3,657 research outputs found
Official Statistics, Building Censuses, and OpenStreetMap Completeness in Italy
The present study provides a simplified framework verifying the degree of coverage and completeness of settlement maps derived from the OpenStreetMap (OSM) database at the national scale, with a possible use in official statistics. Measuring the completeness of the objects (i.e., buildings) derived from OpenStreetMap database supports its potential use in building/population censuses and other diachronic surveys, as well as administrative sources such as the register of building permits and land-use cadasters. A series of measurements at different scales are proposed and tested for Italy, in line with earlier studies. While recognizing the potential of the OpenStreetMap database for official statistics, the present work underlines the urgent need of an additional (spatially explicit) analysis overcoming the data heterogeneity and sub-optimal coverage of the OSM information source
XMM-Newton observations of ULIRGs I: A Compton-thick AGN in IRAS19254-7245
We present the XMM-Newton observation of the merging system IRAS 19254-7245,
also known as The Superantennae, whose southern nucleus is classified as a
Seyfert 2 galaxy. The XMM-Newton data have allowed us to perform a detailed
X-ray imaging and spectral analysis of this system. We clearly detect, for the
first time in this system, a strong EW ~ 1.4 keV Fe emission line at 6.49+/-0.1
keV (rest-frame). The X-ray spectrum requires a soft thermal component (kT~0.9
keV; L(0.5-2) ~ 4E41 cgs), likely associated with the starburst, and a hard
power-law continuum above 2 keV (observed L(2-10) ~ 4E42 cgs). We confirm the
flatness of this latter component, already noted in previous ASCA data. This
flatness, together with the detection of the strong Fe-Kalpha line and other
broad band indicators, suggest the presence of a Compton-thick AGN with
intrinsic luminosity > 1E44 cgs. We show that a Compton-thick model can
perfectly reproduce the X-ray spectral properties of this object.Comment: 6 pages, 4 figures, Latex manuscript, Accepted for publication in
Astronomy and Astrophysic
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