Search Publications
New insights into SNR evolution revealed by the discovery of recombining plasmas
Yamaguchi, Hiroya; Ozawa, Midori; Ohnishi, Takao
We report the discovery of recombining plasmas in three supernova remnants (SNRs) with the Suzaku X-ray astronomy satellite. During SNR's evolution, the expanding supernova ejecta and the ambient matter are compressed and heated by the reverse and forward shocks to form an X-ray emitting hot plasma. Since ionization proceeds slowly compared to sho…
A teardrop-shaped ionosphere at Venus in tenuous solar wind
Coates, A. J.; Barabash, S.; Lundin, R. +9 more
A very tenuous solar wind regime, following a series of large coronal mass ejections, impacted Venus during early August, 2010. STEREO-B downstream from Venus observed that the solar wind density at Earth orbit dropped to ∼0.1 #/cm3 and persisted at this value over 1 day. A similar low value was observed at Earth in 1999 and has attract…
A Period Distribution of X-Ray Binaries Observed in the Central Region of M31 with Chandra and the Hubble Space Telescope
Zezas, A.; Murray, S. S.; Garcia, M. R. +4 more
Almost all Galactic black hole (BH) binaries with low-mass donor stars are transient X-ray sources; we expect most of the X-ray transients observed in external galaxies to be BH binaries also. Obtaining period estimates for extragalactic transients is challenging, but the resulting period distribution is an important tool for modeling the evolutio…
Observational Constraints on the Molecular Gas Content in Nearby Starburst Dwarf Galaxies
McQuinn, Kristen B. W.; Cannon, John M.; Dolphin, Andrew E. +5 more
Using star formation histories derived from optically resolved stellar populations in 19 nearby starburst dwarf galaxies observed with the Hubble Space Telescope, we measure the stellar mass surface densities of stars newly formed in the bursts. By assuming a star formation efficiency (SFE), we then calculate the inferred gas surface densities pre…
Electron dynamics in the reconnection ion diffusion region
Fazakerley, A. N.; Daly, P. W.; Nakamura, R. +4 more
We investigate and compare Cluster observations of electron dynamics in different locations of the ion diffusion region for magnetic reconnection in the Earth's magnetotail. On the basis of the 2-D reconstructed magnetic field map from Cluster 1 (C1), we pinpoint that the observed Hall field is ∼6000 km (∼9 ion inertial lengths) away from the magn…
Evidence of merging in the Seyfert galaxy NGC 3393, revealed by modelling the spectra
Contini, M.
The discovery (Fabbiano et al. 2001) of two active black holes in the Seyfert galaxy NGC 3393, which are separated by about 490 light years, has revealed a merging event. This has led us to look for other evidence of galaxy collision and merging, using an analysis of the observed spectra in different frequency ranges. In the narrow-line region (NL…
Location of the magnetodisk in the nightside outer magnetosphere of Saturn near equinox based on ion densities
Thomsen, M.; Szego, K.; Bebesi, Z. +4 more
We investigate ion densities derived from measurements by the Cassini Plasma Spectrometer, to determine how these ions are distributed around the magnetodisk of Saturn. The magnetodisk is a variable plasma structure, here we fitted the simple structural model of Arridge et al. (2011) as a reference for the location of the central line of the magne…
Solar Energetic Particle Events and the Kiplinger Effect
Kahler, S. W.
The Kiplinger effect is an observed association of solar energetic (E > 10 MeV) particle (SEP) events with a "soft-hard-harder" (SHH) spectral evolution during the extended phases of the associated solar hard (E > 30 keV) X-ray (HXR) flares. Besides its possible use as a space weather predictor of SEP events, the Kiplinger effect has been in…
Detection of an exoplanet around the evolved K giant HD 66141
Lee, B. -C.; Park, M. -G.; Han, I. +2 more
Aims: We have been carrying out a precise radial velocity (RV) survey for K giants to search for and study the origin of the low-amplitude and long-periodic RV variations.
Methods: We present high-resolution RV measurements of the K2 giant HD 66141 from December 2003 to January 2011 using the fiber-fed Bohyunsan Observatory Echelle Spect…
Preliminary results on γ Dor and δ Sct-γ Dor hybrid s in the CoRoT exo-field of LRa01
Hareter, M.
The 131 days long, high-precision light curves observed in the CoRoT exo-field during LRa01 were investigated for γ Dor and δ Sct-γ Dor hybrid stars. In total 418 γ Dor and 274 δ Sct-γ Dor hybrid candidates were identified. For a fraction of these candidates spectra are available obtained at the Anglo-Australian Observatory. Effective temperatures…