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Register a new userGOLD Mine: A new Galaxy Database on the WEB
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The galaxy database GOLDmine (http://goldmine.mib.infn.it/) has been significantly updated (Sept/1/2003) The new features include: a) Sample extension:the GOLDmine sample has been extended from the original Virgo cluster + Coma supercluster regions to include the clusters: A262, Cancer, A2147, A2151, A2197, A2199. 382 galaxies from the GCGC (with m_p<15.7) have been added in these regions. b) New query keys: 1) query by near position (and near name). 2) query by available images. c) Routinary image update: 1) 59 (B). 72 (V) and 70 (H_alpha) new frames from observations carried on by the GOLDmine team in spring 2003. 2) 157 new optical (drift-scan) spectra from observations carried on by the GOLDmine team in 2002-2003. 3) 225 B frames of VCC galaxies taken with the INT (kindly provided by S. Sabatini). 4) 56 B frames of galaxies in A1367 taken with the CFHT (kindly provided by M. Treyer). 5) 20 (H), 32 (K) band frames of bright Virgo members (from 2MASS). The new numbers in GOLDmine are: 3649 galaxies, 706 V-band frames, 858 B-band frames, 385 H_alpha frames (NET), 385 H_alpha frames (OFF-band), 1241 H-band frames, 114 K-band frames, 323 Spectra All frames are available in FITS (and jpg) format.
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The new World Wide Web site GOLDMine (Galaxy On Line Database Milano Network) (http://goldmine.mib.infn.it) contains a multiwavelength data-base of an optically selected sample of 3267 galaxies in the Virgo cluster and in the Coma Supercluster. It is designed for professional astronomers who wish to find data and images for these galaxies. Data, gathered in 15 years of observational campaigns by the authors or taken from the literature include general parameters (catalogue names, celestial coordinates, morphological type, recessional velocity etc.); multiwavelength continuum photometry (total UV, U, B, V, J, H, K, FIR and radio magnitudes/flux densities); line photometry (HI, H_2, H_alpha); dynamical parameters (rotational velocity from the HI and H_alpha lines, velocity dispersion) and structural parameters (light concentration index, effective radius and brightness, asymptotic magnitude) in the optical (B and V) and Near Infrared (H or K) bands. Images include finding charts, optical (B and V), H_alpha, Near Infrared (H and/or K) and true color RGB frames (when available). Radial light profiles obtained from the B, V, H or K band images are also available. Integrated optical spectra along with broad Spectral Energy Distributions (SED) from the UV to the radio domain are given. All images can be obtained in JPG format, but the original (reduced) FITS images can be downloaded as well. The database will be updated regularly and will be extended to other local clusters and superclusters. Astronomers who wish to have their images included in GOLDMine are strongly encouraged to send us their material.
The query log of a DBMS is a powerful resource. It enables many practical applications, including query optimization and user experience enhancement. And yet, mining SQL queries is a difficult task. The fundamental problem is that queries are symbolic objects, not vectors of numbers. Therefore, many popular statistical concepts, such as means, regression, or decision trees do not apply. Most authors limit themselves to ad hoc algorithms or approaches based on neighborhoods, such as k Nearest Neighbors. Our project is to challenge this limitation. We introduce methods to manipulate SQL queries as if they were vectors, thereby unlocking the whole statistical toolbox. We present three families of methods: feature maps, kernel methods, and Bayesian models. The first technique directly encodes queries into vectors. The second one transforms the queries implicitly. The last one exploits probabilistic graphical models as an alternative to vector spaces. We present the benefits and drawbacks of each solution, highlight how they relate to each other, and make the case for future investigation.
This white paper emphasizes the potential of QSO absorption lines in the rest-frame far/extreme UV at rest-frame wavelengths from ~500 to 2000 A. In this wavelength range, species such as Ne VIII, Na IX, and Mg X can be detected, providing diagnostics of gas with temperatures >> 10^{6} K, as well as banks of adjacent ions such as O I, O II, O III, O IV, O V, and O VI (and similarly N I - N V; S II - S VI; Ne II - Ne VIII, etc.), which constrain physical conditions with unprecedented precision. A UV spectrograph with good sensitivity down to observed wavelengths of 1000 A can detect these new probes in absorption systems with redshift z(abs) > 0.3, and at these redshifts, the detailed relationships between the absorbers and nearby galaxies and large-scale environment can be studied from the ground. By observing QSOs at z = 1.0 - 1.5, HST has started to exploit extreme-UV QSO absorption lines, but HST can only reach a small number of these targets. A future, more sensitive UV spectrograph could open up this new discovery space.
Data from the Herschel Space Observatory is freely available to the public but no uniformly processed catalogue of the observations has been published so far. To date, the Herschel Science Archive does not contain the exact sky coverage (footprint) of individual observations and supports search for measurements based on bounding circles only. Drawing on previous experience in implementing footprint databases, we built the Herschel Footprint Database and Web Services for the Herschel Space Observatory to provide efficient search capabilities for typical astronomical queries. The database was designed with the following main goals in mind: (a) provide a unified data model for meta-data of all instruments and observational modes, (b) quickly find observations covering a selected object and its neighbourhood, (c) quickly find every observation in a larger area of the sky, (d) allow for finding solar system objects crossing observation fields. As a first step, we developed a unified data model of observations of all three Herschel instruments for all pointing and instrument modes. Then, using telescope pointing information and observational meta-data, we compiled a database of footprints. As opposed to methods using pixellation of the sphere, we represent sky coverage in an exact geometric form allowing for precise area calculations. For easier handling of Herschel observation footprints with rather complex shapes, two algorithms were implemented to reduce the outline. Furthermore, a new visualisation tool to plot footprints with various spherical projections was developed. Indexing of the footprints using Hierarchical Triangular Mesh makes it possible to quickly find observations based on sky coverage, time and meta-data. The database is accessible via a web site (http://herschel.vo.elte.hu) and also as a set of REST web service functions.
Information on any given topic is often scattered across the web. Previously this scatter has been characterized through the distribution of a set of facts (i.e. pieces of information) across web pages, showing that typically a few pages contain many facts on the topic, while many pages contain just a few. While such approaches have revealed important scatter phenomena, they are lossy in that they conceal how specific facts (e.g. rare facts) occur in specific types of pages (e.g. fact-rich pages). To reveal such regularities, we construct bi-partite networks, consisting of two types of vertices: the facts contained in webpages and the webpages themselves. Such a representation enables the application of a series of network analysis techniques, revealing structural features such as connectivity, robustness, and clustering. We discuss the implications of each of these features to the users ability to find comprehensive information online. Finally, we compare the bipartite graph structure of webpages and facts with the hyperlink structure between the webpages.
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