• A 2500 deg2 CMB Lensing Map from Combined South Pole Telescope and Planck Data

      Omori, Y.; Chown, R.; Simard, G.; Story, K. T.; Aylor, K.; Baxter, E. J.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; et al. (IOP PUBLISHING LTD, 2017-11-07)
      We present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and Planck temperature data. The 150 GHz temperature data from the 2500 deg(2) SPT-SZ survey is combined with the Planck 143 GHz data in harmonic space to obtain a temperature map that has a broader l coverage and less noise than either individual map. Using a quadratic estimator technique on this combined temperature map, we produce a map of the gravitational lensing potential projected along the line of sight. We measure the auto-spectrum of the lensing potential C-L(phi phi), and compare it to the theoretical prediction for a.CDM cosmology consistent with the Planck 2015 data set, finding a best-fit amplitude of 0.95(-0.06)(+0.06) (stat.)(-0.01)(+0.01)+ (sys.). The null hypothesis of no lensing is rejected at a significance of 24 sigma. One important use of such a lensing potential map is in cross-correlations with other dark matter tracers. We demonstrate this cross-correlation in practice by calculating the cross-spectrum, C-L(phi) G, between the SPT+ Planck lensing map and Wide-field Infrared Survey Explorer (WISE) galaxies. We fit C-L(phi G) to a power law of the form p(L) = a(L/L-0)(-b) with a, L-0, and b fixed, and find eta(phi G) = C-L(phi G)/p(L) = 0.94(-0.04)(+0.04), which is marginally lower, but in good agreement with eta(phi G) = 1.00-(+0.02)(0.01), the best-fit amplitude for the cross-correlation of Planck-2015 CMB lensing and WISE galaxies over similar to 67% of the sky. The lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey, whose footprint nearly completely covers the SPT 2500 deg(2) field.
    • Cluster Cosmology Constraints from the 2500 deg2 SPT-SZ Survey: Inclusion of Weak Gravitational Lensing Data from Magellan and the Hubble Space Telescope

      Bocquet, S.; Dietrich, J. P.; Schrabback, T.; Bleem, L. E.; Klein, M.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Bayliss, M.; et al. (IOP PUBLISHING LTD, 2019-06-13)
      We derive cosmological constraints using a galaxy cluster sample selected from the 2500 deg(2) SPT-SZ survey. The sample spans the redshift range 0.25 < z < 1.75 and contains 343 clusters with SZ detection significance xi > 5. The sample is supplemented with optical weak gravitational lensing measurements of 32 clusters with 0.29 < z < 1.13 (from Magellan and Hubble Space Telescope) and X-ray measurements of 89 clusters with 0.25 < z < 1.75 (from Chandra). We rely on minimal modeling assumptions: (i) weak lensing provides an accurate means of measuring halo masses, (ii) the mean SZ and X-ray observables are related to the true halo mass through power-law relations in mass and dimensionless Hubble parameter E(z) with a priori unknown parameters, and (iii) there is (correlated, lognormal) intrinsic scatter and measurement noise relating these observables to their mean relations. We simultaneously fit for these astrophysical modeling parameters and for cosmology. Assuming a flat nu Lambda CDM model, in which the sum of neutrino masses is a free parameter, we measure Omega(m) = 0.276 +/- 0.047, sigma(8) = 0.781 +/- 0.037, and sigma(8)(Omega(m)/0.3)(0.2) = 0.766 +/- 0.025. The redshift evolutions of the X-ray Y-X-mass and M-gas-mass relations are both consistent with self-similar evolution to within 1 sigma. The mass slope of the Y-X-mass relation shows a 2.3 sigma deviation from self-similarity. Similarly, the mass slope of the M-gas-mass relation is steeper than self-similarity at the 2.5 sigma level. In a nu omega CDM cosmology, we measure the dark energy equation-of-state parameter w = -1.55 +/- 0.41 from the cluster data. We perform a measurement of the growth of structure since redshift z similar to 1.7 and find no evidence for tension with the prediction from general relativity. This is the first analysis of the SPT cluster sample that uses direct weak-lensing mass calibration and is a step toward using the much larger weak-lensing data set from DES. We provide updated redshift and mass estimates for the SPT sample.
    • A Comparison of Cosmological Parameters Determined from CMB Temperature Power Spectra from the South Pole Telescope and the Planck Satellite

      Aylor, K.; Hou, Z.; Knox, L.; Story, K. T.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H-M.; Chown, R.; et al. (IOP PUBLISHING LTD, 2017-11-21)
      The Planck cosmic microwave background temperature data are best fit with a Lambda CDM model that mildly contradicts constraints from other cosmological probes. The South Pole Telescope (SPT) 2540 deg(2) SPT-SZ survey offers measurements on sub-degree angular scales (multipoles 650 <= l <= 2500) with sufficient precision to use as an independent check of the Planck data. Here we build on the recent joint analysis of the SPT-SZ and Planck data in Hou et al. by comparing Lambda CDM parameter estimates using the temperature power spectrum from both data sets in the SPT-SZ survey region. We also restrict the multipole range used in parameter fitting to focus on modes measured well by both SPT and Planck, thereby greatly reducing sample variance as a driver of parameter differences and creating a stringent test for systematic errors. We find no evidence of systematic errors from these tests. When we expand the maximum multipole of SPT data used, we see low-significance shifts in the angular scale of the sound horizon and the physical baryon and cold dark matter densities, with a resulting trend to higher Hubble constant. When we compare SPT and Planck data on the SPT-SZ sky patch to Planck full-sky data but keep the multipole range restricted, we find differences in the parameters n(s) and A(s)e(-2 tau). We perform further checks, investigating instrumental effects and modeling assumptions, and we find no evidence that the effects investigated are responsible for any of the parameter shifts. Taken together, these tests reveal no evidence for systematic errors in SPT or Planck data in the overlapping sky coverage and multipole range and at most weak evidence for a breakdown of Lambda CDM or systematic errors influencing either the Planck data outside the SPT-SZ survey area or the SPT data at l > 2000.
    • A Comparison of Maps and Power Spectra Determined from South Pole Telescope and Planck Data

      Hou, Z.; Aylor, K.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H-M.; Chown, R.; Crawford, T. M.; Crites, A. T.; et al. (IOP PUBLISHING LTD, 2018-01-17)
      We study the consistency of 150 GHz data from the South Pole Telescope (SPT) and 143 GHz data from the Planck satellite over the patch of sky covered by the SPT-SZ survey. We first visually compare the maps and find that the residuals appear consistent with noise after accounting for differences in angular resolution and filtering. We then calculate (1) the cross-spectrum between two independent halves of SPT data, (2) the cross-spectrum between two independent halves of Planck data, and (3) the cross-spectrum between SPT and Planck data. We find that the three cross-spectra are well fit (PTE = 0.30) by the null hypothesis in which both experiments have measured the same sky map up to a single free calibration parameter-i.e., we find no evidence for systematic errors in either data set. As a by-product, we improve the precision of the SPT calibration by nearly an order of magnitude, from 2.6% to 0.3% in power. Finally, we compare all three cross-spectra to the full-sky Planck power spectrum and find marginal evidence for differences between the power spectra from the SPT-SZ footprint and the full sky. We model these differences as a power law in spherical harmonic multipole number. The best-fit value of this tilt is consistent among the three cross-spectra in the SPT-SZ footprint, implying that the source of this tilt is a sample variance fluctuation in the SPT-SZ region relative to the full sky. The consistency of cosmological parameters derived from these data sets is discussed in a companion paper.

      Haan, T. de; Benson, B. A.; Bleem, L. E.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Bayliss, M.; Bocquet, S.; Brodwin, Mark; et al. (IOP PUBLISHING LTD, 2016-11-18)
      We present cosmological parameter constraints obtained from galaxy clusters identified by their SunyaevZel'dovich effect signature in the 2500 square-degree South Pole Telescope Sunyaev Zel'dovich (SPT-SZ) survey. We consider the 377 cluster candidates identified at z > 0.25 with a detection significance greater than five, corresponding to the 95% purity threshold for the survey. We compute constraints on cosmological models using the measured cluster abundance as a function of mass and redshift. We include additional constraints from multi-wavelength observations, including Chandra X-ray data for 82 clusters and a weak lensing-based prior on the normalization of the mass-observable scaling relations. Assuming a spatially flat Lambda CDM cosmology, we combine the cluster data with a prior on H-0 and find sigma(8)= 0.784. +/- 0.039 and Omega(m) = 0.289. +/- 0.042, with the parameter combination sigma(8) (Omega(m)/0.27)(0.3) = 0.797 +/- 0.031. These results are in good agreement with constraints from the cosmic microwave background (CMB) from SPT, WMAP, and Planck, as well as with constraints from other cluster data sets. We also consider several extensions to Lambda CDM, including models in which the equation of state of dark energy w, the species-summed neutrino mass, and/or the effective number of relativistic species (N-eff) are free parameters. When combined with constraints from the Planck CMB, H-0, baryon acoustic oscillation, and SNe, adding the SPT cluster data improves the w constraint by 14%, to w = -1.023 +/- 0.042.

      Crawford, T. M.; Chown, R.; Holder, G. P.; Aird, K. A.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H-M.; Crites, A. T.; et al. (IOP PUBLISHING LTD, 2016-12-09)
      We present maps of the Large and Small Magellanic Clouds from combined South Pole Telescope (SPT) and Planck data. The Planck satellite observes in nine bands, while the SPT data used in this work were taken with the three-band SPT-SZ camera, The SPT-SZ bands correspond closely to three of the nine Planck bands, namely those centered at 1.4, 2.1, and 3.0 mm. The angular resolution of the Planck data ranges from 5 to 10 arcmin, while the SPT resolution ranges from 1.0 to 1.7 arcmin. The combined maps take advantage of the high resolution of the SPT data and the long-timescale stability of the space-based Planck observations to deliver robust brightness measurements on scales from the size of the maps down to similar to 1 arcmin. In each band, we first calibrate and color-correct the SPT data to match the Planck data, then we use noise estimates from each instrument and knowledge of each instrument's beam to make the inverse-variance-weighted combination of the two instruments' data as a function of angular scale. We create maps assuming a range of underlying emission spectra and at a range of final resolutions. We perform several consistency tests on the combined maps and estimate the expected noise in measurements of features in them. We compare maps from this work to those from the Herschel HERITAGE survey, finding general consistency between the data sets. All data products described in this paper are available for download from the NASA Legacy Archive for Microwave Background Data Analysis server.
    • Mass Calibration of Optically Selected DES Clusters Using a Measurement of CMB-cluster Lensing with SPTpol Data

      Raghunathan, S.; Patil, S.; Baxter, E.; Benson, B. A.; Bleem, L. E.; Chou, T. L.; Crawford, T. M.; Holder, G. P.; McClintock, T.; Reichardt, C. L.; et al. (IOP PUBLISHING LTD, 2019-02-20)
      We use cosmic microwave background (CMB) temperature maps from the 500 deg(2) SPTpol survey to measure the stacked lensing convergence of galaxy clusters from the Dark Energy Survey (DES) Year-3 redMaPPer (RM) cluster catalog. The lensing signal is extracted through a modified quadratic estimator designed to be unbiased by the thermal Sunyaev-Zel'dovich (tSZ) effect. The modified estimator uses a tSZ-free map, constructed from the SPTpol 95 and 150 GHz data sets, to estimate the background CMB gradient. For lensing reconstruction, we employ two versions of the RM catalog: a flux-limited sample containing 4003 clusters and a volume-limited sample with 1741 clusters. We detect lensing at a significance of 8.7 sigma(6.7 sigma) with the flux (volume)-limited sample. By modeling the reconstructed convergence using the Navarro-Frenk-White profile, we find the average lensing masses to be M-200 m =(1.62(-0.25)(+0.35) [stat.] +/- 0.04 [sys.] and (1.28(-0.18)(+0.14) [stat.] +/- 0.03 [sys.] x 10(14) M-circle dot for the volume- and flux-limited samples, respectively. The systematic error budget is much smaller than the statistical uncertainty and is dominated by the uncertainties in the RM cluster centroids. We use the volume-limited sample to calibrate the normalization of the mass-richness scaling relation, and find a result consistent with the galaxy weak-lensing measurements from DES.
    • Measurements of the Cross-spectra of the Cosmic Infrared and Microwave Backgrounds from 95 to 1200 GHz

      Viero, M. P.; Reichardt, C. L.; Benson, B. A.; Bleem, L. E.; Bock, J.; Carlstrom, J. E.; Chang, C. L.; Cho, H-M.; Crawford, T. M.; Crites, A. T.; et al. (American Astronomical Society, 2019-08-16)
      We present measurements of the power spectra of cosmic infrared background (CIB) and cosmic microwave background (CMB) fluctuations in six frequency bands. Maps at the lower three frequency bands, 95, 150, and 220 GHz (3330, 2000, and 1360 μm) are from the South Pole Telescope, while the upper three frequency bands, 600, 857, and 1200 GHz (500, 350, 250 μm) are observed with Herschel/SPIRE. From these data, we produce 21 angular power spectra (6 auto- and 15 cross-frequency) spanning the multipole range 600 ≤ ℓ≤ 11,000. Our measurements are the first to cross-correlate measurements near the peak of the CIB spectrum with maps at 95 GHz, complementing and extending the measurements from Planck Collaboration et al. at 143–857 GHz. The observed fluctuations originate largely from clustered, infrared-emitting, dusty star-forming galaxies, the CMB, and to a lesser extent radio galaxies, active galactic nuclei, and the Sunyaev–Zel'dovich effect.

      Bayliss, M.; Ruel, J.; Stubbs, C. W.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; et al. (IOP PUBLISHING LTD, 2016-11-09)
      We present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg(2) of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of [O II] lambda lambda 3727, 3729 and H-delta, and the 4000 angstrom break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m*). Finally, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or similar to 20% of the full SPT-SZ sample.