arXiv subjects

J. Childers

Publications and source records attributed to J. Childers.

2 recordsLinked to original sources

arXiv2006

Angular power spectrum of the FastICA CMB component from BEAST data

We present the angular power spectrum of the CMB component extracted with FastICA from the Background Emission Anisotropy Scanning Telescope (BEAST) data. BEAST is a 2.2 meter off-axis telescope with a focal plane comprising 8 elements at Q (38-45 GHz) and Ka (26-36 GHz) bands. It operates from the UC White Mountain Research Station at an altitude of 3800 meters. The BEAST CMB angular power spectrum has been already calculated by O'Dwyer et.al. using only the Q band data. With two input channels FastICA returns two possible independent components. We found that one of these two has an unphysical spectral behaviour while the other is a reasonable CMB component. After a detailed calibration procedure based on Monte-Carlo (MC) simulations we extracted the angular power spectrum for the identified CMB component and found a very good agreement with the already published BEAST CMB angular power spectrum and with the WMAP data.

astro-ph↗

arXiv1999

A Spin Modulated Telescope to Make Two Dimensional CMB Maps

We describe the HEMT Advanced Cosmic Microwave Explorer (HACME), a balloon borne experiment designed to measure sub-degree scale Cosmic Microwave Background anisotropy over hundreds of square degrees, using a unique two dimensional scanning strategy. A spinning flat mirror that is canted relative to its spin axis modulates the direction of beam response in a nearly elliptical path on the sky. The experiment was successfully flown in February of 1996, achieving near laboratory performance for several hours at float altitude. A map free of instrumental systematic effects is produced for a 3.5 hour observation of 630 square degrees, resulting in a flat band power upper limit of (l(l+1)C_l/2 pi)^0.5 < 77 microK at l = 38 (95% confidence). The experiment design, flight operations and data, including atmospheric effects and noise performance, are discussed.

astro-ph↗