We investigated the relation between compact jet emission and X-ray variability properties of all black hole transients with multiwavelength coverage during their outburst decays. We studied the evolution of all power spectral components (including low frequency quasi-periodic oscillations), and related this evolution to changes in jet properties tracked by radio and infrared observations. We g...

The realization that the total energy of GRBs is correlated to their jet break angles motivates the search for a similar relation between the peak luminosity, L, and the jet break angles, L ∝ θ. Such a relation implies that the GRB luminosity function determines the angular distribution. We re-derive the GRB luminosity function using the BATSE peak flux distribution and compare the predicted di...

Recently, a very large clustering length has been measured for quasars at a redshift of z ∼ 4. In combination with the observed quasar luminosity function we assess the implications of this clustering for the relationship between quasar luminosity and dark matter halo mass. Our analysis allows for non-linearity and finite scatter in the relation between quasar luminosity and halo mass, as well ...

This contribution briefly reviews the reverberation mapping technique which leads to determination of black hole masses. I focus on the emerging relation between the broad-line region size and the active galactic nucleus (AGN) luminosity, and on an overview of recent results of reverberation mapping studies which are starting to cover the full AGN luminosity range. Preliminary results and time ...

We compared, for Triatoma brasiliensis, the egg-laying process and the mortality of adults under conditions of almost permanent darkness and with normal laboratory luminosity. Mortality did not differ between groups. The egg-laying per vial and per female was significantly greater in the group of normal luminosity. We consider that it is not recommendable to keep the adults of this species unde...

Aims. We report the X-ray properties of young (∼3 Myr) bona fide brown dwarfs of the Taurus Molecular Cloud (TMC). Methods. The XMM-Newton Extended Survey of the TMC (XEST) is a large program designed to systematically investigate the X-ray properties of young stellar/substellar objects in the TMC. In particular, the area surveyed by 15 XMM-Newton pointings (of which three are archival observat...

We investigate newtonian description of accreting compact bodies with hard surfaces, including luminosity and selfgravitation of polytropic perfect fluids. This nonlinear integro-differential problem reduces, under appropriate boundary conditions, to an algebraic relation between luminosity and the gas abundance in stationary spherically symmetric flows. There exist, for a given luminosity, asy...

We show that it is possible to define a purely Photometric Fundamental Plane (PFP) for early–type galaxies. This relation is similar to the standard Fundamental Plane (FP), and is obtained by replacing the velocity dispersion parameter with the difference between the magnitude of a galaxy and that of the mode of the Gaussian luminosity function of E and S0 galaxies. The use of magnitude differe...

In this contribution we report our recent investigation of the gas metallicity in active galactic nuclei and its dependence on luminosity and redshift. We compile large spectroscopic datasets of broad-line and narrowline AGNs, and compare them with the results of our photoionization models. Through the analysis of both the broad and the narrow emission-line regions, we find that: (1) for a give...

We have studied the relation between HI linewidth and optical luminosity in two samples of dwarf galaxies, with special attention to the accuracy of the inclination correction. The first sample consists of rotationally supported galaxies, and has DDO 154 as a prototype. They have HI linewidths significantly larger than predicted by an extrapolation of the Tully-Fisher relation. The deviation fr...