Browsing by Subject "gravitational lensing: weak"

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  • Koksbang, Sofie Marie; Clarkson, Chris (2019)
    Weak lensing will play an important role in future cosmological surveys, including e.g. Euclid and SKA. Sufficiently accurate theoretical predictions are important for correctly interpreting these surveys and hence for extracting correct cosmological parameter estimations. We quantify for the first time in a relativistic setting how many post-Born and lens-lens coupling corrections are required for sub-per cent accuracy of the theoretical weak lensing convergence for z
  • Cibirka, N.; Cypriano, E. S.; Brimioulle, F.; Gruen, D.; Erben, T.; van Waerbeke, L.; Miller, L.; Finoguenov, A.; Kirkpatrick , C.; Henry, J. Patrick; Rykoff, E.; Rozo, E.; Dupke, R.; Kneib, J. -P.; Shan, H.; Spinelli, P. (2017)
    We present a stacked weak-lensing analysis of 27 richness selected galaxy clusters at 0.40
  • Kiiveri, K.; Gruen, D.; Finoguenov, A.; Erben, T.; van Waerbeke, L.; Rykoff, E.; Miller, L.; Hagstotz, S.; Dupke, R.; Henry, J. Patrick; Kneib, J-P; Gozaliasl, G.; Kirkpatrick , C. C.; Cibirka, N.; Clerc, N.; Costanzi, M.; Cypriano, E. S.; Rozo, E.; Shan, H.; Spinelli, P.; Valiviita, J.; Weller, J. (2021)
    The COnstrain Dark Energy with X-ray clusters (CODEX) sample contains the largest flux limited sample of X-ray clusters at 0.35 <z <0.65. It was selected from ROSAT data in the 10 000 square degrees of overlap with BOSS, mapping a total number of 2770 high-z galaxy clusters. We present here the full results of the CFHT CODEX programme on cluster mass measurement, including a reanalysis of CFHTLS Wide data, with 25 individual lensing-constrained cluster masses. We employ LENSFIT shape measurement and perform a conservative colour-space selection and weighting of background galaxies. Using the combination of shape noise and an analytic covariance for intrinsic variations of cluster profiles at fixed mass due to large-scale structure, miscentring, and variations in concentration and ellipticity, we determine the likelihood of the observed shear signal as a function of true mass for each cluster. We combine 25 individual cluster mass likelihoods in a Bayesian hierarchical scheme with the inclusion of optical and X-ray selection functions to derive constraints on the slope alpha, normalization beta, and scatter sigma(ln lambda vertical bar mu) of our richness-mass scaling relation model in log-space: <In lambda vertical bar mu > = alpha mu + beta, with mu = ln (M-200c/M-piv), and M-piv = 10(14.81)M(circle dot). We find a slope alpha = 0.49(-0.15)(+0.20) , normalization exp(beta) = 84.0(-14.8)(+9.2) , and sigma(ln lambda vertical bar mu) = 0.17(-0.09)(+0.13) using CFHT richness estimates. In comparison to other weak lensing richness-mass relations, we find the normalization of the richness statistically agreeing with the normalization of other scaling relations from a broad redshift range (0.0 <z <0.65) and with different cluster selection (X-ray, Sunyaev-Zeldovich, and optical).
  • Euclid Collaboration; Paykari, P.; Keihänen, E.; Kurki-Suonio, H.; Kirkpatrick, C. C. (2020)
    Aims. Our aim is to quantify the impact of systematic effects on the inference of cosmological parameters from cosmic shear.Methods. We present an "end-to-end" approach that introduces sources of bias in a modelled weak lensing survey on a galaxy-by-galaxy level. We propagated residual biases through a pipeline from galaxy properties at one end to cosmic shear power spectra and cosmological parameter estimates at the other end. We did this to quantify how imperfect knowledge of the pipeline changes the maximum likelihood values of dark energy parameters.Results. We quantify the impact of an imperfect correction for charge transfer inefficiency and modelling uncertainties of the point spread function for Euclid, and find that the biases introduced can be corrected to acceptable levels.
  • Mulroy, Sarah L.; Farahi, Arya; Evrard, August E.; Smith, Graham P.; Finoguenov, Alexis; O'Donnell, Christine; Marrone, Daniel P.; Abdulla, Zubair; Bourdin, Herve; Carlstrom, John E.; Democles, Jessica; Haines, Chris P.; Martino, Rossella; Mazzotta, Pasquale; McGee, Sean L.; Okabe, Nobuhiro (2019)
    We present a simultaneous analysis of galaxy cluster scaling relations between weak-lensing mass and multiple cluster observables, across a wide range of wavelengths, that probe both gas and stellar content. Our new hierarchical Bayesian model simultaneously considers the selection variable alongside all other observables in order to explicitly model intrinsic property covariance and account for selection effects. We apply this method to a sample of 41 clusters at 0.15 <z <0.30, with a well-defined selection criteria based on RASS X-ray luminosity, and observations from Chandra/XMM, SZA, Planck, UKIRT, SUSS, and Subaru. These clusters have well-constrained weak-lensing mass measurements based on Subaru/SuprimeCam observations, which serve as the reference masses in our model. We present 30 scaling relation parameters for 10 properties. All relations probing the intracluster gas are slightly shallower than self-similar predictions, in moderate tension with prior measurements, and the stellar fraction decreases with mass. K-band luminosity has the lowest intrinsic scatter with a 95th percentile of 0.16, while the lowest scatter gas probe is gas mass with a fractional intrinsic scatter of 0.16 +/- 0.03. We find no distinction between the core-excised X-ray or high-resolution Sunyaev-Zel'dovich relations of clusters of different central entropy, but find with modest significance that higher entropy clusters have higher stellar fractions than their lower entropy counterparts. We also report posterior mass estimates from our likelihood model.
  • Ade, P. A. R.; Juvela, M.; Keihanen, E.; Kurki-Suonio, H.; Poutanen, T.; Suur-Uski, A. -S.; Tuovinen, J.; Valiviita, J.; Planck Collaboration (2014)
  • Ade, P. A. R.; Juvela, M.; Keihanen, E.; Kurki-Suonio, H.; Lahteenmaki, A.; Leon-Tavares, J.; Poutanen, T.; Suur-Uski, A. -S.; Tuovinen, J.; Valiviita, J.; Planck Collaboration (2014)
  • Planck Collaboration; Aghanim, N.; Keihanen, E.; Kiiveri, K.; Kurki-Suonio, H.; Lindholm, V.; Savelainen, M.; Suur-Uski, A. -S.; Valiviita, J. (2020)
    We present measurements of the cosmic microwave background (CMB) lensing potential using the final Planck 2018 temperature and polarization data. Using polarization maps filtered to account for the noise anisotropy, we increase the significance of the detection of lensing in the polarization maps from 5 sigma to 9 sigma. Combined with temperature, lensing is detected at 40 sigma. We present an extensive set of tests of the robustness of the lensing-potential power spectrum, and construct a minimum-variance estimator likelihood over lensing multipoles 8 (8)Omega (0.25)(m) = 0.589 +/- 0.020 sigma 8 Omega m 0.25 = 0.589 +/- 0.020 (1 sigma errors). Also combining with baryon acoustic oscillation data, we find tight individual parameter constraints, sigma (8)=0.811 +/- 0.019, H-0 = 67.9(-1.3)(+1.2) km s(-1) Mpc(-1) H 0 = 67 . 9 - 1.3 + 1.2 .> km s - 1 . Mpc - 1 , and Omega (m) = 0.303(-0.018)(+0.016) Omega m = 0 . 303 - 0.018 + 0.016 . Combining with Planck CMB power spectrum data, we measure sigma (8) to better than 1% precision, finding sigma (8)=0.811 +/- 0.006. CMB lensing reconstruction data are complementary to galaxy lensing data at lower redshift, having a different degeneracy direction in sigma (8)-Omega (m) space; we find consistency with the lensing results from the Dark Energy Survey, and give combined lensing-only parameter constraints that are tighter than joint results using galaxy clustering. Using the Planck cosmic infrared background (CIB) maps as an additional tracer of high-redshift matter, we make a combined Planck-only estimate of the lensing potential over 60% of the sky with considerably more small-scale signal. We additionally demonstrate delensing of the Planck power spectra using the joint and individual lensing potential estimates, detecting a maximum removal of 40% of the lensing-induced power in all spectra. The improvement in the sharpening of the acoustic peaks by including both CIB and the quadratic lensing reconstruction is detected at high significance.
  • Phriksee, Anirut; Jullo, Eric; Limousin, Marceau; Shan, HuanYuan; Finoguenov, Alexis; Komonjinda, Siramas; Wannawichian, Suwicha; Sawangwit, Utane (2020)
    We present the weak-lensing analysis of 279 CODEX clusters using imaging data from 4200 deg(2) of the DECam Legacy Survey (DECaLS) Data Release 3. The cluster sample results from a joint selection in X-ray, optical richness in the range 20 proportional to M-0 (lambda/40)(F lambda). By measuring the CODEX cluster sample as an individual cluster, we obtain the best-fitting values, M-0 = 3.24(-0.27)(+0.29) x 10(14)M(circle dot), and F-lambda = 1.00(-0.22)(+0.22) for the richness scaling index, consistent with a power-law relation. Moreover, we separate the cluster sample into three richness groups; lambda = 20-30, 30-50, and 50-110, and measure the stacked excess surface mass density profile in each group. The results show that both methods are consistent. In addition, we find an excellent agreement between our weak lensing based scaling relation and the relation obtained with dynamical masses estimated from cluster member velocity dispersions measured by the SDSS-IV/SPIDERS team. This suggests that the cluster dynamical equilibrium assumption involved in the dynamical mass estimates is statistically robust for a large sample of clusters.