%0 Journal Article %J Monthly Notices of the Royal Astronomical Society %D 2018 %T Analysing baryon acoustic oscillations in sparse spectroscopic samples via cross-correlation with dense photometry %A Patej, A. %A Eisenstein, D. J. %K distance scale; large-scale structure of Universe %X We develop a formalism for measuring the cosmological distance scalefrom baryon acoustic oscillations (BAO) using the cross-correlation of asparse redshift survey with a denser photometric sample. This reducesthe shot noise that would otherwise affect the autocorrelation of thesparse spectroscopic map. As a proof of principle, we make the firston-sky application of this method to a sparse sample defined as the z> 0.6 tail of the Sloan Digital Sky Survey's (SDSS) BOSS/CMASS sampleof galaxies and a dense photometric sample from SDSS DR9. We find a2.8σ preference for the BAO peak in the cross-correlation at aneffective z = 0.64, from which we measure the angular diameter distanceDM(z = 0.64) = (2418 ± 73 Mpc)(rs/rs,fid). Accordingly, we expect that using this method to combinesparse spectroscopy with the deep, high-quality imaging that is just nowbecoming available will enable higher precision BAO measurements thanpossible with the spectroscopy alone. %B Monthly Notices of the Royal Astronomical Society %V 477 %P 5090-5103 %8 July 1, 2018 %@ 0035-8711 %G eng %U http://adsabs.harvard.edu/abs/2018MNRAS.477.5090P %3 10.1093/mnras/sty870