TY - JOUR
T1 - The Atacama Cosmology Telescope
T2 - Reionization kSZ trispectrum methodology and limits
AU - MacCrann, Niall
AU - Qu, Frank J.
AU - Namikawa, Toshiya
AU - Bolliet, Boris
AU - Cai, Hongbo
AU - Calabrese, Erminia
AU - Choi, Steve K.
AU - Coulton, William
AU - Darwish, Omar
AU - Ferraro, Simone
AU - Guan, Yilun
AU - Hill, J. Colin
AU - Hilton, Matt
AU - Hlozek, Renée
AU - Kramer, Darby
AU - Madhavacheril, Mathew S.
AU - Moodley, Kavilan
AU - Sehgal, Neelima
AU - Sherwin, Blake D.
AU - Sifón, Cristóbal
AU - Staggs, Suzanne T.
AU - Trac, Hy
AU - Van Engelen, Alexander
AU - Vavagiakis, Eve M.
N1 - Publisher Copyright:
© 2024 The Author(s)
PY - 2024/8/1
Y1 - 2024/8/1
N2 - Patchy reionization generates kinematic Sunyaev–Zel’dovich (kSZ) anisotropies in the cosmic microwave background (CMB). Large-scale velocity perturbations along the line of sight modulate the small-scale kSZ power spectrum, leading to a trispectrum (or four-point function) in the CMB that depends on the physics of reionization. We investigate the challenges in detecting this trispectrum and use tools developed for CMB lensing, such as realization-dependent bias subtraction and cross-correlation based estimators, to counter uncertainties in the instrumental noise and assumed CMB power spectrum. We also find that both lensing and extragalactic foregrounds can impart larger trispectrum contributions than the reionization kSZ signal. We present a range of mitigation methods for both of these sources of contamination, validated on microwave-sky simulations. We use ACT DR6 and Planck data to calculate an upper limit on the reionization kSZ trispectrum from a measurement dominated by foregrounds. The upper limit is about 50 times the signal predicted from recent simulations.
AB - Patchy reionization generates kinematic Sunyaev–Zel’dovich (kSZ) anisotropies in the cosmic microwave background (CMB). Large-scale velocity perturbations along the line of sight modulate the small-scale kSZ power spectrum, leading to a trispectrum (or four-point function) in the CMB that depends on the physics of reionization. We investigate the challenges in detecting this trispectrum and use tools developed for CMB lensing, such as realization-dependent bias subtraction and cross-correlation based estimators, to counter uncertainties in the instrumental noise and assumed CMB power spectrum. We also find that both lensing and extragalactic foregrounds can impart larger trispectrum contributions than the reionization kSZ signal. We present a range of mitigation methods for both of these sources of contamination, validated on microwave-sky simulations. We use ACT DR6 and Planck data to calculate an upper limit on the reionization kSZ trispectrum from a measurement dominated by foregrounds. The upper limit is about 50 times the signal predicted from recent simulations.
KW - cosmic background radiation
KW - cosmology: observations
KW - dark ages, reionization, first stars
KW - large-scale structure of Universe
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U2 - 10.1093/mnras/stae1746
DO - 10.1093/mnras/stae1746
M3 - Article
AN - SCOPUS:85200215875
SN - 0035-8711
VL - 532
SP - 4247
EP - 4260
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -