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Hubble Legacy Archive

Image of the Month for August 2010

WFPC2 Source Lists for M51


Interactive Display for 10877_05 WFPC2: F675W & F450W

Highlighted HLA Features:

This display can be reproduced in the HLA by using the following steps or clicking on the image above. Zoom out and select all of the source list options at the top of the interactive display to make this image.
  1. Type hla.stsci.edu into your browser. Click on the "Enter Site here" button.
  2. Type "M51" in search box ("whirlpool" nickname will also work) and hit the "return/enter" key.
  3. In the Inventory Tab, type "4" (i.e. color images) in box underneath Level column and then hit the "return/enter" key. (Use your mouse to hover over the Level column header to see a description of the Level data field.)
  4. Type "wfpc2" in box underneath Detector column (this will filter to 14 of 427 images) and then hit the "return/enter" key.
  5. Click on "Images" tab.
  6. Locate the "SN2005CS, 10877_05" image and click "Interactive Display".
  7. Click on "DAOphot" and 1266 sources are displayed.
  8. Click on "SExtractor" and 845 sources are displayed.
  9. To display each catalog separately click only the checkbox for that catalog. Continue for "SDSS", "2MASS", "GSC2", "FIRST", and "GALEX."
  10. Name of Source # of sources Color Acronym Meaning Type
    DAOphot 1266 red Using Dominion Astrophysical Observatory Photometry package Point-like sources
    SExtractor 845 blue Using Source Extractor package Extended sources
    SDSS 0 turquoise Sloan Digital Sky Survey Optical Sky Survey
    2MASS 88 green Two Micron All Sky Survey All-sky near-infrared
    GSC2 0 pink Guide Star Catalog 2 All-sky optical
    FIRST 10 orange Faint Images of the Radio Sky at Twenty cm Radio
    GALEX 47 purple Galaxy Evolution Explorer Near-UV and Far-UV

  11. To download data go back to "Inventory" tab.
  12. Remove "4" from Level column and then add "*sn2005*" under the Target column. Hit the "return/enter" key.
  13. You can now select the DAOphot or SExtractor sources lists from the far right columns in the "Inventory" tab, or hit the "Images" tab and select the catalogs from the "Download Source Lists" link.
  14. Click the tab highlighted in yellow that says "1 file/0 datasets, >0 kB". Click "Retrieve HLA Data". The file "HLAdata.zip" will be downloaded to your computer.
  15. Look in the file "hst_10877_05_wfpc2_f675w_wf_daophot_trm.cat" for information about the image and how and when the catalog was made.
  16. Go to the "About Source List" FAQ for more details.
Additional Information:
Plots of the photometeric data are available for ACS but not for WFPC2. Remove "*sn2005*" and "wfpc2" in the "Inventory" tab. In the Detector column box type "*ACS/WFC*" and change Level column to "2", then hit "return/enter" key. Then click on Image Tab and go to image "HST_10182_pb_ACS_WFC_F435W". Next to the DAOPhot and SExtractor carts click on "(plot)". Plots show a F435W luminosity function (including a rough estimate of the detection threshold, i.e. F435W = 25.34 mag) and a size vs. F435W diagram.

Previous HLA Images of the Month