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Linear perturbations in Galileon gravity models (2012)
Journal Article
Barreira, A., Li, B., Baugh, C., & Pascoli, S. (2012). Linear perturbations in Galileon gravity models. Physical Review D, 86(12), Article 124016. https://doi.org/10.1103/physrevd.86.124016

We study the cosmology of Galileon modified gravity models in the linear perturbation regime. We derive the fully covariant and gauge invariant perturbed field equations using two different methods, which give consistent results, and solve them using... Read More about Linear perturbations in Galileon gravity models.

Excursion set theory for modified gravity: correlated steps, mass functions and halo bias (2012)
Journal Article
Lam, T., & Li, B. (2012). Excursion set theory for modified gravity: correlated steps, mass functions and halo bias. Monthly Notices of the Royal Astronomical Society, 426(4), 3260-3270. https://doi.org/10.1111/j.1365-2966.2012.21746.x

We show how correlated steps introduces significant contributions to the modification of the halo mass function in modified gravity models, taking the chameleon models as an example, in the framework of the excursion set approach. This correction app... Read More about Excursion set theory for modified gravity: correlated steps, mass functions and halo bias.

Systematic simulations of modified gravity: symmetron and dilaton models (2012)
Journal Article
Brax, P., Davis, A., Li, B., Winther, H., & Zhao, G. (2012). Systematic simulations of modified gravity: symmetron and dilaton models. Journal of Cosmology and Astroparticle Physics, 2012(10), Article 002. https://doi.org/10.1088/1475-7516/2012/10/002

We study the linear and nonlinear structure formation in the dilaton and symmetron models of modified gravity using a generic parameterisation which describes a large class of scenarios using only a few parameters, such as the coupling between the sc... Read More about Systematic simulations of modified gravity: symmetron and dilaton models.

Redshift-space distortions in f(R) gravity (2012)
Journal Article
Jennings, E., Baugh, C., Li, B., Zhao, G., & Koyama, K. (2012). Redshift-space distortions in f(R) gravity. Monthly Notices of the Royal Astronomical Society, 425(3), 2128-2143. https://doi.org/10.1111/j.1365-2966.2012.21567.x

We use large-volume N-body simulations to predict the clustering of dark matter in redshift space in f(R) modified gravity cosmologies. This is the first time that the non-linear matter and velocity fields have been resolved to such a high level of a... Read More about Redshift-space distortions in f(R) gravity.

Environment dependence of dark matter halos in symmetron modified gravity (2012)
Journal Article
Winther, H., Mota, D., & Li, B. (2012). Environment dependence of dark matter halos in symmetron modified gravity. Astrophysical Journal, 756(2), Article 166. https://doi.org/10.1088/0004-637x/756/2/166

We investigate the environment dependence of dark matter halos in the symmetron modified gravity scenario. The symmetron is one of three known mechanisms for screening a fifth force and thereby recovering general relativity in dense environments. The... Read More about Environment dependence of dark matter halos in symmetron modified gravity.

Excursion set theory for modified gravity: Eulerian versus Lagrangian environments (2012)
Journal Article
Li, B., & Lam, T. (2012). Excursion set theory for modified gravity: Eulerian versus Lagrangian environments. Monthly Notices of the Royal Astronomical Society, 425(1), 730-739. https://doi.org/10.1111/j.1365-2966.2012.21592.x

We have revisited the extended excursion set theory in modified gravity models, taking the chameleon model as an example. Instead of specifying their Lagrangian size, here we define the environments by the Eulerian size, chosen to be of the same orde... Read More about Excursion set theory for modified gravity: Eulerian versus Lagrangian environments.

Modified gravity tomography (2012)
Journal Article
Brax, P., Davis, A., & Li, B. (2012). Modified gravity tomography. Physics Letters B, 715(1-3), 38-43. https://doi.org/10.1016/j.physletb.2012.08.002

We consider the effect of a canonically normalised scalar field degree of freedom on the dynamics of gravity from small to large scales. We show that the effects of modified gravity can be completely captured by the time variations of the scalar field m... Read More about Modified gravity tomography.

Unified description of screened modified gravity (2012)
Journal Article
Brax, P., Davis, A., Li, B., & Winther, H. (2012). Unified description of screened modified gravity. Physical Review D, 86(4), Article 044015. https://doi.org/10.1103/physrevd.86.044015

We consider modified gravity models driven by a scalar field whose effects are screened in high density regions due to the presence of nonlinearities in its interaction potential and/or its coupling to matter. Our approach covers chameleon, f(R) grav... Read More about Unified description of screened modified gravity.

Chameleon f(R) gravity in the virialized cluster (2012)
Journal Article
Lombriser, L., Koyama, K., Zhao, G., & Li, B. (2012). Chameleon f(R) gravity in the virialized cluster. Physical Review D, 85(12), Article 124054. https://doi.org/10.1103/physrevd.85.124054

Current constraints on f(R) gravity from the large-scale structure are at the verge of penetrating into a region where the modified forces become nonlinearly suppressed. For a consistent treatment of observables at these scales, we study cluster quan... Read More about Chameleon f(R) gravity in the virialized cluster.

Halos and Voids in f(R) Gravity (2012)
Journal Article
Li, B., Zhao, G., & Koyama, K. (2012). Halos and Voids in f(R) Gravity. Monthly Notices of the Royal Astronomical Society, 421(4), 3481-3487. https://doi.org/10.1111/j.1365-2966.2012.20573.x

In this paper, we study the distribution of dark matter haloes and voids using high‐resolution simulations in f(R) gravity models with the chameleon mechanism to screen the fifth force in a dense environment. For dark matter haloes, we show that the... Read More about Halos and Voids in f(R) Gravity.

An extended excursion set approach to structure formation in chameleon models (2012)
Journal Article
Li, B., & Efstathiou, G. (2012). An extended excursion set approach to structure formation in chameleon models. Monthly Notices of the Royal Astronomical Society, 421(2), 1431-1442. https://doi.org/10.1111/j.1365-2966.2011.20404.x

In attempts to explain dark energy, a number of models have been proposed in which the formation of a large-scale structure depends on the local environment. These models are highly non-linear and difficult to analyse analytically. N-body simulations... Read More about An extended excursion set approach to structure formation in chameleon models.

Structure formation in the symmetron model (2012)
Journal Article
Davis, A., Li, B., Mota, D., & Winther, H. (2012). Structure formation in the symmetron model. Astrophysical Journal, 748(1), Article 61. https://doi.org/10.1088/0004-637x/748/1/61

Scalar fields, strongly coupled to matter, can be present in nature and still be invisible to local experiments if they are subject to a screening mechanism. The symmetron is one such mechanism that relies on restoration of a spontaneously broken sym... Read More about Structure formation in the symmetron model.

ECOSMOG: an Efficient COde for Simulating MOdified Gravity (2012)
Journal Article
Li, B., Zhao, G., Teyssier, R., & Koyama, K. (2012). ECOSMOG: an Efficient COde for Simulating MOdified Gravity. Journal of Cosmology and Astroparticle Physics, 2012(01), Article 051. https://doi.org/10.1088/1475-7516/2012/01/051

We introduce a new code, ECOSMOG, to run N-body simulations for a wide class of modified gravity and dynamical dark energy theories. These theories generally have one or more new dynamical degrees of freedom, the dynamics of which are governed by the... Read More about ECOSMOG: an Efficient COde for Simulating MOdified Gravity.