Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts

Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec 17 2009 to Jan 8 2010 and Sep 2 to Oct 20 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with ~50% or better probability with a few pointings of wide-field telescopes.Comment: 17 pages. This version (v2) includes two tables and 1 section not included in v1. Accepted for publication in Astronomy & Astrophysic

Santuari e percorsi rituali dell’età del Ferro nella Valle del Chiese

ABSTRACT – Iron Age sanctuaries and ritual itineraries in the Chiese Valley – During a research project in mountain regions in the municipal areas of Gavardo, Villanuova sul Clisi, Vallio, Agnosine and Sabbio Chiese (BS) coordinated by the then Lombardy Archaeological Heritage Superintendency, a series of sites with distinctive features were found. They are located on areas of high ground and have yielded finds dating from the First Iron Age to the Roman period. The nature of these – mostly metal – objects and the sites’ topographical and structural characteristics suggests that this was a group of ritual areas, situated among the hills on pathways that are still used. The distribution pattern appears to show a hierarchy of sites, with structured principal locations and satellite areas. After the discovery of these sites (2004 – 2011) several were investigated by means of archaeological excavation. The largest and most complex, Dos della Rocchetta - Rasine (Sabbio Chiese), was a limestone hill with suggestive karst erosion features: cavities, fissures, arches, small rock shelters, sinkholes and large detached bodies of rock. On the upper plateau a rectangular area has been cut into the rock surface. Here and on the higher crags many metal objects were found (mostly in bronze, complete or broken), together with a much smaller quantity of scorched potsherds, and widespread small burnt bone fragments. The metal artefacts included various kinds of bronze fibula, torc and pendant, silver coins and items in iron. During the final phase of use iron shoetacks are particularly numerous. Around the main site several smaller sites have been identified, at one of which was found an exceptional bronze artefact with an inscription in the ancient alphabet of the Camunni. Smaller sites have been found north of the village of Oriolo (Vallio Terme) and in the Monte Magno area (Gavardo). Study of these contexts – taking into account the constructions present, the natural features chosen, the differing preservation states of the finds and their spatial distribution – has yielded interesting conclusions regarding the rituals conducted in these sanctuaries, which were similar in some respects to those of the brandopferplätze of Alpine tradition

Traceological analysis of an Early Mesolithic site in the Southern Central Alps: preliminary results

The Early Mesolithic of the southern Alps has been largely characterised by two main types of sites: residential camps and hunting stations. This division has been primarily based on the ratio between classes of lithic artefacts, such as between tools and armatures, and between armatures and micro-burins; however, a thorough traceological analysis of these assemblages has rarely been attempted. In this paper, we present the results of the study of the Civdate Camuno site, an Early Mesolithic site located in the Middle Valle Camonica, in the Oglio River valley bottom. Our results indicate that the site cannot be simply classified as a residential camp site, nor as a specialised hunting encampment. Instead, gathered data points towards an interpretation of Cividate Camuno as a secondary (seasonal?) camp, where the main activities were represented by the production and maintenance of weaponry and primary processing of game. As a consequence, this study demonstrates the existence of intermediate situations between so-called residential sites and hunting stations. Out on all stages of use of the tools, revealing for example that the stone axes display remarkably few traces of wear considering their long time use. In this paper I will discuss the findings of the microwear analysis and the toolkit composition