emil +6 more
New images of the FR II radio galaxy Pictor A from the Hubble Space Telescope reveal a previously undiscovered tidal tail, as well as a number of jet knots coinciding with a known X-ray and radio jet. The tidal tail is approximately 5″ wide (3 kpc projected), starting 18″ (12 kpc) from the center of Pictor A, and extends more than 90″ (60 kpc). Th…
Electron acceleration by parallel and perpendicular electric fields during magnetic reconnection without guide field
Chen, L. -J.; Bessho, N.; Bhattacharjee, A. +1 more
Electron acceleration due to the electric field parallel to the background magnetic field during magnetic reconnection with no guide field is investigated by theory and two-dimensional electromagnetic particle-in-cell simulations and compared with acceleration due to the electric field perpendicular to the magnetic field. The magnitude of the para…
Constraints on Spatial Variations in the Fine-structure Constant from Planck
Cooray, Asantha; Smidt, Joseph; O'Bryan, Jon +1 more
We use the cosmic microwave background (CMB) anisotropy data from Planck to constrain the spatial fluctuations of the fine-structure constant α at a redshift of 1100. We use a quadratic estimator to measure the four-point correlation function of the CMB temperature anisotropies and extract the angular power spectrum fine-structure constant spatial…
Vertical structures induced by embedded moonlets in Saturn's rings
Salo, Heikki; Spahn, Frank; Seiß, Martin +1 more
We study the vertical extent of propeller structures in Saturn's rings (i) by extending the model of Spahn and Sremčević (Spahn, F., Sremčević, M. [2000]. Astron. Astrophys., 358, 368-372) to include the vertical direction and (ii) by performing N-body box simulations of a perturbing moonlet embedded into the rings. We find that the gravitational …
Solar illumination control of ionospheric outflow above polar cap arcs
Dandouras, I.; Fear, R. C.; De Keyser, J. +4 more
We measure the flux density, composition, and energy of outflowing ions above the polar cap, accelerated by quasi-static electric fields parallel to the magnetic field and associated with polar cap arcs, using Cluster. Mapping the spacecraft position to its ionospheric foot point, we analyze the dependence of these parameters on the solar zenith a…
Multi-wavelength Analysis of the Galactic Supernova Remnant MSH 11-61A
Auchettl, Katie; Slane, Patrick; Foster, Adam R. +2 more
Due to its centrally bright X-ray morphology and limb brightened radio profile, MSH 11-61A (G290.1-0.8) is classified as a mixed morphology supernova remnant (SNR). H i and CO observations determined that the SNR is interacting with molecular clouds found toward the north and southwest regions of the remnant. In this paper we report on the detecti…