AGN evolution from large and deep X-ray surveys

Over the last few years, the existence of mutual feedback effects between accreting supermassive black holes powering AGN and star formation in their host galaxies has become evident. This means that the formation and the evolution of AGN and galaxies should be considered as one and the same problem. As a consequence, the search for, and the characterization of the evolutive and physical properties of AGN over a large redshift interval is a key topic of present research in the field of observational cosmology. Significant advances have been obtained in the last ten years thanks to the sizable number of XMM-Newton and Chandra surveys, complemented by multiwavelength follow-up programs. We will present some of the recent results and the ongoing efforts (mostly from the COSMOS and CDFS surveys) aimed at obtaining a complete census of accreting Black Holes in the Universe, and a characterization of the host galaxies properties.Comment: 8 pages, 5 figures. Invited talk, to be published in the proceedings of the IAU Symposium 267 "Co-evolution of central Black Holes and galaxies", B.M. Peterson, R.S. Somerville, & T. Storchi-Bergmann, eds

The Iron Line Background

We investigate the presence of iron line emission among faint X-ray sources identified in the 1Ms Chandra Deep Field South and in the 2Ms Chandra Deep Field North. Individual source spectra are stacked in seven redshift bins over the range z=0.5-4. We find that iron line emission is an ubiquitous property of X-ray sources up to z~3. The measured line strengths are in good agreement with those expected by simple pre-Chandra estimates based on X-ray background synthesis models. The average rest frame equivalent width of the iron line does not show significant changes with redshift.Comment: 5 pages, 2 figures, ApJ Letters in press (include emulateapj.sty

AGN and QSOs in the eROSITA All-Sky Survey -- Part I: Statistical properties

Context. The main element of the observing program of the Spectrum-Roentgen-Gamma orbital observatory is a four-year all-sky survey, in the course of which the entire sky will be scanned eight times. Aims. We analyze the statistical properties of AGN and QSOs that are expected to be detected in the course of the eROSITA all-sky survey (eRASS). Methods. According to the currently planned survey strategy and based on the parameters of the Galactic and extragalactic X-ray background as well as on the results of the recent calculations of the eROSITA instrumental background, we computed a sensitivity map of the eRASS. Using the best available redshift-dependent AGN X-ray luminosity function (XLF), we computed various characteristics of the eRASS AGN sample, such as their luminosity- and redshift distributions, and the brightness distributions of their optical counterparts. Results. After four years of the survey, a sky-average sensitivity of ~1x10^(-14) erg/s/cm^2 will be achieved in the 0.5-2.0keV band. With this sensitivity, eROSITA is expected to detect ~3 million AGN on the extragalactic sky (|b|>10deg). The median redshift of the eRASS AGN will be z~1 with ~40% of the objects in the z=1-2 redshift range. About 10^4 - 10^5 AGN are predicted beyond redshift z=3 and about 2 000 - 30 000 AGN beyond redshift z=4, the exact numbers depend on the poorly known behavior of the AGN XLF in the high-redshift and luminosity regimes. Of the detected AGN, the brightest 10% will be detected with more than ~38 counts per PSF HEW, while the faintest 10% will have fewer than ~9 counts. The optical counterparts of ~95% of the AGN will be brighter than I_(AB)=22.5mag. The planned scanning strategy will allow one to search for transient events on a timescale of half a year and a few hours with a 0.5-2.0keV sensitivity of ~2x10^(-14) to ~2x10^(-13) erg/s/cm^2, respectively.Comment: minor additions, accepted for publication in A&

Calibration of force actuators on an adaptive secondary prototype

In the context of the Large Binocular Telescope project, we present the results of force actuator calibrations performed on an adaptive secondary prototype called P45, a thin deformable glass with magnets glued onto its back. Electromagnetic actuators, controlled in a closed loop with a system of internal metrology based on capacitive sensors, continuously deform its shape to correct the distortions of the wavefront. Calibrations of the force actuators are needed because of the differences between driven forces and measured forces. We describe the calibration procedures and the results, obtained with errors of less than 1.5%.Comment: 7 page

Heterogeneous simulation and interoperability of tools applied to the design, integration and development of safety critical systems

A key issue of the assessment of the Model Based Systems Engineering (MBSE) is the integration between the requirement, functional and physical analyses. It turns out into a full capability of correlation and data exchange among the tools currently available to manage those three activities and, in particular, into a tight cooperation between the functional modeling and the physical one, being based on several methods of engineering, widely applied since longtime (mathematical, analytical, numerical and experimental). A successful accomplishment of this task within the frame of the development of the MBSE represents a milestone for both the methodology and the tools of the Systems Engineering. The application of models and simulations to support the engineering activities has spread over different domains and is strictly related to the decision making process applied to finalize an effective system design. Many kind of models are often performed to develop the systems currently populating the wide scenario of complex and smart products. When the product is a result of a material processing, some geometrical models allow describing shape and properties of the manufactured product, whose behavior is then predicted by resorting to some numerical discretization funded on a set of equations to be solved. Those models mainly describe the real nature of system, not only as is designed but even as is manufactured, thus allowing the required verification and validation activities. Due to this motivation those models belong the so–called physical modeling, whose key targets are both a mathematical modeling and a quantitative evaluation of performance. According to the MBSE the above described activity is never sufficient to completely define the details of the system under design and development. Moreover, to face the inherent complexity of new systems, being characterized by a number of functions, components and interfaces, a clear traceability from requirement to numbered part is needed. A bright allocation of each requirement to the system functions first, and to its logical blocks then, is definitely a key issue of the proposed approach. Those two main goals require a preliminary functional modeling activity, never characterized by numbers, while is dominant a prediction of system operation, behavior, interaction with other systems and stakeholders, and even a preliminary definition of well assessed requirements to motivate a consequent set of proposed layouts, based on some selected technolog