An Imprint of Superstructures on the Microwave Background due to the Integrated Sachs-Wolfe Effect

Abstract

We measure hot and cold spots on the microwave background associated with supercluster and supervoid structures identified in the Sloan Digital Sky Survey Luminous Red Galaxy catalog. The structures give a compelling visual imprint, with a mean temperature deviation of 9.6 ± 2.2µK, i.e. above 4σ. We interpret this as a detection of the late-time Integrated Sachs-Wolfe (ISW) effect, in which cosmic acceleration from dark energy causes gravitational potentials to decay, heating or cooling photons passing through density crests or troughs. In a flat universe, the linear ISW effect is a direct signal of dark energy. Subject headings: cosmic microwave background -cosmology: observations -large-scale structure of universe -methods: statistical

On the recovery of ISW fluctuations using large-scale structure tracers and CMB temperature and polarization anisotropies

“…The ISW can also be studied through the bispectrum of the ISWlensing (Hu & Okamoto 2002), which was applied for the first time in Planck Collaboration et al (2014a). Finally, the ISW can also be studied by stacking the CMB fluctuations on the positions of known large-scale superclusters (e.g., Granett, Neyrinck, & Szapudi 2008;Planck Collaboration et al 2014a). In fact these staking analysis indicate some tensions with ΛCDM (e.g., Nadathur, Hotchkiss, & Sarkar 2012;Ilić, Langer, & Douspis 2013) Complementarily to these techniques which detect the ISW statistically, more recent works have presented methods to reconstruct an actual map of the ISW contribution to the CMB sky.…”

“…The technique was applied to obtain an ISW map from CMB, lensing and the NVSS galaxy survey. Other approaches, where only the map of a galaxy number density field traced by a particular Large Scale Structure (LSS) survey is used, have also been proposed: Granett, Neyrinck, & Szapudi (2008) on LRGs from SDSS-DR6, or Francis & Peacock (2010) and Dupé et al (2011) on 2MASS. In this work we present a further generalization of the LCB filter to extract a map of the ISW signal, which allows not only the inclusion of an arbitrary number of surveys but also of CMB polarization information. We perform a thorough study of the performance of the method to reconstruct the ISW effect using a total of three simulated LSS surveys, lensing information and CMB intensity and polarization.…”

Integrated Sachs-Wolfe effect versus redshift test for the cosmological parameters

“…The late time integrated Sachs-Wolfe (ISW) effect [1], also called the Rees-Sciama (RS) effect [2], has recently been suggested (as well and disputed) as the source of observed hot and cold spots in the CMB temperature around some known large scale structuresgalaxy clusters and cosmic voids [3][4][5]. By modeling cluster and void density profiles, and by adjusting cluster masses and void depths, observed temperature excesses/deficits can be matched by ISW predictions [6][7][8][9][10][11].…”

The impact of superstructures in the Cosmic Microwave Background

“…While their individual imprint is drowned in the primordial CMB fluctuations, we can average patches of the CMB at the locations of many superstructures in order to cancel the random CMB fluctuations while enhancing the iSW signal. In their pioneering work, Granett et al (2008) claimed a 4 σ detection of the iSW effect by stacking CMB Figure 1. Map of the theoretical temperature shift due to the 50 voids of Granett et al 2008.…”

“…In their pioneering work, Granett et al (2008) claimed a 4 σ detection of the iSW effect by stacking CMB Figure 1. Map of the theoretical temperature shift due to the 50 voids of Granett et al 2008.…”