Comparison of the crossed and the Gregorian Mizuguchi-Dragone for wide-field millimeter-wave astronomy

Tran, Hung V.; Lee, Adrian V.; Hanany, Shaul; Milligan, Michael; Renbarger, T.

doi:10.1364/ao.47.000103

Cited by 44 publications

(38 citation statements)

References 13 publications

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“…The tele- scope is installed at the James Ax Observatory in the Atacama desert in northern Chile. The HTT is an off-axis Gregorian telescope satisfying the MizuguchiDragone condition (Mizugutch et al (1976); Dragone (1978); Tran et al (2008)), which can provide low cross-polarization and astigmatism over the diffractionlimited field of view. The telescope optics, cryogenic receiver, and electronics are installed on a mount.…”

Section: Instrument and Observationmentioning

confidence: 99%

A Measurement of the Cosmic Microwave Background B-Mode Polarization With Polarbear

Akiba¹,

Anthony²,

Arnold³

et al. 2015

Publications of The Korean Astronomical Society

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Polarbear is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic inflation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1,274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.Key words: cosmic background radiation -cosmology: observations -large-scale structure of the universe 625 626 CHINONE ET AL.

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Section: Instrument and Observationmentioning

confidence: 99%

A Measurement of the Cosmic Microwave Background B-Mode Polarization With Polarbear

Akiba¹,

Anthony²,

Arnold³

et al. 2015

Publications of The Korean Astronomical Society

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“…We find that CATR designs (Compact Test Range, crossed Dragone configuration - Tran et al, 2008), which have proven suitable elsewhere, are not quite feasible given our very short focal length and wide fieldof-view. We are therefore currently studying the optimization of an off-axis Gregorian telescope.…”

Section: Optical Combinermentioning

confidence: 95%

QUBIC: the Q&U Bolometric Interferometer for Cosmology

et al. 2012

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Context. One of the major challenges of modern cosmology is the detection of B-mode polarization anisotropies in the Cosmic Microwave Background. These originate from tensor fluctuations of the metric produced during the inflationary phase. Their detection would therefore constitute a major step towards understanding the primordial Universe. The expected level of these anisotropies is however so small that it requires a new generation of instruments with high sensitivity and extremely good control of systematic effects. Aims. We propose the QUBIC instrument based on the novel concept of bolometric interferometry, bringing together the sensitivity advantages of bolometric detectors with the systematics effects advantages of interferometry. Methods. The instrument will directly observe the sky through an array of entry horns whose signals will be combined together using an optical combiner. The whole set-up is located inside a cryostat. Polarization modulation will be achieved using a rotating half-wave plate and the images of the interference fringes will be formed on two focal planes (separated by a polarizing grid) tiled with bolometers. Results. We show that QUBIC can be considered as a synthetic imager, exactly similar to a usual imager but with a synthesized beam formed by the array of entry horns. Scanning the sky provides an additional modulation of the signal and improve the sky coverage shape. The usual techniques of map-making and power spectrum estimation can then be applied. We show that the sensitivity of such an instrument is comparable with that of an imager with the same number of horns. We anticipate a low level of beam-related systematics thanks to the fact that the synthesized beam is determined by the location of the primary horns. Other systematics should be under good control thanks to an autocalibration technique, specific to our concept, that will permit the accurate determination of most of the systematics parameters.

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“…It is composed of a cryogenic receiver mounted on the Huan Tran telescope (HTT; Tran et al 2008). HTT is a two mirror off-axis Gregorian telescope designed to ensure low cross polarization.…”

Section: Polarbear Experiments and Its Observationsmentioning

confidence: 99%

Making maps of cosmic microwave background polarization for B-mode studies: the POLARBEAR example

Poletti

Fabbian

Jeune

et al. 2017

A&A

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Analysis of cosmic microwave background (CMB) datasets typically requires some filtering of the raw time-ordered data. For instance, in the context of ground-based observations, filtering is frequently used to minimize the impact of low frequency noise, atmospheric contributions and/or scan synchronous signals on the resulting maps. In this work we have explicitly constructed a general filtering operator, which can unambiguously remove any set of unwanted modes in the data, and then amend the map-making procedure in order to incorporate and correct for it. We show that such an approach is mathematically equivalent to the solution of a problem in which the sky signal and unwanted modes are estimated simultaneously and the latter are marginalized over. We investigated the conditions under which this amended map-making procedure can render an unbiased estimate of the sky signal in realistic circumstances. We then discuss the potential implications of these observations on the choice of map-making and power spectrum estimation approaches in the context of B-mode polarization studies. Specifically, we have studied the effects of time-domain filtering on the noise correlation structure in the map domain, as well as impact it may have on the performance of the popular pseudospectrum estimators. We conclude that although maps produced by the proposed estimators arguably provide the most faithful representation of the sky possible given the data, they may not straightforwardly lead to the best constraints on the power spectra of the underlying sky signal and special care may need to be taken to ensure this is the case. By contrast, simplified map-makers which do not explicitly correct for time-domain filtering, but leave it to subsequent steps in the data analysis, may perform equally well and be easier and faster to implement. We focused on polarization-sensitive measurements targeting the B-mode component of the CMB signal and apply the proposed methods to realistic simulations based on characteristics of an actual CMB polarization experiment, POLARBEAR. Our analysis and conclusions are however more generally applicable.

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Comparison of the crossed and the Gregorian Mizuguchi-Dragone for wide-field millimeter-wave astronomy

Cited by 44 publications

References 13 publications

A Measurement of the Cosmic Microwave Background B-Mode Polarization With Polarbear

A Measurement of the Cosmic Microwave Background B-Mode Polarization With Polarbear

QUBIC: the Q&U Bolometric Interferometer for Cosmology

Making maps of cosmic microwave background polarization for B-mode studies: the POLARBEAR example

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