Angular Power Spectra of the Millimeter Wavelength Background Light from Dusty Star-forming Galaxies with the South Pole Telescope

TL;DR

This study measures the angular power spectrum of millimeter-wavelength background light from dusty star-forming galaxies using South Pole Telescope data, detecting both Poisson and clustered components and constraining galaxy properties and redshift distribution.

Contribution

First detection of clustered power from dusty star-forming galaxies at millimeter wavelengths using SPT data, with implications for galaxy dust properties and redshift distribution.

Findings

Detected Poisson and clustered power components in SPT data.

Estimated dust emissivity index beta ~ 2.

Constrained the redshift distribution of background light.

Abstract

We use data from the first 100 square-degree field observed by the South Pole Telescope (SPT) in 2008 to measure the angular power spectrum of temperature anisotropies contributed by the background of dusty star-forming galaxies (DSFGs) at millimeter wavelengths. From the auto and cross-correlation of 150 and 220 GHz SPT maps, we significantly detect both Poisson distributed and, for the first time at millimeter wavelengths, clustered components of power from a background of DSFGs. The spectral indices between 150 and 220 GHz of the Poisson and clustered components are found to be 3.86 +- 0.23 and 3.8 +- 1.3 respectively, implying a steep scaling of the dust emissivity index beta ~ 2. The Poisson and clustered power detected in SPT, BLAST (at 600, 860, and 1200 GHz), and Spitzer (1900 GHz) data can be understood in the context of a simple model in which all galaxies have the same graybody spectrum with dust emissivity index of beta = 2 and dust temperature T_d = 34 K. In this model, half of the 150 GHz background light comes from redshifts greater than 3.2. We also use the SPT data to place an upper limit on the amplitude of the kinetic Sunyaev-Zel'dovich power spectrum at l = 3000 of 13 uK^2 at 95% confidence.