. Comment on J0221+3556 . A gravitational lens; the two lensed components are shown in Figure 4. See Polatidis et al. (1995) and Xu et al. (1995) for other VLBI images at 1.6 and 5 GHz, respectively. VLBApls home page . Last modified: 16 Oct 2000

X-ray astronomy primarily involves the study of plasmas with thermal temperatures in the range of 1E6 to 1E8 K. Such plasmas radiate the bulk of their energy in the X-ray regime, from ca. 0.1 to 10 keV. ... Apart from X-ray continuum emission, produced through processes such as e.g. thermal bremsstrahlung, a significant fraction of the total emissivity of hot thermal plasmas can arise from line emission. ... XMM's science objectives are described here in two parts: . General science objectives . ...

Introduction to PLASMA ASTROPHYSICS (Selected 10 lectures) Boris V. Somov Astronomical Institute and Faculty of Physics Moscow State University Pushino-na-Oke, 2008 Contents Ab out These Lectures 1 Particles and Fields: Exact Self-Consistent Description 1.1 Liouville's theorem . . . . . . . . . . . . . . . . . . . 1.1.1 Continuity in phase space . . . . . . . . . 1.1.2 The character of particle interactions 1.1.3 The Lorentz force, gravity . . . . . . . . . 1.1.4 Collisional friction . . . . . . . . . . . .