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First results from ideal 2-D MHD reconstruction: magnetopause reconnection event seen by Cluster
Teh, W. -L.; Ã-. Sonnerup, B. U.
We have applied a new reconstruction method (Sonnerup and Teh, 2008), based on the ideal single-fluid MHD equations in a steady-state, two-dimensional geometry, to a reconnection event observed by the Cluster-3 (C3) spacecraft on 5 July 2001, 06:23 UT, at the dawn-side Northern-Hemisphere magnetopause. The event has been previously studied by use …
Combined Chandra, XMM-Newton, and Hubble Space Telescope observations of the Galactic globular cluster NGC 2808
Knigge, C.; Long, K. S.; Servillat, M. +6 more
Aims: Using new Chandra X-ray observations and existing XMM-Newton X-ray and Hubble far ultraviolet observations, we aim to detect and identify the faint X-ray sources belonging to the Galactic globular cluster
Methods: We present a Chandra X-r…
A Far Ultraviolet Archival Study of Cataclysmic Variables. I. FUSE and HST STIS Spectra of the Exposed White Dwarf in Dwarf Nova Systems
Szkody, Paula; Sion, Edward M.; Godon, Patrick +3 more
We present a synthetic spectral analysis of Far Ultraviolet Spectroscopic Explorer (FUSE) and Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) spectra of five dwarf novae above and below the period gap during quiescence. We use our synthetic spectral code, including options for the treatment of the hydrogen quasi-molecular sa…
Suzaku Detection of Extended/Diffuse Hard X-Ray Emission from the Galactic Center
Maeda, Yoshitomo; Kokubun, Motohide; Makishima, Kazuo +12 more
Five on-plane regions within ±0°.8 of the galactic center were observed with the Hard X-ray Detector (HXD) and the X-ray Imaging Spectrometer (XIS) aboard Suzaku. From all regions, significant hard X-ray emission was detected with HXD-PIN up to 40keV, in addition to the extended plasma emission which is dominant in the XIS band. The hard X-ray sig…
Origin of X-ray emission from transient black hole candidates in quiescence
Yuan, Feng; Zhang, Hui; Cui, Wei +1 more
We report results from a systematic study of X-ray emission from black hole transients in quiescence. In this state, mass accretion is thought to follow the geometry of an outer optically thick, geometrically thin disc and an inner optically thin, geometrically thick radiatively inefficient accretion flow (RIAF). The inner flow is likely also coup…
Caught in Formation: The Nuclear-Cluster-to-Be in NGC 2139
Böker, Torsten; Ho, Luis C.; Shields, Joseph C. +4 more
Close to its center, the bulgeless galaxy NGC 2139 hosts a star cluster that is younger and less massive than any nuclear star cluster (NC) studied so far. We have measured the Hα velocity field around the photometric center of this galaxy using the VLT ARGUS integral field unit and the GIRAFFE spectrograph in order to constrain different proposed…
Multiscale Edge Detection in the Corona
Gallagher, Peter T.; Young, C. Alex
Coronal Mass Ejections (CMEs) are challenging objects to detect using automated techniques, due to their high velocity and diffuse, irregular morphology. A necessary step to automating the detection process is to first remove the subjectivity introduced by the observer used in the current, standard, CME detection and tracking method. Here we descr…
Observable effects of convection and gravity waves on the Venus condensational cloud
Toon, Owen B.; McGouldrick, Kevin
We present results of a simple two-dimensional model investigating the observable effects that convective motions and gravity waves can have on the condensational Venus cloud. Gravity waves have been observed in the Venus atmosphere in the form of temperature scintillations in the Magellan and Pioneer Venus occultation data. Multiple in situ probe…
Detailed Atmosphere Model Fits to Disk-dominated ULX Spectra
Krolik, Julian H.; Hui, Yawei
We have chosen six ultraluminous X-ray sources from the XMM-Newton archive whose spectra have high signal-to-noise ratio (S/N) and can be fitted solely with a disk model without requiring any power-law component. To estimate systematic errors in the inferred parameters, we fit every spectrum to two different disk models, one based on local blackbo…
Discovery of photospheric Ca X emission lines in the far-UV spectrum of the hottest known white dwarf (KPD 0005+5106)
Rauch, T.; Werner, K.; Kruk, J. W.
For the first time, we have identified photospheric emission lines in the far-UV spectrum of a white dwarf. They were discovered in the Far Ultraviolet Spectroscopic Explorer spectrum of the hot (T eff ≈ 200 000 K) DO white dwarf KPD 0005+5106 and they stem from extremely highly ionized calcium (Ca X λλ 1137, 1159 Å). Their photospheric…