galaxy photometry is impossible

I started writing the introduction for Mykytyn and Patel's coming paper on galaxy photometry. It opens by explaining why it is impossible to know the total flux coming into the telescope from a diffuse object like a galaxy. That's a subject I have spent hours discussing with the great Robert Lupton (Princeton). It is fun to try to get it written down in a paper.


  1. Looking forward to read it! Few snippets would be interesting though

  2. "Diffuse objects like galaxies" ... would you imply that photometry for diffuse objects like resolved prestellar gas cores is impossible as well?

    1. Eli: Probably yes, if there aren't theoretical limits to how low the objects can get in projected density. Anonymous: I will probably (since I can't stop myself) give the flavor of the argument in one of my posts this coming week