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Energetic electrons along the high-latitude magnetopause

Daly, P. W.; Haaland, S. E.; Kronberg, E. A. +2 more

A case study is presented to determine the source of the energetic electron layer frequently observed along the high-latitude magnetopause. Measurements by the Cluster spacecraft show bursts of field-aligned electrons occurring during time periods with high potential for dayside reconnection. These properties are compared with the expected signatu…

Suzaku Observation of the Supergiant Fast X-Ray Transient AX J1841.0-0536

Koyama, Katsuji; Nobukawa, Masayoshi; Tsuru, Takeshi Go +1 more

We observed the supergiant fast X-ray transient AX J1841.0-0536 with Suzaku in 2011 March. Many short flares with time-scales of a few hundred seconds and a large flare with a peak flux (1.0-10 keV) of ≳; 2 × 10^-10 erg s^-1 cm^-2 were detected. The broad-band (1.0-40 keV) spectrum was fitted with a cut-off power-law …

Study of kinetic Alfvén wave and whistler wave spectra and their implication in solar wind plasma

Sharma, R. P.; Dwivedi, Navin Kumar; Batra, Karuna

This work presents the numerical simulation of the nonlinear evolution of kinetic Alfvén wave (KAW), in a parametric regime consistent with the solar wind plasmas. The nonlinear dynamical equation of KAW satisfies the modified nonlinear Schrödinger equation when incident pump KAW has a small perturbation. Numerical simulation has been done to solv…

Extremely Rapid Star Cluster Disruption in High-shear Circumnuclear Starburst Rings: The Unusual Case of NGC 7742

de Grijs, Richard; Anders, Peter

All known mass distributions of recently formed star cluster populations resemble a "universal" power-law function. Here we assess the impact of the extremely disruptive environment in NGC 7742's circumnuclear starburst ring on the early evolution of the galaxy's high-mass (~10⁵-10⁷ M _⊙) star cluster population. Su…

Simultaneous ground-satellite observations of meso-scale auroral arc undulations

Lester, M.; Milan, S. E.; Sato, N. +4 more

We present simultaneous ground-based and in situ measurements of a train of meso-scale (about 100-300 km) auroral arc undulations, occurring in the postmidnight sector (∼1 MLT) between 0040 UT and 0054 UT on September 21, 2009. The undulations appeared at the auroral poleward boundary, and then moved eastward with a speed of 0.9-2.2 km s^-1

A new method to detect solar-like oscillations at very low S/N using statistical significance testing

Chaplin, William J.; Kjeldsen, Hans; Lund, Mikkel N.

We introduce a new method to detect solar-like oscillations in frequency power spectra of stellar observations, under conditions of very low signal-to-noise ratio. The Moving-Windowed-Power-Search (MWPS) searches the power spectrum for signatures of excess power, over and above slowly varying (in frequency) background contributions from stellar gr…

Study on Stationkeeping for Halo Orbits at EL₁: Dynamics Modeling and Controller Designing

Xu, Ming; Xu, Shijie

This paper deals with the stationkeeping control for halo orbits at EL₁ in the Sun-Earth/Moon system, and proposes an effective adaptive robust controller for the unknown spacecraft mass and perturbation boundaries. The controller has to deal with two divergence sources: one is the instability of the halo orbit, and the other is the per…

Energetic electrons associated with magnetic reconnection in the sheath of interplanetary coronal mass ejection

Zhou, Meng; Li, HuiMin; Deng, XiaoHua +3 more

A SOHO/UVCS study of coronal outflows at the edge of an active region complex

Poletto, G.; Zangrilli, L.

Context. In the past, active regions (ARs) have been suggested as a possible source of the slow solar wind. Their role as solar wind contributors has recently been supported by HINODE observations at low coronal levels.
Aims: Our purpose is to determine whether outflows at the edges of ARs can be detected in higher layers of the corona, suppo…

M94 as a Unique Testbed for Black Hole Mass Estimates and AGN Activity at Low Luminosities

Seth, Anil C.; Constantin, Anca

We discuss the peculiar nature of the nucleus of M94 (NGC 4736) in the context of new measurements of the broad H_alpha emission from HST-STIS observations. We show that this component is unambiguously associated with the high-resolution X-ray, radio, and variable UV sources detected at the optical nucleus of this galaxy. These multi-wavelength ob…