Amber D. Miller

A Measurement of the Angular Power Spectrum of the Microwave Background Made from the High Chilean Andes

We report on a measurement of the angular spectrum of the anisotropy of the microwave sky at 30 and 40 GHz between and . The data, covering roughly 600 deg 2 , support a rise in the angular spectrum l 5 50 l 5 200 to a maximum with mK at . We also give a upper limit of m Ka t at d T …85 l 5 200 2 jd T ! 122 l 5 432 l l 144 GHz. These results come from the first campaign of the Mobile Anisotropy Telescope on Cerro Toco, Chile. To assist in assessing the site, we present plots of the fluctuations in atmospheric emission at 30 and 144 GHz. Subject headings: atmospheric effects — cosmic microwave background — cosmology: observations

Mapping the Cosmic Microwave Background Anisotropy:Combined Analysis of QMAP Flights

We present results from the QMAP balloon experiment, which maps the Cosmic Microwave Background (CMB) and probes its angular power spectrum on degree scales. In two separate flights, data were taken in six channels at two frequency bands between 26 to 46 GHz. We describe our method for mapmaking (removal of 1/f-noise and scan-synchronous offsets) and power spectrum estimation, as well as the results of a joint analysis of the data from both flights. This produces a 527 square degree map of the CMB around the North Celestial Pole, allowing a wide variety of systematic cross-checks. The frequency dependence of the fluctuations is consistent with CMB and inconsistent with Galactic foreground emission. The anisotropy is measured in three multipole bands from l~40 to l~200, and the angular power spectrum shows a distinct rise which is consistent with the Saskatoon results.We present results from the QMAP balloon experiment, which maps the cosmic microwave background (CMB) and probes its angular power spectrum on degree scales. In two separate flights, data were taken in six channels at two frequency bands between 26 and 46 GHz. We describe our method for mapmaking (removal of 1/f-noise and scan-synchronous offsets) and power spectrum estimation as well as the results of a joint analysis of the data from both flights. This produces a 527 deg2 map of the CMB around the north celestial pole, allowing a wide variety of systematic cross-checks. The frequency dependence of the fluctuations is consistent with CMB and inconsistent with Galactic foreground emission. The anisotropy is measured in three multipole bands from l~40 to l~200, and the angular power spectrum shows a distinct rise that is consistent with the Saskatoon results.

A Galaxy-weighted Measure of the Relative Peculiar-Velocity Dispersion

The relative pair dispersion of galaxies has for the past decade been the standard measure of the thermal energy of fluctuations in the observed galaxy distribution. This statistic is known to be unstable, since it is a pair-weighted measure that is very sensitive to rare, rich clusters of galaxies. As a more stable alternative, we present here a single-particle-weighted statistic ?1, which can be considered as an estimate of the one-dimensional rms peculiar-velocity dispersion of galaxies relative to their neighbors and which can be interpreted by means of a filtered version of the cosmic energy equation. We calculate this statistic for the all-sky survey of IRAS galaxies, finding ?1 = 95 ? 16 km s-1. The UGC catalog yields a higher value, ?1 = 130 ? 15 km s-1. We calibrate our procedure by means of mock catalogs constructed from N-body simulations and find that our method is stable and has modest biases which can easily be corrected. We use the measured values of ?1 in a filtered Layzer-Irvine equation to obtain an estimate of

The QMAP and MAT/TOCO Experiments for Measuring Anisotropy in the Cosmic Microwave Background

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A measurement of the angular power spectrum of the cmb from l = 100 to 400

--> ? ?/b -->2. We find that

Mapping the CMB I: the first flight of the QMAP experiment

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A Measurement of the Angular Power Spectrum of the Cosmic Microwave Background from [CLC][ITAL]l[/ITAL][/CLC] = 100 to 400

--> ? 0.14?0.05 for both the IRAS and UGC catalogs, which is slightly lower than other recent determinations but is consistent with a trend of an effective ? that increases gradually with scale.

A Measurement of the Angular Power Spectrum of the Cosmic Microwave Background from l = 100 to 400

We describe two related experiments that measured the anisotropy in the cosmic microwave background (CMB). QMAP was a balloon-borne telescope that flew twice in 1996, collecting data on degree angular scales with an array of six high electron mobility transistor-based amplifiers (HEMTs). QMAP used an interlocking scan strategy to directly produce high signal-to-noise ratio CMB maps over a limited region of sky. The QMAP gondola was then refitted for ground-based work as the MAT/TOCO experiment. Observations were made from 5200 m on Cerro Toco in Northern Chile in 1997 and 1998 using time domain beam synthesis. MAT/TOCO measured the rise and fall of the CMB angular spectrum, thereby localizing the position of the first peak to lpeak = 216 ± 14. In addition to describing the instruments, we discuss the data selection methods, check for systematic errors, and compare the MAT/TOCO results to those from recent experiments. The previously reported data are updated to account for a small calibration shift and corrected to account for a small contribution from known sources of foreground emission. The resulting amplitude of the first peak for 160 < l < 240 is δTpeak = 80.9 ± 3.4 ± 5.1 μK, where the first uncertainty is statistical and the second is from calibration.

Mapping the Cosmic Microwave Background Anisotropy:The Second Flight of the QMAP Experiment

We report on a measurement of the angular spectrum of the cosmic microwave background (CMB) between l ≈ 100 and l ≈ 400 made at 144 GHz from Cerro Toco in the Chilean altiplano. When the new data are combined with previous data at 30 and 40 GHz taken with the same instrument observing the same section of sky, we find (1) a rise in the angular spectrum to a maximum with δTl ≈ 85 μK at l ≈ 200 and a fall at l > 300, thereby localizing the peak near l ≈ 200, and (2) that the anisotropy at l ≈ 200 has the spectrum of the CMB.

Galactic Contamination in the QMAP Experiment

We report on the first flight of the balloon-borne QMAP experiment. The experiment is designed to make a map of the cosmic microwave background anisotropy on angular scales from 0.7 to several degrees. Using the map we determine the angular power spectrum of the anisotropy in multipole bands from l~40 to l~140. The results are consistent with the Saskatoon (SK) measurements. The frequency spectral index (measured at low l) is consistent with that of CMB and inconsistent with either Galactic synchrotron or free-free emission. The instrument, measurement, analysis of the angular power spectrum, and possible systematic errors are discussed.We report on the first flight of the balloon-borne QMAP experiment. The experiment is designed to make a map of the cosmic microwave background (CMB) anisotropy on angular scales from 0fdg70 to several degrees. Using the map, we determine the angular power spectrum of the anisotropy in multipole bands from l~40 to l~140. The results are consistent with the SK (from Saskatoon, Saskatchewan, Canada) measurements. The frequency spectral index (measured at low l) is consistent with that of CMB and inconsistent with either Galactic synchrotron or free-free emission. The instrument, measurement, analysis of the angular power spectrum, and possible systematic errors are discussed.