scholarly journals Scalar absorption cross section of rotating black holes with tidal charge

2021 ◽  
Vol 104 (12) ◽  
Author(s):  
Ednilton S. de Oliveira
Keyword(s):  
Black Holes ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Absorption Cross ◽  
Rotating Black Holes

scholarly journals On-axis scalar absorption cross section of Kerr–Newman black holes: Geodesic analysis, sinc and low-frequency approximations

2018 ◽  
Vol 27 (11) ◽  
pp. 1843012 ◽  
Author(s):  
Carolina L. Benone ◽  
Luiz C. S. Leite ◽  
Luís C. B. Crispino ◽  
Sam R. Dolan
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Rotation Axis ◽  
Low Frequency ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Absorption Cross ◽  
Newman Black Hole

We investigate null geodesics impinging parallel to the rotation axis of a Kerr–Newman black hole, and show that the absorption cross section for a massless scalar field in the eikonal limit can be described in terms of the photon orbit parameters. We compare our sinc and low-frequency approximations with numerical results, showing that they are in excellent agreement.

scholarly journals Absorption by stringy black holes

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Sérgio V. M. C. B. Xavier ◽  
Carolina L. Benone ◽  
Luís C. B. Crispino
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Massless Scalar ◽  
Absorption Cross ◽  
Charged Black Holes ◽  
Hole Charge ◽  
Newman Black Hole ◽  
The Difference

AbstractWe investigate the absorption of planar massless scalar waves by a charged rotating stringy black hole, namely a Kerr–Sen black hole. We compute numerically the absorption cross section and compare our results with those of the Kerr–Newman black hole, a classical general relativity solution. In order to better compare both charged black holes, we define the ratio of the black hole charge to the extreme charge as Q. We conclude that Kerr–Sen and Kerr–Newman black holes have a similar absorption cross section, with the difference increasing for higher values of Q.

Absorption of zero-mass planar waves by dirty black holes

2018 ◽  
Vol 27 (11) ◽  
pp. 1843017 ◽  
Author(s):  
Caio F. B. Macedo ◽  
Luiz C. S. Leite ◽  
Luís C. B. Crispino
Keyword(s):  
Black Holes ◽  
Cross Section ◽  
Accretion Disks ◽  
Absorption Cross Section ◽  
Scalar Fields ◽  
Massless Scalar ◽  
Absorption Cross ◽  
Thin Spherical Shell ◽  
Nonlinear Nature ◽  
Selection Of

Astrophysical black holes are often with companions, including other gravitating objects, accretion disks, electromagnetic fields, and others. Because of the nonlinear nature of general relativity, it is difficult to account for the gravitational effects of these companions, which can only be investigated analytically for very few cases. In this paper, we consider black holes with surrounding matter — often called dirty black holes — and analyze the absorption cross section of massless scalar fields. We start by laying out the generic setup for spherically symmetric scenarios and then specify for a simple model. We consider planar massless scalar waves impinging upon a Schwarzschild black hole surrounded by a thin spherical shell, and compute the absorption cross section. We present a selection of numerical results complementary to those presented in [C. F. B. Macedo, L. C. S. Leite and L. C. B. Crispino, Phys. Rev. D 93 (2016) 024027, arXiv:1511.08781 [gr-qc]] for arbitrary frequencies, considering different values of the shell position as well as its mass.

Absorption cross section of black holes with global monopole

2013 ◽  
Vol 22 (7) ◽  
pp. 070401 ◽  
Author(s):  
Hai Huang ◽  
Yong-Jiu Wang ◽  
Ju-Hua Chen
Keyword(s):  
Black Holes ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Absorption Cross ◽  
Global Monopole

scholarly journals Scalar waves in regular Bardeen black holes: Scattering, absorption and quasinormal modes

2016 ◽  
Vol 25 (09) ◽  
pp. 1641008 ◽  
Author(s):  
Caio F. B. Macedo ◽  
Luís C. B. Crispino ◽  
Ednilton S. de Oliveira
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Quasinormal Modes ◽  
Scalar Fields ◽  
Scattering Cross Section ◽  
Massless Scalar ◽  
Absorption Cross ◽  
Scattering Cross

We discuss the phenomenology of massless scalar fields around a regular Bardeen black hole, namely absorption cross-section, scattering cross-section and quasinormal modes. We compare the Bardeen and Reissner–Nordström black holes, showing limiting cases for which their properties are similar.

scholarly journals On the temperature dependence of the absorption cross-section for black holes in string theory

2015 ◽  
Vol 24 (09) ◽  
pp. 1542011 ◽  
Author(s):  
Filipe Moura
Keyword(s):  
Black Holes ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Low Frequency ◽  
Spherically Symmetric ◽  
Absorption Cross ◽  
Explicit Dependence ◽  
Superstring Theory ◽  
Classical Level ◽  
Extremal Limit

We study the low frequency absorption cross-section of spherically symmetric nonextremal d-dimensional black holes. In the presence of α′ corrections, this quantity must have an explicit dependence on the Hawking temperature of the form 1/TH. This property of the low frequency absorption cross-section is shared by the D1-D5 system from type IIB superstring theory already at the classical level, without α′ corrections. We apply our formula to the simplest example, the classical d-dimensional Reissner–Nordström solution, checking that the obtained formula for the cross-section has a smooth extremal limit. We also apply it for a d-dimensional Tangherlini-like solution with α′3 corrections.

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