2024/05/30 by Nickolas Kokron, Kokron, Nickolas, José Luis Bernal +3 · 2 citations
Physics and Astronomy · Engineering · #Astrophysics and Cosmic Phenomena #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research
paper · pdf · doi:10.48550/arxiv.2405.20369
We investigate the potential of CO rotational lines at redshifts z∼ 0-6 being an appreciable source of extragalactic foreground anisotropies in the cosmic microwave background. Motivated by previous investigations, we specifically focus on the frequency bands and small scales probed by ground-based surveys. Using an empirical parameterization for the relation between the infrared luminosity of galaxies and their CO line luminosity, conditioned on sub-mm observations of CO luminosity functions from J=1 to J=7 at ν= \100,250\ GHz, we explore how uncertainty in the CO luminosity function translates into uncertainty in the signature of CO emission in the CMB. We find that at ℓ = 3000 the amplitude of the CO cross-correlation with the CIB could be detectable in an ACT-like experiment with 90, 150 and 220 GHz bands, even in the scenarios with the lowest amplitude consistent with sub-mm data. We also investigate, for the first time, the amplitude of the CO×CIB correlation between different frequency bands and find that our model predicts that this signal could be the second-largest extragalactic foreground at certain wavelengths, behind the CIB cross-frequency spectrum. This implies current observations can potentially be used to constrain the bright end of CO luminosity functions, which are difficult to probe with current sub-mm telescopes due to the small volumes they survey. Our findings corroborate past results and have significant implications in template-based searches for CMB secondaries, such as the kinetic Sunyaev Zel'dovich effect, using the frequency-dependent high-ℓ TT power spectrum.