Speaker
Description
The Lyman-α forest is detected as the series of absorption lines in the quasar spectra, caused by the Lyman-α transitions of neutral hydrogen in the low-density, high-redshift intergalactic medium (IGM). It is a biased continuous tracer of the quasi-linear matter density field, and the auto (cross) correlation function of the forests (with quasars) has been used to detect the Baryon Acoustic Oscillations (BAO) signal. The Damped Lyman-α System (DLAs) is one of the most important systematics in the Lyman-α BAO analysis. DLAs are strong absorption regions in Lyman-alpha forests caused by neutral hydrogen along the sightline with extremely high column densities, usually $log(\text{NHI})>=20$. We present an accurate model to characterize the impact of DLAs on the measurement of the Lyman-α correlation function, as well as the BAO fitting.
