arXiv subjects

M. Shimon

Publications and source records attributed to M. Shimon.

At least 19 recordsLinked to original sources

arXiv2018

A Measurement of the Cosmic Microwave Background B-Mode Polarization Power Spectrum at Sub-Degree Scales with POLARBEAR

We report a measurement of the B-mode polarization power spectrum in the cosmic microwave background (CMB) using the POLARBEAR experiment in Chile. The faint B-mode polarization signature carries information about the Universe's entire history of gravitational structure formation, and the cosmic inflation that may have occurred in the very early Universe. Our measurement covers the angular multipole range 500 < l < 2100 and is based on observations of an effective sky area of 25 square degrees with 3.5 arcmin resolution at 150 GHz. On these angular scales, gravitational lensing of the CMB by intervening structure in the Universe is expected to be the dominant source of B-mode polarization. Including both systematic and statistical uncertainties, the hypothesis of no B-mode polarization power from gravitational lensing is rejected at 97.1% confidence. The band powers are consistent with the standard cosmological model. Fitting a single lensing amplitude parameter A_BB to the measured band powers, A_BB = 1.12 +/- 0.61 (stat) +0.04/-0.12 (sys) +/- 0.07 (multi), where A_BB = 1 is the fiducial WMAP-9 LCDM value. In this expression, "stat" refers to the statistical uncertainty, "sys" to the systematic uncertainty associated with possible biases from the instrument and astrophysical foregrounds, and "multi" to the calibration uncertainties that have a multiplicative effect on the measured amplitude A_BB.

astro-ph.CO↗

arXiv2014

Measurement of the Cosmic Microwave Background Polarization Lensing Power Spectrum with the POLARBEAR experiment

Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial Cosmic Microwave Background (CMB) and thereby induces new, small-scale $B$-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity $E$- and $B$-mode polarization mapped over $\sim30$ square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing $B$-modes is found at 4.2$σ$ (stat.+sys.) significance. The amplitude of matter fluctuations is measured with a precision of $27\%$, and is found to be consistent with the Lambda Cold Dark Matter ($Λ$CDM) cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing $B$-mode signal in searches for primordial gravitational waves.

astro-ph.CO↗

arXiv2014

Evidence for Gravitational Lensing of the Cosmic Microwave Background Polarization from Cross-correlation with the Cosmic Infrared Background

We reconstruct the gravitational lensing convergence signal from Cosmic Microwave Background (CMB) polarization data taken by the POLARBEAR experiment and cross-correlate it with Cosmic Infrared Background (CIB) maps from the Herschel satellite. From the cross-spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0$σ$ and evidence for the presence of a lensing $B$-mode signal at a significance of 2.3$σ$. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null-tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.

astro-ph.CO↗

arXiv2013

Self-Calibration of BICEP1 Three-Year Data and Constraints on Astrophysical Polarization Rotation

Cosmic Microwave Background (CMB) polarimeters aspire to measure the faint $B$-mode signature predicted to arise from inflationary gravitational waves. They also have the potential to constrain cosmic birefringence which would produce non-zero expectation values for the CMB's $TB$ and $EB$ spectra. However, instrumental systematic effects can also cause these $TB$ and $EB$ correlations to be non-zero. In particular, an overall miscalibration of the polarization orientation of the detectors produces $TB$ and $EB$ spectra which are degenerate with isotropic cosmological birefringence, while also introducing a small but predictable bias on the $BB$ spectrum. The \bicep three-year spectra, which use our standard calibration of detector polarization angles from a dielectric sheet, are consistent with a polarization rotation of $α= -2.77^\circ \pm 0.86^\circ \text{(statistical)} \pm 1.3^\circ \text{(systematic)}$. We revise the estimate of systematic error on the polarization rotation angle from the two-year analysis by comparing multiple calibration methods. We investigate the polarization rotation for the \bicep 100 GHz and 150 GHz bands separately to investigate theoretical models that produce frequency-dependent cosmic birefringence. We find no evidence in the data supporting either these models or Faraday rotation of the CMB polarization by the Milky Way galaxy's magnetic field. If we assume that there is no cosmic birefringence, we can use the $TB$ and $EB$ spectra to calibrate detector polarization orientations, thus reducing bias of the cosmological $B$-mode spectrum from leaked $E$-modes due to possible polarization orientation miscalibration. After applying this "self-calibration" process, we find that the upper limit on the tensor-to-scalar ratio decreases slightly, from $r<0.70$ to $r<0.65$ at $95\%$ confidence.

astro-ph.IM↗

arXiv2012

The bolometric focal plane array of the Polarbear CMB experiment

The Polarbear Cosmic Microwave Background (CMB) polarization experiment is currently observing from the Atacama Desert in Northern Chile. It will characterize the expected B-mode polarization due to gravitational lensing of the CMB, and search for the possible B-mode signature of inflationary gravitational waves. Its 250 mK focal plane detector array consists of 1,274 polarization-sensitive antenna-coupled bolometers, each with an associated lithographed band-defining filter. Each detector's planar antenna structure is coupled to the telescope's optical system through a contacting dielectric lenslet, an architecture unique in current CMB experiments. We present the initial characterization of this focal plane.

astro-ph.IM↗

arXiv2012

The POLARBEAR Experiment

We present the design and characterization of the POLARBEAR experiment. POLARBEAR will measure the polarization of the cosmic microwave background (CMB) on angular scales ranging from the experiment's 3.5 arcminute beam size to several degrees. The experiment utilizes a unique focal plane of 1,274 antenna-coupled, polarization sensitive TES bolometers cooled to 250 milliKelvin. Employing this focal plane along with stringent control over systematic errors, POLARBEAR has the sensitivity to detect the expected small scale B-mode signal due to gravitational lensing and search for the large scale B-mode signal from inflationary gravitational waves. POLARBEAR was assembled for an engineering run in the Inyo Mountains of California in 2010 and was deployed in late 2011 to the Atacama Desert in Chile. An overview of the instrument is presented along with characterization results from observations in Chile.

astro-ph.IM↗

arXiv2012

Constraints on the Neutrino Mass from SZ Surveys

Statistical measures of galaxy clusters are sensitive to neutrino masses in the sub-eV range. We explore the possibility of using cluster number counts from the ongoing PLANCK/SZ and future cosmic-variance-limited surveys to constrain neutrino masses from CMB data alone. The precision with which the total neutrino mass can be determined from SZ number counts is limited mostly by uncertainties in the cluster mass function and intracluster gas evolution; these are explicitly accounted for in our analysis. We find that projected results from the PLANCK/SZ survey can be used to determine the total neutrino mass with a (1σ) uncertainty of 0.06 eV, assuming it is in the range 0.1-0.3 eV, and the survey detection limit is set at the 5σsignificance level. Our results constitute a significant improvement on the limits expected from PLANCK/CMB lensing measurements, 0.15 eV. Based on expected results from future cosmic-variance-limited (CVL) SZ survey we predict a 1σuncertainty of 0.04 eV, a level comparable to that expected when CMB lensing extraction is carried out with the same experiment. A few percent uncertainty in the mass function parameters could result in up to a factor \sim 2-3 degradation of our PLANCK and CVL forecasts. Our analysis shows that cluster number counts provide a viable complementary cosmological probe to CMB lensing constraints on the total neutrino mass.

astro-ph.CO↗

arXiv2011

Ultra High Energy Cosmology with POLARBEAR

Observations of the temperature anisotropy of the Cosmic Microwave Background (CMB) lend support to an inflationary origin of the universe, yet no direct evidence verifying inflation exists. Many current experiments are focussing on the CMB's polarization anisotropy, specifically its curl component (called "B-mode" polarization), which remains undetected. The inflationary paradigm predicts the existence of a primordial gravitational wave background that imprints a unique B-mode signature on the CMB's polarization at large angular scales. The CMB B-mode signal also encodes gravitational lensing information at smaller angular scales, bearing the imprint of cosmological large scale structures (LSS) which in turn may elucidate the properties of cosmological neutrinos. The quest for detection of these signals; each of which is orders of magnitude smaller than the CMB temperature anisotropy signal, has motivated the development of background-limited detectors with precise control of systematic effects. The POLARBEAR experiment is designed to perform a deep search for the signature of gravitational waves from inflation and to characterize lensing of the CMB by LSS. POLARBEAR is a 3.5 meter ground-based telescope with 3.8 arcminute angular resolution at 150 GHz. At the heart of the POLARBEAR receiver is an array featuring 1274 antenna-coupled superconducting transition edge sensor (TES) bolometers cooled to 0.25 Kelvin. POLARBEAR is designed to reach a tensor-to-scalar ratio of 0.025 after two years of observation -- more than an order of magnitude improvement over the current best results, which would test physics at energies near the GUT scale. POLARBEAR had an engineering run in the Inyo Mountains of Eastern California in 2010 and will begin observations in the Atacama Desert in Chile in 2011.

astro-ph.CO↗

arXiv2010

The new generation CMB B-mode polarization experiment: POLARBEAR

We describe the Cosmic Microwave Background (CMB) polarization experiment called Polarbear. This experiment will use the dedicated Huan Tran Telescope equipped with a powerful 1,200-bolometer array receiver to map the CMB polarization with unprecedented accuracy. We summarize the experiment, its goals, and current status.

astro-ph.IM↗

arXiv2010

Neutrino Mass Inference from SZ Surveys

The growth of structure in the universe begins at the time of radiation-matter equality, which corresponds to energy scales of $\sim 0.4 eV$. All tracers of dark matter evolution are expected to be sensitive to neutrino masses on this and smaller scales. Here we explore the possibility of using cluster number counts and power spectrum obtained from ongoing SZ surveys to constrain neutrino masses. Specifically, we forecast the capability of ongoing measurements with the PLANCK satellite and the ground-based SPT experiment, as well as measurements with the proposed EPIC satellite, to set interesting bounds on neutrino masses from their respective SZ surveys. We also consider an ACT-like CMB experiment that covers only a few hundred ${\rm deg^{2}}$ also to explore the tradeoff between the survey area and sensitivity and what effect this may have on inferred neutrino masses. We find that for such an experiment a shallow survey is preferable over a deep and low-noise scanning scheme. We also find that projected results from the PLANCK SZ survey can, in principle, be used to determine the total neutrino mass with a ($1σ$) uncertainty of $0.28 eV$, if the detection limit of a cluster is set at the $5σ$ significance level. This is twice as large as the limits expected from PLANCK CMB lensing measurements. The corresponding limits from the SPT and EPIC surveys are $\sim 0.44 eV$ and $\sim 0.12 eV$, respectively. Mapping an area of 200 deg$^{2}$, ACT measurements are predicted to attain a $1σ$ uncertainty of 0.61 eV; expanding the observed area to 4,000 deg$^{2}$ will decrease the uncertainty to 0.36 eV.

astro-ph.CO↗

arXiv2010

Using Big Bang Nucleosynthesis to Extend CMB Probes of Neutrino Physics

We present calculations showing that upcoming Cosmic Microwave Background (CMB) experiments will have the power to improve on current constraints on neutrino masses and provide new limits on neutrino degeneracy parameters. The latter could surpass those derived from Big Bang Nucleosynthesis (BBN) and the observationally-inferred primordial helium abundance. These conclusions derive from our Monte Carlo Markov Chain (MCMC) simulations which incorporate a full BBN nuclear reaction network. This provides a self-consistent treatment of the helium abundance, the baryon number, the three individual neutrino degeneracy parameters and other cosmological parameters. Our analysis focuses on the effects of gravitational lensing on CMB constraints on neutrino rest mass and degeneracy parameter. We find for the PLANCK experiment that total (summed) neutrino mass $M_ν > 0.29$ eV could be ruled out at $2σ$ or better. Likewise neutrino degeneracy parameters $ξ_{ν_{e}} > 0.11$ and $| ξ_{ν_{μ/τ}} | > 0.49$ could be detected or ruled out at $2σ$ confidence, or better. For POLARBEAR we find that the corresponding detectable values are $M_ν> 0.75 {\rm eV}$, $ξ_{ν_{e}} > 0.62$, and $| ξ_{ν_{μ/τ}}| > 1.1$, while for EPIC we obtain $M_ν> 0.20 {\rm eV}$, $ξ_{ν_{e}} > 0.045$, and $|ξ_{ν_{μ/τ}}| > 0.29$. Our forcast for EPIC demonstrates that CMB observations have the potential to set constraints on neutrino degeneracy parameters which are better than BBN-derived limits and an order of magnitude better than current WMAP-derived limits.

astro-ph.CO↗

arXiv2009

Redshift Dependence of the CMB Temperature from S-Z Measurements

We have determined the CMB temperature, $T(z)$, at redshifts in the range 0.023-0.546, from multi-frequency measurements of the S-Z effect towards 13 clusters. We extract the parameter $α$ in the redshift scaling $T(z)=T_{0}(1+z)^{1-α}$, which contrasts the prediction of the standard model ($α=0$) with that in non-adiabatic evolution conjectured in some alternative cosmological models. The statistical analysis is based on two main approaches: using ratios of the S-Z intensity change, $ΔI$, thus taking advantage of the weak dependence of the ratios on IC gas properties, and using directly the $ΔI$ measurements. In the former method dependence on the Thomson optical depth and gas temperature is only second order in these quantities. In the second method we marginalize over these quantities which appear to first order in the intensity change. The marginalization itself is done in two ways - by direct integrations, and by a Monte Carlo Markov Chain approach. Employing these different methods we obtain two sets of results that are consistent with $α=0$, in agreement with the prediction of the standard model.

astro-ph.CO↗

arXiv2009

CMB Polarization Systematics Due to Beam Asymmetry: Impact on Cosmological Birefringence

The standard cosmological model is assumed to respect parity symmetry. Under this assumption the cross-correlations of the CMB's temperature anisotropy and `gradient'-like polarization, with the `curl'-like polarization identically vanish over the full sky. However, extensions of the standard model which allow for light scalar field or axion coupling to the electromagnetic field, or coupling to the Riemann gravitational field-strength, as well as other modifications of field theories, may induce a rotation of the CMB polarization plane on cosmological scales and manifest itself as nonvanishing TB and EB cross-correlations. Recently, the degree of parity violation (reflected in polarization rotation) was constrained using data from BOOMERANG, WMAP and QUAD. Forecasts have been made for near-future experiments (e.g. PLANCK) to further constrain parity- and Lorentz-violating terms in the fundamental interactions of nature. Here we consider a real-world effect induced by a class of telescope beam systematics which can mimic the rotation of polarization plane or otherwise induce nonvanishing TB and EB correlations. In particular, adopting the viewpoint that the primary target of future experiments will be the inflationary B-mode signal, we assume the beam-systematics of the upcoming PLANCK and POLARBEAR experiments are optimized towards this goal, and explore the implications of the allowed levels of beam systematics on the resulting precision of polarization-rotation measurements.

astro-ph.CO↗

arXiv2009

CMB Beam Systematics: Impact on Lensing Parameter Estimation

The CMB's B-mode polarization provides a handle on several cosmological parameters most notably the tensor-to-scalar ratio, $r$, and is sensitive to parameters which govern the growth of large scale structure (LSS) and evolution of the gravitational potential. The primordial gravitational-wave- and secondary lensing-induced B-mode signals are very weak and therefore prone to various foregrounds and systematics. In this work we use Fisher-matrix-based estimations and apply, for the first time, Monte-Carlo Markov Chain (MCMC) simulations to determine the effect of beam systematics on the inferred cosmological parameters from five upcoming experiments: PLANCK, POLARBEAR, SPIDER, QUIET+CLOVER and CMBPOL. We consider beam systematics which couple the beam substructure to the gradient of temperature anisotropy and polarization (differential beamwidth, pointing and ellipticity) and beam systematics due to differential beam normalization (differential gain) and orientation (beam rotation) of the polarization-sensitive axes (the latter two effects are insensitive to the beam substructure). We determine allowable levels of beam systematics for given tolerances on the induced parameter errors and check for possible biases in the inferred parameters concomitant with potential increases in the statistical uncertainty. All our results are scaled to the 'worst case scenario'. In this case and for our tolerance levels, the beam rotation should not exceed the few-degree to sub-degree level, typical ellipticity is required to be 1% level, the differential gain allowed level is a few parts in $10^{3}$ to $10^{4}$, differential beamwidth upper limits are of the sub-percent level and differential pointing should not exceed the few- to sub-arcsec level.

astro-ph↗

arXiv2009

Power Spectra of CMB Polarization by Scattering in Clusters

Mapping CMB polarization is an essential ingredient of current cosmological research. Particularly challenging is the measurement of an extremely weak B-mode polarization that can potentially yield unique insight on inflation. Achieving this objective requires very precise measurements of the secondary polarization components on both large and small angular scales. Scattering of the CMB in galaxy clusters induces several polarization effects whose measurements can probe cluster properties. Perhaps more important are levels of the statistical polarization signals from the population of clusters. Power spectra of five of these polarization components are calculated and compared with the primary polarization spectra. These spectra peak at multipoles $\ell \geq 3000$, and attain levels that are unlikely to appreciably contaminate the primordial polarization signals.

astro-ph.CO↗

arXiv2006

Modeling Integrated Properties and the Polarization of the Sunyaev-Zeldovich Effect

Two little explored aspects of Compton scattering of the CMB in clusters are discussed: The statistical properties of the Sunyaev-Zeldovich (S-Z) effect in the context of a non-Gaussian density fluctuation field, and the polarization patterns in a hydrodynamcially-simulated cluster. We have calculated and compared the power spectrum and cluster number counts predicted within the framework of two density fields that yield different cluster mass functions at high redshifts. This is done for the usual Press & Schechter mass function, which is based on a Gaussian density fluctuation field, and for a mass function based on a chi^2-distributed density field. We quantify the significant differences in the respective integrated S-Z observables in these two models. S-Z polarization levels and patterns strongly depend on the non-uniform distributions of intracluster gas and on peculiar and internal velocities. We have therefore calculated the patterns of two polarization components that are produced when the CMB is doubly scattered in a simulated cluster. These are found to be very different than the patterns calculated based on spherical clusters with uniform structure and simplified gas distribution.

astro-ph↗

arXiv2006

CMB Polarization due to Scattering in Clusters

Scattering of the cosmic microwave background (CMB) in clusters of galaxies polarizes the radiation. We explore several polarization components which have their origin in the kinematic quadrupole moments induced by the motion of the scattering electrons, either directed or random. Polarization levels and patterns are determined in a cluster simulated by the hydrodynamical Enzo code. We find that polarization signals can be as high as $\sim 1 μ$K, a level that may be detectable by upcoming CMB experiments.

astro-ph↗

arXiv2005

The Sunyaev-Zeldovich Effect

This brief, general review the Sunyaev-Zeldovich (S-Z) effect includes a description of the calculation of the total intensity change and polarization components, a discussion of the basic properties of the S-Z power spectrum and cluster number counts, and a summary of the main observational results.

astro-ph↗