CMB-HD Foregrounds: Simulations, Source Detection, and Foreground Removal
Abstract
We present simulations of the microwave sky at 2.5 arcsecond resolution over 100 square degrees, generated from existing full-sky, lower-resolution simulations, and use them to demonstrate extragalactic foreground removal for a CMB-HD survey. Our cleaning method detects and removes the cosmic infrared background and radio galaxies, yielding source catalogs that are 95% complete down to flux limits of 0.008 and 0.04 mJy at 90 and 148 GHz, respectively. It also identifies and removes galaxy clusters via the thermal Sunyaev-Zel'dovich effect, producing a cluster sample that is nearly complete above M500c = 5 × 1013 M⊙. After cleaning, the residual foreground-plus-noise power spectrum of the coadded 90 and 148 GHz temperature map is 50% higher than previous idealized estimates, increasing cosmological parameter uncertainties for an 11-parameter ΛCDM + Neff + ∑ mν + TAGN + AkSZ + nkSZ model by less than 7%. The small impact on cosmological parameters reflects the strong constraining power of CMB polarization, the temperature-polarization cross spectra, and CMB lensing spectra reconstructed from polarization-only estimators, all of which are minimally affected by extragalactic foregrounds. In particular, the survey remains a sensitive probe of light thermal relic particles, achieving σ(Neff) = 0.0154, which can exclude any new species (ΔNeff ≥ 0.027) with at least 90% confidence. Our simulation and foreground-removal codes are publicly available and should aid the development of analysis pipelines for ultradeep, ultrahigh-resolution microwave surveys.
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BibTeX
@misc{macinnis2026cmbhd,
title = {{CMB-HD Foregrounds: Simulations, Source Detection, and Foreground Removal}},
author = {Amanda MacInnis and Joshua Ange and Neelima Sehgal and Joshua A. Kable and Isabelle Blackstad},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.16128},
eprint = {2609.16128},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.16128},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - CMB-HD Foregrounds: Simulations, Source Detection, and Foreground Removal
AU - Amanda MacInnis
AU - Joshua Ange
AU - Neelima Sehgal
AU - Joshua A. Kable
AU - Isabelle Blackstad
PY - 2026
DA - 2026/09/14
PB - arXiv
DO - 10.48550/arxiv.2609.16128
UR - https://arxiv.org/abs/2609.16128
AB - We present simulations of the microwave sky at 2.5 arcsecond resolution over 100 square degrees, generated from existing full-sky, lower-resolution simulations, and use them to demonstrate extragalactic foreground removal for a CMB-HD survey. Our cleaning method detects and removes the cosmic infrared background and radio galaxies, yielding source catalogs that are 95% complete down to flux limits of 0.008 and 0.04 mJy at 90 and 148 GHz, respectively. It also identifies and removes galaxy clusters via the thermal Sunyaev-Zel'dovich effect, producing a cluster sample that is nearly complete above M_500c = 5 × 10^13 M_⊙. After cleaning, the residual foreground-plus-noise power spectrum of the coadded 90 and 148 GHz temperature map is 50% higher than previous idealized estimates, increasing cosmological parameter uncertainties for an 11-parameter ΛCDM + N_eff + ∑ m_ν + T_AGN + A_kSZ + n_kSZ model by less than 7%. The small impact on cosmological parameters reflects the strong constraining power of CMB polarization, the temperature-polarization cross spectra, and CMB lensing spectra reconstructed from polarization-only estimators, all of which are minimally affected by extragalactic foregrounds. In particular, the survey remains a sensitive probe of light thermal relic particles, achieving σ(N_eff) = 0.0154, which can exclude any new species (ΔN_eff ≥ 0.027) with at least 90% confidence. Our simulation and foreground-removal codes are publicly available and should aid the development of analysis pipelines for ultradeep, ultrahigh-resolution microwave surveys.
ER -