A search for RR Lyrae stars ( RRLS ) in \sim 840 \textrm { deg } ^ { 2 } of the sky in right ascension 150 \arcdeg - 210 \arcdeg and declination -10 \arcdeg - + 10 \arcdeg yielded 1013 type ab and 359 type c RRLS .
This sample is used to study the density profile of the Galactic halo , halo substructures , and the Oosterhoff type of the halo over distances ( d _ { \sun } ) from \sim 5 to \sim 80 kpc .
The halo is flattened towards the Galactic plane , and its density profile steepens in slope at galactocentric distances greater than \sim 25 \textrm { kpc } .
The RRLS in the stellar stream from the Sagittarius dwarf spheroidal ( dSph ) galaxy match well the model of Law & Majewski for the stars that were stripped 1.3 to 3.2 Gyr ago , but not for the ones stripped 3.2 to 5.0 Gyr ago .
Over densities are found at the locations of the Virgo Overdensity and the Virgo Stellar Stream .
Within 1 \arcdeg of 1220-1 , which Jerjen et al .
identify as a halo substructure at d _ { \sun } \sim 24 kpc , there are 4 RRLS that are possibly members .
Away from substructures , the RRLS are a mixture of Oosterhoff types I and II , but mostly OoI ( \sim 73 \% ) .
The accretion of galaxies resembling in RRLS content the most massive Milky Way satellites ( LMC , SMC , For , Sgr ) may explain this preponderance of OoI .
Six new RRLS and 3 new anomalous Cepheids were found in the Sextans dSph galaxy .