Data Products

MAST distributes a standard package of reduced data, as recommended by the WUPPE project. This package includes the WUPPE Halfwave Level 1 Data, which are the calibrated spectra and polarization parameters. There are three main types of files in the package: FITS, ASCII "dump" files, and postscript files. What follows is a brief description of the filetypes. For more detailed information see the documentation on halfwave data links.

MAST modified the filenames slightly from the original WUPPE project naming convention. The MAST filenames follow the conventions:

objectid_pointid_missionnumber_hw.fits
(e.g. phi-per_220311_2_hw.fits)
objectid_pointid_missionnumber_hwa.ps
(e.g. phi-per_220311_2_hwa.ps)
objectid_pointid_missionnumber_hwe.ps
(e.g. phi-per_220311_2_hwe.ps)
objectid_pointid_missionnumber_hw.txt
(e.g. phi-per_220311_2_hw.txt)
flux#_missionnumber.hw_ps
(e.g. flux15_2_hw.ps)

where

objectid is the name of the object actually observed. The names are generally common to all the ASTRO missions (HUT, UIT, WUPPE). For some pointings WUPPE was offset from the HUT or UIT target or WUPPE was co-pointed with HUT on a specific target in a large UIT field. In these cases, the object_id is the object WUPPE actually observed. Appropriate comments are included in the FITS headers.

pointingid is a 6 digit number representing the object identification number which was assigned during the mission. Eash ASTRO shuttle pointing had a unique pointingid number.

missionnumber refers to the ASTRO mission during which the data were acquired. (i.e. 1 or 2)

Filetype:
hw - halfwave polarimeter data
hwa - halfwave plots with Ångstron binning
hwe - halfwave plots with error binning

Extension:
fits - FITS format data
txt - ASCII versions of the FITS files
ps - postscript plots

Halfwave Level 1 Data FITS file

The FITS files may include both polarimetry data and flux or may contain only flux data. The FITS files that include both types of data are generally 34560 bytes in length. The flux-only FITS files are generally 11520 bytes. The set of basic header information includes the primary array keywords and keywords describing the data arrays, target information, telescope engineering data relative to the observations, and calibration information. A set of comments giving the data reduction history is also included along with a special comments section. The primary array data consists of the flux array (1024 data points - 32 bits per data point) in units of ergs/cm²/sec/Å (F_lambda). The binary tables extension includes headers and vectors for wavelength (Angstroms) and the Stokes parameters %Q and %U and the % Error (also 1024 32-bit data points per array.)

For flux-only FITS files, there is no binary table extension.

Halfwave postscript files

Postscript files have been provided in which the Flux (F_lambda), binned percent Polarization and binned Position Angle have been plotted. Two sets of postscript files have been provided for each pointing. In one set, the polarization data are binned to a specific wavelength interval (e.g. 100 Ångstroms). In the other set, the polarization data are binned to a constant error (e.g. 0.05% error). The naming convention follows that of the halfwave fits data except that the fits has been replaced with hwa or hwe for Ångstrom binning or error binning respectively.

For flux only pointings, postscript files were provided in which the flux of the pointing and the estimated scattered light flux have been plotted. Generally plots for three observations are included in each plot. The file names follow convention of flux1_1.hw_ps or flux10_2.hw_ps where the flux number is an arbitrary number.

ASCII dumps of Halfwave FITS files

The WUPPE project also provided ASCII dumps of each of the WUPPE target halfwave FITS files.

The information contained in this page is a condensation of documentation provided by the WUPPE project.