Cygnus A, the nearest truly powerful radio galaxy, resides at the centre of a massive galaxy cluster. Chandra X-ray observations reveal its cocoon shocks, radio lobe cavities and an X-ray jet, which are discussed here. It is argued that X-ray emission from the outer regions of the cocoon shocks is nonthermal. The X-ray jets are best interpreted as synchrotron emission, suggesting that they, rather than the radio jets, are the path of energy flow from the nucleus to the hotspots. In that case, a model shows that the jet flow is non-relativistic and carries in excess of one solar mass per year.

We present the results obtained from our deep survey of lensing clusters aimed at constraining the abundance of star-forming galaxies at z∼6–11.

LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30–240 MHz. The telescope is realized as a phased aperture array without any moving parts. Digital beam forming allows the telescope to point to any part of the sky within a second. Transient buffering makes retrospective imaging of explosive short-term events possible. The scientific focus of LOFAR will initially be on four key science projects (KSPs): (i) Detection of the formation of the very first stars and galaxies in the universe during the so-called epoch of reionization by measuring the power spectrum of the neutral hydrogen 21-cm line (Shaver et al. 1999) on the ∼ 5′ scale; (ii) Low-frequency surveys of the sky with of order 108 expected new sources; (iii) All-sky monitoring and detection of transient radio sources such as γ-ray bursts, X-ray binaries, and exo-planets (Farrell et al. 2004); and (iv) Radio detection of ultra-high energy cosmic rays and neutrinos (Falcke & Gorham 2003) allowing for the first time access to particles beyond 1021 eV (Scholten et al. 2006). Apart from the KSPs open access for smaller projects is also planned. Here we give a brief description of the telescope.

Recent data have radically altered the X-ray perspective on cooling flow clusters. X-ray spectra show that very little of the hot intra-cluster medium is cooler than about 1 keV, despite having short cooling times. In an increasing number of cooling flow clusters, the lobes of a central radio source are found to have created cavities in the hot gas. Generally, the cavities are not overpressured relative to the intra-cluster gas, but act as buoyant bubbles of radio emitting plasma that drive circulation as they rise, mixing and heating the intra-cluster gas. All this points to the radio source, i.e., an active galactic nucleus, as the heat source that prevents gas from cooling to low temperatures. However, heating due to bubbles alone seems to be insufficient, so the energetics of cooling flows remain obscure. We briefly review the data and theory supporting this view and discuss the energetics of cooling flows.

This study explored the surface chemistry and the promise of the binary reaction scheme:

(A) Si-OH+SiCl4 → Si-Cl + HCl

(B) Si-Cl + H2O → Si-OH + HCl

for controlled SiO2 film deposition. In this binary ABAB… sequence, each surface reaction may be self-terminating and ABAB… repetitive cycles may produce layer-by-layer controlled deposition. Using this approach, the growth of SiO2 thin films on Si(100) with atomic layer control was achieved at 600 K with pressures in the 1 to 50 Torr range. The experiments were performed in a small high pressure cell situated in a UHV chamber. This design couples CVD conditions for film growth with a UHV environment for surface analysis using laser-induced thermal desorption (LITD), temperature-programmed desorption (TPD) and Auger electron spectroscopy (AES). The controlled layer-by-layer deposition of SiO2 on Si(100) was demonstrated and optimized using these techniques. A stoichiometric and chlorine-free SiO2 film was also produced as revealed by TPD and AES analysis. SiO2 growth rates of approximately 1 ML of oxygen per AB cycle were obtained at 600 K. These studies demonstrate the methodology of using the combined UHV/high pressure experimental apparatus for optimizing a binary reaction CVD process.