57 research outputs found
Astrophysics in S.Co.P.E
S.Co.P.E. is one of the four projects funded by the Italian Government in
order to provide Southern Italy with a distributed computing infrastructure for
fundamental science. Beside being aimed at building the infrastructure,
S.Co.P.E. is also actively pursuing research in several areas among which
astrophysics and observational cosmology. We shortly summarize the most
significant results obtained in the first two years of the project and related
to the development of middleware and Data Mining tools for the Virtual
Observatory
GRID-Launcher v.1.0
GRID-launcher-1.0 was built within the VO-Tech framework, as a software interface between the UK-ASTROGRID and a generic GRID infrastructures in order to allow any ASTROGRID user to launch on the GRID computing intensive tasks from the ASTROGRID Workbench or Desktop. Even though of general application, so far the Grid-Launcher has been tested on a few selected softwares (VONeural-MLP, VONeural-SVM, Sextractor and SWARP) and on the SCOPE-GRID
The VO-Neural project: recent developments and some applications
VO-Neural is the natural evolution of the Astroneural project which was
started in 1994 with the aim to implement a suite of neural tools for data
mining in astronomical massive data sets. At a difference with its ancestor,
which was implemented under Matlab, VO-Neural is written in C++, object
oriented, and it is specifically tailored to work in distributed computing
architectures. We discuss the current status of implementation of VO-Neural,
present an application to the classification of Active Galactic Nuclei, and
outline the ongoing work to improve the functionalities of the package.Comment: Contributed, Data Centre Alliance Workshops: GRID and the Virtual
Observatory, April 9-11 Munich, to appear in Mem. SAI
Demonstration and Comparison of Operation of Photomultiplier Tubes at Liquid Argon Temperature
Liquified noble gases are widely used as a target in direct Dark Matter
searches. Signals from scintillation in the liquid, following energy deposition
from the recoil nuclei scattered by Dark Matter particles (e.g. WIMPs), should
be recorded down to very low energies by photosensors suitably designed to
operate at cryogenic temperatures. Liquid Argon based detectors for Dark Matter
searches currently implement photo multiplier tubes for signal read-out. In the
last few years PMTs with photocathodes operating down to liquid Argon
temperatures (87 K) have been specially developed with increasing Quantum
Efficiency characteristics. The most recent of these, Hamamatsu Photonics Mod.
R11065 with peak QE up to about 35%, has been extensively tested within the R&D
program of the WArP Collaboration. During these testes the Hamamatsu PMTs
showed superb performance and allowed obtaining a light yield around 7
phel/keVee in a Liquid Argon detector with a photocathodic coverage in the 12%
range, sufficient for detection of events down to few keVee of energy
deposition. This shows that this new type of PMT is suited for experimental
applications, in particular for new direct Dark Matter searches with LAr-based
experiments
The DAME/VO-Neural Infrastructure: an Integrated Data Mining System Support for the Science Community
Astronomical data are gathered through a very large number of heterogeneous
techniques and stored in very diversified and often incompatible data
repositories. Moreover in the e-science environment, it is needed to integrate
services across distributed, heterogeneous, dynamic "virtual organizations"
formed by different resources within a single enterprise and/or external
resource sharing and service provider relationships. The DAME/VONeural project,
run jointly by the University Federico II, INAF (National Institute of
Astrophysics) Astronomical Observatories of Napoli and the California Institute
of Technology, aims at creating a single, sustainable, distributed
e-infrastructure for data mining and exploration in massive data sets, to be
offered to the astronomical (but not only) community as a web application. The
framework makes use of distributed computing environments (e.g. S.Co.P.E.) and
matches the international IVOA standards and requirements. The integration
process is technically challenging due to the need of achieving a specific
quality of service when running on top of different native platforms. In these
terms, the result of the DAME/VO-Neural project effort will be a
service-oriented architecture, obtained by using appropriate standards and
incorporating Grid paradigms and restful Web services frameworks where needed,
that will have as main target the integration of interdisciplinary distributed
systems within and across organizational domains.Comment: 10 pages, Proceedings of the Final Workshop of the Grid Projects of
the Italian National Operational Programme 2000-2006 Call 1575; Edited by
Cometa Consortium, 2009, ISBN: 978-88-95892-02-
A web application for photometric redshift estimation
In the era of massive astronomical datasets, efficient identification of candidate
quasars and the reconstruction of their three dimensional
distribution in the Universe is a key
requirement for constraining some of the main
issues regarding the formation and evolution of
QSOs. A method for the determination of photometric
redshifts of QSOs based on multiwavelength
photometry and on a combination of data
mining techniques will be discussed. This procedure,
specifically suited for accompanying the candidate
selection method discussed in (DâAbrusco
et al. 2008), makes use of specific tools developed
under the EuroVO and NVO frameworks for data
gathering, pre-processing and mining, while relying
on the scaling capabilities of the computing
grid. This method allowed us to obtain photometric
redshifts with an increased accuracy (up to 30%)
with respect to the literature
Measurement of the atmospheric muon depth intensity relation with the NEMO Phase-2 tower
The results of the analysis of the data collected with the NEMO Phase-2
tower, deployed at 3500 m depth about 80 km off-shore Capo Passero (Italy), are
presented. Cherenkov photons detected with the photomultipliers tubes were used
to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution
was measured and the results compared with Monte Carlo simulations. An
evaluation of the systematic effects due to uncertainties on environmental and
detector parameters is also included. The associated depth intensity relation
was evaluated and compared with previous measurements and theoretical
predictions. With the present analysis, the muon depth intensity relation has
been measured up to 13 km of water equivalent.Comment: submitted to Astroparticle Physic
Deep sea tests of a prototype of the KM3NeT digital optical module
The first prototype of a photo-detection unit of the future KM3NeT neutrino telescope has been deployed in the deepwaters of the Mediterranean Sea. This digital optical module has a novel design with a very large photocathode area segmented by the use of 31 three inch photomultiplier tubes. It has been integrated in the ANTARES detector for in-situ testing and validation. This paper reports on the first months of data taking and rate measurements. The analysis results highlight the capabilities of the new module design in terms of background suppression and signal recognition. The directionality of the optical module enables the recognition of multiple Cherenkov photons from the same (40)Kdecay and the localisation of bioluminescent activity in the neighbourhood. The single unit can cleanly identify atmospheric muons and provide sensitivity to the muon arrival directions
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