Showing papers by "Mark Halpern published in 2012"
University of Sussex1, Jet Propulsion Laboratory2, California Institute of Technology3, European Space Agency4, Ames Research Center5, University of Edinburgh6, Paris Diderot University7, Imperial College London8, University of Paris-Sud9, Aix-Marseille University10, Cornell University11, University of La Laguna12, Spanish National Research Council13, Complutense University of Madrid14, UK Astronomy Technology Centre15, University of Colorado Boulder16, University of California, Irvine17, Goddard Space Flight Center18, University of Nottingham19, Cardiff University20, University of Padua21, Institut d'Astrophysique de Paris22, University of Cambridge23, University of British Columbia24, European Space Research and Technology Centre25, University of Manchester26, University College London27, Rutherford Appleton Laboratory28, University of Lethbridge29, University of Oxford30, Commonwealth Scientific and Industrial Research Organisation31, University of Hertfordshire32, Harvard University33
TL;DR: The Herschel Multi-tiered Extragalactic Survey (HerMES) is a legacy program designed to map a set of nested fields totalling ∼380deg^2 as mentioned in this paper.
Abstract: The Herschel Multi-tiered Extragalactic Survey (HerMES) is a legacy programme designed to map a set of nested fields totalling ∼380 deg^2. Fields range in size from 0.01 to ∼20 deg^2, using the Herschel-Spectral and Photometric Imaging Receiver (SPIRE) (at 250, 350 and 500 μm) and the Herschel-Photodetector Array Camera and Spectrometer (PACS) (at 100 and 160 μm), with an additional wider component of 270 deg^2 with SPIRE alone. These bands cover the peak of the redshifted thermal spectral energy distribution from interstellar dust and thus capture the reprocessed optical and ultraviolet radiation from star formation that has been absorbed by dust, and are critical for forming a complete multiwavelength understanding of galaxy formation and evolution.
The survey will detect of the order of 100 000 galaxies at 5σ in some of the best-studied fields in the sky. Additionally, HerMES is closely coordinated with the PACS Evolutionary Probe survey. Making maximum use of the full spectrum of ancillary data, from radio to X-ray wavelengths, it is designed to facilitate redshift determination, rapidly identify unusual objects and understand the relationships between thermal emission from dust and other processes. Scientific questions HerMES will be used to answer include the total infrared emission of galaxies, the evolution of the luminosity function, the clustering properties of dusty galaxies and the properties of populations of galaxies which lie below the confusion limit through lensing and statistical techniques.
This paper defines the survey observations and data products, outlines the primary scientific goals of the HerMES team, and reviews some of the early results.
852 citations
University of Sussex1, Jet Propulsion Laboratory2, California Institute of Technology3, European Space Agency4, Ames Research Center5, University of Edinburgh6, Paris Diderot University7, Imperial College London8, Aix-Marseille University9, Cornell University10, Spanish National Research Council11, University of La Laguna12, Complutense University of Madrid13, UK Astronomy Technology Centre14, University of Colorado Boulder15, University of California, Irvine16, Goddard Space Flight Center17, University of Nottingham18, Cardiff University19, University of Padua20, Institut d'Astrophysique de Paris21, University of Cambridge22, University of British Columbia23, European Space Research and Technology Centre24, University of Manchester25, University College London26, University of Lethbridge27, Rutherford Appleton Laboratory28, University of Oxford29, Commonwealth Scientific and Industrial Research Organisation30, University of Hertfordshire31, Harvard University32
TL;DR: The Herschel Multi-tiered Extragalactic Survey (HerMES) is a legacy program designed to map a set of nested fields totalling ~380 deg^2 as mentioned in this paper.
Abstract: The Herschel Multi-tiered Extragalactic Survey, HerMES, is a legacy program designed to map a set of nested fields totalling ~380 deg^2. Fields range in size from 0.01 to ~20 deg^2, using Herschel-SPIRE (at 250, 350 and 500 \mu m), and Herschel-PACS (at 100 and 160 \mu m), with an additional wider component of 270 deg^2 with SPIRE alone. These bands cover the peak of the redshifted thermal spectral energy distribution from interstellar dust and thus capture the re-processed optical and ultra-violet radiation from star formation that has been absorbed by dust, and are critical for forming a complete multi-wavelength understanding of galaxy formation and evolution.
The survey will detect of order 100,000 galaxies at 5\sigma in some of the best studied fields in the sky. Additionally, HerMES is closely coordinated with the PACS Evolutionary Probe survey. Making maximum use of the full spectrum of ancillary data, from radio to X-ray wavelengths, it is designed to: facilitate redshift determination; rapidly identify unusual objects; and understand the relationships between thermal emission from dust and other processes. Scientific questions HerMES will be used to answer include: the total infrared emission of galaxies; the evolution of the luminosity function; the clustering properties of dusty galaxies; and the properties of populations of galaxies which lie below the confusion limit through lensing and statistical techniques.
This paper defines the survey observations and data products, outlines the primary scientific goals of the HerMES team, and reviews some of the early results.
707 citations
University of British Columbia1, Johns Hopkins University2, Max Planck Society3, Princeton University4, Institute for the Physics and Mathematics of the Universe5, University of Toronto6, Perimeter Institute for Theoretical Physics7, University of Minnesota8, Goddard Space Flight Center9, University of Chicago10, Brown University11, University of California, Los Angeles12
TL;DR: In this paper, the authors present cosmological parameter constraints based on the final nine-year WMAP data, in conjunction with additional cosmology data sets, and investigate a number of data combinations and show their LCDM parameter fits are consistent.
Abstract: We present cosmological parameter constraints based on the final nine-year WMAP data, in conjunction with additional cosmological data sets. The WMAP data alone, and in combination, continue to be remarkably well fit by a six-parameter LCDM model. When WMAP data are combined with measurements of the high-l CMB anisotropy, the BAO scale, and the Hubble constant, the densities, Omegabh2, Omegach2, and Omega_L, are each determined to a precision of ~1.5%. The amplitude of the primordial spectrum is measured to within 3%, and there is now evidence for a tilt in the primordial spectrum at the 5sigma level, confirming the first detection of tilt based on the five-year WMAP data. At the end of the WMAP mission, the nine-year data decrease the allowable volume of the six-dimensional LCDM parameter space by a factor of 68,000 relative to pre-WMAP measurements. We investigate a number of data combinations and show that their LCDM parameter fits are consistent. New limits on deviations from the six-parameter model are presented, for example: the fractional contribution of tensor modes is limited to r<0.13 (95% CL); the spatial curvature parameter is limited to -0.0027 (+0.0039/-0.0038); the summed mass of neutrinos is <0.44 eV (95% CL); and the number of relativistic species is found to be 3.84+/-0.40 when the full data are analyzed. The joint constraint on Neff and the primordial helium abundance agrees with the prediction of standard Big Bang nucleosynthesis. We compare recent PLANCK measurements of the Sunyaev-Zel'dovich effect with our seven-year measurements, and show their mutual agreement. Our analysis of the polarization pattern around temperature extrema is updated. This confirms a fundamental prediction of the standard cosmological model and provides a striking illustration of acoustic oscillations and adiabatic initial conditions in the early universe.
468 citations
Princeton University1, University of Oxford2, Carnegie Mellon University3, Sapienza University of Rome4, New Mexico State University5, University of Toronto6, University of Pittsburgh7, Lawrence Berkeley National Laboratory8, University of Utah9, University of Pennsylvania10, Pontifical Catholic University of Chile11, Harvard University12, National Institute of Standards and Technology13, Johns Hopkins University14, University of British Columbia15, University of Nottingham16, Academia Sinica Institute of Astronomy and Astrophysics17, University of California, Santa Barbara18, University of KwaZulu-Natal19, Pennsylvania State University20, New York University21, Goddard Space Flight Center22
TL;DR: Using high-resolution microwave sky maps made by the Atacama Cosmology Telescope, strong evidence for motions of galaxy clusters and groups via microwave background temperature distortions due to the kinematic Sunyaev-Zel'dovich effect is presented.
Abstract: Using high-resolution microwave sky maps made by the Atacama Cosmology Telescope, we for the first time present strong evidence for motions of galaxy clusters and groups via microwave background temperature distortions due to the kinematic Sunyaev-Zel'dovich effect. Galaxy clusters are identified by their constituent luminous galaxies observed by the Baryon Oscillation Spectroscopic Survey, part of the Sloan Digital Sky Survey III. We measure the mean pairwise momentum of clusters, with a probability of the signal being due to random errors of 0.002, and the signal is consistent with the growth of cosmic structure in the standard model of cosmology.
247 citations
Ames Research Center1, University of Edinburgh2, University of Leicester3, Spanish National Research Council4, Complutense University of Madrid5, California Institute of Technology6, University of Sussex7, Goddard Space Flight Center8, University of Nottingham9, Cardiff University10, University of Padua11, UK Astronomy Technology Centre12, European Space Research and Technology Centre13, University of Manchester14, Institut d'Astrophysique de Paris15, University of British Columbia16, University of Hertfordshire17, Harvard University18
TL;DR: Submillimetre and X-rays observations show that rapid star formation was common in the host galaxies of AGN when the Universe was 2–6 billion years old, but that the most vigorous star formation is not observed around black holes above an X-ray luminosity of 1044 ergs per second.
Abstract: The old, red stars that constitute the bulges of galaxies, and the massive black holes at their centres, are the relics of a period in cosmic history when galaxies formed stars at remarkable rates and active galactic nuclei (AGN) shone brightly as a result of accretion onto black holes. It is widely suspected, but unproved, that the tight correlation between the mass of the black hole and the mass of the stellar bulge1 results from the AGN quenching the surrounding star formation as it approaches its peak luminosity2, 3, 4. X-rays trace emission from AGN unambiguously5, whereas powerful star-forming galaxies are usually dust-obscured and are brightest at infrared and submillimetre wavelengths6. Here we report submillimetre and X-ray observations that show that rapid star formation was common in the host galaxies of AGN when the Universe was 2-6 billion years old, but that the most vigorous star formation is not observed around black holes above an X-ray luminosity of 1044 ergs per second. This suppression of star formation in the host galaxy of a powerful AGN is a key prediction of models in which the AGN drives an outflow7, 8, 9, expelling the interstellar medium of its host and transforming the galaxy's properties in a brief period of cosmic time
233 citations
Johns Hopkins University1, Princeton University2, University of British Columbia3, Perimeter Institute for Theoretical Physics4, University of Minnesota5, Max Planck Society6, University of Toronto7, Institute for the Physics and Mathematics of the Universe8, Goddard Space Flight Center9, University of Chicago10, Brown University11, University of California, Los Angeles12
TL;DR: In this paper, the authors present the final nine-year maps and basic results from the WMAP mission, showing that the Big Bang nucleosynthesis is well supported and there is no compelling evidence for a non-standard number of neutrino species (3.84+/-0.40).
Abstract: We present the final nine-year maps and basic results from the WMAP mission. We provide new nine-year full sky temperature maps that were processed to reduce the asymmetry of the effective beams. Temperature and polarization sky maps are examined to separate CMB anisotropy from foreground emission, and both types of signals are analyzed in detail. The WMAP mission has resulted in a highly constrained LCDM cosmological model with precise and accurate parameters in agreement with a host of other cosmological measurements. When WMAP data are combined with finer scale CMB, baryon acoustic oscillation, and Hubble constant measurements, we find that Big Bang nucleosynthesis is well supported and there is no compelling evidence for a non-standard number of neutrino species (3.84+/-0.40). The model fit also implies that the age of the universe is 13.772+/-0.059 Gyr, and the fit Hubble constant is H0 = 69.32+/-0.80 km/s/Mpc. Inflation is also supported: the fluctuations are adiabatic, with Gaussian random phases; the detection of a deviation of the scalar spectral index from unity reported earlier by WMAP now has high statistical significance (n_s = 0.9608+/-0.0080); and the universe is close to flat/Euclidean, Omega_k = -0.0027 (+0.0039/-0.0038). Overall, the WMAP mission has resulted in a reduction of the cosmological parameter volume by a factor of 68,000 for the standard six-parameter LCDM model, based on CMB data alone. For a model including tensors, the allowed seven-parameter volume has been reduced by a factor 117,000. Other cosmological observations are in accord with the CMB predictions, and the combined data reduces the cosmological parameter volume even further. With no significant anomalies and an adequate goodness-of-fit, the inflationary flat LCDM model and its precise and accurate parameters rooted in WMAP data stands as the standard model of cosmology.
229 citations
Princeton University1, University of California, Berkeley2, University of Toronto3, University of Oxford4, Johns Hopkins University5, University of Pennsylvania6, University of British Columbia7, Rutgers University8, University of Miami9, University of Pittsburgh10, University of California, Santa Barbara11, University of KwaZulu-Natal12, National Institute of Standards and Technology13, Pontifical Catholic University of Chile14, Goddard Space Flight Center15
TL;DR: In this paper, the cross-correlation of Atacama cosmology telescope cosmic microwave background (CMB lensing convergence maps with quasar maps made from the Sloan Digital Sky Survey DR8 SDSS-XDQSO photometric catalog is detected for the first time at a significance of 3.8 sigma.
Abstract: We measure the cross-correlation of Atacama cosmology telescope cosmic microwave background (CMB) lensing convergence maps with quasar maps made from the Sloan Digital Sky Survey DR8 SDSS-XDQSO photometric catalog. The CMB lensing quasar cross-power spectrum is detected for the first time at a significance of 3.8 sigma, which directly confirms that the quasar distribution traces the mass distribution at high redshifts z > 1. Our detection passes a number of null tests and systematic checks. Using this cross-power spectrum, we measure the amplitude of the linear quasar bias assuming a template for its redshift dependence, and find the amplitude to be consistent with an earlier measurement from clustering; at redshift z ap 1.4, the peak of the distribution of quasars in our maps, our measurement corresponds to a bias of b = 2.5 +/- 0.6. With the signal-to-noise ratio on CMB lensing measurements likely to improve by an order of magnitude over the next few years, our results demonstrate the potential of CMB lensing crosscorrelations to probe astrophysics at high redshifts.
120 citations
TL;DR: In this article, the authors combine the data from six blank-field surveys carried out at 1.1 mm with AzTEC, totalling 1.6 square degrees in area with root-mean-square depths ranging from 0.4 to 1.7 mJy.
Abstract: The source counts of galaxies discovered at sub-millimetre and millimetre wavelengths provide important information on the evolution of infrared-bright galaxies. We combine the data from six blank-field surveys carried out at 1.1 mm with AzTEC, totalling 1.6 square degrees in area with root-mean-square depths ranging from 0.4 to 1.7 mJy, and derive the strongest constraints to date on the 1.1 mm source counts at flux densities S(1100) = 1-12 mJy. Using additional data from the AzTEC Cluster Environment Survey to extend the counts to S(1100) ~ 20 mJy, we see tentative evidence for an enhancement relative to the exponential drop in the counts at S(1100) ~ 13 mJy and a smooth connection to the bright source counts at >20 mJy measured by the South Pole Telescope; this excess may be due to strong lensing effects. We compare these counts to predictions from several semi-analytical and phenomenological models and find that for most the agreement is quite good at flux densities > 4 mJy; however, we find significant discrepancies (>3sigma) between the models and the observed 1.1 mm counts at lower flux densities, and none of them are consistent with the observed turnover in the Euclidean-normalised counts at S(1100) < 2 mJy. Our new results therefore may require modifications to existing evolutionary models for low luminosity galaxies. Alternatively, the discrepancy between the measured counts at the faint end and predictions from phenomenological models could arise from limited knowledge of the spectral energy distributions of faint galaxies in the local Universe.
101 citations
National Radio Astronomy Observatory1, University of Massachusetts Amherst2, National Institute of Astrophysics, Optics and Electronics3, University of Colorado Boulder4, University of British Columbia5, University of Edinburgh6, Kyoto University7, Sejong University8, University of Tokyo9, Smith College10, Graduate University for Advanced Studies11, University of Hawaii12, California Institute of Technology13
TL;DR: In this paper, the authors combine the data from six blank-field surveys carried out at 1.1 mm with AzTEC, totalling 1.6 deg^2 in area with root-mean-square depths ranging from 0.4 to 1.7 mJy.
Abstract: The source counts of galaxies discovered at submillimetre and millimetre wavelengths provide important information on the evolution of infrared-bright galaxies. We combine the data from six blank-field surveys carried out at 1.1 mm with AzTEC, totalling 1.6 deg^2 in area with root-mean-square depths ranging from 0.4 to 1.7 mJy, and derive the strongest constraints to date on the 1.1 mm source counts at flux densities S_1100= 1–12 mJy. Using additional data from the AzTEC Cluster Environment Survey to extend the counts to S1100∼ 20 mJy, we see tentative evidence for an enhancement relative to the exponential drop in the counts at S_1100∼ 13 mJy and a smooth connection to the bright source counts at >20 mJy measured by the South Pole Telescope; this excess may be due to strong-lensing effects. We compare these counts to predictions from several semi-analytical and phenomenological models and find that for most the agreement is quite good at flux densities ≳ 4 mJy; however, we find significant discrepancies (≳ 3σ) between the models and the observed 1.1-mm counts at lower flux densities, and none of them is consistent with the observed turnover in the Euclidean-normalized counts at S_1100≲ 2 mJy. Our new results therefore may require modifications to existing evolutionary models for low-luminosity galaxies. Alternatively, the discrepancy between the measured counts at the faint end and predictions from phenomenological models could arise from limited knowledge of the spectral energy distributions of faint galaxies in the local Universe.
94 citations
TL;DR: In this paper, the Atacama Cosmology Telescope (ACT) data were collected for 136 days, producing a total of 1423 hours of data (11 TB for the 148 GHz band only), with a daily average of 10.5 hours of observation.
Abstract: We present a description of the data reduction and mapmaking pipeline used for the 2008 observing season of the Atacama Cosmology Telescope (ACT). The data presented here at 148 GHz represent 12% of the 90 TB collected by ACT from 2007 to 2010. In 2008 we observed for 136 days, producing a total of 1423 hours of data (11 TB for the 148 GHz band only), with a daily average of 10.5 hours of observation. From these, 1085 hours were devoted to a 850 deg^2 stripe (11.2 hours by 9.1 deg) centered on a declination of -52.7 deg, while 175 hours were devoted to a 280 deg^2 stripe (4.5 hours by 4.8 deg) centered at the celestial equator. We discuss sources of statistical and systematic noise, calibration, telescope pointing, and data selection. Out of 1260 survey hours and 1024 detectors per array, 816 hours and 593 effective detectors remain after data selection for this frequency band, yielding a 38% survey efficiency. The total sensitivity in 2008, determined from the noise level between 5 Hz and 20 Hz in the time-ordered data stream (TOD), is 32 micro-Kelvin sqrt{s} in CMB units. Atmospheric brightness fluctuations constitute the main contaminant in the data and dominate the detector noise covariance at low frequencies in the TOD. The maps were made by solving the least-squares problem using the Preconditioned Conjugate Gradient method, incorporating the details of the detector and noise correlations. Cross-correlation with WMAP sky maps, as well as analysis from simulations, reveal that our maps are unbiased at multipoles ell > 300. This paper accompanies the public release of the 148 GHz southern stripe maps from 2008. The techniques described here will be applied to future maps and data releases.
75 citations
Princeton University1, University of Oxford2, Carnegie Mellon University3, University of Toronto4, University of California, Berkeley5, University of Pennsylvania6, Pontifical Catholic University of Chile7, National Institute of Standards and Technology8, Johns Hopkins University9, University of British Columbia10, University of Nottingham11, University of Miami12, Rutgers University13, University of Pittsburgh14, University of California, Santa Barbara15, University of KwaZulu-Natal16, Haverford College17, Goddard Space Flight Center18
TL;DR: In this article, a detection of the unnormalized skewness induced by the thermal Sunyaev-Zel'dovich (tSZ) effect in filtered Atacama Cosmology Telescope (ACT) 148 GHz cosmic microwave background temperature maps is presented.
Abstract: We present a detection of the unnormalized skewness (T(sup ~)(sup 2)(n(circumflex)) induced by the thermal Sunyaev-Zel'dovich (tSZ) effect in filtered Atacama Cosmology Telescope (ACT) 148 GHz cosmic microwave background temperature maps. Contamination due to infrared and radio sources is minimized by template subtraction of resolved sources and by constructing a mask using outlying values in the 218 GHz (tSZ-null) ACT maps. We measure (T(sup ~)(sup 3) (n(circumflex)) = -31 plus or minus 6 micro-K(sup 3) (measurement error only) or plus or minus 14 micro-K(sup 3) (including cosmic variance error) in the filtered ACT data, a 5sigma detection. We show that the skewness is a sensitive probe of sigma(sub 8), and use analytic calculations and tSZ simulations to obtain cosmological constraints from this measurement. From this signal alone we infer a value of sigma(sub 8) = 0.78 sup +0.03 sub -0.04 (68% C.L.) sup +0.05 sub -0.16. Our results demonstrate that measurements of nonGaussianity can be a useful method for characterizing the tSZ effect and extracting the underlying cosmological information.
TL;DR: The Keck array as mentioned in this paper is a multi-camera CMB polarimeter with 256 polarization pairs of antenna-coupled transition edge sensor (TES) bolometers, which is used to search for the primordial B-mode polarization signal imprinted in the CMB.
Abstract: The Keck array is a new multi-camera Cosmic Microwave Background (CMB) polarimeter. Each camera contains 256 polarization pairs of antenna-coupled transition edge sensor (TES) bolometers. We recently deployed three of five cameras at the geographic South Pole, and plan to deploy the final two cameras in early 2012. This new telescope is an ideal instrument to search for the primordial B-mode polarization signal imprinted in the CMB by inflationary gravitational waves. We will discuss the design of the detectors and receivers, the status of current observations, and report on progress toward upgrading the instrument with the full compliment of polarized receivers.
TL;DR: In this article, a combined fit to angular power spectra of unresolved infrared point sources from the Planck satellite (at 217,353,545 and 857 GHz, over angular scales 100 < I < 2200), the Balloonborne Large-Aperture Submillimeter Telescope (BLAST; 250, 350 and 500 microns; 1000 < I> < 9000), and from correlating BLAST and Atacama Cosmology Telescope (ACT; 148 and 218 GHz) maps is performed.
Abstract: We perform a combined fit to angular power spectra of unresolved infrared (IR) point sources from the Planck satellite (at 217,353,545 and 857 GHz, over angular scales 100 < I < 2200), the Balloonborne Large-Aperture Submillimeter Telescope (BLAST; 250, 350 and 500 microns; 1000 < I < 9000), and from correlating BLAST and Atacama Cosmology Telescope (ACT; 148 and 218 GHz) maps. We find that the clustered power over the range of angular scales and frequencies considered is well fit by a simple power law of the form C_l\propto I(sup -n) with n = 1.25 +/- 0.06. While the IR sources are understood to lie at a range of redshifts, with a variety of dust properties, we find that the frequency dependence of the clustering power can be described by the square of a modified blackbody, nu(sup beta) B(nu,T_eff), with a single emissivity index beta = 2.20 +/- 0.07 and effective temperature T_eff= 9.7 K. Our predictions for the clustering amplitude are consistent with existing ACT and South Pole Telescope results at around 150 and 220 GHz, as is our prediction for the effective dust spectral index, which we find to be alpha_150-220 = 3.68 +/- 0.07 between 150 and 220 GHz. Our constraints on the clustering shape and frequency dependence can be used to model the IR clustering as a contaminant in Cosmic Microwave Background anisotropy measurements. The combined Planck and BLAST data also rule out a linear bias clustering model.
Stanford University1, Cardiff University2, California Institute of Technology3, University of British Columbia4, University of Toronto5, Harvard University6, Jet Propulsion Laboratory7, University of Minnesota8, Centre national de la recherche scientifique9, National Institute of Standards and Technology10, University of California, San Diego11, University of Chicago12, Case Western Reserve University13
TL;DR: The Bicep2 and Keck Array experiments are designed to measure the polarization of the cosmic microwave background (CMB) on angular scales of 2-4 degrees (l = 50-100) as mentioned in this paper.
Abstract: The Bicep2 and Keck Array experiments are designed to measure the polarization of the cosmic microwave background (CMB) on angular scales of 2-4 degrees (l = 50–100). This is the region in which the B-mode signal, a signature prediction of cosmic inflation, is expected to peak. Bicep2 was deployed to the South Pole at the end of 2009 and is in the middle of its third year of observing with 500 polarization-sensitive detectors at 150 GHz. The Keck Array was deployed to the South Pole at the end of 2010, initially with three receivers—each similar to Bicep2. An additional two receivers have been added during the 2011-12 summer. We give an overview of the two experiments, report on substantial gains in the sensitivity of the two experiments after post-deployment optimization, and show preliminary maps of CMB polarization from Bicep2.
Jet Propulsion Laboratory1, California Institute of Technology2, University of Wales3, Stanford University4, University of British Columbia5, University of Toronto6, Harvard University7, Centre national de la recherche scientifique8, University of Minnesota9, National Institute of Standards and Technology10, University of Chicago11, Case Western Reserve University12
TL;DR: In this paper, the authors report on how they have modified their designs to mitigate the differential steering errors between the polarization pairs' beam centroids due to microstrip cross talk and gradients of penetration depth in the niobium thin films of their millimeter wave circuits.
Abstract: Between the BICEP2 and Keck Array experiments, we have deployed over 1500 dual polarized antenna coupled bolometers to map the Cosmic Microwave Background’s polarization We have been able to rapidly deploy these detectors because they are completely planar with an integrated phased-array antenna Through our experience in these experiments, we have learned of several challenges with this technology- specifically the beam synthesis in the antenna- and in this paper we report on how we have modified our designs to mitigate these challenges In particular, we discus differential steering errors between the polarization pairs’ beam centroids due to microstrip cross talk and gradients of penetration depth in the niobium thin films of our millimeter wave circuits We also discuss how we have suppressed side lobe response with a Gaussian taper of our antenna illumination pattern These improvements will be used in Spider, Polar-1, and this season’s retrofit of Keck Array
University of Toronto1, Princeton University2, California Institute of Technology3, University of Oxford4, Pontifical Catholic University of Chile5, University of California, Berkeley6, University of Pennsylvania7, Rutgers University8, National Institute of Standards and Technology9, University of British Columbia10, Paris Diderot University11, University of Nottingham12, University of KwaZulu-Natal13, University of Pittsburgh14, University of Tokyo15, Johns Hopkins University16, Cardiff University17, Stanford University18, West Chester University of Pennsylvania19, Goddard Space Flight Center20
TL;DR: In this paper, the authors present measurements of the auto-and cross-frequency correlation power spectra of the cosmic (sub)millimeter background at 250, 350, and 500 μm (1200, 860, and 600 GHz).
Abstract: We present measurements of the auto- and cross-frequency correlation power spectra of the cosmic (sub)millimeter background at 250, 350, and 500 μm (1200, 860, and 600 GHz) from observations made with the Balloon-borne Large Aperture Submillimeter Telescope (BLAST); and at 1380 and 2030 μm (218 and 148 GHz) from observations made with the Atacama Cosmology Telescope (ACT). The overlapping observations cover 8.6 deg^2 in an area relatively free of Galactic dust near the south ecliptic pole. The ACT bands are sensitive to radiation from the cosmic microwave background, to the Sunyaev-Zel'dovich effect from galaxy clusters, and to emission by radio and dusty star-forming galaxies (DSFGs), while the dominant contribution to the BLAST bands is from DSFGs. We confirm and extend the BLAST analysis of clustering with an independent pipeline and also detect correlations between the ACT and BLAST maps at over 25σ significance, which we interpret as a detection of the DSFGs in the ACT maps. In addition to a Poisson component in the cross-frequency power spectra, we detect a clustered signal at 4σ, and using a model for the DSFG evolution and number counts, we successfully fit all of our spectra with a linear clustering model and a bias that depends only on redshift and not on scale. Finally, the data are compared to, and generally agree with, phenomenological models for the DSFG population. This study demonstrates the constraining power of the cross-frequency correlation technique to constrain models for the DSFGs. Similar analyses with more data will impose tight constraints on future models.
California Institute of Technology1, University of Toronto2, Cardiff University3, McMaster University4, University of Edinburgh5, University of Nottingham6, Australian Astronomical Observatory7, University of British Columbia8, University of Pennsylvania9, University of Arizona10, Complutense University of Madrid11, University of La Laguna12, Spanish National Research Council13
TL;DR: In this article, the mean mid-infrared to sub-millimetre flux densities of massive (M * ≳ 10^(11) M *⊙) galaxies at redshifts 1.7 2 were measured and it was shown that star formation is a plausible mechanism for size evolution in this population as a whole.
Abstract: We present measurements of the mean mid-infrared to submillimetre flux densities of massive (M_* ≳ 10^(11) M_⊙) galaxies at redshifts 1.7 2 (spheroid-like) population may be forming stars at a median [interquartile] SFR = 14[9, 20] M_⊙ yr^(−1), if at all. Finally, we show that star formation is a plausible mechanism for size evolution in this population as a whole, but find only marginal evidence that it is what drives the expansion of the spheroid-like galaxies.
Stanford University1, Cardiff University2, California Institute of Technology3, University of British Columbia4, University of Toronto5, Harvard University6, Jet Propulsion Laboratory7, Centre national de la recherche scientifique8, University of Minnesota9, National Institute of Standards and Technology10, University of Chicago11, Case Western Reserve University12
TL;DR: The Keck Array (SPUD) as discussed by the authors was used to observe the cosmic microwave background's polarization in the winter of 2011 at the South Pole and achieved a sensitivity of 11.5 µK (CMB)√s in the 2012 configuration.
Abstract: The Keck Array (SPUD) began observing the cosmic microwave background's polarization in the winter of 2011 at the South Pole. The Keck Array follows the success of the predecessor experiments BICEP and BICEP2, 1 using five on-axis refracting telescopes. These have a combined imaging array of 2500 antenna-coupled TES bolometers read with a SQUID- based time domain multiplexing system. We will discuss the detector noise and the optimization of the readout. The achieved sensitivity of the Keck Array is 11.5 µK_(CMB)√s in the 2012 configuration.
Journal Article•
TL;DR: In this article, the Atacama Cosmology Telescope (ACT) data were collected for 136 days, producing a total of 1423hr of data (11TB for the 148 GHz band only), with a daily average of 10.5hr of observation.
Abstract: We present a description of the data reduction and mapmaking pipeline used for the 2008 observing season of the Atacama Cosmology Telescope (ACT). The data presented here at 148 GHz represent 12% of the 90 TB collected by ACT from 2007 to 2010. In 2008 we observed for 136 days, producing a total of 1423 hr of data (11 TB for the 148 GHz band only), with a daily average of 10.5 hr of observation. From these, 1085 hr were devoted to an 850 deg2 stripe (11.2 hr by 9.°1) centered on a declination of –52.°7, while 175 hr were devoted to a 280 deg2 stripe (4.5 hr by 4.°8) centered at the celestial equator. The remaining 163 hr correspond to calibration runs. We discuss sources of statistical and systematic noise, calibration, telescope pointing, and data selection. For the 148 GHz band, out of 1260 survey hours and 1024 detectors in the array, 816 hr and 593 effective detectors remain after data selection, yielding a 38% survey efficiency. The total sensitivity in 2008, determined from the noise level between 5 Hz and 20 Hz in the time-ordered data stream (TOD), is in cosmic microwave background units. Atmospheric brightness fluctuations constitute the main contaminant in the data and dominate the detector noise covariance at low frequencies in the TOD. The maps were made by solving the least-squares problem using the Preconditioned Conjugate Gradient method, incorporating the details of the detector and noise correlations. Simulations, as well as cross-correlations with Wilkinson Microwave Anisotropy Probe sky maps on large angular scales, reveal that our maps are unbiased at multipoles l > 300. This paper accompanies the public release of the 148 GHz southern stripe maps from 2008. The techniques described here will be applied to future maps and data releases.
TL;DR: In this article, the authors report on the design and first light performance of the first TES bolometer array installed in ZEUS-2 and report the progress to install two additional arrays tuned to provide similar performance across the remaining telluric windows between 200-850 microns.
Abstract: We have recently commissioned the 2nd generation redshift(z) and Early Universe Spectrometer (ZEUS-2) at the Caltech
Submillimeter Observatory ZEUS-2 is a long-slit grating spectrometer (R~1000) for observations in the submillimeter
wavelength regime that is optimized for observations of redshifted far-infrared spectral lines from galaxies in the early
universe Here we report on the design and first light performance of the first TES bolometer array installed in ZEUS-2
This array features 280 pixels each 126 mm square and arranged to provide ~35 pixel spectra at ~8 spatial positions on
the sky A 1/4-wavelength back short of 100 micron and gold mesh absorber matching the impedance of free space
provides near 90% quantum efficiency for the 350 and 450 micron telluric windows Array readout is done using SQUID
multiplexers and the Multichannel Electronics We will also report on the progress to install two additional arrays tuned
to provide similar performance across the remaining telluric windows between 200-850 microns
TL;DR: The SCUBA-2 is a 10,000 pixel wide-field submillimetre camera, recently commissioned and now operational at the James Clerk Maxwell Telescope (JCMT) as discussed by the authors.
Abstract: SCUBA-2 is a revolutionary 10,000 pixel wide-field submillimetre camera, recently commissioned and now operational
at the James Clerk Maxwell Telescope (JCMT). Twin focal planes each consist of four 32 by 40 sub-arrays of
superconducting Transition Edge Sensor (TES) bolometers, the largest combined low temperature bolometer arrays in
operation, to provide simultaneous imaging at wavelengths of 450 and 850 microns. SCUBA-2 was designed to map
large areas of sky more than 100 times faster than the original ground breaking SCUBA instrument and has achieved this
goal. In this paper we describe the performance of the instrument and present results of characterising the eight science
grade TES bolometer arrays. We discuss the steps taken to optimise the setup of the TES arrays to maximise mapping
speed and show how critical changes to the sub-array module thermal design, the introduction of independent focal plane
and 1K temperature control and enhancements to the cryogenics have combined to significantly improve the overall
performance of the instrument.
TL;DR: In this article, the authors discuss the challenges and steps taken to optimise the performance of the SCUBA-2 arrays and maximise the mapping speed of the instrument, and present results of characterising the eight 1280 bolometer arrays and show the performance.
Abstract: SCUBA-2 is a state of the art 10,000 pixel submillimeter camera providing wide-field simultaneous imaging at 450 and 850 microns. The instrument is in the final stages of commissioning at the JCMT and is the largest low temperature detector array in operation. Twin focal planes each consist of four 32 by 40 sub-arrays of superconducting Transition Edge Sensor (TES) bolometers, with inline SQUID time-division multiplexed readout. In this paper we discuss the challenges and steps taken to optimise the performance of the SCUBA-2 arrays and maximise the mapping speed of the instrument. We present results of characterising the eight 1280 bolometer arrays and show the performance of the detectors and the instrument.
TL;DR: The Keck Array (SPUD) as discussed by the authors was used to observe the cosmic microwave background's polarization in the winter of 2011 at the South Pole using five on-axis refracting telescopes with a combined imaging array of 2500 antenna-coupled TES bolometers read with a SQUID-based time domain multiplexing system.
Abstract: The Keck Array (SPUD) began observing the cosmic microwave background's polarization in the winter of 2011 at the South Pole. The Keck Array follows the success of the predecessor experiments Bicep and Bicep2, using five on-axis refracting telescopes. These have a combined imaging array of 2500 antenna-coupled TES bolometers read with a SQUID-based time domain multiplexing system. We will discuss the detector noise and the optimization of the readout. The achieved sensitivity of the Keck Array is 11.5 {\mu}K_(CMB)*sqrt{s} in the 2012 configuration.
Harvard University1, Cardiff University2, California Institute of Technology3, Jet Propulsion Laboratory4, Centre national de la recherche scientifique5, University of Minnesota6, University of British Columbia7, National Institute of Standards and Technology8, Stanford University9, University of Chicago10, Case Western Reserve University11, University of Toronto12
TL;DR: In this paper, the main beam shape and beam shape mismatch between co-located orthogonally-polarized detector pairs is investigated for the Keck Array, and the implications of measured differential beam parameters on temperature to polarization leakage in CMB analysis are discussed.
Abstract: The Keck Array (SPUD) is a set of microwave polarimeters that observes from the South Pole at degree angular scales in search of a signature of Inflation imprinted as B-mode polarization in the Cosmic Microwave Background (CMB). The first three Keck Array receivers were deployed during the 2010-2011 Austral summer, followed by two new receivers in the 2011-2012 summer season, completing the full five-receiver array. All five receivers are currently observing at 150 GHz. The Keck Array employs the field-proven BICEP/ BICEP2 strategy of using small, cold, on-axis refractive optics, providing excellent control of systematics while maintaining a large field of view. This design allows for full characterization of far-field optical performance using microwave sources on the ground. We describe our efforts to characterize the main beam shape and beam shape mismatch between co-located orthogonally-polarized detector pairs, and discuss the implications of measured differential beam parameters on temperature to polarization leakage in CMB analysis.
Stanford University1, Cardiff University2, California Institute of Technology3, University of British Columbia4, University of Toronto5, Harvard University6, Jet Propulsion Laboratory7, University of Minnesota8, Centre national de la recherche scientifique9, National Institute of Standards and Technology10, University of California, San Diego11, University of Chicago12, Case Western Reserve University13
TL;DR: The BICEP2 and Keck Array experiments are designed to measure the polarization of the cosmic microwave background (CMB) on angular scales of 2-4 degrees (l=50-100) as mentioned in this paper.
Abstract: The BICEP2 and Keck Array experiments are designed to measure the polarization of the cosmic microwave background (CMB) on angular scales of 2-4 degrees (l=50-100). This is the region in which the B-mode signal, a signature prediction of cosmic inflation, is expected to peak. BICEP2 was deployed to the South Pole at the end of 2009 and is in the middle of its third year of observing with 500 polarization-sensitive detectors at 150 GHz. The Keck Array was deployed to the South Pole at the end of 2010, initially with three receivers--each similar to BICEP2. An additional two receivers have been added during the 2011-12 summer. We give an overview of the two experiments, report on substantial gains in the sensitivity of the two experiments after post-deployment optimization, and show preliminary maps of CMB polarization from BICEP2.
Jet Propulsion Laboratory1, California Institute of Technology2, University of Wales3, Stanford University4, University of British Columbia5, University of Toronto6, Harvard University7, Centre national de la recherche scientifique8, University of Minnesota9, National Institute of Standards and Technology10, University of Chicago11, Case Western Reserve University12
TL;DR: In this article, the authors report on how they have modified their designs to mitigate the differential steering errors between the polarization pairs' beam centroids due to microstrip cross talk and gradients of penetration depth in the niobium thin films of their millimeter wave circuits.
Abstract: Between the BICEP2 and Keck Array experiments, we have deployed over 1500 dual polarized antenna coupled bolometers to map the Cosmic Microwave Background's polarization. We have been able to rapidly deploy these detectors because they are completely planar with an integrated phased-array antenna. Through our experience in these experiments, we have learned of several challenges with this technology- specifically the beam synthesis in the antenna- and in this paper we report on how we have modified our designs to mitigate these challenges. In particular, we discus differential steering errors between the polarization pairs' beam centroids due to microstrip cross talk and gradients of penetration depth in the niobium thin films of our millimeter wave circuits. We also discuss how we have suppressed side lobe response with a Gaussian taper of our antenna illumination pattern. These improvements will be used in Spider, Polar-1, and this season's retrofit of Keck Array.