IRSAs Browse Products for FLS_HECTOSPEC Collection


Overview

FLS Ancillary MMT/Hectospec data accompany the paper Papovich et al. (2006), AJ, in press. IRSA serves the three primary catalog/table data products and multi-part FITS spectra files from the FLS Ancillary MMT/Hectospec second data release (v2), using spatial searches in Atlas. IRSA has created additional browse products, including spectra previews and ASCII spectrum table files for all MMT/Hectospec data. These browse products are available from Atlas search results, through additional columns in the FLS MMT/Hectospec Spectroscopic Catalog (fls_v2.mmt_spectra.tbl), described below. For more information on the catalog format and column desciptions, click here.

Accessing IRSA's MMT/Hectospec Browse Products

Run a spatial query on the FLS_HECTOSPEC data using Atlas. Search results show source position footprints on a background sky image, along with a list of sources for each of the FLS_HECTOSPEC catalogs for which the search was successful. If your search results include entries in the FLS MMT/Hectospec Spectroscopic Catalog (fls_v2.mmt_spectra.tbl), click on the catalog to access IRSA's MMT/Hectospec browse products. HTML links to four browse products have been added to the last four columns in the table:
  • The first link, Spec_Preview, is a spectrum preview binned by a factor of 11 in wavelength. Binning was done in order to try to match the spectra in Papovich et al. (2006), AJ, in press [Figures 4 and 7]. Please note that masking of bad pixels has not been done to the IRSA preview spectra, but has been done to the spectra plotted in the publication. For more information on how IRSA created the spectra preview files, please see section below.
  • The second link, Spec_ascii_table_nobinning, is an ASCII file, in IPAC table format, of the Wavelength and Flux of the spectrum, without wavelength binning. The information was extracted from from the multi-part FITS image, matching the FIELD and FIBER number to the correct FITS image and row number, respectively, from extensions 0 [Wavelength] and 1 [Flux].
  • The third link, Spec_ascii_table_binned, is an ASCII file, in IPAC table format, of the Wavelegth and Flux of the spectrum, with wavelength binning factor of 11. The information was extracted from from the multi-part FITS image, matching the FIELD and FIBER number to the correct FITS image and row number, respectively, from extensions 0 [Wavelength] and 1 [Flux].
  • The fourth link, Hectospec_multipart_FITS, is the multi-part FITS file which holds the spectra-related data for this catalog row entry.

Creating ASCII spectra tables and spectra previews

FLS MMT/Hectospec spectra preview plots were created using the multi-part FITS images for each of the 5 FIELDs (spHect-131, spHect-132, spHect-133, spHect-134 and spHect-135), per FIBER number (FITS image row number), from extensions 0 [Wavelength] and 1 [Flux]. FTOOLS and IRAF were used to extract the values from the FITS files in order to create ASCII spectra in IPAC table format:
  • FTOOL 'fextract' pulled extensions 0 and 1 into separate FITS images from the original multi-part FITS files [output: ext0.fits, ext1.fits]
  • FTOOL 'fimgbin' binned FITS images by a factor of 11 into new FITS images [output: ext0bin.fits, ext1bin.fits]
  • IRAF 'listpix' created ASCII pixel files for both sets of FITS images [binned output: ext0bin.lis, ext1bin.lis; unbinned output: ext0.lis, ext1.lis]
  • A Unix script was used to "grep" the row/FIELD number from the ASCII pixel list files, and "paste" the ext0 and ext1 single column data into an ASCII two-column table file of wavelength and flux. Formatting and header information was added to conform to the IPAC table format. This process was done for both the binned and unbinned datasets. [output: spHect-FIELD#-0300_row#_spec_nobin.tbl, spHect-FIELD#-0300_row#_spec.tbl]
  • GNU graph was used to create gif plots of the binned ASCII spectra files
The naming scheme for each file is broken down below:
  1. The prefix "spHect-"
  2. the FIELD number (131, 132, 133, 134, or 135)
  3. The image "row" number (FIBER number)
  4. One of the following suffixes:
    • "_spec.gif" (binned spectra)
    • "_spec_nobin.gif" (unbinned spectra)
    • "_spec.tbl" (binned ASCII table)
    • "_spec_nobin.tbl" (unbinned ASCII table)
To access all the FLS MMT/Hectospec spectra previews, click here.

To access all the FLS MMT/Hectospec ASCII spectra tables, click here.