We used the standard geometrical thin accretion theory to obtain the accretion rates in Seyfert 1 galaxies and quasars. Combining accretion rates with the bolometric luminosity, we obtained the accretion efficiency. We found most of Seyfert 1 galaxies and radio quiet quasars have lower accretion efficiencies while most of the radio loud quasars possess higher accretion efficiencies. This findin...

Spectroscopic surveys of submillimetre(submm)-selected sources have uncovered optically bright galaxies at z 1 close to the positions of several submm sources. Naive statistical analyses suggest that these galaxies are associated with the submm emission. However, in some cases, it is difficult to understand this association given the relatively modest redshifts and unprepossessing spectral char...

We report on the results of a search for Lyα emission from the host galaxy of the z = 2.140 GRB 011211 and other galaxies in its surrounding field. We detect Lyα emission from the host as well as from six other galaxies in the field. The restframe equivalent width of the Lyα line from the GRB 011211 host is about 21 Å. This is the fifth detection of Lyα emission out of five possible detections ...

Active Galactic Nuclei (AGN) play an important role in many aspects of the modern cosmology, and of particular interest is the issue of the interplay between AGN and their host galaxy. Using X–ray and optical data sets, we have explored the properties of a large sample of AGNs in the Subaru/XMM-Newton Deep Survey (SXDS) field, and studied their evolution in relation with the evolution of their ...

While often the point sources in X-ray surveys are dominated by AGN, with the high sensitivity of modern X-ray telescopes such as Chandra and XMM-Newton normal/starburst galaxies are also being detected in large numbers. We have made use of Bayesian statistics for both the selection of galaxies from deep X-ray surveys and in the analysis of the luminosity functions for galaxies. These technique...

During the course of an investigation of the interaction of the radio galaxy M84 and its ambient cluster gas, we found excess X-ray emission aligned with the northern radio jet. The emission extends from the X-ray core of the host galaxy as a weak bridge and then brightens to a local peak coincident with the first detectable radio knot at ≈ 2.5 from the core. The second radio knot at 3.3 is bri...

CO observations of 0 < z < 4 radio galaxies are presented. The LCO upper limits for the high-redshift powerful radio galaxies (HzPRGs: z > 1, P408MHz > 10 27 Watts Hz) are consistent with no evolution in molecular gas (H2) mass with redshift and/or radio power. Of the lowredshift powerful radio galaxies (LzPRGs: z < 0.2, P408MHz > 10 23.5 W Hz) observed, only one F-R II galaxy has been detected...

Using the extremely high S/N quasar absorption-line sample described in the first paper of the series, we investigate which intergalactic C IV absorption line systems could be directly associated with galactic outflows at z = 2 − 3.5 from an analysis of the velocity widths of the C IV absorption line systems. Only about half the systems with a peak τ(CIV) above 0.4 in the λ1548 Å line (roughly ...

Herschel will represent a breakthrough in the study of nearby gas-rich and gas-poor galaxies, as it will for the first time permit imaging photometric and spectroscopic observations of their ISM in the FIRsubmm wavelength range. The unprecedented sensitivity and angular resolution of Herschel will furthermore yield a breakthrough in our understanding of distant galaxies and AGN, as their gas an...

Image decomposition of galaxies is now routinely used to estimate the structural parameters of galactic components. In this work, I address questions on the reliability of this technique. In particular, do bars and AGN need to be taken into account to obtain the structural parameters of bulges and discs? And to what extent can we trust image decomposition when the physical spatial resolution is...