Документ взят из кэша поисковой машины. Адрес оригинального документа : http://hea-www.harvard.edu/astrostat/talks_1011/vk_20101109.pdf Дата изменения: Tue Nov 9 18:25:43 2010 Дата индексирования: Tue Oct 2 03:47:29 2012 Кодировка:

logN-logS
A Measuring Stick for the Universe
Vinay Kashyap (CfA)

Tuesday, November 9, 2010


log10(N>S)-log10(S)
cumulative number of sources detectable at a given telescopic sensitivity S = [ergs s-1 cm-2] N = number of sources brighter than S

Tuesday, November 9, 2010


simple example
uniformly distributed source population all sources have same intrinsic luminosity for telescope sensitivity S, source will be detectable to

f (L) = (L - L0 )

number of sources within this distance

Tuesday, November 9, 2010


simple example
uniformly distributed source population all sources have same intrinsic luminosity for telescope sensitivity S, source will be detectable to

f (L) = (L - L0 )

number of sources within this distance

Tuesday, November 9, 2010


simplified general case

cosmology makes it more complicated

Tuesday, November 9, 2010


typical case
a set of detected sources with observed counts with associated detector location, background, exposure background and exposure determine detection threshold detection probability is usually tabulated Problem: Model N(>S) as a single power-law or broken power-law
Tuesday, November 9, 2010


logN-logS
Next up: Andreas Zezas (Univ. of Crete)

Tuesday, November 9, 2010