Testing the spherical evolution of cosmic voids

Demchenko, Vasiliy; Cai, Yan-Chuan; Heymans, Catherine; Peacock, J. A.

doi:10.1093/mnras/stw2030

Cited by 22 publications

(24 citation statements)

References 51 publications

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“…This result is consistent with previous studies into the spherical evolution of voids, which found that the largest voids are better approximated by a spherical model than the smallest voids (e.g. Achitouv et al 2015;Demchenko et al 2016). A likely reason for this is that there are many more ways to merge smaller voids to form a lower ellipticity void than a high ellipticity void, and hence a greater number of approximately spheroidal large voids form than approximately ellipsoidal large voids.…”

Section: Shapessupporting

confidence: 91%

Cosmic voids in evolving dark sector cosmologies: the low-redshift universe

Adermann

Elahi

Lewis

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present a comparison of void properties between the standard model of cosmology, Λ Cold Dark Matter (ΛCDM), and two alternative cosmological models with evolving and interacting dark sectors: a quintessence model (φCDM) and a Coupled Dark Matter-Dark Energy (CDE) model. Using N-body simulations of these models, we derive several measures of void statistics and properties, including distributions of void volume, ellipticity, prolateness, and average density. We find that the volume distribution derived from the CDE simulation deviates from the volume distribution derived from the ΛCDM simulation in the present-day universe, suggesting that the presence of a coupled dark sector could be observable through this statistic. We also find that the distributions of void ellipticity and prolateness are practically indistinguishable among the three models over the redshift range z = 0.0 − 1.0, indicating that simple void shape statistics are insensitive to small changes in dark sector physics. Interestingly, we find that the distributions of average void density measured in each of the three simulations are distinct from each other. In particular, voids on average tend to be emptiest under a quintessence model, and densest under the ΛCDM model. Our results suggest that it is the scalar field present in both alternative models that causes emptier voids to form, while the coupling of the dark sector mitigates this effect by slowing down the evacuation of matter from voids.

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Section: Shapessupporting

confidence: 91%

Cosmic voids in evolving dark sector cosmologies: the low-redshift universe

Adermann

Elahi

Lewis

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…These simulations show the gravitational collapse of dark matter (DM) into a web-like structure, establishing the 'skeleton' for baryonic matter, which falls into the DM's potential well. Within this framework, the growth factor of voids with redshift can be used to constrain the energy density and equation of state parameter of dark energy (DE) (Lavaux & Wandelt 2010;Demchenko et al 2016), which causes the Universe's accelerated expansion. The low density in voids also makes them clean probes of global cosmological parameters, as their interior is less affected by baryonic physics than denser regions (Bos et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Studying galaxy troughs and ridges using weak gravitational lensing with the Kilo-Degree Survey

Brouwer

Demchenko

Harnois-Déraps

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We study projected underdensities in the cosmic galaxy density field known as 'troughs', and their overdense counterparts, which we call 'ridges'. We identify these regions using a bright sample of foreground galaxies from the photometric Kilo-Degree Survey (KiDS), specifically selected to mimic the spectroscopic Galaxy And Mass Assembly survey (GAMA). Using background galaxies from KiDS, we measure the weak gravitational lensing profiles of the troughs/ridges. We quantify the amplitude of their lensing strength A as a function of galaxy density percentile rank P and galaxy overdensity δ, and find that the skewness in the galaxy density distribution is reflected in the total mass distribution measured by weak lensing. We interpret our results using the mock galaxy catalogue from the Marenostrum Institut de Ciències de l'Espai (MICE) simulation, and find a good agreement with our observations. Using signal-to-noise weights derived from the Scinet LIghtCone Simulations (SLICS) mock catalogue we optimally stack the lensing signal of KiDS troughs with an angular radius θ A = {5, 10, 15, 20} arcmin, resulting in {16.8, 14.9, 10.13, 7.55} σ detections. Finally, we select troughs using a volume-limited sample of galaxies, split into two redshift bins between 0.1 < z < 0.3. For troughs/ridges with transverse comoving radius R A = 1.9 h −1 70 Mpc, we find no significant difference in the comoving Excess Surface Density as a function of P and δ between the low-and high-redshift sample. Using the MICE and SLICS mocks we predict that trough and ridge evolution could be detected with gravitational lensing using deeper and wider lensing surveys, such as those from the Large Synoptic Survey Telescope and Euclid.

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“…Despite ambiguities in their exact definition, it has been observed in simulations that voids are quite spherical [67,68], and therefore it is expected that the spherical expansion model for their abundance must work well (differently from halos, for which spherical collapse alone is not a very good approximation [69]). In this work, we use N-body simulations of ΛCDM as well as fðRÞ and symmetron models of modified gravity in order to identify cosmic voids and study their abundance distribution.…”

Section: Introductionmentioning

confidence: 99%

Modeling void abundance in modified gravity

et al. 2017

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Reprinted with permission from the American Physical Society: Physical Review D, 95, 024018 c (2017) by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We use a spherical model and an extended excursion set formalism with drifting diffusive barriers to predict the abundance of cosmic voids in the context of general relativity as well as fðRÞ and symmetron models of modified gravity. We detect spherical voids from a suite of N-body simulations of these gravity theories and compare the measured void abundance to theory predictions. We find that our model correctly describes the abundance of both dark matter and galaxy voids, providing a better fit than previous proposals in the literature based on static barriers. We use the simulation abundance results to fit for the abundance model free parameters as a function of modified gravity parameters, and show that counts of dark matter voids can provide interesting constraints on modified gravity. For galaxy voids, more closely related to optical observations, we find that constraining modified gravity from void abundance alone may be significantly more challenging. In the context of current and upcoming galaxy surveys, the combination of void and halo statistics including their abundances, profiles and correlations should be effective in distinguishing modified gravity models that display different screening mechanisms.

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Testing the spherical evolution of cosmic voids

Cited by 22 publications

References 51 publications

Cosmic voids in evolving dark sector cosmologies: the low-redshift universe

Cosmic voids in evolving dark sector cosmologies: the low-redshift universe

Studying galaxy troughs and ridges using weak gravitational lensing with the Kilo-Degree Survey

Modeling void abundance in modified gravity

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