528 research outputs found

    Narrow band imaging and long slit spectroscopy of UGC 5101

    Get PDF
    UGC 5101 (z = 0.04; D is approximately equal to 240 Mpc) is one of the so called Ultraluminous IRAS sources. Two important properties of the members of this group are their L(sub IR) is greater than or equal to 10(exp 12) solar luminosity, and their space density in the universe up to z is less than 0.1 is equal or even larger than the space density of the quasars. Further noteworthy features of the Ultraluminous IRAS sources are their being morphologically peculiar and the fact that they all seem to host active nuclei in their center. We have observed UGC 5101 in an effort to study the interplay between the gas ionized by the central active nucleus and that gas ionized by other processes which may hold important clues to the understanding of the entire picture of this object. In particular these other ionizing processes could well be massive stars formed recently after the galactic encounter and shocks possibly also related to the galaxy collision. The data that we discuss were obtained between Dec. 1989 and Jan. 1992 with the WHT 4.2 m telescope using the two-arm spectrograph ISIS. Several spectral frames were obtained at three different position angles: PA 84--along the tail of the galaxy; PA 32--along the dust lane; and PA 110. The blue spectra are centered on the H beta line, while the red spectra are centered on the H alpha line. In the configuration we used for the long slit spectra, the spectral scale was 0.74 A per pixel, and the spatial scale was .37 arcsec per pixel; we also observed the H alpha region with a spectral scale of .37 A per pixel, at position angle 84. The narrow band images were obtained at the auxiliary port of ISIS, with a scale of .2 arcsec per pixel, and were centered at the H alpha wavelength, and on the adjacent continuum. The H alpha images and the spectra support the following model. UGC 5101 hosts an active nucleus; the NLR extends up to about 1.5 kpc and shows a complex velocity field, superimposed on the rotation curve of the galaxy. Besides the NLR, in the H alpha image are visible tow bright cones that extend up to 3 kpc along PA 32. The long slit spectra at PA 32 show that the velocity field of the gas in these regions is peculiar, while the ionization structure of the gas is similar to that of the NLR

    Long slit spectroscopy of NGC 5506

    Get PDF
    The galaxy NGC 5506 hosts an active nucleus, that presents characteristics that are intermediate between Sy1 and Sy2. We discuss long slit spectra of NGC 5506 in the ranges 4675-5475 A and 6300-7125 A, that were obtained at three different position angles, in Apr. 1991 at the WHT 4.2 m telescope. The peculiar kinematics of the emitting gas has already been observed by other researchers; following the model proposed by the other researchers, that the emitting gas is located in two cones, we determined the aperture of the cones. The data, moreover, support the hypothesis that the gas is receding from the nucleus. We modelled the intensity and the ratios of the emission lines, and verified that the active nucleus of NGC 5506 can be described as a Sy1 nucleus, with the UV-X source that is partially obscured to our line of sight. On the contrary, a good fraction of the interstellar gas of the galaxy is directly illuminated and photoionized by the central source. Our data show evidence of star formation close to the nucleus; we estimated the star formation rate, that is high with respect to 'normal' spirals, but not high enough to be comparable to star formation rates in a starburst galaxy

    A N-D VIRTUAL NOTEBOOK ABOUT THE BASILICA OF S. AMBROGIO IN MILAN: INFORMATION MODELING FOR THE COMMUNICATION OF HISTORICAL PHASES SUBTRACTION PROCESS

    Get PDF
    This essay describes the combination of 3D solutions and software techniques with traditional studies and researches in order to achieve an integrated digital documentation between performed surveys, collected data, and historical research. The approach of this study is based on the comparison of survey data with historical research, and interpretations deduced from a data cross-check between the two mentioned sources. The case study is the Basilica of S. Ambrogio in Milan, one of the greatest monuments in the city, a pillar of the Christianity and of the History of Architecture. It is characterized by a complex stratification of phases of restoration and transformation. Rediscovering the great richness of the traditional architectural notebook, which collected surveys and data, this research aims to realize a virtual notebook, based on a 3D model that supports the dissemination of the collected information. It can potentially be understandable and accessible by anyone through the development of a mobile app. The 3D model was used to explore the different historical phases, starting from the recent layers to the oldest ones, through a virtual subtraction process, following the methods of Archaeology of Architecture. Its components can be imported into parametric software and recognized both in their morphological and typological aspects. It is based on the concept of LoD and ReverseLoD in order to fit the accuracy required by each step of the research

    An integrated approach based on traditional archaeological surveys, digital recording techniques & historical documentation for the assessment of threats related to the climate-sensitive territorial context

    Get PDF
    This essay describes an integrated approach - field survey, historic research, climate data, and topography - for the analysis of a complex stratigraphical archaeological site, highlighting its peculiar aspects and its conservation state, and contributing to the studies of this area. The case study is San Calocero monastery in Albenga, one of the most important historical evidence of the city, located on the San Martino Hillside, dating back to the VI century but with a complex historical stratigraphy until the XVI century, along with other relevant archaeological sites, such as the Baptistery, the Ponte Lungo, the churches of San Clemente and San Vittore, which, as long as San Calocero, went through several changes over the years

    A CONTENT-BASED IMMERSIVE EXPERIENCE OF BASILICA OF SANT'AMBROGIO IN MILAN: FROM 3D SURVEY TO VIRTUAL REALITY

    Get PDF
    One of the challenges of the Digital Cultural Heritage (DCH) field is the creation of coherent HBIMs and the dissemination of the collected historical data. The latest development of new technologies has the great potential to realise virtual content-based immersive experiences that are easily available by both experts and non-expert users. On the other hand, they require specific skills and a holistic approach to the study of the building that involves different disciplines.The research that has been carried out for the last five years on one of the greatest monuments in Milan, the Basilica of Sant'Ambrogio, adopted this comprehensive methodology. Although the church is a very well-known building, its turbulent history remains in a certain aspect hidden to the large public. This paper shows the workflow that has been developed for the Basilica, starting from the 3D survey to the historical data acquisition and the study on the church itself, based on a ‘virtual subtraction process’, till the creation of a Virtual Reality experience. This one is the first step of a wider project on eXtended reality (Virtual/Mixed/Augmented Reality) that intends to make the gathered knowledge of the Basilica available to the public.</p

    Immersive Appian Way health infrastructure: human centric Digital Twin (The PAAA Archeological Park of the Appian Way 12km State-Own Section, Unesco Candidature)

    Get PDF
    From Rome to Benevento, the Appian Way (Via Appia Antica) was born as a military road, 'Regina Viarum'. In 312 b.C., consul Appio Claudio extended the infrastructure for 132 miles to Capua. Many transformations and integration occurred across the centuries, resulting in a unique multi-stratified world heritage (landscape, architecture, archaeological remains and tombs along the military way). In the 19th century, Luigi Canina conceived the Appian Way as an outdoor museum, realizing a first state-own section along the 12km here surveyed and described. This year, the Ministry of Culture (MIC) has launched the UNESCO nomination for the road. The article discusses aspects of the mass digitization undertaken by the Parco Archeologico dell'Appia Antica (PAAA, the Archaeological Park of the Appian Way). The aim is to build a Digital Twin of the infrastructure supporting knowledge enhancement, preservation, design, communication and fruition. A virtual space where digital technologies and eXtended Reality are the digital arms of the contemporary Vitruvian humanistic mission and vision of the PAAA Appian Way as a source of wealth and healthiness for all the users and visitors

    A LAYERED-WEB INTERFACE BASED ON HBIM AND 360&deg; PANORAMAS FOR HISTORICAL, MATERIAL AND GEOMETRIC ANALYSIS

    Get PDF
    The latest information technology developments in the field of digital heritage (DH) have enabled the creation of novel virtual experiences favouring information-sharing connected to the 3D digital reconstruction of historical and existing buildings. In recent years, Building Information Modelling for historic buildings (HBIM) projects are the most applied methods to transmit the richness of built heritage from both the geometrical and informative points of view, but they are not always adequate to ensure a simple reading of different type of information for not-expert users. For this reason, further investigations were performed, following a novel SCAN-to-BIM process based on novel Grades of Generation (GOG 9 and 10) in order to digitally represent one of the most complex structure of the Basilica of Sant’Ambrogio in Milan. It is composed of arches supported by pillars, characterised by a double-wave curve, both on its vertical and horizontal axis. The information coming from the previous studies, such as historical documentation, as-found drawings, building archaeology analysis (materials and brick surface texture) and decay data (crack patterns, material discontinuity), was integrated with a novel webimmersive solution able to display 360&deg; pictures, video and HBIM simultaneously. A detailed comparison of the 360 multimedia data of the current arrangement with the one of the HBIM historical phases allow experts and not-experts to analyse the transformation of the arch structures in a new immersive environment with different devices such as laptops, mobile phones and latest virtual and augmented reality (VR-AR) headset
    • …
    corecore