Demonstrating the feasibility of line intensity mapping using mock data of galaxy clustering from simulations

Abstract

Visbal & Loeb (2010) have shown that it is possible to measure theclustering of galaxies by cross correlating the cumulative emissionfrom two different spectral lines which originate at the sameredshift. Through this cross correlation, one can study galaxieswhich are too faint to be individually resolved. This technique, knownas intensity mapping, is a promising probe of the global properties ofhigh redshift galaxies. Here, we test the feasibility of suchmeasurements with synthetic data generated from cosmological darkmatter simulations. We use a simple prescription for associatinggalaxies with dark matter halos and create a realization of emittedradiation as a function of angular position and wavelength over apatch of the sky. This is then used to create synthetic data forthree different hypothetical instruments, one aboard the SpaceInfrared Telescope for Cosmology and Astrophysics (SPICA), anotherconsisting of a pair of ground based radio telescopes designed tomeasure the CO(1-0) and CO(2-1) emission lines, and one on the CornellCaltech Atacama Telescope (CCAT). We find that the line cross powerspectrum can be measured accurately from the synthetic data witherrors consistent with the analytical prediction of Visbal & Loeb(2010). Removal of astronomical backgrounds and masking bright lineemission from foreground contaminating galaxies do not preventaccurate cross power spectrum measurements.