Showing papers by "John E. Carlstrom published in 2020"
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TL;DR: It is shown analytically that spacetimes that deviate from the Kerr metric but satisfy weak-field tests can lead to large deviations in the predicted black-hole shadows that are inconsistent with even the current EHT measurements.
Abstract: The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new and clean gravitational test of the black-hole metric in the strong-field regime. We show analytically that spacetimes that deviate from the Kerr metric but satisfy weak-field tests can lead to large deviations in the predicted black-hole shadows that are inconsistent with even the current EHT measurements. We use numerical calculations of regular, parametric, non-Kerr metrics to identify the common characteristic among these different parametrizations that control the predicted shadow size. We show that the shadow-size measurements place significant constraints on deviation parameters that control the second post-Newtonian and higher orders of each metric and are, therefore, inaccessible to weak-field tests. The new constraints are complementary to those imposed by observations of gravitational waves from stellar-mass sources.
187 citations
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TL;DR: Abazajian et al. as discussed by the authors developed a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, in the presence of Galactic foregrounds and gravitational lensing of the CMB.
Abstract: Author(s): Collaboration, The CMB-S4; :; Abazajian, Kevork; Addison, Graeme E; Adshead, Peter; Ahmed, Zeeshan; Akerib, Daniel; Ali, Aamir; Allen, Steven W; Alonso, David; Alvarez, Marcelo; Amin, Mustafa A; Anderson, Adam; Arnold, Kam S; Ashton, Peter; Baccigalupi, Carlo; Bard, Debbie; Barkats, Denis; Barron, Darcy; Barry, Peter S; Bartlett, James G; Thakur, Ritoban Basu; Battaglia, Nicholas; Bean, Rachel; Bebek, Chris; Bender, Amy N; Benson, Bradford A; Bianchini, Federico; Bischoff, Colin A; Bleem, Lindsey; Bock, James J; Bocquet, Sebastian; Boddy, Kimberly K; Bond, J Richard; Borrill, Julian; Bouchet, Francois R; Brinckmann, Thejs; Brown, Michael L; Bryan, Sean; Buza, Victor; Byrum, Karen; Caimapo, Carlos Hervias; Calabrese, Erminia; Calafut, Victoria; Caldwell, Robert; Carlstrom, John E; Carron, Julien; Cecil, Thomas; Challinor, Anthony; Chang, Clarence L; Chinone, Yuji; Cho, Hsiao-Mei Sherry; Cooray, Asantha; Coulton, Will; Crawford, Thomas M; Crites, Abigail; Cukierman, Ari; Cyr-Racine, Francis-Yan; de Haan, Tijmen; Delabrouille, Jacques; Devlin, Mark; Di Valentino, Eleonora; Dierickx, Marion; Dobbs, Matt; Duff, Shannon; Dunkley, Jo; Dvorkin, Cora; Eimer, Joseph; Elleflot, Tucker; Errard, Josquin; Essinger-Hileman, Thomas; Fabbian, Giulio; Feng, Chang; Ferraro, Simone; Filippini, Jeffrey P; Flauger, Raphael; Flaugher, Brenna; Fraisse, Aurelien A; Frolov, Andrei; Galitzki, Nicholas; Gallardo, Patricio A; Galli, Silvia; Ganga, Ken; Gerbino, Martina; Gluscevic, Vera | Abstract: CMB-S4---the next-generation ground-based cosmic microwave background (CMB) experiment---is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, $r$, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2--3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments given a desired scientific goal. To form a closed-loop process, we couple this semi-analytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for $r g 0.003$ at greater than $5\sigma$, or, in the absence of a detection, of reaching an upper limit of $r l 0.001$ at $95\%$ CL.
114 citations
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TL;DR: In this paper, the authors describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS), and associate SZ-selected clusters, from both SPT-ECS and the SPT SZ survey, with clusters from the DES redMaPPer sample, and find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets.
Abstract: We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 4 threshold, and 10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (l - M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4σ level-with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses.
72 citations
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Case Western Reserve University1, University of Colorado Boulder2, University of Melbourne3, Argonne National Laboratory4, Cardiff University5, Fermilab6, National Institute of Standards and Technology7, University of California, Berkeley8, University of Chicago9, University of KwaZulu-Natal10, McGill University11, California Institute of Technology12, Lawrence Berkeley National Laboratory13, Canadian Institute for Advanced Research14, Harvey Mudd College15, European Southern Observatory16, University of Illinois at Urbana–Champaign17, Stanford University18, University of California, Davis19, University of Michigan20, University of Toronto21, University of Minnesota22, Yale University23, School of the Art Institute of Chicago24, Harvard University25, University of Maryland, College Park26, National Center for Supercomputing Applications27, University of California, Los Angeles28
TL;DR: In this article, the authors report a B-mode power spectrum measurement from the cosmic microwave background (CMB) polarization anisotropy observations made using the SPTpol instrument on the South Pole Telescope.
Abstract: We report a B-mode power spectrum measurement from the cosmic microwave background (CMB) polarization anisotropy observations made using the SPTpol instrument on the South Pole Telescope. This work uses 500 deg2 of SPTpol data, a five-fold increase over the last SPTpol B-mode release. As a result, the bandpower uncertainties have been reduced by more than a factor of two, and the measurement extends to lower multipoles: 52 320.
69 citations
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Jae-Young Kim1, Thomas P. Krichbaum1, Avery E. Broderick2, Avery E. Broderick3 +410 more•Institutions (83)
TL;DR: In this paper, the innermost jet of 3C 279 was resolved using global very long baseline interferometry (VLBI) at 1.3 mm (230 GHz) to study its fine-scale morphology close to the jet base.
Abstract: 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique – global Very Long Baseline Interferometry (VLBI) at 1.3 mm (230 GHz) – to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable γ -ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array (ALMA), at an angular resolution of ∼20 μ as (at a redshift of z = 0.536 this corresponds to ∼0.13 pc ∼ 1700 Schwarzschild radii with a black hole mass M BH = 8 × 108 M ⊙ ). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation. We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across different imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI “core”. This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet. We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1.3 and ∼1.7 μ as day−1 , respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3 mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≲1010 K, a magnitude or more lower than typical values seen at ≥7 mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths.
58 citations
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University of Melbourne1, Cardiff University2, Fermilab3, University of Colorado Boulder4, National Institute of Standards and Technology5, University of California, Berkeley6, University of Hawaii7, Argonne National Laboratory8, University of Chicago9, McGill University10, University of KwaZulu-Natal11, California Institute of Technology12, Lawrence Berkeley National Laboratory13, Canadian Institute for Advanced Research14, Harvey Mudd College15, European Southern Observatory16, University of Illinois at Urbana–Champaign17, Stanford University18, University of California, Davis19, Institut d'Astrophysique de Paris20, University of Michigan21, University of Toronto22, University of Minnesota23, Case Western Reserve University24, Yale University25, School of the Art Institute of Chicago26, Harvard University27, University of Maryland, College Park28, National Center for Supercomputing Applications29, University of California, Los Angeles30
TL;DR: In this article, a search for anisotropic cosmic birefringence in the southern sky at 150 GHz with the SPTpol camera on the South Pole Telescope is presented.
Abstract: We present a search for anisotropic cosmic birefringence in 500 deg2 of southern sky observed at 150 GHz with the SPTpol camera on the South Pole Telescope. We reconstruct a map of cosmic polarization rotation anisotropies using higher-order correlations between the observed cosmic microwave background (CMB) E and B fields. We then measure the angular power spectrum of this map, which is found to be consistent with zero. The nondetection is translated into an upper limit on the amplitude of the scale-invariant cosmic rotation power spectrum, L(L+1)CααL/2π<0.10×10−4 rad2 (0.033 deg2, 95% C.L.). This upper limit can be used to place constraints on the strength of primordial magnetic fields, B1 Mpc<17 nG (95% C.L.), and on the coupling constant of the Chern-Simons electromagnetic term gaγ<4.0×10−2/HI (95% C.L.), where HI is the inflationary Hubble scale. For the first time, we also cross-correlate the CMB temperature fluctuations with the reconstructed rotation angle map, a signal expected to be nonvanishing in certain theoretical scenarios, and find no detectable signal. We perform a suite of systematics and consistency checks and find no evidence for contamination.
56 citations
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TL;DR: In this paper, the authors compare the performance of EHT radiative transfer codes with the results of the Event Horizon Telescope (EHT) Collaboration to model the supermassive black hole in the giant elliptical galaxy M87.
Abstract: The Event Horizon Telescope (EHT) Collaboration has recently produced the first resolved images of the central supermassive black hole in the giant elliptical galaxy M87. Here we report on tests of the consistency and accuracy of the general relativistic radiative transfer codes used within the collaboration to model M87* and Sgr A*. We compare and evaluate (1) deflection angles for equatorial null geodesics in a Kerr spacetime; (2) images calculated from a series of simple, parameterized matter distributions in the Kerr metric using simplified emissivities and absorptivities; (3) for a subset of codes, images calculated from general relativistic magnetohydrodynamics simulations using different realistic synchrotron emissivities and absorptivities; (4) observables for the 2017 configuration of EHT, including visibility amplitudes and closure phases. The error in total flux is of order 1% when the codes are run with production numerical parameters. The dominant source of discrepancies for small camera distances is the location and detailed setup of the software "camera" that each code uses to produce synthetic images. We find that when numerical parameters are suitably chosen and the camera is sufficiently far away the images converge and that for given transfer coefficients, numerical uncertainties are unlikely to limit parameter estimation for the current generation of EHT observations. The purpose of this paper is to describe a verification and comparison of EHT radiative transfer codes. It is not to verify EHT models more generally.
52 citations
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TL;DR: Themis is demonstrated to be able to reproduce prior EHT analyses, extend these, and do so in a computationally efficient manner that can efficiently exploit modern high-performance computing facilities.
Abstract: The Event Horizon Telescope (EHT) provides the unprecedented ability to directly resolve the structure and dynamics of black hole emission regions on scales smaller than their horizons. This has the potential to critically probe the mechanisms by which black holes accrete and launch outflows, and the structure of supermassive black hole spacetimes. However, accessing this information is a formidable analysis challenge for two reasons. First, the EHT natively produces a variety of data types that encode information about the image structure in nontrivial ways; these are subject to a variety of systematic effects associated with very long baseline interferometry and are supplemented by a wide variety of auxiliary data on the primary EHT targets from decades of other observations. Second, models of the emission regions and their interaction with the black hole are complex, highly uncertain, and computationally expensive to construct. As a result, the scientific utilization of EHT observations requires a flexible, extensible, and powerful analysis framework. We present such a framework, Themis, which defines a set of interfaces between models, data, and sampling algorithms that facilitates future development. We describe the design and currently existing components of Themis, how Themis has been validated thus far, and present additional analyses made possible by Themis that illustrate its capabilities. Importantly, we demonstrate that Themis is able to reproduce prior EHT analyses, extend these, and do so in a computationally efficient manner that can efficiently exploit modern high-performance computing facilities. Themis has already been used extensively in the scientific analysis and interpretation of the first EHT observations of M87.
51 citations
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TL;DR: In this paper, the authors analyzed M87* data collected with prototype EHT arrays in 2009, 2011, 2012, and 2013 and found that the M87 * morphology in 2009-2017 was consistent with a persistent asymmetric ring of approximately 40 µas diameter.
Abstract: The Event Horizon Telescope (EHT) has recently delivered the first resolved images of M87*, the supermassive black hole in the center of the M87 galaxy. These images were produced using 230 GHz observations performed in 2017 April. Additional observations are required to investigate the persistence of the primary image feature—a ring with azimuthal brightness asymmetry—and to quantify the image variability on event horizon scales. To address this need, we analyze M87* data collected with prototype EHT arrays in 2009, 2011, 2012, and 2013. While these observations do not contain enough information to produce images, they are sufficient to constrain simple geometric models. We develop a modeling approach based on the framework utilized for the 2017 EHT data analysis and validate our procedures using synthetic data. Applying the same approach to the observational data sets, we find the M87* morphology in 2009–2017 to be consistent with a persistent asymmetric ring of ~40 μas diameter. The position angle of the peak intensity varies in time. In particular, we find a significant difference between the position angle measured in 2013 and 2017. These variations are in broad agreement with predictions of a subset of general relativistic magnetohydrodynamic simulations. We show that quantifying the variability across multiple observational epochs has the potential to constrain the physical properties of the source, such as the accretion state or the black hole spin.
50 citations
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University of Melbourne1, Cardiff University2, Fermilab3, National Institute of Standards and Technology4, University of Colorado Boulder5, University of California, Berkeley6, Argonne National Laboratory7, University of Chicago8, McGill University9, University of KwaZulu-Natal10, California Institute of Technology11, Lawrence Berkeley National Laboratory12, Canadian Institute for Advanced Research13, Harvey Mudd College14, European Southern Observatory15, University of Illinois at Urbana–Champaign16, Stanford University17, University of California, Davis18, University of Paris19, University of Michigan20, University of Toronto21, Case Western Reserve University22, Yale University23, School of the Art Institute of Chicago24, Harvard University25, University of Maryland, College Park26, University of California, Los Angeles27
TL;DR: In this article, the cosmological constraints based on the cosmic microwave background (CMB) lensing potential power spectrum measurement from the recent 500 deg2 SPTpol survey were presented.
Abstract: We present cosmological constraints based on the cosmic microwave background (CMB) lensing potential power spectrum measurement from the recent 500 deg2 SPTpol survey, the most precise CMB lensing measurement from the ground to date. We fit a flat ΛCDM model to the reconstructed lensing power spectrum alone and in addition with other data sets: baryon acoustic oscillations (BAO), as well as primary CMB spectra from Planck and SPTpol. The cosmological constraints based on SPTpol and Planck lensing band powers are in good agreement when analyzed alone and in combination with Planck full-sky primary CMB data. With weak priors on the baryon density and other parameters, the SPTpol CMB lensing data alone provide a 4% constraint on ${\sigma }_{8}{{\rm{\Omega }}}_{m}^{0.25}=0.593\pm 0.025$. Jointly fitting with BAO data, we find ${\sigma }_{8}=0.779\pm 0.023$, ${{\rm{\Omega }}}_{m}={0.368}_{-0.037}^{+0.032}$, and ${H}_{0}={72.0}_{-2.5}^{+2.1}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$, up to $2\sigma $ away from the central values preferred by Planck lensing + BAO. However, we recover good agreement between SPTpol and Planck when restricting the analysis to similar scales. We also consider single-parameter extensions to the flat ΛCDM model. The SPTpol lensing spectrum constrains the spatial curvature to be ${{\rm{\Omega }}}_{K}=-0.0007\pm 0.0025$ and the sum of the neutrino masses to be $\sum {m}_{
u }\lt 0.23$ eV at 95% C.L. (with Planck primary CMB and BAO data), in good agreement with the Planck lensing results. With the differences in the signal-to-noise ratio of the lensing modes and the angular scales covered in the lensing spectra, this analysis represents an important independent check on the full-sky Planck lensing measurement.
50 citations
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University of California, Berkeley1, Argonne National Laboratory2, Harvard University3, Cardiff University4, Stanford University5, Fermilab6, National Institute of Standards and Technology7, University of Chicago8, University of Melbourne9, Ludwig Maximilian University of Munich10, University of Missouri–Kansas City11, McGill University12, University of KwaZulu-Natal13, California Institute of Technology14, Lawrence Berkeley National Laboratory15, Canadian Institute for Advanced Research16, University of Colorado Boulder17, Harvey Mudd College18, European Southern Observatory19, University of Illinois at Urbana–Champaign20, University of California, Davis21, Massachusetts Institute of Technology22, University of Michigan23, University of Oslo24, University of Toronto25, University of Minnesota26, Case Western Reserve University27, Yale University28, University of Trieste29, School of the Art Institute of Chicago30, University of Maryland, College Park31, University of California, Los Angeles32
TL;DR: In this article, the authors presented a catalog of galaxy cluster candidates detected in 100 square degrees surveyed with the SPTpol receiver on the South Pole Telescope, which contains 89 candidates detected with a signal-to-noise ratio greater than 4.6.
Abstract: We present a catalog of galaxy cluster candidates detected in 100 square degrees surveyed with the SPTpol receiver on the South Pole Telescope. The catalog contains 89 candidates detected with a signal-to-noise ratio greater than 4.6. The candidates are selected using the Sunyaev–Zel'dovich effect at 95 and 150 GHz. Using both space- and ground-based optical and infrared telescopes, we have confirmed 81 candidates as galaxy clusters. We use these follow-up images and archival images to estimate photometric redshifts for 66 galaxy clusters and spectroscopic observations to obtain redshifts for 13 systems. An additional two galaxy clusters are confirmed using the overdensity of near-infrared galaxies only and are presented without redshifts. We find that 15 candidates (18% of the total sample) are at redshift z ≥ 1.0, with a maximum confirmed redshift of ${z}_{\max }=1.38\pm 0.10$. We expect this catalog to contain every galaxy cluster with ${M}_{500c}\gt 2.6\times {10}^{14}{M}_{\odot }{{h}}_{70}^{-1}$ and z > 0.25 in the survey area. The mass threshold is approximately constant above z = 0.25, and the complete catalog has a median mass of approximately ${M}_{500c}=2.7\times {10}^{14}{M}_{\odot }{{h}}_{70}^{-1}$. Compared to previous SPT works, the increased depth of the millimeter-wave data (11.2 and 6.5 μK-arcmin at 95 and 150 GHz, respectively) makes it possible to find more galaxy clusters at high redshift and lower mass.
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University of Colorado Boulder1, University of Illinois at Urbana–Champaign2, University of California, Santa Barbara3, University of Chicago4, Diego Portales University5, National Institute of Standards and Technology6, Fermilab7, Argonne National Laboratory8, University of Cambridge9, Dalhousie University10, California Institute of Technology11, Lawrence Berkeley National Laboratory12, University of California, Berkeley13, McGill University14, Canadian Institute for Advanced Research15, European Southern Observatory16, University of California, Davis17, University of Michigan18, University of Oslo19, Ludwig Maximilian University of Munich20, Max Planck Society21, University of Minnesota22, University of Melbourne23, Case Western Reserve University24, School of the Art Institute of Chicago25, University of Texas at Austin26, Harvard University27, Stanford University28, Goddard Space Flight Center29, University of Toronto30
TL;DR: In this article, the authors presented a catalog of emissive point sources detected in the SPT-SZ survey, a contiguous 2530 square degree area surveyed with the South Pole Telescope (SPT) from 2008-2011 in three bands centered at 95, 150, and 220 GHz.
Abstract: We present a catalog of emissive point sources detected in the SPT-SZ survey, a contiguous 2530 square degree area surveyed with the South Pole Telescope (SPT) from 2008–2011 in three bands centered at 95, 150, and 220 GHz. The catalog contains 4845 sources measured at a significance of 4.5σ or greater in at least one band, corresponding to detections above approximately 9.8, 5.8, and 20.4 mJy in 95, 150, and 220 GHz, respectively. The spectral behavior in the SPT bands is used for source classification into two populations based on the underlying physical mechanisms of compact, emissive sources that are bright at millimeter wavelengths: synchrotron radiation from active galactic nuclei and thermal emission from dust. The latter population includes a component of high-redshift sources often referred to as submillimeter galaxies (SMGs). In the relatively bright flux ranges probed by the survey, these sources are expected to be magnified by strong gravitational lensing. The survey also contains sources consistent with protoclusters, groups of dusty galaxies at high redshift undergoing collapse. We cross-match the SPT-SZ catalog with external catalogs at radio, infrared, and X-ray wavelengths and identify available redshift information. The catalog splits into 3980 synchrotron-dominated and 865 dust-dominated sources, and we determine a list of 506 SMGs. Ten sources in the catalog are identified as stars. We calculate number counts for the full catalog, and synchrotron and dusty components, using a bootstrap method and compare our measured counts with models. This paper represents the third and final catalog of point sources in the SPT-SZ survey.
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TL;DR: In this paper, the authors presented a catalog of emissive point sources detected in the SPT-SZ survey, a contiguous 2530-square-degree area surveyed with the South Pole Telescope (SPT) from 2008 - 2011 in three bands centered at 95, 150, and 220 GHz.
Abstract: We present a catalog of emissive point sources detected in the SPT-SZ survey, a contiguous 2530-square-degree area surveyed with the South Pole Telescope (SPT) from 2008 - 2011 in three bands centered at 95, 150, and 220 GHz. The catalog contains 4845 sources measured at a significance of 4.5 sigma or greater in at least one band, corresponding to detections above approximately 9.8, 5.8, and 20.4 mJy in 95, 150, and 220 GHz, respectively. Spectral behavior in the SPT bands is used for source classification into two populations based on the underlying physical mechanisms of compact, emissive sources that are bright at millimeter wavelengths: synchrotron radiation from active galactic nuclei and thermal emission from dust. The latter population includes a component of high-redshift sources often referred to as submillimeter galaxies (SMGs). In the relatively bright flux ranges probed by the survey, these sources are expected to be magnified by strong gravitational lensing. The survey also contains sources consistent with protoclusters, groups of dusty galaxies at high redshift undergoing collapse. We cross-match the SPT-SZ catalog with external catalogs at radio, infrared, and X-ray wavelengths and identify available redshift information. The catalog splits into 3980 synchrotron-dominated and 865 dust-dominated sources and we determine a list of 506 SMGs. Ten sources in the catalog are identified as stars. We calculate number counts for the full catalog, and synchrotron and dusty components, using a bootstrap method and compare our measured counts with models. This paper represents the third and final catalog of point sources in the SPT-SZ survey.
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University of Melbourne1, Cardiff University2, Fermilab3, National Institute of Standards and Technology4, University of Colorado Boulder5, University of California, Berkeley6, University of Pennsylvania7, Argonne National Laboratory8, University of Chicago9, University of KwaZulu-Natal10, McGill University11, California Institute of Technology12, Lawrence Berkeley National Laboratory13, Canadian Institute for Advanced Research14, Harvey Mudd College15, European Southern Observatory16, University of Illinois at Urbana–Champaign17, Stanford University18, University of California, Davis19, University of Michigan20, Max Planck Society21, University of Toronto22, Case Western Reserve University23, Yale University24, School of the Art Institute of Chicago25, Harvard University26, University of Maryland, College Park27, University of California, Los Angeles28
TL;DR: In this article, the authors reported new measurements of millimeter-wave power spectra in the angular multipole range (APM) of the angular scales of the SZ and SZ bispectrum.
Abstract: We report new measurements of millimeter-wave power spectra in the angular multipole range $2000 \le \ell \le 11,000$ (angular scales $5^\prime \gtrsim \theta \gtrsim 1^\prime$). By adding 95 and 150\,GHz data from the low-noise 500 deg$^2$ SPTpol survey to the SPT-SZ three-frequency 2540 deg$^2$ survey, we substantially reduce the uncertainties in these bands. These power spectra include contributions from the primary cosmic microwave background, cosmic infrared background, radio galaxies, and thermal and kinematic Sunyaev-Zel'dovich (SZ) effects. The data favor a thermal SZ (tSZ) power at 143\,GHz of $D^{\rm tSZ}_{3000} = 3.42 \pm 0.54~ \mu {\rm K}^2$ and a kinematic SZ (kSZ) power of $D^{\rm kSZ}_{3000} = 3.0 \pm 1.0~ \mu {\rm K}^2$. This is the first measurement of kSZ power at $\ge 3\,\sigma$. We study the implications of the measured kSZ power for the epoch of reionization, finding the duration of reionization to be $\Delta z_{re} = 1.0^{+1.6}_{-0.7}$ ($\Delta z_{re}< 4.1$ at 95% confidence), when combined with our previously published tSZ bispectrum measurement.
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TL;DR: The SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations that takes into account several realistic atmospheric, instrumental, and calibration effects is presented.
Abstract: Context. Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are the most important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a direct comparison with observational data. Aims. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. Methods. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a millimetre VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects, compared to the addition of thermal noise only. Using synthetic data based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M 87, we performed case studies to assess the image quality that can be obtained with the current and future EHT array for different weather conditions. Results. Our synthetic observations show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of our GRMHD source models can be recovered robustly with the EHT2017 array after performing calibration steps, which include fringe fitting, a priori amplitude and network calibration, and self-calibration. With the planned addition of new stations to the EHT array in the coming years, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images.
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TL;DR: The Synthetic Measurement for long baseline arrays (SYMBA) as discussed by the authors is a novel synthetic data generation pipeline for very long baseline interferometry (VLBI) observations, which takes into account several realistic atmospheric, instrumental and calibration effects.
Abstract: Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a comparison with observational data. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a mm VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects. Based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M87, we performed case studies to assess the attainable image quality with the current and future EHT array for different weather conditions. The results show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of the input models can be recovered robustly after performing calibration steps. With the planned addition of new stations to the EHT array, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images.
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TL;DR: In this article, the first simultaneous Bayesian parameter inference and optimal reconstruction of the gravitational lensing of the cosmic microwave background (CMB), using 100 deg$^2$ of polarization observations from the SPT-pol receiver on the South Pole Telescope, was performed.
Abstract: We perform the first simultaneous Bayesian parameter inference and optimal reconstruction of the gravitational lensing of the cosmic microwave background (CMB), using 100 deg$^2$ of polarization observations from the SPTpol receiver on the South Pole Telescope. These data reach noise levels as low as 5.8 $\mu$K-arcmin in polarization, which are low enough that the typically used quadratic estimator (QE) technique for analyzing CMB lensing is significantly sub-optimal. Conversely, the Bayesian procedure extracts all lensing information from the data and is optimal at any noise level. We infer the amplitude of the gravitational lensing potential to be $A_\phi\,{=}\,0.949\,{\pm}\,0.122$ using the Bayesian pipeline, consistent with our QE pipeline result, but with 17\% smaller error bars. The Bayesian analysis also provides a simple way to account for systematic uncertainties, performing a similar job as frequentist "bias hardening," and reducing the systematic uncertainty on $A_\phi$ due to polarization calibration from almost half of the statistical error to effectively zero. Finally, we jointly constrain $A_\phi$ along with $A_{\rm L}$, the amplitude of lensing-like effects on the CMB power spectra, demonstrating that the Bayesian method can be used to easily infer parameters both from an optimal lensing reconstruction and from the delensed CMB, while exactly accounting for the correlation between the two. These results demonstrate the feasibility of the Bayesian approach on real data, and pave the way for future analysis of deep CMB polarization measurements with SPT-3G, Simons Observatory, and CMB-S4, where improvements relative to the QE can reach 1.5 times tighter constraints on $A_\phi$ and 7 times lower effective lensing reconstruction noise.
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Argonne National Laboratory1, University of Chicago2, Fermilab3, University of California, Berkeley4, Cardiff University5, SLAC National Accelerator Laboratory6, Stanford University7, McGill University8, National Institute of Standards and Technology9, Canadian Institute for Advanced Research10, University of Colorado Boulder11, University of California, Los Angeles12, Case Western Reserve University13, University of Illinois at Urbana–Champaign14, Harvey Mudd College15, Lawrence Berkeley National Laboratory16, University of Toronto17, Harvard University18
TL;DR: In this article, the authors present the successful implementation and performance of the South Pole Telescope 3G readout as measured on-sky, showing that low-frequency noise in the readout will not limit sky power on large angular scales.
Abstract: Frequency-domain multiplexing (fMux) is an established technique for the readout of large arrays of transition-edge sensor (TES) bolometers. Each TES in a multiplexing module has a unique AC voltage bias that is selected by a resonant filter. This scheme enables the operation and readout of multiple bolometers on a single pair of wires, reducing thermal loading onto sub-Kelvin stages. The current receiver on the South Pole Telescope, SPT-3G, uses a 68x fMux system to operate its large-format camera of ∼
∼
16,000 TES bolometers. We present here the successful implementation and performance of the SPT-3G readout as measured on-sky. Characterization of the noise reveals a median pair-differenced 1/f knee frequency of 33 mHz, indicating that low-frequency noise in the readout will not limit SPT-3G’s measurements of sky power on large angular scales. Measurements also show that the median readout white noise level in each of the SPT-3G observing bands is below the expectation for photon noise, demonstrating that SPT-3G is operating in the photon-noise-dominated regime.
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Fermilab1, University of Chicago2, Cardiff University3, Stanford University4, SLAC National Accelerator Laboratory5, University of California, Berkeley6, Argonne National Laboratory7, McGill University8, National Institute of Standards and Technology9, Canadian Institute for Advanced Research10, University of Colorado Boulder11, University of California, Los Angeles12, Case Western Reserve University13, University of Illinois at Urbana–Champaign14, Harvey Mudd College15, Lawrence Berkeley National Laboratory16, University of Toronto17, Harvard University18
TL;DR: In this article, a transition-edge sensor (TES) wafer was replaced with a new wafer fabricated with Al-Mn TESs instead of the Ti/Au design originally deployed for SPT-3G.
Abstract: SPT-3G is a polarization-sensitive receiver, installed on the South Pole Telescope, that measures the anisotropy of the cosmic microwave background (CMB) from degree to arcminute scales. The receiver consists of ten 150-mm-diameter detector wafers, containing a total of
∼16,000
∼16,000
transition-edge sensor (TES) bolometers observing at 95, 150, and 220 GHz. During the 2018–2019 austral summer, one of these detector wafers was replaced by a new wafer fabricated with Al–Mn TESs instead of the Ti/Au design originally deployed for SPT-3G. We present the results of in-laboratory characterization and on-sky performance of this Al–Mn wafer, including electrical and thermal properties, optical efficiency measurements, and noise-equivalent temperature. In addition, we discuss and account for several calibration-related systematic errors that affect measurements made using frequency-domain multiplexing readout electronics.
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University of Illinois at Urbana–Champaign1, University of Chicago2, Cardiff University3, Stanford University4, University of California, Berkeley5, Argonne National Laboratory6, University of Michigan7, McGill University8, Smithsonian Institution9, University of Colorado Boulder10, University of California, Los Angeles11, Case Western Reserve University12, Fermilab13, Lawrence Berkeley National Laboratory14, University of Toronto15
TL;DR: In this paper, the authors present two prescriptions for broadband (77 - 252 ε;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large format planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements.
Abstract: We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.
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01 Feb 2020
TL;DR: In this article, the authors present the status of an on-going 1500 sq. deg. survey with the SPT-3G receiver, a new mm-wavelength camera on the 10m diameter South Pole Telescope (SPT).
Abstract: The cosmic microwave background (CMB) encodes information about the content and evolution of the universe. The presence of light, weakly interacting particles impacts the expansion history of the early universe, which alters the temperature and polarization anisotropies of the CMB. In this way, current measurements of the CMB place interesting constraints on the neutrino energy density and mass, as well as on the abundance of other possible light relativistic particle species. We present the status of an on-going 1500 sq. deg. survey with the SPT-3G receiver, a new mm-wavelength camera on the 10-m diameter South Pole Telescope (SPT). The SPT-3G camera consists of 16,000 superconducting transition edge sensors, a 10x increase over the previous generation camera, which allows it to map the CMB with an unprecedented combination of sensitivity and angular resolution. We highlight projected constraints on the abundance of sterile neutrinos and the sum of the neutrino masses for the SPT-3G survey, which could help determine the neutrino mass hierarchy.