Getting around cosmic variance

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.56.4511· OSTI ID:632688

Kamionkowski, M ^[1]; Loeb, A ^[2]

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1. Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027 (United States)
2. Astronomy Department, Harvard University, Cambridge, Massachusetts 02138 (United States)

Cosmic microwave background (CMB) anisotropies probe the primordial density field at the edge of the observable Universe. There is a limiting precision ({open_quotes}cosmic variance{close_quotes}) with which anisotropies can determine the amplitude of primordial mass fluctuations. This arises because the surface of last scatter (SLS) probes only a finite two-dimensional slice of the Universe. Probing other SLS{close_quote}s observed from different locations in the Universe would reduce the cosmic variance. In particular, the polarization of CMB photons scattered by the electron gas in a cluster of galaxies provides a measurement of the CMB quadrupole moment seen by the cluster. Therefore, CMB polarization measurements toward many clusters would probe the anisotropy on a variety of SLS{close_quote}s within the observable Universe, and hence reduce the cosmic-variance uncertainty. {copyright} {ital 1997} {ital The American Physical Society}

• Research Organization: Columbia University
• DOE Contract Number: FG02-92ER40699
• OSTI ID: 632688
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 8 Vol. 56; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AMPLITUDES
ANISOTROPY
BACKGROUND RADIATION
COSMIC RADIATION
DENSITY
ELECTRON GAS
FLUCTUATIONS
GALAXY CLUSTERS
MASS
MICROWAVE RADIATION
PHOTON-ELECTRON INTERACTIONS
PHOTONS
POLARIZATION
QUADRUPOLES
UNIVERSE