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MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on angular scales of 10 arcminutes to 5 degrees

S. Hanany, P. Ade, A. Balbi, J. Bock, J. Borrill, A. Boscaleri, P. de Bernardis, P. G. Ferreira, V. V. Hristov, A. H. Jaffe, A. E. Lange, A. T. Lee, P. D. Mauskopf, C. B. Netterfield, S. Oh, E. Pascale, B. Rabii, P. L. Richards, G. F. Smoot, R. Stompor, C. D. Winant, J. H. P. Wu

TL;DR

MAXIMA-1 delivers a high-fidelity map and angular power spectrum of CMB anisotropy over $36 \leq \ell \leq 785$ from a balloon-borne platform, using three 150 GHz and one 240 GHz photometer to achieve ~10 arcmin resolution over ~100 deg^2. The analysis employs maximum-likelihood mapmaking, phase-synchronous signal mitigation, and a MADCAP-based power-spectrum estimator, with careful calibration via the CMB dipole and Jupiter beams and thorough tests for systematics. The resulting spectrum exhibits a pronounced acoustic peak near $\ell \approx 220$, consistent with inflationary adiabatic ΛCDM cosmologies and in agreement with BOOMERANG after cross-calibration. Foregrounds are shown to be subdominant, and extensive robustness checks support the reliability of the measurements, underscoring the feasibility and value of balloon-borne CMB observations for cosmology.

Abstract

We present a map and an angular power spectrum of the anisotropy of the cosmic microwave background (CMB) from the first flight of MAXIMA. MAXIMA is a balloon-borne experiment with an array of 16 bolometric photometers operated at 100 mK. MAXIMA observed a 124 square degrees region of the sky with 10 arcminute resolution at frequencies of 150, 240 and 410 GHz. The data were calibrated using in-flight measurements of the CMB dipole anisotropy. A map of the CMB anisotropy was produced from three 150 and one 240 GHz photometer without need for foreground subtractions. Analysis of this CMB map yields a power spectrum for the CMB anisotropy over the range 36 < l < 785. The spectrum shows a peak with an amplitude of 78 +/- 6 micro-Kelvin at l ~ 220 and an amplitude varying between ~40 micro-Kelvin and ~50 micro-Kelvin for 400 < l < 785.

MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on angular scales of 10 arcminutes to 5 degrees

TL;DR

MAXIMA-1 delivers a high-fidelity map and angular power spectrum of CMB anisotropy over from a balloon-borne platform, using three 150 GHz and one 240 GHz photometer to achieve ~10 arcmin resolution over ~100 deg^2. The analysis employs maximum-likelihood mapmaking, phase-synchronous signal mitigation, and a MADCAP-based power-spectrum estimator, with careful calibration via the CMB dipole and Jupiter beams and thorough tests for systematics. The resulting spectrum exhibits a pronounced acoustic peak near , consistent with inflationary adiabatic ΛCDM cosmologies and in agreement with BOOMERANG after cross-calibration. Foregrounds are shown to be subdominant, and extensive robustness checks support the reliability of the measurements, underscoring the feasibility and value of balloon-borne CMB observations for cosmology.

Abstract

We present a map and an angular power spectrum of the anisotropy of the cosmic microwave background (CMB) from the first flight of MAXIMA. MAXIMA is a balloon-borne experiment with an array of 16 bolometric photometers operated at 100 mK. MAXIMA observed a 124 square degrees region of the sky with 10 arcminute resolution at frequencies of 150, 240 and 410 GHz. The data were calibrated using in-flight measurements of the CMB dipole anisotropy. A map of the CMB anisotropy was produced from three 150 and one 240 GHz photometer without need for foreground subtractions. Analysis of this CMB map yields a power spectrum for the CMB anisotropy over the range 36 < l < 785. The spectrum shows a peak with an amplitude of 78 +/- 6 micro-Kelvin at l ~ 220 and an amplitude varying between ~40 micro-Kelvin and ~50 micro-Kelvin for 400 < l < 785.

Paper Structure

This paper contains 8 sections, 2 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Instrumentation
  3. Observations
  4. Pointing Reconstruction and Calibration
  5. Map and Angular Power Spectrum
  6. Foregrounds
  7. Tests for Systematic Errors
  8. Discussion

Figures (2)

  • Figure 1: A Wiener filtered map of the CMB anisotropy with 10 resolution from MAXIMA-1. The map is made using data from three 150 GHz and one 240 GHz photometer and contains 15,000 5$\times$5 pixels. We used the angular power spectrum shown in the top panel of Figure \ref{['fig:power_spectrum']} as the prior for the Wiener filter. Pixel boundaries have been smoothed using interpolation.
  • Figure 2: Top panel: Angular power spectrum of the CMB anisotropy from the MAXIMA-1 map shown, in Figure \ref{['fig:maxima1_map']} (filled circles). The error bars are 68% confidence intervals calculated using the offset log-normal likelihood functions of bjk00. The solid (dashed) curve is the best fit ($\Lambda$CDM) inflationary adiabatic cosmology to the MAXIMA-1 and COBE/DMR data. The models have ($\Omega_{b}$, $\Omega_{cdm}$, $\Omega_{\Lambda}$, $n$, $h$) = (0.1, 0.6, 0.3, 1.08, 0.53), and (0.05, 0.35, 0.6,1 ,0.65), respectively balbi_00. The open circles are the estimated power spectrum of the difference between two independent maps, each produced by a weighted-average of the maps from a pair of photometers. Bottom panel: A comparison of the MAXIMA power spectrum with that of the recently reported BOOMERANG experiment debernardis00. Consistency between the power spectra has been achieved by scaling the MAXIMA-1 (BOOMERANG) power spectrum down (up) by a factor equal to its 8% (20%) $1\sigma$ calibration uncertainty. These data show a suggestion of a peak at $\ell \sim 525$.