Search Publications

Titan's plasma environment: 3D hybrid kinetic modeling of the TA flyby and comparison with CAPS-ELS and RPWS LP observations

Hartle, R. E.; Sittler, E. C.; Cooper, J. F. +2 more

In this report we discuss the global plasma environment of the TA flyby from the perspective of 3D hybrid modeling. In our model the background, pickup, and ionospheric ions are considered as particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our …

On the possible correlation of Galactic very-high energy source locations and enhancements of the surface density in the Galactic plane

Torres, D. F.; de Oña Wilhelmi, E.; Pedaletti, G.

Aims: The association of very-high energy sources with regions of the sky rich in dust and gas has been noticed in the study of individual very-high energy (VHE; E ≳ 100 GeV) sources. However, the statistical significance of this correlation for the whole population of TeV detections has not been assessed yet. Here, we present a study of the …

Faint X-Ray Binaries and their Optical Counterparts in M31

Barmby, P.; Vulic, N.; Gallagher, S. C.

X-ray binaries (XRBs) are probes of both star formation and stellar mass, but more importantly remain one of the only direct tracers of the compact object population. To investigate the XRB population in M31, we utilized all 121 publicly available observations of M31 totalling over 1 Ms from Chandra's ACIS instrument. We studied 83 star clusters i…

On vortex motion in chromospheric network boundaries

Tavabi, E.

A large percent of spicules shows a surge-like behavior on the solar limb, supporting a multi-component model with twisted threads. The counterpart of limb spicules foot-points is investigated on the disk, and this re-examination indicates that the interpretation of transverse motion of off-limb spicules could directly be related to rotational mot…

Effect of plasma torus density variations on the morphology and brightness of the Io footprint

Crary, F.; Payan, A. P.; Rajendar, A. +1 more

We develop a 2-D-layered model of the Io plasma torus to study the apparent "shutoff" of the Io footprint in 2007, when it disappeared beneath a region of diffuse emissions, roughly coincident with a massive eruption of Tvashtar Paterae. First, we investigate the effects of Io's location in the plasma torus and validate our model results against H…

Spacecraft Doppler tracking with possible violations of LLI and LPI: preliminary bounds on LLI from Mars Express

Xie, Yi; Huang, Yong; Zhang, Yu-Fei +2 more

Three-way spacecraft Doppler tracking is currently widely used and it plays an important role in the control and navigation of deep space missions. Using the theory of three-way Doppler tracking, including possible violations of the local Lorentz invariance (LLI) and the local position invariance (LPI), we analyze the post-fit residuals of three-w…

Analytical model of rotating two-cell convection at Saturn

Waite, J. H.; Burch, J. L.; Hill, T. W. +1 more

We use an analytical model of magnetosphere-ionosphere coupling to show that an asymmetric ring current (RC) pressure with an m=1 longitudinal dependence can initiate a rotating two-cell interchange potential. The model extends prior similar work by considering both cold plasma interchange and warm plasma pressure. This model predicts that within …

Nonadiabatic acceleration of plasma sheet ions related to ion cyclotron waves

Dandouras, I.; Rème, H.; Cao, J. B. +2 more

The story of Seyfert galaxy RE J2248-511: from intriguingly ultrasoft to unremarkably average

Page, M. J.; Done, C.; Wiersema, K. +7 more

RE J2248-511 is one of only 14 non-blazar active galactic nuclei (AGN) detected in the far-ultraviolet (FUV) by the ROSAT Wide Field Camera implying a large ultrasoft X-ray flux. This soft X-ray excess is strongly variable on year time-scales, a common property of narrow-line Seyfert 1s, yet its optical line widths classify this source as a broad-…

PACS photometer calibration block analysis

Balog, Z.; Marton, G.; Müller, T. G. +3 more

The absolute stability of the PACS bolometer response over the entire mission lifetime without applying any corrections is about 0.5 % (standard deviation) or about 8 % peak-to-peak. This fantastic stability allows us to calibrate all scientific measurements by a fixed and time-independent response file, without using any information from the PACS…