Source counts

  • #1

Homework Statement


if the intrinsic brightness of a class of radio galaxies fades as the universe ages, such that those that we see further away are brighter, having a linear increase in luminosity with distance r, what would be the slope of a graph of log N(s) versus log S for these objects.


Homework Equations





The Attempt at a Solution


I know that usually, the slope would be -1.5, but as it says those that we see further away are brighter, i would expect that you would see more objects above the threshold S. So im thinking that the slope would not be -1.5.

Instead of using S=L/(4pi r^2), would i say that L=r, as it says having a linear increase in luminosity with r?
 

Answers and Replies

Related Threads on Source counts

  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
2
Views
3K
Replies
9
Views
14K
Replies
1
Views
1K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
7
Views
1K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
2K
Top