2017/10/31 by Hồ Nam Nguyễn, Ho Nam Nguyen, Neelima Sehgal +2 · 1 citation
Physics and Astronomy · #Anisotropy #Astronomy #Astrophysics #Cold dark matter #Cosmic microwave background #Cosmology #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark energy #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitational lens #Matter power spectrum #Optics #Physics #Redshift #Spectral density #Statistics #Weak gravitational lensing #astro-ph.CO #hep-ph
paper · pdf · doi:10.1103/physrevd.99.023502
published as Phys. Rev. D 99, 023502 (2019) · 14 pages, 10 figures; version matches that accepted by PRD; expanded systematics section
openalex created_date 2017/10/20 · arxiv created 2018/11/08 · openalex publication_date 2019/01/07 · arxiv updated 2019/01/16 · openalex updated_date 2026/08/05
We present a method to measure the small-scale matter power spectrum using high-resolution measurements of the gravitational lensing of the cosmic microwave background (CMB). To determine whether small-scale structure today is suppressed on scales below 10 kiloparsecs (corresponding to M\ensuremath≤109 M_\ensuremath\bigodot), one needs to probe CMB-lensing modes out to L\ensuremath≈35,000, requiring a CMB experiment with about 20 arcsecond resolution or better. We show that a CMB survey covering 4,000 square degrees of sky, with an instrumental sensitivity of 0.5 \ensuremathμK\text\ensuremath-arcmin at 18 arcsecond resolution, could distinguish between cold dark matter and an alternative, such as 1 keV warm dark matter or 10^\ensuremath-22 eV fuzzy dark matter with about 4\ensuremathσ significance. A survey of the same resolution with 0.1 \ensuremathμK\text\ensuremath-arcmin noise could distinguish between cold dark matter and these alternatives at better than 20\ensuremathσ significance; such high-significance measurements may also allow one to distinguish between a suppression of power due to either baryonic effects or the particle nature of dark matter, since each impacts the shape of the lensing power spectrum differently. CMB temperature maps yield higher signal-to-noise than polarization maps in this small-scale regime; thus, systematic effects, such as from extragalactic astrophysical foregrounds, need to be carefully considered. However, these systematic concerns can likely be mitigated with known techniques. Next-generation CMB lensing may thus provide a robust and powerful method of measuring the small-scale matter power spectrum.