Example of how the pure parallel program works. While a nearby quasar is observed by COS, the WFC3 is turned on to collect data on a nearby, random parallel field.
Locations of the WISP parallel fields. There are a total of 385 fields within the program: 136 have been released as HLSPs at MAST to-date.
WISP is a large HST "pure-parallel" program using the WFC3 G102 and G141 grisms to obtain images, spectra, and catalogs of star forming galaxies between redshifts 0.5 to 2.5. The primary science goals are to measure the star formation history over the last ~10 billion years, probe galaxy clustering on Mpc scales at redshifts 1 < z < 2, constrain the evolution of dust extinction and metallicity as functions of mass and luminosity, and to conduct a serendeipitous search for highly luminous Lyman alpha emitters beyond redshifts z > 6.
Each galaxy+instrument is organized into a subdirectory structure, based on the Parallel Field ("par") number.
Example (Parallel Field #152): par152/
Several files are available in each fields' subdirectory. The data products all start with the same prefix ("hlsp_wisp_hst_wfc3"). The file names also include the field number ("par1", "par22", etc.), and the filters associated with the data product, which can be either "all", "f110w", "f140w", "g102", "g141", or a hyphen-separated combination. The file extensions and contents of the files are:
1dspectra/ = Subdirectory containing the extracted spectra for all objects in the field. It's contents are as follows:
_spectra-header.txt This text file contains header information for each extracted spectrum, such as the central coordinates for the first exposure, the filters used, and exposure times. It also includes descriptions of what each column represents within the "_spec1d.dat" files. The same header applies for each extracted spectrum in the folder.
_spec1d.dat These text tables contain the wavelengths, fluxes, flux errors, flux contaminations, and flux source flag for each target. The "zeroth" column (last column in the file) is a flag that can be one of three integers: 0=no contamination, 1=contamination from the zeroth order, and 2=edge truncation. The source ID is included in the filename, e.g., "hlsp_wisp_hst_wfc3_par1-0025a_g102-g141_v5.0_spec1d.dat" is the spectrum for source #25 in parallel field #1.
_catalog-header.txt = This text file contains header information for the first exposure taken in the direct imager sequence of observations. Information includes the central coordinates and date/time of the (first) observation.
_cat.txt = Source catalog for the given filter, derived from the direct images using SExtractor. Source IDs between 1000 and 2000 are sources detected only in the bluer filter, while sources with IDs greater than 2000 are detected only in the redder filter.
_drz.fits = Drizzled science image for the given filter. The "f110w" and "f140w" are from the imager, the "g101" and "g141" are the 2D spectral images from the grism.
Each field has an entry in the table below. You can browse the entire directory contents using the "browse" link inside the "Field" column. Hover over any of the "IMG" links to see a preview image (both for the direct images and the grism images). Click on the "IMG" links to download the FITS files. Click on the "CAT" links to download the catalog FITS file for that filter/grism. You can also download a tarball of all the extracted spectra for the field using the links in the last column.
Note: The table is sortable after the rows' background colors become alternately colored white and blue. This takes a few seconds for most browsers. All other functionality is ready immediately.