Probing supervoids with weak lensing

Abstract

The cosmic microwave background (CMB) has non-Gaussian features in the temperature fluctuations. An anomalous cold spot surrounded with a hot ring, called the Cold Spot is one of such features. If a large underdence region (supervoid) resides towards the Cold Spot, we would be able to detect a systematic shape distortion in the images of background source galaxies via weak lensing effect. In order to estimate the detectability of such signals, we used the data of $N$-body simulations to simulate full-sky ray-tracing of source galaxies. We searched for a most prominent underdense region using the simulated convergence maps smoothed at a scale of 20 degree and obtained tangential shears around it. The lensing signal expected in a concordant $\Lambda$CDM model can be detected at a signal-to-noise ratio $S/N\sim 3$. If a supervoid with a radius of $\sim 200h^{-1}\text{Mpc}$ and a density contrast ${\delta }_0\sim -0.3$ at the centre resides at a redshift $z\sim 0.2$, on-going and near-future weak gravitational lensing surveys would detect a lensing signal with $S/N\gtrsim 4$ without resorting to stacking. From the tangential shear profile, we can obtain a constraint on the projected mass distribution of the supervoid.

7 pages, 4 figures, 2 tables, accepted for publication in MNRAS

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Cited by in corpus (6)

• Dark Energy Survey Year 1 Results: Curved-Sky Weak Lensing Mass Map
• The DES view of the Eridanus supervoid and the CMB Cold Spot
• Subaru Hyper Suprime-Cam excavates colossal over- and under-dense structures over 360 deg2 out to z=1
• Cosmic voids and induced hyperbolicity
• HD 42659: The only known roAp star in a spectroscopic binary observed with B photometry, TESS and SALT
• Environmental effects on halo abundance and weak lensing peak statistics toward large underdense regions