The CMB power spectrum out to l=1400 measured by the VSA

TL;DR

This paper presents measurements of the cosmic microwave background power spectrum up to l=1400 using the VSA, resolving multiple acoustic peaks and providing data crucial for cosmological parameter estimation.

Contribution

The study extends the CMB power spectrum measurement to higher multipoles with the VSA, resolving multiple peaks and improving constraints on cosmological models.

Findings

Resolved the first three acoustic peaks in the CMB power spectrum.

Observed the expected decline in power at high l.

Started to constrain the position and height of the fourth peak.

Abstract

We have observed the cosmic microwave background (CMB) in three regions of sky using the Very Small Array (VSA) in an extended configuration with antennas of beamwidth 2 degrees at 34 GHz. Combined with data from previous VSA observations using a more compact array with larger beamwidth, we measure the power spectrum of the primordial CMB anisotropies between angular multipoles l = 160 - 1400. Such measurements at high l are vital for breaking degeneracies in parameter estimation from the CMB power spectrum and other cosmological data. The power spectrum clearly resolves the first three acoustic peaks, shows the expected fall off in power at high l and starts to constrain the position and height of a fourth peak.