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Register a new userA measurement of the secondary-CMB and millimeter-wave-foreground bispectrum using 800 square degrees of South Pole Telescope data
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We present a measurement of the angular bispectrum of the millimeter-wave sky in observing bands centered at roughly 95, 150, and 220 GHz, on angular scales of $1^prime lesssim theta lesssim 10^prime$ (multipole number $1000 lesssim l lesssim 10000$). At these frequencies and angular scales, the main contributions to the bispectrum are expected to be the thermal Sunyaev-Zeldovich (tSZ) effect and emission from extragalactic sources, predominantly dusty, star-forming galaxies (DSFGs) and active galactic nuclei. We measure the bispectrum in 800 $mathrm{deg}^2$ of three-band South Pole Telescope data, and we use a multi-frequency fitting procedure to separate the bispectrum of the tSZ effect from the extragalactic source contribution. We simultaneously detect the bispectrum of the tSZ effect at $>$10$sigma$, the unclustered component of the extragalactic source bispectrum at $>$5$sigma$ in each frequency band, and the bispectrum due to the clustering of DSFGs---i.e., the clustered cosmic infrared background (CIB) bispectrum---at $>$5$sigma$. This is the first reported detection of the clustered CIB bispectrum. We use the measured tSZ bispectrum amplitude, compared to model predictions, to constrain the normalization of the matter power spectrum to be $sigma_8 = 0.787 pm 0.031$ and to predict the amplitude of the tSZ power spectrum at $l = 3000$. This prediction improves our ability to separate the thermal and kinematic contributions to the total SZ power spectrum. The addition of bispectrum data improves our constraint on the tSZ power spectrum amplitude by a factor of two compared to power spectrum measurements alone and demonstrates a preference for a nonzero kinematic SZ (kSZ) power spectrum, with a derived constraint on the kSZ amplitude at $l=3000$ of A_kSZ $ = 2.9 pm 1.6 mu$K$^2$, or A_kSZ $ = 2.6 pm 1.8 mu$K$^2$ if the default A_kSZ > 0 prior is removed.
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We present a cosmic microwave background (CMB) lensing map produced from a linear combination of South Pole Telescope (SPT) and emph{Planck} temperature data. The 150 GHz temperature data from the $2500 {rm deg}^{2}$ SPT-SZ survey is combined with the emph{Planck} 143 GHz data in harmonic space, to obtain a temperature map that has a broader $ell$ 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 $C_{L}^{phiphi}$, and compare it to the theoretical prediction for a $Lambda$CDM cosmology consistent with the emph{Planck} 2015 data set, finding a best-fit amplitude of $0.95_{-0.06}^{+0.06}({rm Stat.})! _{-0.01}^{+0.01}({rm Sys.})$. 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+emph{Planck} lensing map and Wide-field Infrared Survey Explorer (emph{WISE}) galaxies. We fit $C_{L}^{phi G}$ to a power law of the form $p_{L}=a(L/L_{0})^{-b}$ with $a=2.15 times 10^{-8}$, $b=1.35$, $L_{0}=490$, and find $eta^{phi G}=0.94^{+0.04}_{-0.04}$, 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 emph{Planck}-2015 CMB lensing and emph{WISE} galaxies over $sim67%$ of the sky. The lensing potential map presented here will be used for cross-correlation studies with the Dark Energy Survey (DES), whose footprint nearly completely covers the SPT $2500 {rm deg}^2$ field.
We use South Pole Telescope data from 2008 and 2009 to detect the non-Gaussian signature in the cosmic microwave background (CMB) produced by gravitational lensing and to measure the power spectrum of the projected gravitational potential. We constrain the ratio of the measured amplitude of the lensing signal to that expected in a fiducial LCDM cosmological model to be 0.86 +/- 0.16, with no lensing disfavored at 6.3 sigma. Marginalizing over LCDM cosmological models allowed by the WMAP7 results in a measurement of A_lens=0.90+/-0.19, indicating that the amplitude of matter fluctuations over the redshift range 0.5 <~ z <~ 5 probed by CMB lensing is in good agreement with predictions. We present the results of several consistency checks. These include a clear detection of the lensing signature in CMB maps filtered to have no overlap in Fourier space, as well as a curl diagnostic that is consistent with the signal expected for LCDM. We perform a detailed study of bias in the measurement due to noise, foregrounds, and other effects and determine that these contributions are relatively small compared to the statistical uncertainty in the measurement. We combine this lensing measurement with results from WMAP7 to improve constraints on cosmological parameters when compared to those from WMAP7 alone: we find a factor of 3.9 improvement in the measurement of the spatial curvature of the Universe, Omega_k=-0.0014+/-0.0172; a 10% improvement in the amplitude of matter fluctuations within LCDM, sigma_8=0.810+/ 0.026; and a 5% improvement in the dark energy equation of state, w=-1.04+/-0.40. When compared with the measurement of w provided by the combination of WMAP7 and external constraints on the Hubble parameter, the addition of the lensing data improve the measurement of w by 15% to give w=-1.087+/-0.096.
We report the results of an 87 square-degree point-source survey centered at R.A. 5h30m, decl. -55 deg. taken with the South Pole Telescope (SPT) at 1.4 and 2.0 mm wavelengths with arc-minute resolution and milli-Jansky depth. Based on the ratio of flux in the two bands, we separate the detected sources into two populations, one consistent with synchrotron emission from active galactic nuclei (AGN) and one consistent with thermal emission from dust. We present source counts for each population from 11 to 640 mJy at 1.4 mm and from 4.4 to 800 mJy at 2.0 mm. The 2.0 mm counts are dominated by synchrotron-dominated sources across our reported flux range; the 1.4 mm counts are dominated by synchroton-dominated sources above ~15 mJy and by dust-dominated sources below that flux level. We detect 141 synchrotron-dominated sources and 47 dust-dominated sources at S/N > 4.5 in at least one band. All of the most significantly detected members of the synchrotron-dominated population are associated with sources in previously published radio catalogs. Some of the dust-dominated sources are associated with nearby (z << 1) galaxies whose dust emission is also detected by the Infrared Astronomy Satellite (IRAS). However, most of the bright, dust-dominated sources have no counterparts in any existing catalogs. We argue that these sources represent the rarest and brightest members of the population commonly referred to as sub-millimeter galaxies (SMGs). Because these sources are selected at longer wavelengths than in typical SMG surveys, they are expected to have a higher mean redshift distribution and may provide a new window on galaxy formation in the early universe.
We compare cosmic microwave background lensing convergence maps derived from South Pole Telescope (SPT) data with galaxy survey data from the Blanco Cosmology Survey, the Wide-field Infrared Survey Explorer, and a new large Spitzer/IRAC field designed to overlap with the SPT survey. Using optical and infrared catalogs covering between 17 and 68 square degrees of sky, we detect correlation between the SPT convergence maps and each of the galaxy density maps at >4 sigma, with zero cross-correlation robustly ruled out in all cases. The amplitude and shape of the cross-power spectra are in good agreement with theoretical expectations and the measured galaxy bias is consistent with previous work. The detections reported here utilize a small fraction of the full 2500 square degree SPT survey data and serve as both a proof of principle of the technique and an illustration of the potential of this emerging cosmological probe.
We present APEX SABOCA 350micron and LABOCA 870micron observations of 11 representative examples of the rare, extremely bright (S_1.4mm > 15mJy), dust-dominated millimeter-selected galaxies recently discovered by the South Pole Telescope (SPT). All 11 sources are robustly detected with LABOCA with 40 < S_870micron < 130mJy, approximately an order of magnitude higher than the canonical submillimeter galaxy (SMG) population. Six of the sources are also detected by SABOCA at >3sigma, with the detections or upper limits providing a key constraint on the shape of the spectral energy distribution (SED) near its peak. We model the SEDs of these galaxies using a simple modified blackbody and perform the same analysis on samples of SMGs of known redshift from the literature. These calibration samples inform the distribution of dust temperature for similar SMG populations, and this dust temperature prior allows us to derive photometric redshift estimates and far infrared luminosities for the sources. We find a median redshift of <z> = 3.0, higher than the <z> = 2.2 inferred for the normal SMG population. We also derive the apparent size of the sources from the temperature and apparent luminosity, finding them to appear larger than our unlensed calibration sample, which supports the idea that these sources are gravitationally magnified by massive structures along the line of sight.
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