Constraint on the region emitting the 7 keV line: a widely extended photo ionized plasma?
Good Candidate predicted by illuminated disk models:
³Accretion disk corona² : r ~108- 1010 cm, n ~ 1015 - 1016 cm-3
Model predictions: a) A spatially extended photo ionized
layer on the top of a Shakura-Sunyaev disk, b) more external layers (Corona)
where the Compton temperature goes up to few x106 K (Jimenez-Garate et al, 2001)
1) Upper limit:
€ 7 keV Þ log x>3.3
" x= Lx/(nr2) = ionization
parameter
" Lx= 1.6 x1037 erg/s
Þ nr2
>
8x1033 cm-12) Lower
limit:
€ Simplest single -T plasma:
€ L line = 7.7x1031 erg/s
€ T = 230 eV
Þ n2V >3 x1055 cm-3 (EM)
3) R > R Alfven
= 3.6 107 cm
Upper limit
Lower limit