X-ray spectra transmitted through Compton-thick absorbers

X-ray spectra transmitted through matter which is optically thick to Compton scattering are computed by means of Monte Carlo simulations. Applications to the BeppoSAX data of the Seyfert 2 galaxy in Circinus, and to the spectral modeling of the Cosmic X-ray Background, are discussed.Comment: 10 pages. Accepted for publication in New Astronom

Novel calibrations of virial black hole mass estimators in active galaxies based on X-ray luminosity and optical/NIR emission lines

Accurately weigh the masses of SMBH in AGN is currently possible for only a small group of local and bright broad-line AGN through reverberation mapping (RM). Statistical demographic studies can be carried out considering the empirical scaling relation between the size of the BLR and the AGN optical continuum luminosity. However, there are still biases against low-luminosity or reddened AGN, in which the rest-frame optical radiation can be severely absorbed/diluted by the host and the BLR emission lines could be hard to detect. Our purpose is to widen the applicability of virial-based SE relations to reliably measure the BH masses also for low-luminosity or intermediate/type 2 AGN that are missed by current methodology. We achieve this goal by calibrating virial relations based on unbiased quantities: the hard X-ray luminosities, in the 2-10 keV and 14-195 keV bands, that are less sensitive to galaxy contamination, and the FWHM of the most important rest-frame NIR and optical BLR emission lines. We built a sample of RM AGN having both X-ray luminosity and broad optical/NIR FWHM measurements available in order to calibrate new virial BH mass estimators. We found that the FWHM of the H$\alpha$, H$\beta$ and NIR lines (i.e. Pa$\alpha$, Pa$\beta$ and HeI$\lambda$10830) all correlate each other having negligible or small offsets. This result allowed us to derive virial BH mass estimators based on either the 2-10 keV or 14-195 keV luminosity. We took also into account the recent determination of the different virial coefficients $f$ for pseudo and classical bulges. By splitting the sample according to the bulge type and adopting separate $f$ factors we found that our virial relations predict BH masses of AGN hosted in pseudobulges $\sim$0.5 dex smaller than in classical bulges. Assuming the same average $f$ factor for both populations, a difference of $\sim$0.2 dex is still found.Comment: 11 pages, 2 figures, 4 tables, accepted for publication on A&

On the AGN radio luminosity distribution and the black hole fundamental plane

We have studied the dependence of the AGN nuclear radio (1.4 GHz) luminosity on both the AGN 2-10 keV X-ray and the host-galaxy K-band luminosity. A complete sample of 1268 X-ray selected AGN (both type 1 and type 2) has been used, which is the largest catalogue of AGN belonging to statistically well defined samples where radio, X and K band information exists. At variance with previous studies, radio upper limits have been statistically taken into account using a Bayesian Maximum Likelihood fitting method. It resulted that a good fit is obtained assuming a plane in the 3D L_R-L_X-L_K space, namely logL_R= xi_X logL_X + xi_K logL_K + xi_0, having a ~1 dex wide (1 sigma) spread in radio luminosity. As already shown, no evidence of bimodality in the radio luminosity distribution was found and therefore any definition of radio loudness in AGN is arbitrary. Using scaling relations between the BH mass and the host galaxy K-band luminosity, we have also derived a new estimate of the BH fundamental plane (in the L_5GHz -L_X-M_BH space). Our analysis shows that previous measures of the BH fundamental plane are biased by ~0.8 dex in favor of the most luminous radio sources. Therefore, many AGN studies, where the BH fundamental plane is used to investigate how AGN regulate their radiative and mechanical luminosity as a function of the accretion rate, or many AGN/galaxy co-evolution models, where radio-feedback is computed using the AGN fundamental plane, should revise their conclusions.Comment: Submitted to MNRAS. Revised version after minor referee comments. 12 pages, 12 figure

The Contribution of Air Logistics to the Development of Sicilian Economy

The role, played by globalization and the “just in time” supplying logic in present world economic scenario, implies that the opportunity of frequent, quick, safe and low-priced freight deliveries can be considered a key element for competitiveness. For these reasons, transportation systems, in the last years, have been characterized by the diffusion of intermodality and the “hub and spoke” distribution pattern. The phenomenon of organizing freight transport services according to a network and modal integration logic, has involved also the air transport field: to meet the new requirements of freight transportation market, in many cases, airline companies have become “global players”, expanding their network, in order to develop links among the main economic centres in the world. The goods moving by air can be defined as “top range products”; which means that only high value products (“market value” and “need value”) and the perishable ones (from a physical and economic point of view) demand air transport. The research described in this abstract aims at determining the contribution that can derive from air logistics to face a challenging problem: overcoming the peripheral role, in international trade, played by Sicily, which can boast high quality outputs in the agroindustrial sector and in the high technology one. The research consists of the following stages: 1. Analysing the sicilian freight transport system, with regard to the demand-supply relationship, paying particular attention to the commodity typologies mentioned above. 2. Identifying key actions for the air cargo services, in order to make Sicily improve in competitiveness, also taking into account the possibility of connecting Sicily with hub airports. 3. Determining the economic and social impact of the proposed solutions, considering different evolutionary scenarios and using also input-output analysis techniques.

The development of air traffic in Sicily

The aim of this work is to analyse the air traffic development that interested the airport system in Sicily, consisting of the airport of Palermo “Falcone –Borsellino”, the airport of Catania “Fontanarossa” and that one of Trapani-Birgi “Vincenzo Florio”. The analysis of the possible growth of air traffic volume and performance in Sicily was mainly suggested by the growing importance of the Mediterranean region like a new crossroad of the worldwide traffic on the East-West line. It gives a new chance for the development of this area that mustn’t be loosed. Globalization and the migrant flows from South and East towards the Western Europe, makes of the southern Italy a strategic knot for passengers and goods movements. So, new investments and infrastructures improvements that will be realized in this area are a value added not only for the southern Italy but also for the whole country. We have examined the potential demand attraction for passengers and goods movements in the Sicilian airports considered. For a more careful evaluation of the changes occurred into Sicilian air transport system, the research aimed to: § determine their "catchment area" through the evaluation of accessibility (isochrones); § analyse the air traffic data and the existing degree of integration, not only between the airports and the area, but also in terms of demand in the short and in the long period. Finally, we have evaluated the possibility of integration of traffic flows management among the two airports of Palermo and Trapani, in order to analyse if this two airports are complementary rather than competitors.