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Chan, S. J., Sidher, S. D., Swinyard, B. M., Hutchinson, M. G., Lord, S., Molinari, S., Unger, S. J., & Leeks, S. J. 2001, in ASP Conf. Ser., Vol. 238, Astronomical Data Analysis Software and Systems X, eds. F. R. Harnden, Jr., F. A. Primini, & H. E. Payne (San Francisco: ASP), 365

The LWS Interactive Analysis (LIA) Package

S. J. Chan, S. D. Sidher,1 B. M. Swinyard, M. G. Hutchinson
Space Science Department, Rutherford Appleton Laboratory, U.K.

S. Lord, S. Molinari, S. J. Unger2
Infrared Processing & Analysis Center, California Institute of Technology, U.S.A.

S. J. Leeks
Department of Physics, Queen Mary, University of London, U.K.

Abstract:

We report on our on-going software project the LWS Interactive Analysis (LIA), which has been developed under the IDL environment. This is a processing and analysis software package for the Long Wavelength Spectrometer (LWS) aboard the Infrared Space Observatory ( ISO). There are three classes of routines are available under LIA: Inspection Routines, Recalibration Routines, and Interactive Routines.

1. LWS: Long Wavelength Spectrometer

The European Space Agency (ESA) Infrared Space Observatory ( ISO) was launched on 17 November 1995. The Long Wavelength Spectrometer (LWS) is one of two complementary spectrometers aboard ISO. The LWS contains ten dectectors to cover the wavelength range 43-196.9$\mu$m. It operates in two observing modes, corresponding to medium and high spectral resolution. In medium resolution mode, the LWS contains a reflection grating to give a spectral resolving power ( $\lambda / \Delta\lambda$) from  $\sim$ 150 to 200. In high resolution mode, a Fabry-Perot (FP) Interferometer is inserted before the grating to give a spectral resolution ranging from 6800-9700 across the entire wavelength range (Clegg et al. 1996; Swinyard et al. 1999).

2. LIA: LWS Interactive Analysis

2.1. Introduction

The LWS Interactive Analysis (LIA) is a software package designed to allow users to inspect, reprocess, and recalibrate their LWS data with the possibility of interactively customizing the various data reduction stages to their particular set of data. It is a joint development of the ISO-LWS Instrument Team at Rutherford Appleton Laboratories (RAL, UK--the PI institute) and the Infrared Processing & Analysis Center (IPAC, USA). LIA development started in 1997 (Sidher et al. 1997). The current version is LIA 8.1. The final version will be LIA 10, which will operate on products from OLP 10--the final pipeline processing software to be released. The current version of LIA can be obtained via LIA/UKIDC web site and LIA/IPAC web site.

2.2. LIA and ISAP

LIA is written under the Interactive Data Language (IDL) environment. The programming language used in this package is also IDL. IDL provides the ability to plot and visualize data easily and immediately. The ISO Spectral Analysis Package (ISAP), which is required to run LIA, is also written in IDL.

Figure 1: Inspection Routine: inspect_spd - An interactive tool displays SPD results before and after the application of the standard deglitching algorithm.
\begin{figure}
\epsscale{.70}
\plotone{D-03a.eps}
\end{figure}

ISAP is a software package for the reduction and scientific analysis of the ISO SWS (Short Wavelength Spectrometer) and LWS Auto Analysis Results (AARs). AARs are the end product of the official automatic pipeline processing, which processes the raw data as they are received from the satellite, via a number of intermediate stages.

During the early post- ISO mission stage, the calibration accuracy of these products was generally good to within 20% on average. One of the advantages of LIA is that it allows users to check the quality of their scientific and calibrated data, and also to recalibrate them if necessary.

2.3. The LIA routines

There are three classes of routines are available under LIA. They are Inspection Routines, Recalibration Routines, and Interactive Routines.

Inspection Routines
allow users to inspect their pipeline products as produced through the Standard Processing Stage and the Auto Analysis Stage (e.g., inspect_spd routine, see Figure 1).

Figure 2: Interactive Routine: gui_fpmf - This tool is written for Interactive FP Multi Gaussian Fitting for a single "blended" line.
\begin{figure}
\epsscale{.70}
\plotone{D-03b.eps}
\end{figure}

Interactive Routines
allow users to customize the data reduction process and to tune the algorithms used in the data reduction (e.g., gui_fpmf routine, see Figure 2).

Figure 3: Recalibration Routine: fp_proc - An interactive tool produces calibrated LSAN files for FP observations.
\begin{figure}
\epsscale{.70}
\plotone{D-03c.eps}
\end{figure}

Recalibration Routines
allow users to recalibrate the data reprocessed using the interactive routines, or to make a complete non-interactive reprocessing using defaults other than those used by the automatic Off-Line Processing (OLP; e.g., fp_proc routine, see Figure 3).

2.4. Routines Planned for LIA 10

Automatic routines: One of the advantages of LIA 10 will be that it process large amounts of data without manual intervention.

Planned recalibration routines

Acknowledgments

S. J. Chan thanks the Program Organizing Committee of the Tenth Annual Conference on Astronomical Data Analysis Software and Systems for offering her financial support to attend the conference.

References

Clegg, P. E., et al. 1996, A&A, 315, L38

Sidher, S. D. 1997, ESA SP-419, 297

Swinyard, B. M., et al. 1998, in SPIE Proc., Vol. 3354, 888



Footnotes

... Sidher,1
Department of Physics, Queen Mary, University of London, U.K.
... Unger2
Department of Physics, Queen Mary, University of London, U.K.

© Copyright 2001 Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, California 94112, USA
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