All Outputs (202)

Spherical collapse in Galileon gravity: fifth force solutions, halo mass function and halo bias (2013)
Journal Article
Barreira, A., Li, B., Baugh, C., & Pascoli, S. (2013). Spherical collapse in Galileon gravity: fifth force solutions, halo mass function and halo bias. Journal of Cosmology and Astroparticle Physics, 11(2013), Article 056. https://doi.org/10.1088/1475-7516/2013/11/056

We study spherical collapse in the Quartic and Quintic Covariant Galileon gravity models within the framework of the excursion set formalism. We derive the nonlinear spherically symmetric equations in the quasi-static and weak-field limits, focusing... Read More about Spherical collapse in Galileon gravity: fifth force solutions, halo mass function and halo bias.

Revisiting the matter power spectra in f(R) gravity (2013)
Journal Article
He, J., Li, B., & Jing, Y. (2013). Revisiting the matter power spectra in f(R) gravity. Physical Review D, 88(10), Article 103507. https://doi.org/10.1103/physrevd.88.103507

In this paper, we study the nonlinear matter power spectrum in a specific family of f(R) models that can reproduce the ΛCDM background expansion history, using high resolution N-body simulations based on the ecosmog code. We measure the matter power... Read More about Revisiting the matter power spectra in f(R) gravity.

Simulating the quartic Galileon gravity model on adaptively refined meshes (2013)
Journal Article
Li, B., Barreira, A., Baugh, C., Hellwing, W., Koyama, K., Pascoli, S., & Zhao, G. (2013). Simulating the quartic Galileon gravity model on adaptively refined meshes. Journal of Cosmology and Astroparticle Physics, 2013(11), Article 12. https://doi.org/10.1088/1475-7516/2013/11/012

We develop a numerical algorithm to solve the high-order nonlinear derivative-coupling equation associated with the quartic Galileon model, and implement it in a modified version of the ramses N-body code to study the effect of the Galileon field on... Read More about Simulating the quartic Galileon gravity model on adaptively refined meshes.

Hierarchical clustering in chameleon f(R) gravity (2013)
Journal Article
Hellwing, W., Li, B., Frenk, C., & Cole, S. (2013). Hierarchical clustering in chameleon f(R) gravity. Monthly Notices of the Royal Astronomical Society, 435(4), 2806-2821. https://doi.org/10.1093/mnras/stt1430

We use a suite of high-resolution state-of-the-art N-body dark matter simulations of chameleon f(R) gravity to study the higher order volume-averaged correlation functions ξ n ¯ ¯ ¯ together with the hierarchical nth-order correlation amplitudes S n... Read More about Hierarchical clustering in chameleon f(R) gravity.

Nonlinear structure formation in the cubic Galileon gravity model (2013)
Journal Article
Barreira, A., Li, B., Hellwing, W., Baugh, C., & Pascoli, S. (2013). Nonlinear structure formation in the cubic Galileon gravity model. Journal of Cosmology and Astroparticle Physics, 2013(10), Article 027. https://doi.org/10.1088/1475-7516/2013/10/027

We model the linear and nonlinear growth of large scale structure in the Cubic Galileon gravity model, by running a suite of N-body cosmological simulations using the ECOSMOG code. Our simulations include the Vainshtein screening effect, which reconc... Read More about Nonlinear structure formation in the cubic Galileon gravity model.

Testing gravity theories via transverse Doppler and gravitational redshifts in galaxy clusters (2013)
Journal Article
Zhao, H., Peacock, J., & Li, B. (2013). Testing gravity theories via transverse Doppler and gravitational redshifts in galaxy clusters. Physical Review D, 88(4), Article 043013. https://doi.org/10.1103/physrevd.88.043013

There is growing interest in testing alternative gravity theories using the subtle gravitational redshifts in clusters of galaxies. However, current models all neglect a transverse Doppler redshift of similar magnitude, and some models are not self-c... Read More about Testing gravity theories via transverse Doppler and gravitational redshifts in galaxy clusters.

Modeling halo mass functions in chameleon f(R) gravity (2013)
Journal Article
Lombriser, L., Li, B., Koyama, K., & Zhao, G. (2013). Modeling halo mass functions in chameleon f(R) gravity. Physical Review D, 87(12), Article 123511. https://doi.org/10.1103/physrevd.87.123511

On cosmological scales, observations of the cluster abundance currently place the strongest constraints on f(R) gravity. These constraints lie in the large-field limit, where the modifications of general relativity can correctly be modeled by setting... Read More about Modeling halo mass functions in chameleon f(R) gravity.

Exploring Vainshtein mechanism on adaptively refined meshes (2013)
Journal Article
Li, B., Zhao, G., & Koyama, K. (2013). Exploring Vainshtein mechanism on adaptively refined meshes. Journal of Cosmology and Astroparticle Physics, 2013(05), Article 023. https://doi.org/10.1088/1475-7516/2013/05/023

There has been a lot of research interest in modified gravity theories which utilise the Vainshtein mechanism to recover standard general relativity in regions with high matter density, such as the Dvali-Gabadadze-Porrati and Galileon models. The str... Read More about Exploring Vainshtein mechanism on adaptively refined meshes.

Parameter space in Galileon gravity models (2013)
Journal Article
Barreira, A., Li, B., Sanchez, A., Baugh, C., & Pascoli, S. (2013). Parameter space in Galileon gravity models. Physical Review D, 87(10), Article 103511. https://doi.org/10.1103/physrevd.87.103511

We present the first constraints on the full parameter space of the Galileon modified gravity model, considering both the cosmological parameters and the coefficients which specify the additional terms in the Lagrangian due to the Galileon field, whi... Read More about Parameter space in Galileon gravity models.

Voids in modified gravity: excursion set predictions (2013)
Journal Article
Clampitt, J., Cai, Y., & Li, B. (2013). Voids in modified gravity: excursion set predictions. Monthly Notices of the Royal Astronomical Society, 431(1), 749-766. https://doi.org/10.1093/mnras/stt219

We investigate the behaviour of the fifth force in voids in chameleon models using the spherical collapse method. Contrary to Newtonian gravity, we find the fifth force is repulsive in voids. The strength of the fifth force depends on the density ins... Read More about Voids in modified gravity: excursion set predictions.

Systematic simulations of modified gravity: chameleon models (2013)
Journal Article
Brax, P., Davis, A., Li, B., Winther, H., & Zhao, G. (2013). Systematic simulations of modified gravity: chameleon models. Journal of Cosmology and Astroparticle Physics, 2013(04), Article 029. https://doi.org/10.1088/1475-7516/2013/04/029

In this work we systematically study the linear and nonlinear structure formation in chameleon theories of modified gravity, using a generic parameterisation which describes a large class of models using only 4 parameters. For this we have modified t... Read More about Systematic simulations of modified gravity: chameleon models.

Modified gravity spins up galactic halos (2013)
Journal Article
Lee, J., Zhao, G., Li, B., & Koyama, K. (2013). Modified gravity spins up galactic halos. Astrophysical Journal, 763(1), Article 28. https://doi.org/10.1088/0004-637x/763/1/28

We investigate the effect of modified gravity on the specific angular momentum of galactic halos by analyzing the halo catalogs at z = 0 from high-resolution N-body simulations for a f(R) gravity model that meets the solar-system constraint. It is sh... Read More about Modified gravity spins up galactic halos.

The non-linear matter and velocity power spectra in f(R) gravity (2013)
Journal Article
Li, B., Hellwing, W., Koyama, K., Zhao, G., Jennings, E., & Baugh, C. (2013). The non-linear matter and velocity power spectra in f(R) gravity. Monthly Notices of the Royal Astronomical Society, 428(1), 743-755. https://doi.org/10.1093/mnras/sts072

We study the matter and velocity divergence power spectra in a f(R) gravity theory and their time evolution measured from several large-volume N-body simulations with varying box sizes and resolution. We find that accurate prediction of the matter po... Read More about The non-linear matter and velocity power spectra in f(R) gravity.

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.