46 research outputs found
Analysis of CMB foregrounds using a database for Planck
Within the scope of the Planck IDIS (Integrated Data Information System)
project we have started to develop the data model for time-ordered data and
full-sky maps. The data model is part of the Data Management Component (DMC), a
software system designed according to a three-tier architecture which allows
complete separation between data storage and processing. The DMC is already
being used for simulation activities and the modeling of some foreground
components. We have ingested several Galactic surveys into the database and
used the science data-access interface to process the data. The data structure
for full-sky maps utilises the HEALPix tessellation of the sphere. We have been
able to obtain consistent measures of the angular power spectrum of the
Galactic radio continuum emission between 408 MHz and 2417 MHz.Comment: 7 pages, 6 figures. To appear in the Proceedings of the MPA/ESO/MPE
Joint Astronomy Conference "Mining The Sky
Organization of the Euclid Data Processing: Dealing with Complexity
The data processing development and operations for the Euclid mission (part of the ESA Cosmic Vision 2015-2025 Plan) is distributed within a Consortium composed of 14 countries and 1300+ persons: this imposes a high degree of complexity to the design and implementation of the data processing facilities. The focus of this paper is on the efforts to define an organisational structure capable of handling in manageable terms such a complexity
The Grid in INAF
Abstract. This paper presents an overview of the Grid-related projects in which Insitutes of INAF (Istituto Nazionale di Astrofisica) were involved, starting from the GRID.IT project until the recent and currently in progress participation to EGEE (Enabling Grids for EsciencE), the main project for the setup of a Grid Infrastructure for Science in Europe. The paper will give an overview of these activities putting particular emphasis on some key pilot projects, like the simulations of the Planck mission and the development of tools to widen the Grid capabilities to meet the needs of astrophysical applications
Star Counts in the Globular Cluster Omega Centauri. I. Bright Stellar Components
We present an extensive photometry on HB, RGB, and MSTO stars in Omega Cen.
The central regions of the cluster were covered with a mosaic of F435W, F625W,
and F658N-band data collected with ACS/HST. The outer reaches were covered with
a large set of U,B,V,I-band data collected with the [email protected] ESO/MPI telescope.
The final catalogue includes ~1.7 million stars. We identified ~3,200 likely HB
stars and ~12,500 stars brighter than the subgiant branch and fainter than the
RGB bumps. The HB morphology changes with the radial distance. The relative
number of extreme HB stars decreases from ~30% to ~21% when moving from the
center toward the outer regions of the cluster, while the fraction of less hot
HB stars increases from ~62% to ~72%. We performed a detailed comparison
between observed ratios of different stellar tracers and predictions based on
canonical evolutionary models with a primordial helium (Y=0.23) content and
metal abundances (Z=0.0002,0.001) that bracket the observed spread in
metallicity of Omega Cen stars. We found that the empirical star counts of HB
stars are on average larger (30%-40%) than predicted. Moreover, the rate of HB
stars is 43% larger than the MSTO rate. The discrepancy between the rate of HB
compared with the rate of RG and MSTO stars supports the evidence that we are
facing a true excess of HB stars. The same comparison was performed by assuming
a mix of stellar populations made with 70% of canonical stars and 30% of
He-enhanced stars. The discrepancy between theory and observations decreases by
a factor of two when compared with rates predicted by canonical He content
models, but still 15%-25% (Y=0.42) and 15%-20% (Y=0.33) higher than observed.
Furthermore, the ratio between HB and MSTO star counts are ~24% (Y=0.42) and
30% (Y=0.33) larger than predicted lifetime ratios.Comment: 54 pages, 17 figures,to be published in ApJ, see link at
http://stellari.wiki.zoho.co
enabling access to astronomical databases through the grid a case study
In recent years great efforts have been spent in the astronomical community to allow a global and seamless electronic access to distributed astronomical data repositories, and to enable scientific analysis on them. A system capable of providing these services over distributed databases and computer resources is called a Virtual Observatory (VO). VOs are still in the study phase, with many projects around the world now delivering their first prototype implementations. In the meanwhile grid technologies have started to emerge and consolidate and are now expected to play a fundamental role in the development of Astrophysical Virtual Observatories. We report here about our activities aimed at integrating in the grid environment a system, developed in Padova, specifically designed for accessing very large astronomical catalogues. We evaluated several possible solutions, including the use of a tool for accessing databases developed by the European Data Grid (EDG) project, but finally we decided to adopt a web services based architecture, retaining the security infrastructure provided by the EDG software. We plan to evolve towards an implementation fully compliant with the latest Open Grid Service Architecture specification, but without loosing compatibility with the grid middleware adopted in our project. This work is being conducted in the framework of Grid.it, a project, funded by the Italian Ministry for Education, University and Research, aimed at studying a grid infrastructure for scientific research in Italy and developing specific software tools and protype applications that run on it. This catalogue access system will eventually become one of the first building blocks of the Italian Virtual Observatory, currently under development in the framework of a closely-related project, named DRACO. To this end, starting from the design phase of our system, and where applicable, we adopted the standards set forth by the International Virtual Observatory Alliance (IVOA)
VO-compliant workflows and science gateways
Abstract Workflow and science gateway technologies have been widely adopted by scientific communities as a valuable tool to carry out complex experiments. They offer the possibility to perform computations for data analysis and simulations, whereas hiding details of the complex infrastructures underneath. There are many workflow management systems covering a large variety of generic services coordinating execution of workflows. In this paper we describe our experiences in creating workflows oriented science gateway based on gUSE/WS-PGRADE technology and in particular we discuss the efforts devoted to develop a VOcompliant web environment