1,843 research outputs found
Carthographical base for territorial planning in Lombardy Region
No full textIn compliance with regionallaw n.12 dated 11 March 2005 -"Law far the govemment of the territory"- and with the Implementing Rules of Inspire, Lombardy Region is completing the realization oftopographic databases at different scales; for this purpose Lombardy Region has published standards and technical specifications.
The aim is to create and share a unique regional database that can be implemented through GIS, and that is able to share and
manipulate data. This up-to-date and shared database will be the geographicaI reference point for ali Urban location based Services. In order to stimulate this production, Lombardy Region
has introduced a funding calI to promote associations among local administrations on the topic of geographic information services based upon open source code and standards
Observables from inflation: gravitational waves and magnetic fields
No full textThe inflationary paradigm represents a fascinating and elegant way of explaining crucial cosmological phenomena; moreover it is remarkably in agreement with current cosmological observations.
However we are still blind to many aspects of the physics encoded in such a process and an unequivocal probe of such a mechanism is still lacking. On the other hand inflation suggests the solution to current open cosmological questions, as the observation of magnetic fields in the intergalactic medium.
In order to investigate in depth the inflationary mechanism, one possibility is offered by the new era of gravitational wave detectors. In the first part of the thesis we focus on this aspect of the inflationary epoch.
Any inflationary model predicts the production of a stochastic gravitational wave background (tensor modes) due to quantum fluctuations of the gravitational field.
Moreover, in some scenarios, the presence of additional fields besides the inflaton and the gravitational field gives rise to efficient sources of gravitational waves, activating the so-called classical production.
Inflationary gravitational wave signals turn out to represent a unique and exciting window on the origin and evolution of the universe, and a possibility of investigating the underlying theory of gravity.
We point out the significant role of primordial gravitational waves in testing the inflationary mechanism itself and in constraining many aspects of the inflationary physics, exploiting the validity/violation of an inflationary consistency relation.
Being inflationary gravitational waves a promising way of exploring many aspects of the physics of the early universe, we provide an updated picture of the current status and the observational prospects of inflationary tensor modes, with a particular focus on the possibility of a direct gravitational wave detection offered by current and upcoming laser interferometer detectors.
Then we perform a dedicated forecast analysis of the capabilities of the LISA (Laser Interferometer Space Antenna) experiment in probing the inflationary physics. In particular, the capabilities of LISA in measuring a stochastic gravitational wave background are presented.
Furthermore, we calculate the gravitational wave signal expected at the LISA frequencies for a number of selected inflationary models.
We collect and re-elaborate current limits on the present time gravitational wave spectral energy density, and the sensitivity curves of LISA and other experiments, in order to outline current and expected constraints on the parameter space of the selected inflationary models.
The results we find show the efficiency of the method, suggesting an exciting direction in order to investigate inflationary physics and a validation of the significant science that can be done by an experiment as LISA.
In the second part of the thesis another interesting aspect of the inflationary mechanism is considered, i.e. the possibility of a significant magnetogenesis.
Gamma-ray observations from blazars point out the presence of magnetic fields in the intergalactic medium, where no charged plasma are present. This fact suggests a primordial origin of such fields.
Interestingly, the inflationary mechanism provides a fascinating way of explaining the presence of magnetic fields at cosmological scales.
In a dedicated section, the main models of inflationary magnetogenesis are outlined.
A common aspect of these models is the associated overproduction of curvature and tensor perturbations with respect to single-field slow-roll inflation.
In general, observational constraints obtained by CMB measurements on such quantities lead to relevant restrictions on the associated production of magnetic fields.
Other limits are provided by keeping under control the backreaction of the electromagnetic fields.
In particular, we consider the case proposed from Caprini, where a magnetogenesis mechanism able to explain current gamma-ray observations and to start the galactic dynamo takes place.
We calculate the correction to the scalar spectrum and bispectrum (the latter related to primordial non-gaussianities) with respect to single-field slow-roll inflation generated in such a scenario. We find that the strongest constraints on the model originate from the non-observation of a scalar bispectrum of CMB anisotropies. Nevertheless, we found that even when those stringent constraints are taken into consideration, that scenario provides a robust explanation of the observed magnetic fields for a reasonably high energy scale of inflation
La carta dei sentieri della Comunità Montana Valtellina di Tirano. Il progetto pilota della val Grosina
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Specifiche tecniche aerofotogrammetriche per la realizzaizone del Database topografico alle scale 1:1000 e 1:2000 - Specifiche tecniche aerofotogrammetriche per la realizzaizone del Database topografico alle scale 1:5000 e 1:10000 - Specifiche di contenuto e schema fisico di consegna del database topografico - Specifiche tecniche per l'aggiornamento di cartografie numeriche ed il loro adeguamento al database topografico
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