Search Publications
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…
Micron-sized forsterite grains in the pre-planetary nebula of IRAS 17150-3224. Searching for clues to the mysterious evolution of massive AGB stars
Waters, L. B. F. M.; Blommaert, J. A. D. L.; Min, M. +3 more
Aims: We study the grain properties and location of the forsterite crystals in the circumstellar environment of the pre-planetary nebula (PPN) IRAS 17150-3224 in order to learn more about the as yet poorly understood evolutionary phase prior to the PPN.
Methods: We use the best-fit model for IRAS 17150-3224 of Meixner et al. (2002, ApJ, …
Strategy to minimize dust foregrounds in B -mode searches
Kovetz, Ely D.; Kamionkowski, Marc
The Planck satellite has identified several patches of sky with low polarized dust emission, obvious targets for searches for the cosmic microwave background B -mode signal from inflationary gravitational waves. Still, given the Planck measurement uncertainties, the polarized dust foregrounds in these different candidate patches may differ by an o…
Anomalous Earth flybys of spacecraft
Wilhelm, Klaus; Dwivedi, Bhola N.
A small deviation from the