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result(s) for
"Maria Rosa Panzera"
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The SpaceInn SISMA archive
2017
The Spectroscopic Indicators in a SeisMic Archive (SISMA) has been built in the framework of the FP7 SpaceInn project to contain the 7013 HARPS spectra observed during the CoRoT asteroseismic groundbased program, along with their variability and asteroseismic indicators. The spectra pertain to 261 stars spread around the whole Herztsprung-Russell diagram: 72 of them were CoRoT targets while the others were observed in order to better characterize their variability classes. The Legacy Data lightcurves of the CoRoT targets are also stored in the archive.
Journal Article
Promoting access to and use of seismic data in a large scientific community
by
Gizon, Laurent
,
Roth, Markus
,
Abed, Mahfoudh
in
Archives & records
,
Astronomical models
,
Buffalo
2017
The growing amount of seismic data available from space missions (SOHO, CoRoT, Kepler, SDO,…) but also from ground-based facilities (GONG, BiSON, ground-based large programmes…), stellar modelling and numerical simulations, creates new scientific perspectives such as characterizing stellar populations in our Galaxy or planetary systems by providing model-independent global properties of stars such as mass, radius, and surface gravity within several percent accuracy, as well as constraints on the age. These applications address a broad scientific community beyond the solar and stellar one and require combining indices elaborated with data from different databases (e.g. seismic archives and ground-based spectroscopic surveys). It is thus a basic requirement to develop a simple and effcient access to these various data resources and dedicated tools. In the framework of the European project SpaceInn (FP7), several data sources have been developed or upgraded. The Seismic Plus Portal has been developed, where synthetic descriptions of the most relevant existing data sources can be found, as well as tools allowing to localize existing data for given objects or period and helping the data query. This project has been developed within the Virtual Observatory (VO) framework. In this paper, we give a review of the various facilities and tools developed within this programme. The SpaceInn project (Exploitation of Space Data for Innovative Helio- and Asteroseismology) has been initiated by the European Helio- and Asteroseismology Network (HELAS).
Conference Proceeding
The Brera Multi-scale Wavelet (BMW) ROSAT HRI source catalog. II: application to the HRI and first results
by
Maria Rosa Panzera
,
Tagliaferri, Gianpiero
,
Campana, Sergio
in
Algorithms
,
Automobile industry
,
Automobiles
1999
The wavelet detection algorithm (WDA) described in the accompanying paper by Lazzati et al. is made suited for a fast and efficient analysis of images taken with the High Resolution Imager (HRI) instrument on board the ROSAT satellite. An extensive testing is carried out on the detection pipeline: HRI fields with different exposure times are simulated and analysed in the same fashion as the real data. Positions are recovered with few arcsecond errors, whereas fluxes are within a factor of two from their input values in more than 90% of the cases in the deepest images. At variance with the ``sliding-box'' detection algorithms, the WDA provides also a reliable description of the source extension, allowing for a complete search of e.g. supernova remnant or cluster of galaxies in the HRI fields. A completeness analysis on simulated fields shows that for the deepest exposures considered (~120 ks) a limiting flux of \\~3x10^{-15} erg/cm2/s can be reached over the entire field of view. We test the algorithm on real HRI fields selected for their crowding and/or presence of extended or bright sources (e.g. cluster of galaxies and of stars, supernova remnants). We show that our algorithm compares favorably with other X-ray detection algorithms such as XIMAGE and EXSAS. A complete catalog will result from our analysis: it will consist of the Brera Multi-scale Wavelet Bright Source Catalog (BMW-BSC) with sources detected with a significance >4.5 sigma and of the Faint Source Catalog (BMW-FSC) with sources at >3.5 sigma. A conservative estimate based on the extragalactic log(N)-log(S) indicates that at least 16000 sources will be revealed in the complete analysis of the whole HRI dataset.
The Brera Multi-scale Wavelet (BMW) ROSAT HRI source catalog. I: the algorithm
by
Maria Rosa Panzera
,
Tagliaferri, Gianpiero
,
Rosati, Piero
in
Algorithms
,
Automobile industry
,
Automobiles
1999
We present a new detection algorithm based on the wavelet transform for the analysis of high energy astronomical images. The wavelet transform, due to its multi-scale structure, is suited for the optimal detection of point-like as well as extended sources, regardless of any loss of resolution with the off-axis angle. Sources are detected as significant enhancements in the wavelet space, after the subtraction of the non-flat components of the background. Detection thresholds are computed through Monte Carlo simulations in order to establish the expected number of spurious sources per field. The source characterization is performed through a multi-source fitting in the wavelet space. The procedure is designed to correctly deal with very crowded fields, allowing for the simultaneous characterization of nearby sources. To obtain a fast and reliable estimate of the source parameters and related errors, we apply a novel decimation technique which, taking into account the correlation properties of the wavelet transform, extracts a subset of almost independent coefficients. We test the performance of this algorithm on synthetic fields, analyzing with particular care the characterization of sources in poor background situations, where the assumption of Gaussian statistics does not hold. For these cases, where standard wavelet algorithms generally provide underestimated errors, we infer errors through a procedure which relies on robust basic statistics. Our algorithm is well suited for the analysis of images taken with the new generation of X-ray instruments equipped with CCD technology which will produce images with very low background and/or high source density.
The BMW X-ray Cluster Survey
by
Guzzo, Luigi
,
Molinari, Emilio
,
Maria Rosa Panzera
in
Automobile industry
,
Automobiles
,
Clusters
2001
We describe the main features of the BMW survey of serendipitous X-ray clusters, based on the still unexploited ROSAT-HRI archival observations. The sky coverage, surface density and first deep optical CCD images of the candidates indicate that this sample can represent an excellent complement to the existing PSPC deep cluster surveys and will provide us with a fully independent probe of the evolution of the cluster abundance, in addition to significantly increasing the number of clusters known at z>0.6.
Advances in SiC-reinforced cementitious composites for aerostatic thrust bearings based on full factorial design
by
dos Santos, Júlio César
,
Assunção Rosa, Fábio
,
Maia Pires, Pabllo Miguel
in
Control
,
Engineering
,
Materials Engineering
2025
Aerostatic thrust bearings utilise air as a lubricant to support loads while minimising friction and wear. The airflow within these bearings is controlled by a restrictor, which can be constructed from various materials, including porous substances. The selection of a porous material for the restrictor is particularly influenced by factors such as permeability, stiffness, and homogeneity. This work proposes a microstructural design for air restrictors based on compacted cementitious composites. A novel cementitious composite, consisting of silicon carbide (SiC) particles and Portland cement, is fabricated through cold pressing at 10 MPa and a low water-to-cement ratio of 0.30. To evaluate the effects of SiC particle size and weight fraction on the physical and mechanical properties of the composites, a statistical design approach is employed. The response variables include apparent density, apparent porosity, oxygen permeability coefficient, compressive strength, flexural strength, and dynamic modulus. In general, a significant reduction in density, compressive strength, flexural strength, and dynamic modulus, along with an increase in porosity and oxygen permeability, is achieved by composites made with smaller SiC particles. A higher weight fraction of SiC reduces bulk density and compressive strength, while increasing porosity and oxygen permeability. Finally, composites made with 67 wt% of fine SiC particles exhibit promising characteristics for aerostatic bearings, particularly in terms of porosity and permeability.
Journal Article