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Astronomical Data Analysis Software and Systems VII
ASP Conference Series, Vol. 145, 1998
R. Albrecht, R. N. Hook and H. A. Bushouse, e
Ö Copyright 1998 Astronomical Society of the Pacific. All rights reserved.
ds.
The IUE Archive at Villafranca
M. Barylak and J. D. Ponz
ESA Villafranca
P.O. Box 50727, 28080 Madrid, Spain
Abstract.
The International Ultraviolet Explorer (IUE) mission has produced
a large collection of spectroscopic data containing about 104,000 spectra
of ca. 9,600 di#erent objects. The IUE Final Archive (IUEFA) project
will generate a high quality and uniform spectral archive during the final
phase of the mission (when specialized knowledge on the instrument and
calibration procedures are still available), and maintain it so that it is
accessible to the scientific community.
This contribution describes the IUEFA project at Villafranca, and
the plans to make the archive available to the scientific community under
through the INES (IUE New Extracted Spectra) project.
1. Introduction
There is no doubt that scientific archives represent an invaluable resource. The
IUEFA will provide important reference information for current and future UV
space missions. No maintenance and support of a data archive was foreseen
in IUE's original mission plan. Hence, in the context of the IUEFA project, a
special e#ort has been dedicated to the definition of the mission archive and its
distribution to the scientific community world­wide. It has been said and truly
written that ``IUE has led the way in promoting archiving services''.
2. The Final Archive
The IUE Final Archive (IUEFA) was defined as a project between NASA, ESA
and PPARC, according to the following main requirements:
. Produce a uniformly processed archive. Through the years of the mission,
IUESIPS has experienced several modifications and di#erent calibrations
have been used, so that it has been di#cult to compare data processed at
di#erent epochs.
. Apply new image processing algorithms to improve the photometric accu­
racy and signal­to­noise ratio of the reduced spectra.
. New calibrations have been derived to estimate absolute fluxes and new
blaze models have been incorporated to better correct for the ripple e#ect
in high­dispersion spectra.
404

The IUE Archive at Villafranca 405
ARCHIVE
RAW
PIPELINE
NEWSIPS
SERVER
ON­LINE
PARAMETERS
MASTER
ARCHIVE
Figure 1. Final Archive data flow.
. Quality control on instrument and observational parameters. Special at­
tention was devoted to the compilation and verification of a set of image
parameters, identified as Core Data Items, that are required to adequately
re­process the raw image and are essential for scientific analysis.
. Archived spectra written in standard FITS format (Ponz et al. 1994) on
high density optical disks.
. Compatibility of output products generated at both observing stations.
3. The Production at Villafranca
Based upon the previous requirements, NEWSIPS (Garhart et al. 1997) was de­
veloped and implemented at both GSFC and VILSPA observing stations. The
main elements for the production system, depicted in Figure 1, are: (1) Raw
archive stored on optical disks, provides the input images to the NEWSIPS pro­
duction pipeline. (2) Image parameters, defining the main object characteristics
and instrumental setup. These parameters determine the calibration options,
provide quality control information and are maintained under a relational data
base management system (DBMS) (Barylak, 1996). (3) Pipeline (NEWSIPS),
implemented under MIDAS. (4) Master archive, stored on optical disks. (5) On­
line data server with extracted spectra -- both two­dimensional and absolutely
calibrated fluxes -- available on­line.

406 Barylak and Ponz
4. Project Status
The number of observations in the archive is about 70,000 low and 30,000 high
resolution images. The volume of the information of the master archive is shown
in Table 1, indicating the size in Gbytes for each file type.
Table 1. Archive volume (sizes in Gbytes).
Data set Low res. High res. Total
Raw images 42.0 18.0 60.0
Linearized 168.0 72.0 240.0
2D spectra 16.8 72.0 88.8
1D spectra 4.2 36.0 40.2
Total 231.0 198.0 429.0
At the time of writing, the raw archive is complete and all image parameters
have been verified. Local processing at Villafranca and data exchange with
GSFC are well advanced, so that the low­dispersion set is nearly finished and
more than 50 % of the high­dispersion spectra have been processed and are
available on the data server. The master archive will be completed by December
1997.
5. The Data Server
Access to the ESA IUE data server (Yurrita & Barylak, 1997) is available at the
address http://iuearc.vilspa.esa.es/. This server implements the following
basic features:
User identification The user logs into the data server to identify a new session.
This accounting system allows users to recall queries and retrieve data from
previous sessions and supports detailed usage statistics.
Query by form A simple form allows searching for objects by name, position,
object type and observing date. Instrument parameters such as camera
name, dispersion or aperture can also be specified.
List of observations The result of the search is a list of observations that can
be used to plot selected spectra or to transfer the selected data to the local
node, using di#erent compression methods.
6. INES: The IUEFA Data Distribution System
After completion of IUEFA, data distribution is planned following the original,
low­cost, distributed archive concept of ULDA/USSP (Wamsteker, et al. 1989).

The IUE Archive at Villafranca 407
The INES (IUE New Extracted Spectra) project will contain (1) the re­
extracted set of low­dispersion spectra together with all high­dispersion obser­
vations re­sampled to the low­dispersion domain, (2) the two dimensional line­
by­line spectra, and (3) a new version of high­dispersion spectra, with orders
concatenated.
INES will be based on the following structure:
Principal center: Master archive repository, containing all the data items in­
dicated above. Distributes the compressed versions of the archive to the
National hosts via CD­ROMs.
National hosts: Located in di#erent countries, containing the INES access
catalogue and serving the absolute flux calibrated 1D spectra via HTTP.
End users: Unlimited number of nodes that access the archive at the National
hosts via standard WWW browsers.
The suggested configuration for the National host data server is based upon
a PC running the Linux operating system. Our prototype is running under the
free DBMS MySQL employing Perl to interface with both the APACHE HTTP
server and the WWW browser. This data server also implements the syntax pro­
posed for information exchange among remote astronomical services (see ASU
http://vizier.u­strasbg.fr/doc/asu.html). Furthermore, the access cata­
logue includes references to IUE spectra included in scientific publications which
can be retrieved via the standard BIBCODE as defined in the NASA Astrophysics
Data System (ADS) (Eichhorn et al. 1998).
References
Barylak, M. 1996, ESA IUE Newsletter No. 46, February 1996, 19
Eichhorn, G., Accomazzi, A., Grant, C.S., Kurtz, M.J., & Murray, S.S. 1998,
this volume
Garhart, M.P., Smith, M.A., Levay, K.L., & Thompson, R.W. 1997, NEWSIPS
Information Manual, version 2.0
Gonz’alez­Riestra, R., Cassatella, A., & de la Fuente, A. 1992, Record of the
IUE Three Agency Coordination Meeting, November 1992, D­78
Kinney, A.L., Bohlin R.C., & Neil, J.D. 1991, PASP, 103, 694
Linde, P., & Dravins, D. 1990, ESA SP­310, 605
NASA/Science O#ce of Standards and Technology 1995, Definition of the Flex­
ible Image Transport System (FITS), NOST 100­1.1
Ponz, J.D., Thompson, R.W., & Mu”noz, J.R. 1994, A&AS, 105, 53
Wamsteker, W., Driessen, C., Mu”noz, J.R., Hassall, B.J.M., Pasian, F., Barylak,
M., Russo, G., Egret, D., Murray, J., Talavera, A., & Heck, A. 1989,
A&A, 79, 1
Yurrita, I., & Barylak, M. 1997, Access to the ESA IUE Data Server, ESA IUE
Newsletter No. 47, January 1997, 34.