δ 11B as tracer of slab dehydration and mantle evolution in Western Anatolia Cenozoic Magmatism

Boron isotope data are presented for Cenozoic Western Anatolia rocks, which define two main associations: (i) calc-alkaline, shoshonitic and ultra-potassic rocks (Early to Middle Miocene); and (ii) Late Miocene–Quaternary intraplate alkali basalts. Boron data, together with Sr–Nd isotope and other trace elements, are consistent with a progressive dehydration of the slab, producing fluid phases gradually depleted in B (and ¹¹B). These fluids were added to the supraslab mantle, triggering a partial melting that gave rise to orogenic magmatism. The stretching and tearing of the slab caused by the faster convergence of Greece over Africa with respect to Anatolia facilitated an interaction of the upwelling subslab asthenosphere with residual slab-fluids during the Late Miocene followed by production of typical intraplate magmas during the Pleistocene–Holocene, whose relatively high δ¹¹B (approximately −2‰) is considered representative of the local asthenosphere not affected by subduction contamination.     

Properties of dusty tori in active galactic nuclei – I. The case of SWIRE/SDSS quasars

We derive the properties of dusty tori in active galactic nuclei from the comparison of observed spectral energy distributions (SEDs) of SDSS quasars and a precomputed grid of torus models. The observed SEDs comprise SDSS photometry, Two-Micron All-Sky Survey J , H and K data, whenever available, and mid-infrared (mid-IR) data from the Spitzer Wide-area InfraRed Extragalactic Survey. The adopted model is that of Fritz, Franceschini & Hatziminaoglou. The fit is performed by standard  χ²  -minimization; the model, however, can be a multicomponent comprising a stellar and a starburst component, whenever necessary. Models with low equatorial optical depth, τ_9.7, were allowed as well as 'traditional' models with  τ_9.7≥ 1.0  , corresponding to   A _V≥ 22  and the results were compared. Fits using high optical depth tori models only produced dust more compactly distributed than in the configuration where all τ_9.7 models were permitted. Tori with decreasing dust density with the distance from the centre were favoured while there was no clear preference for models with or without angular variation of the dust density. The computed outer radii of the tori are of some tens of parsecs large but can reach, in a few cases, a few hundreds of parsecs. The mass of dust, M _Dust, and IR luminosity, L _IR, integrated in the wavelength range between 1 and 1000 μm, do not show significant variations with redshift, once the observational biases are taken into account. Objects with 70-μm detections, representing 25 per cent of the sample, are studied separately and the starburst contribution (whenever present) to the IR luminosity can reach, in the most extreme but very few cases, 80 per cent.     

An ESA NEOCC Effort to Eliminate High Palermo Scale Virtual Impactors

In this work we summarize the initial results of a targeted effort of the ESA NEO Coordination Centre to obtain additional observational data in order to eliminate or reduce the impact probability estimate of a subset of the known near-Earth objects representing the highest fraction of the total known impact risk, as measured by the Palermo Scale.     

Polyphase thrusting and dyke emplacement in the central Southern Alps (Northern Italy)

The Triassic succession of the central Southern Alps (Italy) is stacked into several units bounded by south-verging low-angle thrust faults, which are related to two successive steps of crustal shortening. The thrust surfaces are cut by high-angle extensional and strike-slip faults, which controlled the emplacement of hypabissal magmatic intrusions that post-date thrusts motions. Intrusion ages based on SHRIMP U–Pb zircon dating span between 42 ± 1 and 39 ± 1 Ma, suggesting close time relationships with the earliest Adamello intrusion stages and, more in general, with the widespread calc-alkaline magmatism described in the Southern Alps. Fission-track ages of magmatic apatites are indistinguishable from U–Pb crystallization ages of zircons, suggesting that the intrusion occurred in country rocks already exhumed above the partial annealing zone of apatite (depth < 2–4 km). These data indicate that the central Southern Alps were already structured and largely exhumed in the Middle Eocene. Although we describe minor faults affecting magmatic bodies and local reactivations of older structures, no major internal deformations have occurred in the area after the Bartonian. Neogene deformations were instead concentrated farther south, along the frontal part of the belt.     

Design of a high update-rate star sensor for arcsec-level attitude determination from balloon-borne X/γ astronomy platforms

This paper describes the design of a star sensor based upon a high dynamic range CCD in order to reach an arcsec-level attitude determination in balloon-borne missions. A custom star identification software was developed and laboratory-tested on a prototype assembled using commercial components. A set of numerical simulations have been carried out to study the dependence on the pointing precision of the centroid position accuracy, the number of detected stars and the effect of the image focusing. Moreover, the role of the electronic noise and the discrete pixel structure on the light signals is identified by the analysis of numerical simulations. Laboratory tests confirm that the arcsec pointing accuracy with a 1 Hz update rate can be achieved with our combination of custom-developed software and selected hardware components.     

Final analysis of ELAIS 15-μm observations: method, reduction and catalogue

We present the final analysis of the European Large Area Infrared Space Observatory ( ISO ) Survey (ELAIS) 15-μm observations, carried out with the ISO Camera (ISOCAM) instrument on board the ISO .
The data-reduction method, known as the Lari Method, is based on a mathematical model of the behaviour of the detector and was specifically designed for the detection of faint sources in ISOCAM/ISO Photopolarimeter (ISOPHOT) data. The method is fully interactive and leads to very reliable and complete source lists.
The resulting catalogue includes 1923 sources detected with signal-to-noise ratio of  > 5  in the 0.5–100 mJy flux range and over an area of 10.85 deg² split into four fields, making it the largest non-serendipitous extragalactic source catalogue obtained to date from the ISO data.
This paper presents the concepts underlying the data-reduction method together with its latest enhancements. The data-reduction process, the production and basic properties of the resulting catalogue are discussed. The catalogue quality is assessed by means of detailed simulations, optical identifications and comparison with previous analyses.     

1D velocity structure of the Po River plain (Northern Italy) assessed by combining strong motion and ambient noise data

Strong ground motions recorded on the sedimentary deposits of the Po River alluvial plain during the Emilia (Northern Italy) Mw 5.7 earthquake of May 29, 2012 are used to assess the vertical profile of shear-wave velocity above the limestone basement. Data were collected by a linear array installed for site effect studies after the Mw 5.9 mainshock of May 20, 2012. The array stations, equipped with both strong and weak motion sensors, are aligned in the South–North direction, at distances ranging from 1 to 26 km from the epicenter. The vertical components of ground motion show very distinctive, large-amplitude, low-frequency dispersive wave trains. Wavelet analysis yields group-velocity dispersion curve in the 0.2–0.7 Hz frequency band. The availability of a long ambient noise record allows estimates of the site resonance frequency along with its stability among stations. The joint inversion of dispersion of surface waves and ellipticity curves derived from ambient noise H/V allows extending investigations down to the sediment-limestone interface, at a depth of about 5,000 m. Our results add new information about the velocity structure at a scale that is intermediate between the local scale already investigated by other authors with small-aperture arrays using ambient noise and the regional scale inferred from modeling of seismogram waveforms recorded at hundreds of kilometers from the source.