We present metallicities of 2690 RR0 Lyrae stars observed toward the MACHO Survey fields in the Galactic Bulge .
These [ { Fe } / { H } ] values are based upon an empirically calibrated relationship that uses the Fourier coefficients of the light curve and are accurate to \pm 0.2 dex .
The majority of the RR0 Lyrae stars in our sample are located in the Galactic Bulge , but 255 RR0 stars are associated with Sagittarius dwarf galaxy .
We find that the RR0 Lyrae stars that belong to the Galactic Bulge have average metallicities \hbox { $ [ { Fe } / { H } ] $ } = - 1.25 , with a broad metallicity range from \hbox { $ [ { Fe } / { H } ] $ } = - 2.26 to -0.15 .
The RR0 stars from Sagittarius dwarf galaxy have lower average metallicity of \hbox { $ [ { Fe } / { H } ] $ } = -1.55 \pm 0.02 , with an intrinsic dispersion of 0.25 dex , similar to that in the bulge .
A correlation between metallicity and galactocentric distance is found , in a sense that for the metal-poor RR0 Lyrae stars ( [ { Fe } / { H } ] < - 1.5 dex ) , the closer a star is to the Galactic center , on average , the more metal rich it is .
However , for the metal-rich RR0 Lyrae stars ( [ { Fe } / { H } ] > - 1.2 dex ) , this trend is reversed .
Using mean magnitudes of MACHO RR Lyrae stars , we searched for the evidence of the Galactic bar , and found marginal evidence of a bar .
The absence of a strong bar indicates that the RR Lyrae in the bulge represent a different population than the majority of the bulge stars , which are metal rich and are part of a bar .