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Free, publiclyaccessible full text available August 1, 2024

Abstract We provide the first combined cosmological analysis of the South Pole Telescope (SPT) and Planck cluster catalogs. The aim is to provide an independent calibration for Planck scaling relations, exploiting the cosmological constraining power of the SPTSZ cluster catalog and its dedicated weak lensing (WL) and Xray followup observations. We build a new version of the Planck cluster likelihood. In the ν Λ CDM scenario, focusing on the mass slope and mass bias of Planck scaling relations, we find α SZ = 1.49 − 0.10 + 0.07 and 1 − b SZ = 0.69 − 0.14 + 0.07 , respectively. The results for the mass slope show a ∼4 σ departure from the selfsimilar evolution, α SZ ∼ 1.8. This shift is mainly driven by the matter density value preferred by SPT data, Ω m = 0.30 ± 0.03, lower than the one obtained by Planck data alone, Ω m = 0.37 − 0.06 + 0.02 . The mass bias constraints are consistent both with outcomes of hydrodynamical simulations and external WL calibrations, (1 − b ) ∼ 0.8, and with results required by the Planck cosmic microwave background cosmology, (1 − b ) ∼ 0.6. From this analysis, we obtain a new catalog of Planck cluster masses M 500 . We estimate the ratio between the published Planck M SZ masses and our derived masses M 500 , as a “measured mass bias,” 1 − b M . We analyze the mass, redshift, and detection noise dependence of 1 − b M , finding an increasing trend toward high redshift and low mass. These results mimic the effect of departure from selfsimilarity in cluster evolution, showing different dependencies for the lowmass, highmass, low z , and high z regimes.more » « less

ABSTRACT Expanding from previous work, we present weaklensing (WL) measurements for a total sample of 30 distant (zmedian = 0.93) massive galaxy clusters from the South Pole Telescope Sunyaev–Zel’dovich (SPTSZ) Survey, measuring galaxy shapes in Hubble Space Telescope (HST) Advanced Camera for Surveys images. We remove cluster members and preferentially select z ≳ 1.4 background galaxies via V − I colour, employing deep photometry from VLT/FORS2 and GeminiSouth/GMOS. We apply revised calibrations for the WL shape measurements and the source redshift distribution to estimate the cluster masses. In combination with earlier Magellan/Megacam results for lowerredshifts clusters, we infer refined constraints on the scaling relation between the SZ detection significance and the cluster mass, in particular regarding its redshift evolution. The mass scale inferred from the WL data is lower by a factor $0.76^{+0.10}_{0.14}$ (at our pivot redshift z = 0.6) compared to what would be needed to reconcile a flat Planck νΛCDM cosmology (in which the sum of the neutrino masses is a free parameter) with the observed SPTSZ cluster counts. In order to sensitively test the level of (dis)agreement between SPT clusters and Planck, further expanded WL followup samples are needed.more » « less

Abstract We show the improvement to cosmological constraints from galaxy cluster surveys with the addition of cosmic microwave background (CMB)cluster lensing data. We explore the cosmological implications of adding mass information from the 3.1 σ detection of gravitational lensing of the CMB by galaxy clusters to the Sunyaev–Zel’dovich (SZ) selected galaxy cluster sample from the 2500 deg 2 SPTSZ survey and targeted optical and Xray followup data. In the ΛCDM model, the combination of the cluster sample with the Planck power spectrum measurements prefers σ 8 Ω m / 0.3 0.5 = 0.831 ± 0.020 . Adding the cluster data reduces the uncertainty on this quantity by a factor of 1.4, which is unchanged whether the 3.1 σ CMBcluster lensing measurement is included or not. We then forecast the impact of CMBcluster lensing measurements with future cluster catalogs. Adding CMBcluster lensing measurements to the SZ cluster catalog of the ongoing SPT3G survey is expected to improve the expected constraint on the dark energy equation of state w by a factor of 1.3 to σ ( w ) = 0.19. We find the largest improvements from CMBcluster lensing measurements to be for σ 8 , where adding CMBcluster lensing data to the cluster number counts reduces the expected uncertainty on σ 8 by respective factors of 2.4 and 3.6 for SPT3G and CMBS4.more » « less

Abstract Including millimeterwave data in multiwavelength studies of the variability of active galactic nuclei (AGN) can provide insights into AGN physics that are not easily accessible at other wavelengths. We demonstrate in this work the potential of cosmic microwave background (CMB) telescopes to provide longterm, highcadence millimeterwave AGN monitoring over large fractions of sky. We report on a pilot study using data from the SPTpol instrument on the South Pole Telescope (SPT), which was designed to observe the CMB at arcminute and larger angular scales. Between 2013 and 2016, SPTpol was used primarily to observe a single 500 deg^{2}field, covering the entire field several times per day with detectors sensitive to radiation in bands centered at 95 and 150 GHz. We use SPT 150 GHz observations to create AGN light curves, and we compare these millimeterwave light curves to those at other wavelengths, in particular
γ ray and optical. In this Letter, we focus on a single source, PKS 2326502, which has extensive, daytimescale monitoring data in gammaray, optical, and now millimeterwave between 2013 and 2016. We find PKS 2326502 to be in a flaring state in the first 2 yr of this monitoring, and we present a search for evidence of correlated variability between millimeterwave, opticalR band, andγ ray observations. This pilot study is paving the way for AGN monitoring with current and upcoming CMB experiments such as SPT3G, Simons Observatory, and CMBS4, including multiwavelength studies with facilities such as Vera C. Rubin Observatories Large Synoptic Survey Telescope. 
We consider a (very) simple version of the restricted three body problem in general relativity. The background geometry is given by a Schwarzschild solution governing the motion of two bodies of masses $m_1$ and $m_2$. We assume that corrections to the trajectory of the body of mass $m_1$ due to the presence of the mass $m_2$ are given by a Newtonian approximation where Poisson's equation is solved with respect to the Schwarzschild background geometry. Under these assumptions, we derive approximate equations of motion for the corrections to the trajectory of the body of mass $m_1$.more » « less

ABSTRACT We search for the signature of cosmological shocks in stacked gas pressure profiles of galaxy clusters using data from the South Pole Telescope (SPT). Specifically, we stack the latest Comptony maps from the 2500 deg2 SPTSZ survey on the locations of clusters identified in that same data set. The sample contains 516 clusters with mean mass $\langle M_{\rm 200m}\rangle = 10^{14.9} \, {\rm M}_\odot$ and redshift 〈z〉 = 0.55. We analyse in parallel a set of zoomin hydrodynamical simulations from the three hundred project. The SPTSZ data show two features: (i) a pressure deficit at R/R200m = 1.08 ± 0.09, measured at 3.1σ significance and not observed in the simulations, and; (ii) a sharp decrease in pressure at R/R200m = 4.58 ± 1.24 at 2.0σ significance. The pressure deficit is qualitatively consistent with a shockinduced thermal nonequilibrium between electrons and ions, and the second feature is consistent with accretion shocks seen in previous studies. We split the cluster sample by redshift and mass, and find both features exist in all cases. There are also no significant differences in features along and across the cluster major axis, whose orientation roughly points towards filamentary structure. As a consistency test, we also analyse clusters from the Planck and Atacama Cosmology Telescope Polarimeter surveys and find quantitatively similar features in the pressure profiles. Finally, we compare the accretion shock radius ($R_{\rm sh,\, acc}$) with existing measurements of the splashback radius (Rsp) for SPTSZ and constrain the lower limit of the ratio, $R_{\rm sh,\, acc}/R_{\rm sp}\gt 2.16 \pm 0.59$.