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FUSE Browse Files

Welcome to the Multimission Archive at Space Telescope Science Institute (MAST). This page provides information on the FUSE browse files; a collection of web pages accessible from both the MAST FUSE search page and, eventually, as data links from the Atrophysics Data System (ADS).

The MAST FUSE preview pages include a gif plot file containing three summed spectra, links to summed spectra of each of the four detectors, links to various gif plot files showing information on the individual exposures obtained in the observation, a link to an ASCII file of FITS keywords (based on the topmost displayed spectrum), a link to display/customized a merged spectrum, and a link to this help file.

The FUSE "quick-look" plots show calibrated flux (in units of ergs/cm^2/sec/A and smoothed over 4 points) as a function of wavelength (in Angstroms). Spectra were extracted with the IDL routine obtained from the FUSE project. The plots are shown in the following order:

  • SiC2A from 910 to 1009 Angstroms,
  • LiF1A from 985 to 1085 Angstroms,
  • LiF2A from 1084 to 1182 Angstroms,

Following the combined summed plot are links to four gif images showing summed plots for each channel (i.e., A and B) for each detector (LiF1, LiF2, SiC1, SiC2). The wavelength range covered is as shown.

  • LiF1A from 985 to 1085 Angstroms,
  • LiF1B from 1092 to 1190 Angstroms,
  • LiF2B from 975 to 1078 Angstroms,
  • LiF2A from 1084 to 1182 Angstroms,
  • SiC1B from 910 to 995 Angstroms,
  • SiC1A from 1000 to 1094 Angstroms,
  • SiC2A from 910 to 1009 Angstroms,
  • SiC2B from 1013 to 1106 Angstroms,

Note that the actual data range as extracted from the FITS files may vary slightly from that shown in the preview plots (i.e., by less than a couple Angstroms).

Following the summed detector plots is a table of links to gif images showing data from the individual exposures. Each row of the table contains data for one exposure. The three columns include the following information:

  • exposure number: the number assigned to the exposure by the project,
  • Spectral image: four links (one for each detector) to plots showing the position of the extraction slit superimposed on the spectrum.
  • Count Rate: a relative count rate versus time showing how well the target stays centered in the aperture.

Customize Plot Option

The FUSE preview page offers the option of displaying and modifying a plot of flux versus wavelength. These plots were created by the MAST staff by merging the coadded spectra provided by the FUSE project. The fluxes and wavelengths were binned over 4 points, producing plots containing roughly 10,000 points. Note that there is 1 gap (of roughly a few Angstroms) in the spectral coverage, near 1085 A. These points are flagged with the error vector in the FUSE FITS files, but are shown in these plots with flux values of 0.0.

Cutomizing the size and range of plotted values can be useful for viewing a particular spectral feature, or sizing the plot for better printing. In addition to the plot, the customized plot page displays the mission and target name, number of plotted points, and the min and max wavelength and flux values of the extracted data.

The user can "customize" the plot parameters described below. Note the process can be repeated until the right scale and dimensions are determined.

  • Wavelength Limits - The minimum and maximum displayed wavelengths can be specified by the user. Setting both limits to 0.0 will allow the program to pick the best plot limits. Leaving one value as 0.0 however will result in 0.0 being used for that particular plot limit. The wavelength limits are specified in the same units as shown on the plot (i.e., Angstroms).
  • Flux Limits - As with the wavelengths, the minimum and maximum displayed flux values (specified in the same units shown) can be specified by the user. This option is particularly useful for viewing continuum levels in spectra whose preview plot scale was determined by strong spectral features or camera artifacts.
  • Plot Dimensions - The user may adjust the X and Y limits of the displayed plot (in pixels) up to a maximum size of 850 by 640 pixels.

The FUSE preview images were provided by the FUSE project.