IVOA NEWSLETTER - May 2012 (pdf)

Created: April 30, 2012 - 22:01 UTC

The International Virtual Observatory Alliance (IVOA) was formed in June 2002 with a mission to facilitate the international coordination and collaboration necessary for the development and deployment of the tools, systems and organizational structures necessary to enable the international utilization of astronomical archives as an integrated and interoperating virtual observatory. The IVOA now comprises 19 VO programs from Argentina, Armenia, Australia, Brazil, Canada, China, Europe, France, Germany, Hungary, India, Italy, Japan, Russia, Spain, Ukraine, the United Kingdom, and the United States and an inter-governmental organization (ESA). Membership is open to other national and international programs according to the IVOA Guidelines for Participation. You can read more about the IVOA and what we do at http://www.ivoa.net/pub/info/.

What is the VO?

The Virtual Observatory (VO) aims to provide a research environment that will open up new possibilities for scientific research based on data discovery, efficient data access, and interoperability. The vision is of global astronomy archives connected via the VO to form a multiwavelength digital sky that can be searched, visualized, and analyzed in new and innovative ways. VO projects worldwide working toward this vision are already providing science capabilities with new tools and services. This newsletter, aimed at astronomers, highlights VO tools and technologies for doing astronomy research, recent papers, and upcoming events.

IVOA news

This issue is dedicated to the memory of Dr. Dave De Young, one of the pioneers of the Virtual Observatory movement. Dave, who was an astronomer at NOAO from 1980 until his retirement in September 2011, was Project Scientist of the National Virtual Observatory (2002-2009) and of the Virtual Astronomical Observatory (2009-2011). He was a a great source of strength and inspiration for the IVOA, of which he was the Vice-Chair (2006-2007) and Chair (2007-2008). Through his role as the Chair of the Standing Committee on Science Priorities (2008-2011) Dave did much to target VO efforts towards applications to scientific issues, rather than just technology development. Dave’s presence will be greatly missed at IVOA meetings, during the sessions, as well as in the evenings where he dazzled everyone with his knowledge, wisdom and personality.
- Ajit Kembhavi (IVOA Chair) -

VO applications highlights

US VAO Data Discovery Portal

Find datasets from thousands of astronomical collections known to the VO and over wide areas of the sky. This includes important collections from archives around the world. Feedback on your experience with the tool is appreciated – please send your comments, suggestions, and questions to the VAO Help Desk.

More information: http://www.usvao.org/tools

VOSA (VO Sed Analyzer) 3.0

VOSA is a tool developed by the Spanish VO to determine physical parameters (e.g. temperatures, gravities, masses, ages) of astronomical objects through the comparison of photometry gathered from VO services, with collections of theoretical models. VOSA 3.0 represents a profound change with respect to previous versions: new VO services, new theoretical collections, and new functionalities such as template fitting and estimation of the extinction, making VOSA a powerful tool in many areas of research astrophysics. VOSA can also be used as a platform to develop new specific applications for different astrophysical problems benefiting from a common methodological base (e.g., Sanchez-Janssen 2011IAUS..277..230S).

More information: http://svo.cab.inta-csic.es/theory/vosa

US VAO Cross-Comparison Tool

Perform fast positional cross-matches between an input table of up to 1 million sources and common astronomical source catalogs, such as 2MASS, SDSS DR7 and USNO-B. Feedback on your experience with the tool is appreciated – please send your comments, suggestions, and questions to the VAO Help Desk.

More information: http://www.usvao.org/tools

VOPlot v1.8 Beta

VOPlot v1.8Beta includes many enhancements and bug fixes. To name a few v1.8Beta supports multi-grid plots for 2D Scatter-Plot which allows the user to have multiple plots having grid size from 1x1 to 3x3 in a single window. Paginated view is added to see data in tabular format which allows user to navigate systematically. Provision to label Lat/Long lines is also added. Users can now plot a cumulative histogram for all histogram types. VOPlot 1.8Beta shows the metadata of a FITS file instantaneously while the actual loading happens in background. VOPlot v1.8Beta also provides better handling of “faulty data” while parsing an ASCII file.

More information: http://vo.iucaa.ernet.in/~voi/voplot.htm

CDS XMatch Service

CDS Xmatch is a new service for efficient positional cross-matching of very large catalogues. Input catalogues include all (~10000) VizieR tables, a tabular view of the Simbad database, plus GALEX, UKIDSS DR5 LAS, SDSS DR8, and user-uploaded tables. The service has been designed for large jobs; for example, the entire SDSS DR8 can be cross-matched with the 2MASS point source catalogue in less than 17 minutes, resulting in ~55x106 cross-matched associations with separations <2.5", and producing a ~15GB output file.

More information: http://cdsxmatch.u-strasbg.fr/xmatch

US VAO Time Series Search Tool

Discover time-series data from the Harvard Time Series Center, Catalina Real-time Transient Survey, and the NASA Exoplanet archive - and analyze them with the NASA Exoplanet Archive periodogram application. Feedback on your experience with the tool is appreciated – please send your comments, suggestions, and questions to the VAO Help Desk.

More information: http://www.usvao.org/tools

Some recent papers about VO-enabled science

Identification of red high proper-motion objects in Tycho-2 and 2MASS catalogues using Virtual Observatory tools

Jiménez-Esteban, F. M.; Caballero, J. A.; Dorda, R.; Miles-Páez, P. A.; Solano, E.

Astronomy & Astrophysics, Volume 539, id.A86

With available Virtual Observatory tools, we looked for new M dwarfs in the solar neighbourhood and M giants with high tangential velocities. From an all-sky cross-match between the optical Tycho-2 and the near-infrared 2MASS catalogues, we selected objects with proper motions μ > 50 mas yr-1 and very red VT - Ks colours. For the most interesting targets, we collected multi-wavelength photometry, constructed spectral energy distributions, estimated effective temperatures and surface gravities from fits to atmospheric models, performed time-series analysis of ASAS V-band light curves, and assigned spectral types from low-resolution spectroscopy obtained with CAFOS at the 2.2 m Calar Alto telescope. We got a sample of 59 bright red high proper-motion objects, including fifty red giants, four red dwarfs, and five objects reported in this work for the first time. The five new stars have magnitudes VT ≈ 10.8-11.3 mag, reduced proper motions midway between known dwarfs and giants, near-infrared colours typical of giants, and effective temperatures Teff ≈ 2900-3400 K. From our time-series analysis, we discovered a long secondary period in Ruber 4 and an extremely long primary period in Ruber 6. With the CAFOS spectra, we confirmed the red giant nature of Ruber 7 and 8, the last of which seems to be one of the brightest metal-poor M giants ever identified.

Refereed Publications

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