Accretion disks around neutron and strange stars inR+aR2gravity

Staykov, Kalin V.; Doneva, Daniela D.; Yazadjiev, Stoytcho S.

doi:10.1088/1475-7516/2016/08/061

Cited by 17 publications

(17 citation statements)

References 51 publications

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“…When the parameter α increases (in modulus) further, the flux becomes even larger than that in GR (in this connection, see Ref. [19] where the case of extremely large values of α 10 ≈ −2 × 10 4 has been considered). However, as pointed out earlier, we do not consider here such large α's, remaining within the constraints imposed by the strong gravity regime [11].…”

Section: B Results Of Calculationsmentioning

confidence: 99%

“…Modification of gravity can affect a number of important physical characteristics of NSs which can, in principle, be directly verified observationally. Among them are the mass-radius (M − R) relation [16][17][18], the properties of electromagnetic radiation from the surface of accretion disks [19], and the structure of internal and external magnetic fields [20][21][22][23]. Considering such objects within the framework of different types of f (R) gravities and using various equations of state (EoSs) for neutron matter, one can reveal the allowed forms of f (R) and EoSs satisfying the observational constraints.…”

Section: Introductionmentioning

confidence: 99%

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Anisotropic neutron stars in R2 gravity

Folomeev

2018

Phys. Rev. D

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We consider static neutron stars within the framework of R 2 gravity. The neutron fluid is described by three different types of realistic equations of state (soft, moderately stiff, and stiff). Using the observational data on the neutron star mass-radius relation, it is demonstrated that the characteristics of the objects supported by the isotropic fluid agree with the observations only if one uses the soft equation of state. We show that the inclusion of the fluid anisotropy enables one also to employ more stiff equations of state to model configurations that will satisfy the observational constraints sufficiently. Also, using the standard thin accretion disk model, we demonstrate potentially observable differences, which allow us to distinguish the neutron stars constructed within the modified gravity framework from those described in Einstein's general relativity.

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Section: B Results Of Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Anisotropic neutron stars in R2 gravity

Folomeev

2018

Phys. Rev. D

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“…Moreover the radiation emanating from the disk is considered under the assumption of black body radiation resulting from thermodynamic equilibrium of the disk. Thin accretion disk models and their properties in f (R) modified gravity have been investigated in [55][56][57]. In extra dimensions within the context of modified gravity, such as Kaluza-Klein and brane world scenarios, accretion disks have been studied in [58][59][60].…”

Section: Introductionmentioning

confidence: 99%

Thin accretion disks and charged rotating dilaton black holes

Heydari-Fard

Sepangi

2020

Eur. Phys. J. C

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Einstein-Maxwell-dilaton theory is an interesting theory of gravity for studying scalar fields in the context of no-hair theorem. In this work, we consider static charged dilaton and charged, slowly rotating dilaton black holes in Einstein-Maxwell-dilaton gravity. We investigate the accretion process in thin disks around such black holes, using the Novikov-Thorne model. The electromagnetic flux, temperature distribution, energy conversion efficiency and also innermost stable circular orbits of thin disks are obtained and effects of dilaton and rotation parameters are studied. For the static and slowly rotating black holes the results are compared to that of Schwarzschild and Kerr, respectively.

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“…Accretion around wormholes has also been an active area of research [32,33], more so because wormholes are special types of objects sourced by materials that violate at least the Null Energy Condition (hence exotic). Research included also other types of objects, e.g., quark, boson and fermion stars, brane-world black holes, gravastars, naked singularities (NS) [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50], f (R)-modified gravity models of black holes [51][52][53] and so on. One of the most promising method to distinguish different types of astrophysical objects through their accretion disk properties is the profile analysis of K α iron line [54][55][56][57][58].…”

Section: Introductionmentioning

confidence: 99%

Accretion disk around the rotating Damour–Solodukhin wormhole

Karimov¹,

Izmailov²,

Nandi³

2019

Eur. Phys. J. C

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A new rotating generalization of the Damour-Solodukhin wormhole (RDSWH), called Kerr-like wormhole, has recently been proposed and investigated by Bueno et al. for echoes in the gravitational wave signal. We show a novel feature of the RDSWH, viz., that the kinematic properties such as the ISCO or marginally stable radius r ms , efficiency and the disk potential V eff are independent of λ (which means they are identical to their KBH counterparts for any given spin). Differences however appear in the emissivity properties for higher values 0.1 < λ ≤ 1 (say) and for the extreme spin a = 0.998. The kinematic and emissivity are generic properties as variations of the wormhole mass and the rate of accretion within the model preserve these properties. Specifically, the behavior of the luminosity peak is quite opposite to each other for the two objects, which could be useful from the viewpoint of observations. Apart from this, an estimate of the difference Δ λ in the maxima of flux of radiation F(r) shows non-zero values but is too tiny to be observable at present for λ < 10 −3 permitted by the strong lensing bound. The broad conclusion is that RDSWH are experimentally indistinguishable from KBH by accretion characteristics.

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Accretion disks around neutron and strange stars inR+aR²gravity

Cited by 17 publications

References 51 publications

Anisotropic neutron stars in R2 gravity

Anisotropic neutron stars in R2 gravity

Thin accretion disks and charged rotating dilaton black holes

Accretion disk around the rotating Damour–Solodukhin wormhole

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