We have cross-correlated the galaxies from the IRAS 2 Jy redshift survey sample and the 0.7 Jy projected sample with the all-sky cosmic X-ray background ( CXB ) map obtained from the HEAO-1 A2 experiment .
We have detected a significant correlation signal between surface density of IRAS galaxies and the X-ray background intensity , with W _ { xg } = \frac { \langle { \delta I \delta N } \rangle } { \langle { I } \rangle \langle { N } \rangle } of several times 10 ^ { -3 } .
While this correlation signal has a significant implication for the contribution of the local universe to the hard ( E > 2 keV ) X-ray background , its interpretation is model dependent .

We have developed a formulation to model the cross-correlation between CXB surface brightness and galaxy counts .
This includes the effects of source clustering and the X-ray – far infrared luminosity correlation .
Using an X-ray flux limited sample of AGNs , which has IRAS 60 \mu m measurements , we have estimated the contribution of the AGN component to the observed CXB – IRAS galaxy count correlations in order to see whether there is an excess component , i.e .
contribution from low X-ray luminosity sources .
We have applied both the analytical approach and Monte-Carlo simulations for the estimations .

Our estimate of the local X-ray volume emissivity in the 2 – 10 keV band is \rho _ { x } \approx ( 4.3 \pm 1.2 ) \times 10 ^ { 38 } h _ { 50 } erg s ^ { -1 } Mpc ^ { -3 } , consistent with the value expected from the luminosity function of AGNs alone .
This sets a limit to the local volume emissivity from lower-luminosity sources ( e.g .
star-forming galaxies , liners ) to \rho _ { x } \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $ \sim$ } } } \hbox { $% < $ } } } 2 \times 10 ^ { 38 } h _ { 50 } erg s ^ { -1 } Mpc ^ { -3 } .