has developed a user-friendly, interactive web-accessed database for browsing and analyzing FUSE ... easy access to the FUSE scientific data and sort them out using various criteria. The website offers ... SQL beginners. For more technical ...
Astrophysics in the Far Ultraviolet, Five Years of Discovery with FUSE ASP Conference Series, Vol. 348, 2006 Sonneborn, Moos & Andersson
The IAP FUSE Database: An Interactive Web Tool ´ J.-M. D´esert, V. Lebouteiller, G. H´ebrard, A. Lecavelier des Etangs, S. Lacour, M. Andr´e, R. Ferlet, & A. Vidal-Madjar Institut d’Astrophysique de Paris, CNRS, 98 bis Boulevard Arago, F-75014 Paris, France Abstract. The French FUSE team, supported by CNES (the French space agency), has developed a user-friendly, interactive web-accessed database for browsing and analyzing FUSE spectra (http://fuse.iap.fr). Nearly three thousand FUSE observations are publicly available. At this stage of the FUSE project, it is important to provide the world-wide astronomical community with fast and easy access to the FUSE scientific data and sort them out using various criteria. The website offers fast access to observation data sets, multiple search cross correlation, user defined plots, as well as real-time calculations on the calibrated and raw FITS files. To enlarge the capabilities, this database is linked to other astronomical resources.
1.
Scientific Content
The FUSE mission archive presently contains more than 30,000 calibrated spectra and their corresponding original two-dimensional images obtained in the interval 1999-2004. The primary FUSE mission archive site is the Multi-Mission Archive at the Space Telescope Science Institute (MAST). Even though it is complete, only data after the six-month proprietary period become available to the astronomical community. In this paper we describe features of an on-line database for researchers interested in downloading and browsing FUSE Far-UV spectral data designed and developed by the French FUSE Team at the Institute d’Astrophysique de Paris (IAP). The complete set of public FUSE spectral data is provided to the IAP by MAST under a Letter of Agreement between NASA and CNES covering French participation in he FUSE mission. The scientific content of the database is very rich. Many different types of objects have been observed with FUSE for different purposes in the FUV wavelength range of 905-1187 ˚ A. The main characteristics of the archived spectra are shown in Table 1. All FUSE data products are in standard Flexible Image Transport System (FITS) format with the data contained in binary extensions. Due to the optical design of the FUSE instrument each exposure on a target produces independent SiC and LiF spectra for each detector segment (1 and 2) hence a total of 8 separate spectra (2 spectra (LiF+SIC) x 2 segments x 2 detectors). Data are recorded in histogram (HIST) or time-tagged (TTAG) modes, through the low- (LWRS), medium- (MDRS), or highresolution (HIRS) slit. Details of the FUSE mission and instrument may be found in Moos et al. (2000) and Sahnow et al. (2002). The FUSE calibration pipeline (version 2.4) generates three co-added spectra (one for each aperture) for TTAG exposures and 1 co-added spectrum for HIST exposures. Finally, the pipeline produces a merged spectrum for each observation (i.e. a co-addition of all the exposures) called ALL spectra. The co-added spectra are provided only for overview or quick look purposes and should not be used for scientific analysis. The user is strongly advised to shift and co-add spectra separately for each of the independant channels (SiC1, SiC2, LiF1, and LiF2) and for a given slit, after correction for relative
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wavelength offsets between individual calibrated exposures (typically, a few FUSE pixels). This correction procedure slightly improves the spectral resolution and yields some averaging out of the fixed-pattern noise in the detector, acting as a random FP split procedure H´ebrard (G.); Kruk et al. (2002)) Table 1.
2.
Overall Caracteristics of the Spectra within the FUSE Archive Parameters
Values
Number of Observation Total public observation Spectrum bandpass (nm) Spectral Resolution Signal-to-noise ratio
~3600 ~2800 90.5-118.7 15000 2000 3 to 30
The user’s interface
We designed two interfaces which are available on the web, a fast access one and a SQL navigator accessible through the website: http://fuse.iap.fr
2.1.
The Quick and Easy Access Interface
The principal Web page of the database interface is written in PHP and is designed in a similar way as the MAST archive Web page in order to facilitate its use by the customers of this database. Targets can be searched using either object-naming conventions, positions or basic astronomical characteristics, such as the magnitude or the spectral type. The results of a search are then listed in the second dedicated Web page. Then the user can instantaneously download the archived calibrated scientific spectra. Finally, this interface allows to plot builds on-the-fly ALL spectra which have been reduced using the latest FUSE calibration pipeline CalFUSE available at that time. Not only the spectrum is accessible but also all available information about targets and observations.
2.2.
The SQL access interface
A more complete interface gives access to the whole database sending all kinds of request in SQL language. As the quick access interface, it allows neighbor searches, and cross correlations with other catalogues. This site provides a user’s specification query features as well as tool tips interface for all fields request. In order to help the user, we give a self-documentation of terms and tables, and a tutorial for new navigators and SQL beginners. For more technical details see D´esert et al. (in preparation).
3.
Database Connections
The IAP FUSE database is linked to the MAST archive. Targets are resolved using either the NASA/IPAC Extragalactic Database (NED) or Simbad Astronomical database operated at Centre de Donn´ees astronomiques de Strasbourg (CDS). Users can also access the FUSE database through requests from the Vizier Catalogue Service maintained by the CDS. This permits users to generate queries from other sites to cross-correlate, compare, and plot FUSE data using Virtual Observatory (VO) protocols. Finally, the
The FUSE database, an interactive web tool
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archive was developed under the current International Virtual Observatory Alliance standards of interoperability, allowing astronomers to access the spectrum with various VO-tools already available to the worldwide community. Plans for future development in terms of improvements of spectral UV features, web services or on-line reduction, as well as data analysis, are currently being studied. Our spectral manipulation program ”XIPLOT”, an IDL-based program developed by the French FUSE team, can be used to plot data and FITS, co-plot, shift and co-add FUSE exposures. This public tool is available at the French FUSE website.
4.
Scientific Issues
Various cross-correlations with other catalogues have been applied to the present database using the powerful tool Vizier from CDS, in order to mine scientific data or to prepare new proposals. As an example, more than one hundred detections of molecular lines if HD in the interstellar medium have been found and catalogued in an automatic manner thanks to this database. This allows a survey and analysis of this molecule throughout the Galactic disk (Lacour et al., 2006, these proceedings). Such a tool has been useful for the detection of the H− ion in the ISM with FUSE ; it as also contributed to the detection of very small-scale molecular structures in the Magellanic Clouds (Lacour et al. 2004) Acknowledgments. Many thanks to Martin Lemoine and George Sonneborn for their useful comments. If the IAP FUSE database was helpful for your research work, the following acknowledgment would be appreciated:This research has made use of the IAP FUSE database, operated at IAP, Paris, France. References Andr´e, M. K., Le Petit, F., P., Ferlet, R., Roueff, E., Civeit, T., D´esert, J.-M., Lacour, S., & Vidal-Madjar, A., 2004, A&A,422, 483-504 H´ebrard, G., et al. 2002, ApJS, 140, 103-114 Kruk, J. W., et al. 2002, ApJS, 140, 19 Lacour, S., et al. 2004, astro-ph/0410033 Moos, H. W., et al. 2000, ApJ, 538, L1 Sahnow, D. J., et al. 2000, ApJ, 538, L7
