Galaxy cluster lensing masses in modified lensing potentials

Li, Baojiu; Jennings, Elise; Merten, Julian; King, Lindsay J.; Baugh, C. M.; Pascoli, Silvia

doi:10.1093/mnras/stv2211

Cited by 41 publications

(43 citation statements)

References 143 publications

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“…Any potential time-evolution of α over this range will be negligible, although we note that more detailed modelling may be required if a sample of useful clusters at redshifts z ≫ 0.1 were to be found. Previous studies have consistently found that the properties of halos are largely unmodified in galileon cosmologies (Barreira et al 2014b(Barreira et al , 2015, especially inside the Vainshtein radius. Outside, at distances larger than ∼ 2 Mpc, more detailed modelling may be required, although M 87, which we consider below, lies well within the Vainshtein radius of the Virgo cluster so this is not a caveat to the results we obtain here.…”

Section: Galaxy Clustersmentioning

confidence: 89%

Tests of Gravity Theories Using Supermassive Black Holes

Sakstein¹,

Jain²,

Hui

2017

ApJL

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Scalar-tensor theories of gravity generally violate the strong equivalence principle, namely compact objects have a suppressed coupling to the scalar force, causing them to fall slower. A black hole is the extreme example where such a coupling vanishes, i.e. black holes have no scalar hair. We explore observational scenarios for detecting strong equivalence principle violation, focusing on galileon gravity as an example. For galaxies in-falling towards galaxy clusters, the supermassive black hole can be offset from the galaxy center away from the direction of the cluster. Well resolved images of galaxies around nearby clusters can therefore be used to identify the displaced black hole via the star cluster bound to it. We show that this signal is accessible with imaging surveys, both ongoing ones such as the Dark Energy Survey, and future ground and space based surveys. Already, the observation of the central black hole in M 87 places new constraints on the galileon parameters, which we present here. O(1) matter couplings are disfavored for a large region of the parameter space. We also find a novel phenomenon whereby the black hole can escape the galaxy completely in less than one billion years.

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Section: Galaxy Clustersmentioning

confidence: 89%

Tests of Gravity Theories Using Supermassive Black Holes

Sakstein¹,

Jain²,

Hui

2017

ApJL

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“…(6) the "RR" model. Further work on the RR and RT models has been presented in [51][52][53][54][55][56][57][58][59].…”

Section: An Overview Of Nonlocal Modelsmentioning

confidence: 99%

Conformal symmetry and nonlinear extensions of nonlocal gravity

Cusin¹,

Foffa²,

Maggiore³

et al. 2016

Phys. Rev. D

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We study two nonlinear extensions of the nonlocal R□ −2 R gravity theory. We extend this theory in two different ways suggested by conformal symmetry, either replacing □ −2 with ð−□ þ R=6Þ −2 , which is the operator that enters the action for a conformally-coupled scalar field, or replacing □ −2 with the inverse of the Paneitz operator, which is a four-derivative operator that enters in the effective action induced by the conformal anomaly. We show that the former modification gives an interesting and viable cosmological model, with a dark energy equation of state today w DE ≃ −1.01, which very closely mimics ΛCDM and evolves asymptotically into a de Sitter solution. The model based on the Paneitz operator seems instead excluded by the comparison with observations. We also review some issues about the causality of nonlocal theories, and we point out that these nonlocal models can be modified so to nicely interpolate between Starobinski inflation in the primordial universe and accelerated expansion in the recent epoch.

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“…Many different approaches have been used to calculate E-mail: manolo@roe.ac.uk cluster masses; taking advantage of clusters acting as gravitational lenses (eg., Kneib 2008, Applegate et al 2014, Barreira et al 2015, Gonzalez et al 2015, using the SunyaevZeldovich effect (eg. Sunyaev & Zeldovich 1970, Birkinshaw & Lancaster 2008, Olamaie, Hobson & Grainge 2013, Churazov, Vikhlinin & Sunyaev 2015, assuming hydrostatic equilibrium and calculating the intracluster medium (ICM) temperature from their X-ray emission (eg., Sarazin 2008, Martino et al 2014, Nelson et al 2014 or using the clusters' galaxy member velocities and assuming dynamical equilibrium (eg., Saro et al 2013, Sifón et al 2013, Tempel et al 2014 or not (eg., Diaferio & Geller 1997, Diaferio 1999).…”

Section: Introductionmentioning

confidence: 99%

Galaxy cluster's rotation

Manolopoulou

Plionis

2016

Mon. Not. R. Astron. Soc.

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We study the possible rotation of cluster galaxies, developing, testing and applying a novel algorithm which identifies rotation, if such does exist, as well as its rotational centre, its axis orientation, rotational velocity amplitude and, finally, the clockwise or counterclockwise direction of rotation on the plane of the sky. To validate our algorithms we construct realistic Monte Carlo mock rotating clusters and confirm that our method provides robust indications of rotation. We then apply our methodology on a sample of Abell clusters with z 0.1 with member galaxies selected from the Sloan Digital Sky Survey (SDSS) DR10 spectroscopic data base. After excluding a number of substructured clusters, which could provide erroneous indications of rotation, and taking into account the expected fraction of misidentified coherent substructure velocities for rotation, provided by our Monte-Carlo simulation analysis, we find that ∼ 23% of our clusters are rotating under a set of strict criteria. Loosening the strictness of the criteria, on the expense of introducing spurious rotation indications, we find this fraction increasing to ∼ 28%. We correlate our rotation indicators with the cluster dynamical state, provided either by their Bautz-Morgan type or by their Xray isophotal shape and find for those clusters showing rotation within 1.5 h −1 70 Mpc that the significance of their rotation is related to the dynamically younger phases of cluster formation but after the initial anisotropic accretion and merging has been completed. Finally, finding rotational modes in galaxy clusters could lead to the necessity of correcting the dynamical cluster mass calculations.

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Galaxy cluster lensing masses in modified lensing potentials

Cited by 41 publications

References 143 publications

Tests of Gravity Theories Using Supermassive Black Holes

Tests of Gravity Theories Using Supermassive Black Holes

Conformal symmetry and nonlinear extensions of nonlocal gravity

Galaxy cluster's rotation

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