Mitigating foreground bias to the CMB lensing power spectrum for a CMB-HD survey

The authors develop a strategy to mitigate two major observational foreground biases introduced in Cosmic Microwave Background (CMB) lensing studies. Using realistic simulations that include extragalactic foregrounds, they show how both the thermal Sunyaev-Zel'dovich effect and the Cosmic Infrared Background can be accounted for, leading to decontaminated CMB temperature maps, which are critical for ensuring future survey effectiveness in establishing the CMB auto spectrum on small scales ($\ensuremath{\le}10k\phantom{\rule{0}{0ex}}p\phantom{\rule{0}{0ex}}c$).