C <scp>ii</scp> and H <scp>i</scp> 21-cm line intensity mapping from the EoR: impact of the light-cone effect on auto and cross-power spectra

ABSTRACT C ii line intensity mapping (LIM) is a potential technique to probe the early galaxies from Epoch of Reionization (EoR). Several experiments e.g. CONCERTO, TIME, CCAT-p are underway map LIM signal fluctuations EoR, enabling us estimate power-spectrum and × 21-cm cross-power spectrum. The observed will have its time evolution embedded in it along sight due finite traveltime origin observer. We investigated this so-called light-cone effect on statistics our seminumerically simulated EoR. Using suit neutral hydrogen maps corresponding boxes, we shown that can impact power spectrum by more than 15 per cent at large scales ($k\sim 0.1\, \text{Mpc}^{-1}$, $z$ = 6.8). also drops with decreasing redshift within range considered here (7.2 ≲ 6). affected light cone, models where reionization ends before 6, find maximum reach up 20 cent. At 6.4, comparatively pronounced variation history cross-power. Faster histories drastic conclude need incorporate cone order properly model signal, constrain EoR-related astrophysical parameters using