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The narrow-line quasar NAB 0205+024 observed with XMM-Newton
Brandt, W. N.; Vaughan, S.; Fabian, A. C. +2 more
The XMM-Newton observation of the narrow-line quasar NAB 0205+024 reveals three striking differences since it was last observed in X-rays with ASCA. First, the 2-10 keV power law is notably steeper. Secondly, a hard X-ray flare is detected, very similar to that seen in I Zw 1. Thirdly, a strong and broad emission feature is detected with the bulk …
Spectrum of Solar Type I Continuum Noise Storm in the 50-80 MHz Band and Plasma Characteristics in the Associated Source Region
Sundaram, G. A. Shanmugha; Subramanian, K. R.
Continuum observations of a solar noise storm in the frequency range of 50-80 MHz observed with the Gauribidanur radio spectrograph during 2000 September 26 and 27 are presented here. The radio spectral index of the noise storm continuum in the 50-80 MHz band is found to be ~3.65 during the above period. The noise storm continuum radiation is expl…
Detecting compact dark matter in galaxy clusters via gravitational microlensing: A2218 and A370
Kneib, J. -P.; Lewis, G. F.; Ibata, R. A. +1 more
After decades of searching, the true nature of dark matter still eludes us. One potential probe of the form of dark matter in galaxy clusters is to search for microlensing variability in the giant arcs and arclets. In this paper, a simple method is introduced to characterize pixel variability in the limit of high optical depth to microlensing. Exp…
Comparing Chandra and SIRTF Observations for Obscured Starbursts and Active Galactic Nuclei at High Redshift
Zezas, A.; Charmandaris, V.; Weedman, D.
Tracking the star formation rate to high redshifts requires knowledge of the contribution from both optically visible and obscured sources. The dusty, optically obscured galaxies can be located by X-ray and infrared surveys. To establish criteria for selecting such sources based only on X-ray and infrared surveys, we determine the ratio of infrare…
Conjugate comparison of Super Dual Auroral Radar Network and Cluster electron drift instrument measurements of E × B plasma drift
Balogh, A.; Tsyganenko, N. A.; Quinn, J. M. +6 more
Much of our current understanding of magnetospheric electrodynamics is based on the assumption that magnetic field lines often behave as electrostatic equipotentials. This assumption has allowed hemispheric patterns of ionospheric convection to be interpreted in terms of the large-scale circulation of plasma in the magnetosphere. However, the exte…
Estimation of the Three-Dimensional Space Speed of a Coronal Mass Ejection Using Metric Radio Data
Ramesh, R.; Kathiravan, C.
We present an independent method for obtaining the three-dimensional space speed of a coronal mass ejection in the lower solar atmosphere through ray-tracing analysis of the thermal radio counterpart of its frontal loop in the metric wavelength range. The scheme was tested on the halo event observed on 1998 January 21, obtaining an estimated space…
Comet Hyakutake (C/1996 B2): Spectacular disconnection event and the latitudinal structure of the solar wind
Brandt, J. C.; Snow, M.; Mikuz, H. +2 more
Images of comet Hyakutake (C/1996 B2) are analyzed in conjunction with solar wind data from spacecraft to determine the relationship between solar wind conditions and plasma tail morphology. The disconnection event (DE) on March 25, 1996 is analyzed with the aid of data from the IMP-8 and WIND Earth-orbiting spacecraft and the DE is found to be co…
My Cruise Through the World of Astronomy
Blaauw, Adriaan
I was born in 1914 in Amsterdam. I grew up there, filling my teenage years with activities as an amateur astronomer. I later studied at Leiden University and volunteered at Leiden Observatory. From 1938 to 1945, I was assistant at the Kapteyn Institute in Groningen, including during the war years 1940 1945, returning to Leiden in October 1945. Aft…
Multicolour CCD measurements of nearby visual double stars. II
Strigachev, A.; Lampens, P.
We present accurate CCD astrometric and photometric data for 31 nearby visual double stars in the standard filters BVRI. The observations were collected with a 1.3-m telescope in 2001-2002 The results consist of relative astrometric positions (epoch, angular separation and position angle) and differential BVRI photometry of the components. Mean er…
Plasma convection across the polar cap, plasma mantle and cusp: Cluster EDI observations
Klecker, B.; Rème, H.; Quinn, J. +8 more
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