Search Publications
Source Matching in the SDSS and Rass: which Galaxies are Really X-Ray Sources?
Hoyle, Fiona; Parejko, John K.; Constantin, Anca +1 more
The current view of galaxy formation holds that all massive galaxies harbor a massive black hole at their center, but that these black holes are not always in an actively accreting phase. X-ray emission is often used to identify accreting sources, but for galaxies that are not harboring quasars (low-luminosity active galaxies), the X-ray flux may …
The Nearby and Extremely Metal-poor Galaxy CGCG 269-049
Windhorst, Rogier A.; Kim, Hwihyun; Jansen, Rolf A. +2 more
We present Hubble Space Telescope (HST) and Spitzer Space Telescope images and photometry of the extremely metal-poor (Zcong 0.03 Z⊙) blue dwarf galaxy CGCG 269-049. The HST images reveal a large population of red giant and asymptotic giant branch stars, ruling out the possibility that the galaxy has recently formed. From the magnitude …
On the relation between DC current locations and an EUV bright point: A case study
Madjarska, M. S.; Büchner, J.; Santos, J. C. +1 more
Context: Motion of the photospheric plasma forces the footpoints of magnetic flux tubes to move. This can give rise to electric currents in the solar atmosphere. The dissipation of these electric currents and the consequent heating of the solar plasma may be responsible for the formation of Extreme-UltraViolet (EUV) and X-ray bright points. Earlie…
Phase structure of Pc3 waves observed by Cluster and ground stations near the cusp
Dunlop, M. W.; Zong, Q. G.; Liu, Y. H. +4 more
Ground observations of Pc3 ULF waves at high latitude show enhanced pulsation activity near the cusp. To investigate this, typical Pc3 pulsation events from 0920 to 1010 UT on 1 April 2004 have been selected that are simultaneously observed by the Cluster satellites and Zhongshan, Davis, and Mawson magnetometers, Antarctica. When Cluster was locat…
Next generation UV coronagraph instrumentation for solar cycle-24
Kohl, John L.; Cranmer, Steven R.; Raymond, John C. +4 more
Ultraviolet coronagraph observations of the extended solar corona (defined here as 1.5 to 10 solar radii from Sun-center) have become a powerful tool for obtaining detailed empirical descriptions of coronal holes, streamers, and coronal mass ejections. The empirical models resulting from ultraviolet coronagraph observations provide the constraints…
Apsidal motion in southern eccentric eclipsing binaries: GL Car, QX Car, NO Pup and V366 Pup
Wolf, M.; Zejda, M.; de Villiers, S. N.
The study of apsidal motion in eccentric eclipsing binaries (EEB) provides an important observational test of theoretical models of stellar structure and evolution. The Southern hemisphere contains many interesting and also neglected binary systems. New accurate photoelectric times of minimum light have been obtained for the detached early-type So…
Electron structure of the magnetopause boundary layer: Cluster/Double Star observations
Escoubet, C. P.; Pitout, F.; Zong, Q. -G. +16 more
We present a comparison of two events, monitored by the Double Star and Cluster spacecraft at separate locations on the dayside magnetopause, which exhibit distinct properties at high and low latitudes in the magnetopause boundary layer during the occurrence of low-latitude reconnection. On 6 April 2004, the four Cluster and TC-1 spacecraft were o…
Are there current-sheet-like structures in the Earth's magnetotail as in the solar wind - results and implications from high time resolution magnetic field measurements by Cluster
Li, G.; Lee, E.; Parks, G.
Recent studies of solar wind MHD turbulence show that current-sheet-like structures are common in the solar wind and they are a significant source of solar wind MHD turbulence intermittency. While numerical simulations have suggested that such structures can arise from non-linear interactions of MHD turbulence, a recent study by Borovsky (2006), u…
Discovery of Extended X-Ray Emission from an Unidentified TeV Source, HESS J1614-518, Using the Suzaku Satellite
Koyama, Katsuji; Matsumoto, Hironori; Bamba, Aya +8 more
We report Suzaku results concerning HESS J1614-518, which is the brightest extended TeV gamma-ray source discovered in the Galactic plane survey conducted using the H.E.S.S. telescope. We discovered three X-ray objects in the field of view of the X-ray Imaging Spectrometer, which were designated as Suzaku J1614-5141 (src A), Suzaku J1614-5152 (src…
Spectral Evolution of GRB060904A Observed with Swift and Suzaku --- Possibility of Inefficient Electron Acceleration
Yamaoka, Kazutaka; Maeno, Shouta; Murakami, Toshio +39 more
We observed an X-ray afterglow of GRB 060904A with the Swift and Suzaku satellites. We found rapid spectral softening during both the prompt tail phase and the decline phase of an X-ray flare in the Swift/BAT and Swift/XRT data. The observed spectra were fit by power-law photon indices which rapidly changed from Γ = 1.51+0.04-0.03<…