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Simulating Interferometers for the CMB Sky. Eric Lopez UC Berkeley With Peter Timbie and the Observational Cosmology Group, UW Madison. Outline of Talk. CMB 101 What is a Power Spectrum? Polarization and B-modes The EPIC mission The Basics of Interferometers My Simulation Method
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Simulating Interferometers for the CMB Sky Eric Lopez UC Berkeley With Peter Timbie and the Observational Cosmology Group, UW Madison
Outline of Talk • CMB 101 • What is a Power Spectrum? • Polarization and B-modes • The EPIC mission • The Basics of Interferometers • My Simulation Method • Spiral Interferometer Arrays • The Results
The Cosmic Microwave Background • Emitted during recombination 400,000 years after Big Bang. • Temperature was 3,000 K when emitted, and has since cooled to 2.73 K • Primary Temperature Anisotropies occur at about 20 μK
Polarization and the B-Modes • Light from the CMB is partially polarized • Polarization map is split into 2 components: E-Modes (the curl-less part) and B-Modes (the divergence-less part) • B-Modes are believed to be caused by gravitational waves from inflation • E-modes occur at about 1µK, while B-Modes occur at about 100nK
The Einstein Polarization Interferometer for Cosmology (EPIC)
Basics of Interferometers • Each unique baseline corresponds to a particular angular scale on the sky • Longer baselines → smaller angular scales→ larger multipole moments • Each baseline defines a radius in the UV plane • Want as many unique baselines as possible • Max of N(N-1)/2 Baselines for N horns
The Amazing Spiral Array 30.2 cm 64 Horns , Each 2.5 cm wide, with secondary mirror 7.5 cm wide
The Results • First peak clearly visible • Minimal power loss due to beam • Spiral array reproduces recognizable power spectrum even at 10% bandwidth Made using spiral array configuration on a 20° by 20° map, with a 10% bandwidth, and a 15° beam.
The End Special Thanks to: Peter Timbie SiddarthMalu The Observational Cosmology Group, UW Madison JPL, NASA, and CALTECH for use of HEALPIX and CMBFAST Images provided by: Peter Timbie http://en.wikipedia.org http://antwrp.gsfc.nasa.gov/apod/astropix.html http://lambda.gsfc.nasa.gov/cmbfast/ MMVII