Guide to NED Spectra Results Pages

(Latest Revision: 19 October 2009)

These pages display the results of your search for spectra. There are two main results pages, compact and detailed. Both pages start with the following information:

  • A summary line with the name of the object you requested. This is linked to NED's object database, allowing you to retrieve the data and literature references currently stored by NED for the object.
  • If your input name is for one of NED's multiple object types, e.g. "GPair", the search will next return a list of the matching objects with a serial number link to the spectra for each object, their positions, distances from the position for the multiple object entry, object types, redshifts, numbers of spectra, and flags for "Essential Notes", if applicable. Otherwise, you will see the output page without a list.

All of the information given on the detailed results page is accessible through links on the default compact results page. Here is some information about each page.

  • The compact output page gives, for each of the spectra in NED for your object, the following images and information:
    1. An optional "postage-stamp" preview of the DSS image in JPEG format for the galaxy with the slit or aperture (with its correct length or diameter, and position angle, where known) superposed on the image. Apertures plotted in red indicate that the exact placement of the slit/fiber/beam was not provided with the spectra. Therefore, the "best" position available in NED at the time the data were ingested was used to generate the overlay. Apertures plotted in purple indicate that an observed position provided with the spectrum (from the FITS header, observation log, or relevant journal article) was used to generate the overlay. Finally, the yellow apertures show the actual regions within the red or purple boundaries from which the one-dimensional spectra were extracted.

      Clicking on the image will retrieve it, and -- if your browser is configured to display JPEG images -- display it.

    2. An optional preview of the spectrum itself. Clicking on the preview will display the spectrum in a separate window. (Note that the units used for this display of the spectra are those in the original paper; NED has done no transformation of units for the images of the spectra.) There is also a link here which allows you to start the Specview tool. Java must be enabled in your browser in order for you to use Specview.
    3. You may retrieve the data table from which the spectrum's image is built. These are usually available in at least the author's original ASCII formatted tables, NED's standardized ASCII tables with homogenized units, and HTML VOTable format. The data may also be available in gzipped FITS format, as well as directly from an "External Resource", usually one of the data archive centers. A link to the reference and NED's abstract is also provided.
    4. Brief "Observational Information" is given next, if known:
      • The region of the galaxy observed, usually the nucleus
      • The telescope used to make the observation
      • The instrument used to obtain the spectrum
      • An indication whether the spectrum has an absolute calibration
      • The reference frame, usually as observed, or as redshifted to the rest frame of the galaxy
      • A link to the full data description of the object and the observing details
    5. Finally, information about the spectral coverage and resolution are provided.

  • The detailed output page with the full description of the spectra has the following data:
    1. The left side of the page has
      • A preview image showing the slit orientation and position angle superposed on a DSS image of the object. This image is clickable and shows an enlarged version in a new window.
      • A clickable preview image of the spectrum, along with a link to start the Specview tool. Java must be enabled in your browser in order for you to use Specview.
      • Data retrieval links allow you to retrieve the data table from which the spectrum's image is built. These are usually available in at least the author's original ASCII formatted tables, NED's standardized ASCII tables with homogenized units, and HTML VOTable format. The data may also be available in gzipped FITS format, as well as directly from an "External Resource", usually one of the data archive centers.
    2. The right side of the page has the detailed data themselves:
      • Object information including
        1. Published name and position (with system, type, and equinox) for the object, as well as the published position precessed to J2000
        2. NED's cross-identified values for the object name and J2000 position
      • Observational details when known, including
        1. Observed region, usually the "Nucleus"
        2. Telescope and instrument names, along with instrumental details when given in the published paper
        3. Pass band details when given
        4. Seeing and air mass when given
        5. Integration time when given
        6. Flux and channel units
        7. Reference frame, usually "Observed" or "Observatory", sometimes redshifted to the galaxy rest frame
        8. Flux calibration and sky subtraction flags
        9. Reference code linked to NED's title/author and abstract list
        10. Miscellaneous notes

The output pages may have more information specific to the data set being displayed. For example, the SINGS (Spitzer Infrared Nearby Galaxies Survey) spectra include Aperture/Beam and Extracted Region sizes. These are both shown on the DSS image, the Aperture in purple and the Extracted Region in yellow. The Extracted Region shows the area of the galaxy to which the displayed spectra apply; the Aperture/Beam shows the first position in the IRS scanning raster.

We gratefully acknowledge the individuals who have already sent spectra in machine-readable formats for integration into NED.


Use your browser's "Back" button to return to the spectra list.

Back to the Spectra Search Input Page.

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