Arecibo Observatory

AGC 224316

Find the entry of this object in the ALFALFA archive, and use the images and links there to find the answers to these questions. As always, it is most important that you understand how to derive quantitative answers and their uncertainties.

  1. Compute the HI mass of the galaxy. Do you get the same answer as the value given in the ALFALFA database?
  2. Examine carefully the catalogued HI parameters given in the database this galaxy. What do you notice about the appearance of the HI spectrum that seems inconsistent?
  3. Take a look at the nearby ALFALFA source AGC 226056. How far apart are the positions of the two ALFALFA sources on the sky? How does this compare to the size of the ALFA beam?
  4. What is the linear separation if the sources lie the Virgo distance of 16.7 Mpc?
  5. How can you understand the unusual circumstance you noted in 2. above?
  6. Check out the ALFALFA map of Virgo HI21.

SDSS link

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Last updated Sat Oct 20 11:00:33 EDT 2007 by martha