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Дата изменения: Tue May 15 18:15:53 2007
Дата индексирования: Mon Oct 1 23:59:29 2012
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POSTERS

Virginia Botte Dipartimento di Astronomia UniversitЮ di Bologna OI 8446 in NLS1 galaxies ...............................

Alessandra Beifiori Dipartimento di Astronomia UniversitЮ di Padova A. Beifiori, E. M. Corsini, E. Dalla BontЮ, A. Pizzella, M. Sarzi, F. Bertola Upper limits on the mass of supermassive black holes from HST/STIS archival data The growth of supermassive black holes (SBHs) appears to be closely linked with the formation of spheroids. From the observational point of view there is a pressing need to acquire better statistics on SMH masses since the existing samples are preferentially weighted toward earlytype galaxies with very massive SBHs. W ith this motivation we started a project aimed at measuring upper limits of the mass of the SBHs that can be present in the centers of all the nearby galaxies (D<100 Mpc) for which STIS/G750M spectra are available in the HST archive. These upper limits will be derived from the modeling of the central emission-line widths ([NII]6548,6583AA , Halpha, and [SII]6716,6730AA) observed over an aperture of ~0.1'' (R<50 pc). In this poster we present our preliminary results about a subsample of 50 bulges

Giacomo Briani Dipartimento di Astronomia UniversitЮ di Firenze G. Briani, G. Pupillo, S. Aiello, E. Pace, S. Shore, A. Passaro Studio di micrometeoroidi nell'atmosfera terrestre E' stato suggerito che molecole organiche complesse, in grado di catalizzare la sintesi di composti biochimici prebiotici, siano state depositate sulla Terra da corpi extraterrestri nell'arco dei primi 800 milioni di anni dopo la formazione della Terra. Questo scenario Х basato sulla grande abbondanza di composti organici trovati in condriti carboniose. Particelle di polvere interplanetaria, micrometeoroidi (MM) e meteoroidi che sopravvivono, almeno parzialmente, all'ingresso in atmosfera, sono i piЫ plausibili vettori per il trasporto di materiale organico intatto sulla Terra. I MM, in particolare, sono interessanti perchИ rappresentano la maggior parte dell'attuale flusso di materia extraterrestre verso la Terra e probabilmente sono stati la principale fonte di carbonio organico anche per la Terra primordiale. Inoltre i MM possono darci informazioni sui corpi minori del Sistema Solare (probabilmente i loro corpi progenitori sono asteroidi o comete) o direttamente sull'origine del Sistema Solare (alcuni dei MM potrebbero essersi formati proprio durante la condensazione della nebulosa pre-solare). Un punto critico per capire il ruolo dei MM Х il riscaldamento che sperimentano durante il volo atmosferico, quando raggiungono alti valori di temperatura (ai quali le specie organiche

possono sublimare o decomporsi) e perdono parte della loro massa. Noi abbiamo sviluppato un nuovo modello generale per il passaggio di MM attraverso l'atmosfera, in cui si considerano molti processi fisici diversi (variazioni di velocitЮ, temperatura, dimensioni?) ma, allo stesso tempo, complementari. Con il nostro modello vogliamo affrontare il problema da un punto di vista globale e, considerando quelli che possono essere i processi fisici piЫ importanti per stabilire il destino di un MM che entra nell'atmosfera, evidenziare come un dato processo puР essere il risultato di meccanismi fisici diversi. Il modello include le equazioni che descrivono l'evoluzione di velocitЮ, temperatura, massa e dimensioni dei MM ed anche il calcolo della magnitudine delle micrometeore associate. Recentemente Х stato introdotto il calcolo del profilo della temperatura interna, per valutare l'eventuale differenza di temperatura tra la superficie ed il centro di un MM e l'effetto di trasformazioni (ad esempio la deidratazione) dei minerali che costituiscono un MM. Nella presentazione sarЮ discusso il problema generale dell'interazione micrometeoroidiatmosfera, con particolare attenzione a quali possano essere i piЫ importanti processi fisici e a come possano essere modellizzati. Saranno presentati i risultati del nostro modello, insieme ai possibili miglioramenti futuri.

Innocenza BusЮ INAF - Osservatorio Astrofisico di Catania I. BusЮ, G. Catanzaro The outer atmosphere of the RS CVn variable HR 7428 W e infer informations on the physical properties of the outer atmosphere system HR7428 by means of semi-empirical atmospheric modeling of the the system. The work, based on the spectroscopic Halpha and Mg understand the nature of the H alpha broad extra-absorption observed by of the RS CVn binary K2 cool component of II diagnostic, aims to many authors.

Daniela Cardini INAF / IASF Rotational evolution in late type main-sequence stars W e have carried out a study of the rotation-age relationship in a large sample of late type mainsequence stars. The study is based on rotation period data of single stars taken from the literature. From the analysis of the data relative to open clusters and field stars we find that rotational periods decrease linearly with increasing mass in stars of same age. This linear sequence evolves as a power of age (t^0.45). This result is compatible with that obtained by Skumanich (1972) for 1 solar mass stars, and extends its applicability to a broader range of masses.

Andrea Cardullo Dipartimento di Astronomia - UniversitЮ di Padova A. Cardullo, E.M. Corsini, A. Pizzella, F. Bertola Ultraviolet variability in the nucleus of elliptical galaxy NGC 4278 W e searched the Hubble Space Telescope Science Archive to investigate UV variability in the

nuclei of elliptical galaxies. W e looked for galaxies which were observed more than once with ACS and/or W FPC2 imagers. W e detected the presence of a strongly variable point-like source in the nucleus of NGC 4278. This UV flare was previously unknown and we give an estimation of the mass of the central supermassive black hole. A. Cardullo, A. Pizzella, E.M. Corsini, F. Bertola Kinematics and dynamics of low surface-brightness galaxies Major and minor axis stellar and ionized-gas kinematics of a sample of bulge dominated low surface-brightness galaxies is presented. The stellar kinematics, together with broad-band imaging, is used to construct detailed mass models aimed at deriving the central density profile of the dark matter component.

Elisabetta Cesarini Dipartimento di Astronomia - UniversitЮ di Firenze Thermomechanical characterization of materials for future interferometric GW detectors In a broad region between few tens of Hz up to 1 kHz, the sensitivity of interferometric gravitational wave antennae is dominated by thermal excitation of test masses and suspensions vibrational modes. Thermal noise can be reduced by using suitable materials, with low mechanical losses, or by cooling masses and suspensions. In both cases, a thorough experimental characterization of thermomechanical properties of materials, such as thermal conductivity and dissipation, has to be combined with a theoretical understanding of the observed behavior, in order to design a next generation detector. In this poster, the experimental activity of Firenze-Urbino group, in the layout of Virgo collaboration, will be presented; its laboratory is devoted to the experimental study of thermomechanical properties of materials to be employed in test masses. A facility for measuring the thermal conductivity has been set up and tested, and measurements on silicate bonded Si samples, in collaboration with the IGR group in Glasgow, are carried out. A new nodal suspension for measuring the dissipation factor in bulk substrates has been realized and is now under test; this suspension will allow a non disruptive determination of coating losses in coated substrates.

Valentina Cracco Dipartimento di Astronomia UniversitЮ di Padova Morphology and photometry of isolated Seyfert galaxies An important, unresolved, problem about active galactic nuclei (AGN) is the determination of the mechanism responsible for nuclear activity. In particular, gas or other material needs to lose angular momentum to fall into the galaxy nucleus and fuel the supermassive black hole. Many authors proposed a lot of different solutions: circumnuclear star clusters, bars, disks or nuclear spirals, interactions between galaxies, and mergers. Here we present preliminary results about morphological and photometric analysis of a sample of 35 nearby (z<0.03) and isolated or partially isolated Seyfert galaxies, observed through broad-band BVR filters at the 1.8 m Vatican Telescope and the 2.2 m ESO-La Silla Telescope. This work is part of a larger project focused on the study of the possible causes of AGN triggering.

Valentina D'Orazi Dipartimento di Astronomia UniversitЮ di Firenze Chemical abundances in Orion Nebula Cluster from Low-Mass Stars W e present the results of a spectroscopic analysis of pre-main sequence low-mass stars belonging to Orion Nebula Cluster (ONC). Our main goal is the determination of metallicity of our sample of 7 stars, spanning a mass range from 0.9 M0 to 1.4 M0, by means of the fit of Fe I observed profiles with MOOG synthetic profiles. W e find a very close to solar metallicity for most stars, consistentenly with previous results obtained from both B-type main sequence stars (Cunha & Lambert, 1994) and F-G pre-main sequence stars (Cunha, Smith & Lambert 1998). W e also derived Nichel and Titanium abundances for a sub-sample of 4 and 3 stars, respectively: this is the first determination in literature and the [Ni/Fe] and [Ti/Fe] values are roughly solar.

Lisa Gambicorti Dipartimento di Astronomia UniversitЮ di Firenze L. Gambicorti, D. Magrin, M. Munari, E. Pace, I. Pagano, S. Scuderi, B. Shustov. WSO-UV Field Camera Unit preliminary optical layout The W SO-UV telescope, a 1.7 m UV-optimized space observatory, will investigate numerous astrophysical phenomena from planetary science to cosmology. The Field Camera Unit (FCU), an Italian lead project, is one of the focal plane instruments aboard. The FCU will have three channels that will cover a wide spectral range going from 115 nm to 700 nm. It will have imaging and spectropolarimetric capabilities. This poster describes the preliminary optical design of the 3 channels and the expected optical performances.

Silvio Giordano INAF - Osservatorio Astronomico di Torino S. Giordano, A. Cora, C.A. Volpicelli and S. Mancuso MINVIT a Multi INstrumental VIsualization Tool for Solar Physics Data In recent years a lot of effort has been performed to construct systems for the sharing of resources within the solar physics community (eg. EGSO and SOLARNET). Several advanced archives and multi-instrumental analysis systems (e.g SolarSoft) do exist, but there is not availability of a data visualization tool for simultaneous display of multi instrument/wavelength solar data. Meanwhile map server technology has received great attention by the IT Researcher and Geophysical community. In this paper we discuss an example of possible use of Open Source environment for building spatially-enabled Internet applications dedicated to the visualization and analysis of Solar Physics Data set. As we show, MINVIT (Multi INstrumental VIsualization Tool) shall be able to merge images and information produced by different instruments on board SOHO in a single/synoptic image available via W EB. Moreover it allows to display the temporal evolution of data. W e also discuss its integration into Grid Framework, focusing on a middleware be able to query EGSO resources like UOC and SEC in order to include data from several space and ground-based solar observatories.

Domenico Impiombato Dipartimento di Fisica e INFN PERUGIA D. Impiombato, G. Tosti, Collab. TEAM REM Osservazioni ottiche e nel vicino infrarosso di un campione di blazar con il telescopio RE M Il telescopio REM (Rapid Eye Mount), installato a La Silla (Cile) nel giugno del 2003, Х un telescopio di nuova generazione, completamente robotizzato ed Х in grado di ospitare contemporaneamente piЫ strumenti permettendo di eseguire simultaneamente fotometria ottica ed infrarossa oltre a spettroscopia a bassa risoluzione di transienti (soprattutto di prompt afterglow dei gamma-ray burst rivelati dal satellite SW IFT). In questo poster illustriamo il monitoraggio ottico ed infrarosso di campioni blazars che emettono anche nella banda di emissione gamma e che saranno di supporto alla continuazione della ricerca scientifica con le missioni di GLAST ed AGILE ; inoltre presentiamo le osservazioni ed un lavoro di analisi dei dati e dei flares sulle immagini d'archivio delle sorgenti di gennaio 2007.

Simone Marchi Dipartimento di Astronomia UniversitЮ di Padova C. Barbieri, S. Billotta, P. Bolli, G. Bonanno, A. Di Paola, C. Facchinetti, E. Giro, S. Marchi, G. Naletto, T. Occhipinti, C. Pernechele, E. Sain, E. Verroi, M. Zaccariotto, P. Zoccarato. Status of AQUEYE, the fast multichannel photometer for the 182cm telescope at Cima Ekar In 2005 we designed a possible focal plane instrument (QuantEYE) for the 100 m OverW helmingly Large Telescope (OW L) of the European Southern Observatory, as the fastest photon counting astronomical photometer ever conceived, with an array of 100 parallel channels, capable to push the time tagging capabilities toward the pico-second region. Thanks to this extremely high time resolution, and to the enormous photon flux at the output of OW L, it would be possible for the first time to study second-order statistical functions in the photon stream from celestial sources. To acquire real experience with such novel type of astronomical instrumentation, we are now in the process of realizing a small prototype (AquEYE) for the Asiago 182 cm telescope. AquEYE will have four independent photon counting channels. All the main building blocks of Aqueye are in the laboratory, in advanced status of verification and assembly. This paper will describe the main results obtained so far. As example of scientific programs we plan to tackle with it, we plan to follow the ingress and egress of extrasolar transiting planets, in order to determine with the highest accuracy the perturbation of the orbital elements to detect low mass unseen companions.

Lorenzo Matteini Dipartimento di Astronomia - UniversitЮ di Firenze Evoluzione della anisotropia di temperatura dei protoni nel vento solare da 0.3 a 2.5 UA Presentiamo uno studio della evoluzione della anisotropia delle funzioni di distribuzione dei protoni nel vento solare da 0.3 a 2.5 UA. I dati utilizzati provengono delle missioni Helios I, II e Ulysses e riguardano sia il vento veloce che il vento lento. L'evoluzione della anisotropia di temperatura evidenzia il ruolo di instabilitЮ di plasma nell'espansione del vento e nella regolazione della sua dinamica macroscopica. L'anisotropia risultante Х in buon accordo con i vincoli derivanti dalla teoria lineare (Vlasov) e rispecchia gli andamenti trovati in recenti

simulazioni numeriche nelle quali il vento Х predetto espandere lungo un cammino di stabilitЮ marginale della instabilitЮ "fire hose"; i dati Ulysses a grande distanza qui analizzati per la prima volta confermano questo andamento.

Sergio Messina INAF - Osservatorio Astrofisico di Catania The RACE-OC project: Rotation and Activity Evolution in Open Cluster W e present an ongoing project consisting of multiband long-term CCD photometric observations of open stellar clusters of different age, ranging from about 1 to 500 Myr. Our sample consists of twelve clusters, seven of which have already been observed at least in one season. From this project we expect: a) to identify the cluster members, b) to determine the rotation period of the late-type cluster members; c) to determine their rotational period distribution; and c) to study the short-term (rotational) and long-term (cyclical) magnetic variability by using photospheric activity tracers. Once the observations of all clusters will be completed for at least one season, we plan to better describe and model the evolution of the stellar angular momentum from the PMS to the TAMS. Moreover, we intend to investigate in a statistically complete stellar sample the dependence and evolution of magnetic activity on the global stellar parameters in the framework of the current dynamo theories, thanks to the repeated year-to-year observations.

Maurizio Pancrazzi Dipartimento di Astronomia UniversitЮ di Firenze The Data Handling Unit for the World Space Observatory The W orld Space Observatory (W SO) is a space telescope conceived to observe the universe in the UV. The instrument payload consists of three spectrographs and one Field Camera Unit (FCU) composed by three cameras for UV and visible light imaging.FCU instrument (responsibility of Italian team) will produce a huge quantity of data to be transferred in a short time to the control ground stations. The XUVLab of the Department of Astronomy of Florence University is developing the Data Handling Unit for FCU instrument. Since the data volume will be very huge it cannot be possible to store images on the computer mass storage for a long time. At the moment the proposed satellite interface is the MIL1553B which represents a bottleneck dued to its low data rate. In order to avoid very long images transfer time (which could be a very strong constraint against scientific requirement), we are designing a communication interface that uses an hybrid architecture which is capable of high-speed and reliable data transfer.

Linda Podio INAF-Osservatorio Astrofisico di Arcetri Firenze Spectral analysis of stellar jets: from large to small scales Stellar jets play a key role in the overall star formation process. The ejection of these flows, in fact, is deeply connected with the accretion process and they can be responsible for the removal of the excess angular momentum from the disk, thus allowing the material to accrete from it onto the star. To confirm this picture and to constrain the launching mechanism we studied the structure of stellar jets both over large scales and near the source where the acceleration and collimation processes take place.

Maria Letizia Pumo INAF Osservatorio Astrofisico di Catania M.L. Pumo, L. Siess, R.A. ZappalЮ Advanced evolution and final fate of Super-AGB stars Stars having initial masses between ~ 7 and ~ 11 M0 (so-called Super-AGB stars) fill the gap between "intermediate-mass" stars unable to ignite core C-burning and "massive" stars able to evolve through all nuclear burning stages. As a consequence these stars exhibit a very peculiar structural evolution, characterised by offcentre C-igniton folowed by the propagation of a deflagration C-burning front to the centre. After the C-burning phase, Super-AGB stars can end their life either forming a neon-oxygen white dwarf or going through electro-capture supernova becoming a neutron star. Key questions, concerning the advanced (post-He-burning) evolution and the final fate of these starts, have not yet been explicitly investigated. W e address this issue based on the full computation of 90 stellar models, analysing the effects of initial composition, mass loss and convective overshooting. Preliminary results will be presented.

Lara Sidoli INAF / IASF - Milano Recenti scoperte sulle binarie X di grande massa PresenterР le ultime scoperte riguardo le stelle binarie X di grande massa, focalizzandomi su una nuova classe di sorgenti con emissione X concentrata in eventi transienti di breve durata, dell'ordine di qualche ora o pochi giorni.

Maurizio Ternullo INAF Osservatorio Astrofisico di Catania Macchie solari e oscillazioni torsionali ..............

Elena Tundo UniversitЮ di Padova SMBH Mass Function from velocity dispersion and luminosity Black hole masses are tightly correlated with the stellar velocity dispersion of host galaxies, and slightly less-well correlated with the bulge luminosities. There is still debate on which of these predictors can better reproduce the local black hole mass function when coupled with an appropriate distribution function: the Mbh-sigma relation predicts fewer massive black holes than does the Mbh-L relation. This is because the L-sigma in black hole samples currently available is inconsistent with that in the samples from which the distributions of L or sigma are based. This suggests that current black hole samples are biased towards objects with abnormally large  for their luminosities. Assuming that the bias is a

selection rather than physical effect, then the Mbh-sigma and Mbh-L relations currently in the literature are also biased from their true values. Our analysis suggests that the bias in the Mbh-sigma relation is likely to be small, whereas the Mbh-L relation is biased towards predicting more massive black holes for a given luminosity. In this case, the velocity dispersion-based estimate of the intrinsic local supermassive black hole mass function is more reliable.

Delia Volpi Dipartimento di Astronomia - UniversitЮ di Firenze Simulated synchrotron and Inverse Compton emission from Pulsar Wind Nebulae Basing on the set of MHD equations and the evolution equation of the maximum energy of the emitting particles (which includes adiabatic and synchrotron losses along streamlines) a complete set of diagnostic tools aimed at producing synthetic synchrotron emissivity, integrated flux energy, polarization and spectral index maps from relativistic MHD simulation is obtained. A first application of this method is the emission from Pulsar W ind Nebulae (PW Ne). Axisymmetric simulations of PW Ne obtained with the relativistic MHD code by Del Zanna et al.(2003) are directly compared with the observations of the inner structure of Crab Nebula and similar objects in the optical and X-ray bands. The typical observed PW Ne jet-torus morphology is well reproduced even in finer emission details (arcs, rings and the bright knot) and in the velocity ranges. Spectral properties (spectral index maps and integrated spectra) are reproduced. A preliminary work about Inverse Compton on CMB and s ynchrotron photon fields (SSC) has been done. Some scattered radiation emissivity and integrated flux energy maps are obtained.