Dark matter and background light

Overduin, James; Wesson, Paul S.

doi:10.1016/j.physrep.2004.07.006

Cited by 203 publications

(209 citation statements)

References 454 publications

(709 reference statements)

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“…For what concerns the isotropic flux (I), it is known since a long time that it represents a powerful testbed for decaying DM (see for instance Refs. [11][12][13]). For what concerns (II), we are again motivated by the fact that large virialized objects such as galaxy clusters are a promising target for decaying DM (as briefly mentioned above) and, more in particular, by the fact that indeed stringent constraints have been recently derived using Fermi data [14,15]: on the basis of this we explore the constraining power of a complementary observatory such as H.E.S.S.…”

Section: Introductionmentioning

confidence: 99%

Publisher’s Note: Gamma Ray Constraints on Decaying Dark Matter [Phys. Rev. D86, 083506 (2012)]

Cirelli¹,

Moulin²,

Panci³

et al. 2012

Phys. Rev. D

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We derive new bounds on decaying dark matter from the gamma ray measurements of (i) the isotropic residual (extragalactic) background by Fermi and (ii) the Fornax galaxy cluster by H.E.S.S. We find that those from (i) are among the most stringent constraints currently available, for a large range of dark matter masses and a variety of decay modes, excluding half-lives up to $10 26 to few 10 27 seconds. In particular, they rule out the interpretation in terms of decaying dark matter of the e AE spectral features in PAMELA, Fermi and H.E.S.S., unless very conservative choices are adopted. We also discuss future prospects for CTA bounds from Fornax which, contrary to the present H.E.S.S. constraints of (ii), may allow for an interesting improvement and may become better than those from the current or future extragalactic Fermi data.

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Section: Introductionmentioning

confidence: 99%

Publisher’s Note: Gamma Ray Constraints on Decaying Dark Matter [Phys. Rev. D86, 083506 (2012)]

Cirelli¹,

Moulin²,

Panci³

et al. 2012

Phys. Rev. D

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“…Dark energy is responsible for the late time dynamics of the Universe [8,9], and it can explain the observed features of the recent cosmological evolution. The second and equally mysterious component in the Universe, called Dark Matter, an assumed non-baryonic and non-relativistic "substance", is necessary for the explanation of the flat rotation curves of galaxies, and for the virial mass discrepancy in clusters of galaxies [10,11]. The detection/observation of dark matter is restricted by the fact that it interacts only gravitationally.…”

Section: Introductionmentioning

confidence: 99%

“…The detection/observation of dark matter is restricted by the fact that it interacts only gravitationally. Its effects can be observed by observations of the motion of the massive hydrogen clouds around galaxies, or by the motion of the galaxies in clusters [10]. However, despite many decades of intensive observational and experimental efforts the particle nature of dark matter still remains essentially unknown.…”

Section: Introductionmentioning

confidence: 99%

Quantum Cosmology of f(R, T) gravity

Harkó

Liang

2016

Eur. Phys. J. C

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Modified gravity theories have the potential of explaining the recent acceleration of the Universe without resorting to the mysterious concept of dark energy. In particular, it has been pointed out that matter-geometry coupling may be responsible for the recent cosmological dynamics of the Universe, and matter itself may play a more fundamental role in the description of the gravitational processes that usually assumed. In the present paper we study the quantum cosmology of the f (R, T ) theory of gravity, in which the effective Lagrangian of the gravitational field is given by an arbitrary function of the Ricci scalar, and the trace of the matter energy-momentum tensor, respectively. For the background geometry we adopt the Friedmann-RobertsonWalker metric, and we assume that matter content of the Universe consists of a perfect fluid. In this framework we obtain the general form of the gravitational Hamiltonian, of the quantum potential, and of the canonical momenta, respectively. This allows us to formulate the full Wheeler-de Witt equation describing the quantum properties of this modified gravity model. As a specific application we consider in detail the quantum cosmology of the f (R, T ) = F 0 (R) + θ RT model, in which F 0 (R) is an arbitrary function of the Ricci scalar, and θ is a function of the scale factor only. The Hamiltonian form of the equations of motion, and the Wheeler-de Witt equations are obtained, and a time parameter for the corresponding dynamical system is identified, which allows one to formulate the Schrödinger-Wheeler-de Witt equation for the quantum-mechanical description of the model under consideration. A perturbative approach for the study of this equation is developed, and the energy levels of the Universe are obtained by using a twofold degenerate pera e-mail: 253659701@qq.com b e-mail: t.harko@ucl.ac.uk c e-mail: stslsd@mail.sysu.edu.cn turbation approach. A second quantization approach for the description of quantum time is also proposed and briefly discussed.

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“…However, the nature of dark matter, and its constituent particle(s), still remain essentially unknown, despite several decades of intensive research. For reviews on the dark matter problem see [17,18].…”

Section: Introductionmentioning

confidence: 99%

Gravitational, lensing, and stability properties of Bose-Einstein condensate dark matter halos

Harkó

2015

Phys. Rev. D

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The possibility that dark matter, whose existence is inferred from the study of the galactic rotation curves, and from the mass deficit in galaxy clusters, can be in a form of a Bose-Einstein Condensate, has been extensively investigated lately. In the present work, we consider a detailed analysis of the astrophysical properties of the Bose-Einstein Condensate dark matter halos that could provide clear observational signatures that help discriminate between different dark matter models. In the BoseEinstein condensation model dark matter can be described as a non-relativistic, gravitationally confined Newtonian gas, whose density and pressure are related by a polytropic equation of state with index n = 1. The mass and gravitational properties of the condensate halos are obtained in a systematic form, including the mean logarithmic slopes of the density and of the tangential velocity. The lensing properties of the condensate dark matter are investigated in detail. In particular, a general analytical formula for the surface density, an important quantity that defines the lensing properties of a dark matter halos, is obtained in the form of series expansions. This enables arbitraryprecision calculations of the surface mass density, deflection angle, deflection potential, and of the magnification factor, thus giving the possibility of the comparison of the predicted lensing properties of the condensate dark matter halos with observations. The stability properties of the condensate halos are also investigated by using the scalar and the tensor virial theorems, respectively, and the virial perturbation equation for condensate dark matter halos is derived. As an application of the scalar virial theorem we consider the problem of the stability of a slowly rotating and slightly disturbed galactic dark matter halo. For such a halo the oscillations frequencies and the stability conditions are obtained in the linear approximation.

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Dark matter and background light

Cited by 203 publications

References 454 publications

Publisher’s Note: Gamma Ray Constraints on Decaying Dark Matter [Phys. Rev. D86, 083506 (2012)]

Publisher’s Note: Gamma Ray Constraints on Decaying Dark Matter [Phys. Rev. D86, 083506 (2012)]

Quantum Cosmology of f(R, T) gravity

Gravitational, lensing, and stability properties of Bose-Einstein condensate dark matter halos

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