The extended Baryon Oscillation Spectroscopic Survey: measuring the cross-correlation between the MgII flux transmission field and quasars and galaxies at $z=0.59$

Understand

We present the first attempt at measuring the baryonic acoustic oscillations (BAO) in the large scale cross-correlation between the magnesium-II doublet (MgII) flux transmission field and the position of quasar and galaxy tracers.

• The MgII flux transmission continuous field at $0.3 < z < 1.6$ is measured from 500,589 quasar spectra obtained in the Baryonic Oscillation Spectroscopic Survey (BOSS) and the extended BOSS (eBOSS).
• The position of 246,697 quasar tracers and 1,346,776 galaxy tracers are extracted from the Sloan Digital Sky Survey (SDSS) I, II, BOSS and eBOSS catalogs.
• In addition to measuring the cosmological BAO scale and the biased matter density correlation, this study allows tests and improvements to cosmological Lyman-$\alpha$ analyses.