391 research outputs found
Accesso all'archivio dei dati meteo di Cima Ekar
Il sistema attuale di acquisizione di dati meteo nella sede osservativa di Cima Ekar è in funzione dal 2012. Durante questo periodo sono stati raccolti sia i dati relativi alle condizioni atmosferiche (temperatura, umidità , pressione, radiazione solare, velocità e direzione del vento) sia i dati relativi alle temperature dei telescopi, dal basamento al top ring. In questo rapporto tecnico si descrive l’interfaccia web per accedere all'archivio e per visualizzare tali dati
A monitoring tool for a GRID operation center
WorldGRID is an intercontinental testbed spanning Europe and the US
integrating architecturally different Grid implementations based on the Globus
toolkit. The WorldGRID testbed has been successfully demonstrated during the
WorldGRID demos at SuperComputing 2002 (Baltimore) and IST2002 (Copenhagen)
where real HEP application jobs were transparently submitted from US and Europe
using "native" mechanisms and run where resources were available, independently
of their location. To monitor the behavior and performance of such testbed and
spot problems as soon as they arise, DataTAG has developed the EDT-Monitor tool
based on the Nagios package that allows for Virtual Organization centric views
of the Grid through dynamic geographical maps. The tool has been used to spot
several problems during the WorldGRID operations, such as malfunctioning
Resource Brokers or Information Servers, sites not correctly configured, job
dispatching problems, etc. In this paper we give an overview of the package,
its features and scalability solutions and we report on the experience acquired
and the benefit that a GRID operation center would gain from such a tool.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 3 pages, PDF. PSN MOET00
Resolved stellar population of distant galaxies in the ELT era
The expected imaging capabilities of future Extremely Large Telescopes (ELTs)
will offer the unique possibility to investigate the stellar population of
distant galaxies from the photometry of the stars in very crowded fields. Using
simulated images and photometric analysis we explore here two representative
science cases aimed at recovering the characteristics of the stellar
populations in the inner regions of distant galaxies. Specifically: case A) at
the center of the disk of a giant spiral in the Centaurus Group, (mu B~21,
distance of 4.6 Mpc); and, case B) at half of the effective radius of a giant
elliptical in the Virgo Cluster (mu~19.5, distance of 18 Mpc). We generate
synthetic frames by distributing model stellar populations and adopting a
representative instrumental set up, i.e. a 42 m Telescope operating close to
the diffraction limit. The effect of crowding is discussed in detail showing
how stars are measured preferentially brighter than they are as the confusion
limit is approached. We find that (i) accurate photometry (sigma~0.1,
completeness >90%) can be obtained for case B) down to I~28.5, J~27.5 allowing
us to recover the stellar metallicity distribution in the inner regions of
ellipticals in Virgo to within ~0.1 dex; (ii) the same photometric accuracy
holds for the science case A) down to J~28.0, K~27.0, enabling to reconstruct
of the star formation history up to the Hubble time via simple star counts in
diagnostic boxes. For this latter case we discuss the possibility of deriving
more detailed information on the star formation history from the analysis of
their Horizontal Branch stars. We show that the combined features of high
sensitivity and angular resolution of ELTs may open a new era for our knowledge
of the stellar content of galaxies of different morphological type up to the
distance of the Virgo cluster.Comment: 21 pages, 17 figures, PASP accepted in pubblicatio
Stick-Slip Sliding of Water Drops on Chemically Heterogeneous Surfaces
We present a comprehensive study of water drops sliding down chemically heterogeneous surfaces formed by a periodic pattern of alternating hydrophobic and hydrophilic stripes. Drops are found to undergo a stick-slip motion whose average speed is an order of magnitude smaller than that measured on a homogeneous surface having the same static contact angle. This motion is the result of the periodic deformations of the drop interface when crossing the stripes. Numerical simulations confirm this view and are used to elucidate the principles underlying the experimental observations
Characterizing HR3549B using SPHERE
Aims. In this work, we characterize the low mass companion of the A0 field
star HR3549. Methods. We observed HR3549AB in imaging mode with the the NIR
branch (IFS and IRDIS) of SPHERE@VLT, with IFS in YJ mode and IRDIS in the H
band. We also acquired a medium resolution spectrum with the IRDIS long slit
spectroscopy mode. The data were reduced using the dedicated SPHERE GTO
pipeline, purposely designed for this instrument. We employed algorithms such
as PCA and TLOCI to reduce the speckle noise. Results. The companion was
clearly visible both with IRDIS and IFS.We obtained photometry in four
different bands as well as the astrometric position for the companion. Based on
our astrometry, we confirm that it is a bound object and put constraints on its
orbit. Although several uncertainties are still present, we estimate an age of
~100-150 Myr for this system, yielding a most probable mass for the companion
of 40-50MJup and T_eff ~300-2400 K. Comparing with template spectra points to a
spectral type between M9 and L0 for the companion, commensurate with its
position on the color-magnitude diagram.Comment: Accepted by A&A, 13 pages, 10 Figures (Figures 9 and 10 degraded to
reduce the dimension
The Integral Field Spectrograph of SPHERE: the Planet Finder for VLT
SPHERE is an instrument designed and built by a consortium of French, German,
Italian, Swiss and Dutch institutes in collaboration with ESO. The project is
currently in its Phase B. The main goal of SPHERE is to gain at least one order
of magnitude with respect to the present VLT AO facility (NACO) in the direct
detection of faint objects very close to a bright star, especially giant
extrasolar planets. Apart from a high Strehl ratio, the instrument will be
designed to reduce the scattered light of the central bright star and subtract
the residual speckle halo. Sophisticated post-AO capabilities are needed to
provide maximum detectivity and possibly physical data on the putative planets.
The Integral Field Spectrograph (IFS), one of the three scientific channels
foreseen in the SPHERE design, is a very low resolution spectrograph (R~20)
which works in the near IR (0.95-1.35 micron), an ideal wavelength range for
the ground based detection of planetary features. Its goal is to suppress
speckle to a contrast of 10^7, with a goal of 10^8, and at the same time
provide spectral information in a field of view of about 1.5 x 1.5 arcsecs^2 in
proximity of the target star. In this paper we describe the overall IFS design
concept.Comment: Proc. SPIE 6269 (2006), 10 pages, 6 figures, PDF fil
SOXS: a wide band spectrograph to follow up transients
SOXS (Son Of X-Shooter) will be a spectrograph for the ESO NTT telescope
capable to cover the optical and NIR bands, based on the heritage of the
X-Shooter at the ESO-VLT. SOXS will be built and run by an international
consortium, carrying out rapid and longer term Target of Opportunity requests
on a variety of astronomical objects. SOXS will observe all kind of transient
and variable sources from different surveys. These will be a mixture of fast
alerts (e.g. gamma-ray bursts, gravitational waves, neutrino events), mid-term
alerts (e.g. supernovae, X-ray transients), fixed time events (e.g. close-by
passage of minor bodies). While the focus is on transients and variables, still
there is a wide range of other astrophysical targets and science topics that
will benefit from SOXS. The design foresees a spectrograph with a
Resolution-Slit product ~ 4500, capable of simultaneously observing over the
entire band the complete spectral range from the U- to the H-band. The limiting
magnitude of R~20 (1 hr at S/N~10) is suited to study transients identified
from on-going imaging surveys. Light imaging capabilities in the optical band
(grizy) are also envisaged to allow for multi-band photometry of the faintest
transients. This paper outlines the status of the project, now in Final Design
Phase.Comment: 12 pages, 14 figures, to be published in SPIE Proceedings 1070
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