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Optimal Gaussian Phase-Speed Filters in Time-Distance Helioseismology
Birch, A. C.; Couvidat, S.
Gaussian phase-speed filters are widely used in time-distance helioseismology to select specific wave packets whose travel times are then measured at the solar surface. This filtering increases the signal-to-noise (S/N) ratio of the temporal cross-covariances that are fitted to derive the travel times. The central phase speeds of these Gaussian fi…
Studying size and physical properties of the narrow-line region in active galaxies
Haas, Martin; Chini, Rolf; Komossa, Stefanie +2 more
We explore the size and physical properties of the narrow-line region (NLR) in active galaxies via imaging and spectroscopy. From HST [OIII] images, we find striking correlations between the size and the luminosity of the NLR with different slopes for type-1 and type-2 AGNs. We show that the influence of the observers viewing angle with respect to…
Flux closure during a substorm observed by Cluster, Double Star, IMAGE FUV, SuperDARN, and Greenland magnetometers
Wild, J. A.; Lucek, E. A.; Milan, S. E. +5 more
We examine magnetic flux closure during an extended substorm interval on 29 August 2004 involving a two-stage onset and subsequent re-intensifications. Cluster and Double Star provide observations of magnetotail dynamics, while the corresponding auroral evolution, convection response, and substorm current wedge development are monitored by IMAGE F…
PG 0844+349 revisited - is there any outflow?
Wang, T.; Brinkmann, W.; Grupe, D. +1 more
Aims.The detection of high velocity absorption lines from highly ionized material has been reported recently from the X-ray spectrum of the narrow line Seyfert 1 galaxy PG 0844+349 and were interpreted as a relativistic outflow from the source. We studied this outflow because it would have important implications for our understanding of narrow lin…
Time-dependent 3D modulation of Jovian electrons. Comparison with Ulysses/KET observations
Fichtner, H.; Kissmann, R.; Lange, D.
We report on the modelling of the time-dependent transport of a few MeV electrons in the heliosphere. These low-energetic electrons, observed with the Kiel Electron Telescope (KET) on board the Ulysses spacecraft, are for the first time simulated over a complete solar activity cycle on the basis of a time-dependent three-dimensional modulation mod…
Dynamic features in the solar atmosphere with unusual spectral line enhancements and Doppler-shifts
Doyle, J. G.; Dzifćáková, E.; Madjarska, M. S. +2 more
Context.The solar atmosphere contains a wide variety of transient features, here, we discuss data relating to one such feature.
Aims.To explore via simultaneous spectral and imaging data the nature of high-velocity flow events in the solar transition region.
Methods.High spectral and temporal resolution data from SUMER/SoHO plus high resol…
Comparison of surface temperatures measured by the Planetary Fourier Spectrometer (PFS) on Mars Express with predictions from the Berlin Mars near Surface Thermal model (BMST) for the BEAGLE 2 landing site in Isidis Planitia
Arnold, G.; Formisano, V.; Giuranna, M. +4 more
The Isidis Plantita region on Mars is a landing site favored by engineers for its inherent safety. The landing site of Beagle 2 was in this area, as was one of the prime backup landing sites for the Mars Exploration Rover Spirit. Therefore, it seems likely that for future lander missions to Mars this area will be on the shortlist. Within its first…
Direct Observation of Low Coronal Breakout: Does Breakout Precede or Follow Solar Eruption?
Cho, K. -S.; Moon, Y. -J.; Choe, G. S. +3 more
In this Letter, we report a direct SOHO LASCO C1 observation of low coronal ``magnetic breakout'' that occurred during the coronal mass ejection (CME) on 1998 March 23. The LASCO C1 images show that a slowly expanding, small coronal loop on the northeastern limb erupted, becoming a CME with the typical three-part structure (core, void, and front).…
The iron emission line complex of MCG-5-23-16: the long XMM-Newton look
Ptak, A.; Nandra, K.; Turner, T. J. +9 more
We present the results of the simultaneous XMM-Newton and Chandra observations of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is one of the best known examples of a relativistically broadened iron K\alpha line. We find that: a) the soft X-ray emission is likely to be dominated by photoionized gas, b) the complex iron emission line is best mod…
Tracing the location of the reconnection site from the northern and southern cusps
Fuselier, S. A.; Reme, H.; Trattner, K. J. +2 more
Three-dimensional plasma observations in the cusp have been successfully used to investigate the location of the reconnection site at the magnetopause. This technique uses low-velocity cutoffs in the precipitating and mirrored magnetosheath population traveling along open cusp field lines, which are then used to estimate the distance to the reconn…