A realistic study of continuum contamination to line intensity mapping with SPHEREx

par Zucheng Gao (Cambridge University)

jeudi 16 nov. 2023, 11:00 → 12:00 Europe/Paris

Petit Amphi (LAPTh)

Continuum emission is a significant source of systematic contamination in line intensity mapping (LIM). For optical and near-infrared LIM experiments, the intensity maps can be dominated by extragalactic continuum emission rather than the target line emission. Therefore, to extract fully the rich cosmological information contained in the intensity maps, it is essential to remove the continuum contamination. However, modelling intensity maps with continuum contamination is challenging. We investigate these issues here in the context of the SPHEREx mission. We describe the generation of a realistic simulation, which assigns the full spectral energy distribution to each dark matter halo in a self-created light-cone from snapshots of an $N$-body simulation, and generates mock observational maps for all SPHEREx spectral channels. We find that the continuum contamination can be 10--100 times higher than the intensity of the target line. However, our preliminary results indicate that by applying a singular-value-decomposition (SVD) technique, it is possible to extract and remove much of the continuum contamination from the intensity maps. Although broadband residuals remain in the 3D power spectrum of the SVD-cleaned maps compared to that of the target-line emission, we show that the baryon-acoustic-oscillation (BAO) features can still be recovered accurately.