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1. On the halo-mass and radial scale dependence of the lensing is low effect

   https://doi.org/10.1093/mnras/stab189  

   Lange, Johannes U; Leauthaud, Alexie; Singh, Sukhdeep; Guo, Hong; Zhou, Rongpu; Smith, Tristan L; Cyr-Racine, Francis-Yan (February 2021, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT The canonical Lambda cold dark matter (ΛCDM) cosmological model makes precise predictions for the clustering and lensing properties of galaxies. It has been shown that the lensing amplitude of galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS) is lower than expected given their clustering properties. We present new measurements and modelling of galaxies in the BOSS LOWZ sample. We focus on the radial and stellar mass dependence of the lensing amplitude mismatch. We find an amplitude mismatch of around $$35{{\ \rm per\ cent}}$$ when assuming ΛCDM with Planck Cosmological Microwave Background (CMB) constraints. This offset is independent of halo mass and radial scale in the range Mhalo ∼ 1013.3−1013.9h−1 M⊙ and $$r=0.1\!-\!60 \, h^{-1} \mathrm{Mpc}$$ ($$k \approx 0.05\!-\!20 \, h \, {\rm Mpc}^{-1}$$). The observation that the offset is both mass and scale independent places important constraints on the degree to which astrophysical processes (baryonic effects, assembly bias) can fully explain the effect. This scale independence also suggests that the ‘lensing is low’ effect on small and large radial scales probably have the same physical origin. Resolutions based on new physics require a nearly uniform suppression, relative to ΛCDM predictions, of the amplitude of matter fluctuations on these scales. The possible causes of this are tightly constrained by measurements of the CMB and of the low-redshift expansion history. 

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2. The completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: measurement of the growth rate of structure from the small-scale clustering of the luminous red galaxy sample

   https://doi.org/10.1093/mnras/stac1923  

   Chapman, Michael J.; Mohammad, Faizan G.; Zhai, Zhongxu; Percival, Will J.; Tinker, Jeremy L.; Bautista, Julian E.; Brownstein, Joel R.; Burtin, Etienne; Dawson, Kyle S.; Gil-Marín, Héctor; et al (July 2022, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We measure the small-scale clustering of the Data Release 16 extended Baryon Oscillation Spectroscopic Survey Luminous Red Galaxy sample, corrected for fibre-collisions using Pairwise Inverse Probability weights, which give unbiased clustering measurements on all scales. We fit to the monopole and quadrupole moments and to the projected correlation function over the separation range $$7-60\, h^{-1}{\rm Mpc}$$ with a model based on the aemulus cosmological emulator to measure the growth rate of cosmic structure, parametrized by fσ8. We obtain a measurement of fσ8(z = 0.737) = 0.408 ± 0.038, which is 1.4σ lower than the value expected from 2018 Planck data for a flat ΛCDM model, and is more consistent with recent weak-lensing measurements. The level of precision achieved is 1.7 times better than more standard measurements made using only the large-scale modes of the same sample. We also fit to the data using the full range of scales $$0.1\text{--}60\, h^{-1}{\rm Mpc}$$ modelled by the aemulus cosmological emulator and find a 4.5σ tension in the amplitude of the halo velocity field with the Planck + ΛCDM model, driven by a mismatch on the non-linear scales. This may not be cosmological in origin, and could be due to a breakdown in the Halo Occupation Distribution model used in the emulator. Finally, we perform a robust analysis of possible sources of systematics, including the effects of redshift uncertainty and incompleteness due to target selection that were not included in previous analyses fitting to clustering measurements on small scales. 

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3. The Atacama Cosmology Telescope: DR6 Gravitational Lensing Map and Cosmological Parameters

   https://doi.org/10.3847/1538-4357/acff5f  

   Madhavacheril, Mathew S.; Qu, Frank J.; Sherwin, Blake D.; MacCrann, Niall; Li, Yaqiong; Abril-Cabezas, Irene; Ade, Peter A. R.; Aiola, Simone; Alford, Tommy; Amiri, Mandana; et al (February 2024, The Astrophysical Journal)

   Abstract We present cosmological constraints from a gravitational lensing mass map covering 9400 deg²reconstructed from measurements of the cosmic microwave background (CMB) made by the Atacama Cosmology Telescope (ACT) from 2017 to 2021. In combination with measurements of baryon acoustic oscillations and big bang nucleosynthesis, we obtain the clustering amplitudeσ₈= 0.819 ± 0.015 at 1.8% precision, $S_8\equiv {\sigma }_8{\left({\mathrm{\Omega }}_{\mathrm{m}}/0.3\right)}^{0.5}=0.840\pm 0.028$, and the Hubble constantH₀= (68.3 ± 1.1) km s⁻¹Mpc⁻¹at 1.6% precision. A joint constraint with Planck CMB lensing yieldsσ₈= 0.812 ± 0.013, $S_8\equiv {\sigma }_8{\left({\mathrm{\Omega }}_{\mathrm{m}}/0.3\right)}^{0.5}=0.831\pm 0.023$, andH₀= (68.1 ± 1.0) km s⁻¹Mpc⁻¹. These measurements agree with ΛCDM extrapolations from the CMB anisotropies measured by Planck. We revisit constraints from the KiDS, DES, and HSC galaxy surveys with a uniform set of assumptions and find thatS₈from all three are lower than that from ACT+Planck lensing by levels ranging from 1.7σto 2.1σ. This motivates further measurements and comparison, not just between the CMB anisotropies and galaxy lensing but also between CMB lensing probingz∼ 0.5–5 on mostly linear scales and galaxy lensing atz∼ 0.5 on smaller scales. We combine with CMB anisotropies to constrain extensions of ΛCDM, limiting neutrino masses to ∑m_ν< 0.13 eV (95% c.l.), for example. We describe the mass map and related data products that will enable a wide array of cross-correlation science. Our results provide independent confirmation that the universe is spatially flat, conforms with general relativity, and is described remarkably well by the ΛCDM model, while paving a promising path for neutrino physics with lensing from upcoming ground-based CMB surveys. 

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4. Cosmological constraints from the tomographic cross-correlation of DESI Luminous Red Galaxies and Planck CMB lensing

   https://doi.org/10.1088/1475-7516/2022/02/007  

   White, Martin; Zhou, Rongpu; DeRose, Joseph; Ferraro, Simone; Chen, Shi-Fan; Kokron, Nickolas; Bailey, Stephen; Brooks, David; García-Bellido, Juan; Guy, Julien; et al (February 2022, Journal of Cosmology and Astroparticle Physics)

   Abstract We use luminous red galaxies selected from the imaging surveys that are being used for targeting by the Dark Energy Spectroscopic Instrument (DESI) in combination with CMB lensing maps from the Planck collaboration to probe the amplitude of large-scale structure over 0.4 ≤  z  ≤ 1. Our galaxy sample, with an angular number density of approximately 500 deg -2 over 18,000 sq.deg., is divided into 4 tomographic bins by photometric redshift and the redshift distributions are calibrated using spectroscopy from DESI. We fit the galaxy autospectra and galaxy-convergence cross-spectra using models based on cosmological perturbation theory, restricting to large scales that are expected to be well described by such models. Within the context of ΛCDM, combining all 4 samples and using priors on the background cosmology from supernova and baryon acoustic oscillation measurements, we find S 8  = σ 8 (Ω m /0.3) 0.5  = 0.73 ± 0.03. This result is lower than the prediction of the ΛCDM model conditioned on the Planck data. Our data prefer a slower growth of structure at low redshift than the model predictions, though at only modest significance. 

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5. The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and Its Implications for Structure Growth

   https://doi.org/10.3847/1538-4357/acfe06  

   Qu, Frank J.; Sherwin, Blake D.; Madhavacheril, Mathew S.; Han, Dongwon; Crowley, Kevin T.; Abril-Cabezas, Irene; Ade, Peter A. R.; Aiola, Simone; Alford, Tommy; Amiri, Mandana; et al (February 2024, The Astrophysical Journal)

   Abstract We present new measurements of cosmic microwave background (CMB) lensing over 9400 deg²of the sky. These lensing measurements are derived from the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) CMB data set, which consists of five seasons of ACT CMB temperature and polarization observations. We determine the amplitude of the CMB lensing power spectrum at 2.3% precision (43σsignificance) using a novel pipeline that minimizes sensitivity to foregrounds and to noise properties. To ensure that our results are robust, we analyze an extensive set of null tests, consistency tests, and systematic error estimates and employ a blinded analysis framework. Our CMB lensing power spectrum measurement provides constraints on the amplitude of cosmic structure that do not depend on Planck or galaxy survey data, thus giving independent information about large-scale structure growth and potential tensions in structure measurements. The baseline spectrum is well fit by a lensing amplitude ofA_lens= 1.013 ± 0.023 relative to the Planck 2018 CMB power spectra best-fit ΛCDM model andA_lens= 1.005 ± 0.023 relative to the ACT DR4 + WMAP best-fit model. From our lensing power spectrum measurement, we derive constraints on the parameter combination $S_8^{\mathrm{CMBL}}\equiv {\sigma }_8{\left({\mathrm{\Omega }}_m/0.3\right)}^{0.25}$of $S_8^{\mathrm{CMBL}}=0.818\pm 0.022$from ACT DR6 CMB lensing alone and $S_8^{\mathrm{CMBL}}=0.813\pm 0.018$when combining ACT DR6 and PlanckNPIPECMB lensing power spectra. These results are in excellent agreement with ΛCDM model constraints from Planck or ACT DR4 + WMAP CMB power spectrum measurements. Our lensing measurements from redshiftsz∼ 0.5–5 are thus fully consistent with ΛCDM structure growth predictions based on CMB anisotropies probing primarilyz∼ 1100. We find no evidence for a suppression of the amplitude of cosmic structure at low redshifts. 

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