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Search Results: 1 - 10 of 189979 matches for " G. Fasano "
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Analysis of Spaceborne Tandem Configurations for Complementing COSMO with SAR Interferometry
A. Moccia,G. Fasano
EURASIP Journal on Advances in Signal Processing , 2005, DOI: 10.1155/asp.2005.3304
Abstract: This paper analyses the possibility of using a fifth passive satellite for endowing the Italian COSMO-SkyMed constellation with cross- and along-track SAR interferometric capabilities, by using simultaneously flying and operating antennas. Fundamentals of developed models are described and potential space configurations are investigated, by considering both formations operating on the same orbital plane and on separated planes. The study is mainly aimed at describing achievable baselines and their time histories along the selected orbits. The effects of tuning orbital parameters, such as eccentricity or ascending node phasing, are pointed out, and simulation results show the most favorable tandem configurations in terms of achieved baseline components, percentage of the orbit adequate for interferometry, and covered latitude intervals.
Morphological classification of high redshift galaxies
E. Pignatelli,G. Fasano
Physics , 2000,
Abstract: We present GASPHOT, a tool for automated surface photometry and morphological classification of galaxies in deep and wide fields. The requirements for any such tool are reviewed, and its use for the classification of high-z galaxies is presented. In the case if HDF-like images, for galaxies having a magnitude ranging from 24 to 27.5, the uncertainties on the photometric parameters derived from GASPHOT are respectively 0.02-0.1 on magnitude, 0.03 on the logarithm of the scale length, 0.02-0.5 on the Sersic index n used to classify the surface brightness profile of the galaxies. A comparison with the results achieved using Sextractor is presented.
Deep HST imaging surveys and the formation of spheroidal galaxies
G. Rodighiero,A. Franceschini,G. Fasano
Physics , 2001, DOI: 10.1046/j.1365-8711.2001.04354.x
Abstract: We have extended our previous analysis of morphologically selected elliptical and S0 galaxies in the Hubble Deep Field (HDF) North to include HST data in the HDF South and the HDFS-NICMOS areas. Our final sample amounts to 69 E/S0 galaxies with $K<20.15$ over an area of 11 square arcmins. Although a moderately small number over a modest sky area, this sample benefits of the best imaging and photometric data available on high-redshift galaxies. Multi-waveband photometry allows us to estimate with good accuracy the redshifts for the majority of these galaxies which lack a spectroscopic measure. We confirm our previous findings that massive E/S0s tend to disappear from flux-limited samples at $z>1.4$. This adds to the evidence that the rest-frame colours and SEDs of the numerous objects found at $0.8
Surface Photometry of Early-type Galaxies in the Hubble Deep Field
G. Fasano,M. Filippi,F. Bertola
Physics , 1997, DOI: 10.1051/aas:1998206
Abstract: The detailed surface photometry of a sample of early-type galaxies in the Hubble Deep Field is presented as part of a long-term project aimed to settle strong observational constraints to the theories modelling the evolution of elliptical galaxies from the early stages. The sample has been extracted, in the V_606 band, from the catalog by Couch (1996). The analysis of the luminosity and geometrical profiles, carried out on 162 candidates obeying our provisional selection criteria, resulted in a list of 99 'bona fide' early-type galaxies, for which accurate total magnitudes and effective radii were computed. The comparison with the magnitudes given by Williams et al.(1996) indicates that the automated photometry tends to underestimate the total luminosity of the ellipticals. The luminosity profiles of most of galaxies in our sample follow fairly well the deVaucouleurs law (`Normal' profiles). However, a relevant fraction of galaxies, even following the deVaucouleurs law in the main body light distribution, exhibit in the inner region a flattening of the luminosity profile not attributable to the PSF (`Flat' profiles) or, in some cases, a complex (multi-nucleus) structure (`Merger' profiles). The average ellipticity of galaxies belonging to the `Flat' and `Merger' classes is found to be significantly higher than that of the `Normal' galaxies. Moreover, even taken into account the relevant uncertainty of the outer position angle profiles, the amount of isophotal twisting of HDF ellipticals turns out to be significantly larger with respect to that of the local samples.
C. Disanto,F. Alberti,F. Fasano,G. V. Celano
Italian Journal of Food Safety , 2011, DOI: 10.4081/ijfs.2011.1.35
Abstract: Toxoplasmosis is a worldwide protozoarian pathology, caused by Toxoplasma gondii. Toxoplasmosis is a human pathology with an high risk of diffusion because the parasite can be present in many food and sometimes it is very hard to demonstrate a direct relation between clinical cases and food consumption. The aim of this work was to assess toxoplasmosis risk communication performed by veterinary hygienists involved in local health authority (ASL). The results demonstrate that informative campaigns should be organized to show toxoplasmosis risk communication and to organize educational nutrition programs by veterinarians regarding risks caused by animals or parasitized food consumption.
The black hole mass of low redshift radiogalaxies
D. Bettoni,R. Falomo,G. Fasano,F. Govoni
Physics , 2002, DOI: 10.1051/0004-6361:20021869
Abstract: We make use of two empirical relations between the black hole mass and the global properties (bulge luminosity and stellar velocity dispersion) of nearby elliptical galaxies, to infer the mass of the central black hole (M_BH) in low redshift radiogalaxies. Using the most recent determinations of black hole masses for inactive early type galaxies we show that the bulge luminosity and the central velocity dispersion are almost equally correlated (similar scatter) with the central black-hole mass. Applying these relations to two large and homogeneous datasets of radiogalaxies we find that they host black-holes whose mass ranges between ~5x10^7 to ~6x10^9 M_sun (average ~8.9). M_BH is found to be proportional to the mass of the bulge (M_bulge). The distribution of the ratio M_BH/M_bulge has a mean value of 8x10^{-4} and shows a scatter that is consistent with that expected from the associated errors. At variance with previous claims no significant correlation is instead found between M_BH (or M_bulge) and the radio power at 5GHz.
The optical properties of low redshift radio galaxies
F. Govoni,R. Falomo,G. Fasano,R. Scarpa
Physics , 1999,
Abstract: We present morphological and photometric properties of 79 low redshift (z<0.12) radio galaxies extracted from two radio flux limited samples of radio sources. All objects are imaged in the R band and for a subsample we have also obtained B band images. The sample includes sources of both FRI and FRII radio morphological type. Through the decomposition of the luminosity profiles and the analysis of the structural profiles (ellipticity, PA, c4) of the galaxies we are able to characterize in detail the optical properties of the radio galaxies. The average absolute magnitude is M_HOST(tot)=-24.0 with a clear trend for FRI sources to be 0.5 mag brighter than FRII galaxies. In about 40% of the objects observed we find an excess of light in the nucleus that is attributed to the presence of a nuclear point source whose luminosity is on average 1-2% of the total flux of the host galaxy. The luminosity of these nuclear point sources appears correlated with the core radio power of the galaxies. Radio galaxies follow the same mu_e - R_e relationship as normal elliptical galaxies. The distribution of ellipticity, the amount of twisting and shape of isophotes (boxy,disky) do not differ significantly from other ellipticals. The evidence for recent interactions is therefore rather modest. Finally on average radio galaxies are bluer and have a color dispersion larger than normal elliptical galaxies, and the average color gradient in radio galaxies appears slightly steeper than in normal ellipticals. These results support a scenario where radio emission is weakly related with the overall properties and/or the activity have negligible effects on the global characteristics of the host galaxy.
Optical surface photometry of radio galaxies - II. Observations and data analysis
F. Govoni,R. Falomo,G. Fasano,R. Scarpa
Physics , 2000, DOI: 10.1051/aas:2000338
Abstract: Optical imaging observations for 50 radio galaxies are presented. For each object isophotal contours, photometric profiles, structural parameters (position angle, ellipticity, Fourier coefficients), and total magnitudes are given. These observations, obtained in the Cousins R band, complement the data presented in a previous paper and are part of a larger project aimed at studying the optical properties of low redshift (z<0.12) radio galaxies (Govoni et al. 1999). Comments for each individual source are reported.
Low-noise high-voltage DC power supply for nanopositioning applications
Cristian H. Belussi,Mariano Gómez Berisso,Yanina Fasano
Physics , 2014,
Abstract: Nanopositioning techniques currently applied to characterize physical properties of materials interesting for applications at the microscopic scale rely on high-voltage electronic control circuits that should have the lowest possible noise level. Here we introduce a simple, flexible, and custom-built power supply circuit that can provide +375\,V with a noise level below 10\,ppm. The flexibility of the circuit comes from its topology based on discrete MOSFET components that can be suitable replaced in order to change the polarity as well as the output voltage and current.
Early-type Galaxies in the Hubble Deep Field. The -r_e relation and the lack of large galaxies at high redshift
G. Fasano,S. Cristiani,S. Arnouts,M. Filippi
Physics , 1998, DOI: 10.1086/300280
Abstract: We present the results of the detailed surface photometry of a sample of early-type galaxies in the Hubble Deep Field. Effective radii, surface brightnesses and total V_606 magnitudes have been obtained, as well as U_300, B_450, I_814, J, H and K colors, which are compared with the predictions of chemical-spectrophotometric models of population synthesis. Spectroscopic redshifts are available for 23 objects. For other 25 photometric redshifts are given. In the -r_e plane the early-type galaxies of the HDF, once the appropriate K+E corrections are applied, turn out to follow the `rest frame' Kormendy relation. This evidence, linked to the dynamical information gathered by Steidel et al.(1996), indicates that these galaxies, even at z~2-3, lie in the Fundamental Plane, in a virial equilibrium condition. At the same redshifts a statistically significant lack of large galaxies [i.e. with Log r_e(kpc) > 0.2] is observed.
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