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Author Araujo Filho, A.A. url  doi
openurl 
  Title Analysis of a regular black hole in Verlinde's gravity Type Journal Article
  Year 2024 Publication Classical and Quantum Gravity Abbreviated Journal Class. Quantum Gravity  
  Volume 41 Issue 1 Pages 015003 - 30pp  
  Keywords Verlinde's emergent gravity; dark matter; shadows; black hole  
  Abstract This work focuses on the examination of a regular black hole within Verlinde's emergent gravity, specifically investigating the Hayward-like (modified) solution. The study reveals the existence of three horizons under certain conditions, i.e. an event horizon and two Cauchy horizons. Our results indicate regions which phase transitions occur based on the analysis of heat capacity and Hawking temperature. To compute the latter quantity, we utilize three distinct methods: the surface gravity approach, Hawking radiation, and the application of the first law of thermodynamics. In the case of the latter approach, it is imperative to introduce a correction to ensure the preservation of the Bekenstein-Hawking area law. Geodesic trajectories and critical orbits (photon spheres) are calculated, highlighting the presence of three light rings. Additionally, we investigate the black hole shadows. Furthermore, the quasinormal modes are explored using third- and sixth-order Wentzel-Kramers-Brillouin approximations. In particular, we observe stable and unstable oscillations for certain frequencies. Finally, in order to comprehend the phenomena of time-dependent scattering in this scenario, we provide an investigation of the time-domain solution.  
  Address [Araujo Filho, A. A.] Univ Valencia, Ctr Mixto Univ Valencia, CSIC, Dept Fis Teor, Burjassot 46100, Valencia, Spain, Email: dilto@fisica.ufc.br  
  Corporate Author Thesis  
  Publisher IOP Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0264-9381 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001114102700001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5841  
Permanent link to this record
 

 
Author Araujo Filho, A.A.; Furtado, J.; Hassanabadi, H.; Reis, J.A.A.S. url  doi
openurl 
  Title Thermal analysis of photon-like particles in rainbow gravity Type Journal Article
  Year 2023 Publication Physics of the Dark Universe Abbreviated Journal Phys. Dark Universe  
  Volume 42 Issue Pages 101310 - 8pp  
  Keywords Rainbow gravity; Thermodynamics; Bounds  
  Abstract This work is devoted to study the thermodynamic behavior of photon-like particles within the rainbow gravity formalism. To to do this, we chose two particular ansatzs to accomplish our calculations. First, we consider a dispersion relation which avoids UV divergences, getting a positive effective cosmological constant. We provide numerical analysis for the thermodynamic functions of the system and bounds are estimated. Furthermore, a phase transition is also expected for this model. Second, we consider a dispersion relation employed in the context of Gamma Ray Bursts. Remarkably, for this latter case, the thermodynamic properties are calculated in an analytical manner and they turn out to depend on the harmonic series Hn, gamma & UGamma; (z), polygamma & psi;n(z) and zeta Riemann functions & zeta;(z).  
  Address [Araujo Filho, A. A.] Univ Valencia, CSIC, Dept Fis Teor & IFIC, Ctr Mixto Univ Valencia, Valencia 46100, Spain, Email: dilto@fisica.ufc.br;  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001062674000001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5667  
Permanent link to this record
 

 
Author Araujo Filho, A.A.; Hassanabadi, H.; Heidari, N.; Kriz, J.; Zare, S. url  doi
openurl 
  Title Gravitational traces of bumblebee gravity in metric-affine formalism Type Journal Article
  Year 2024 Publication Classical and Quantum Gravity Abbreviated Journal Class. Quantum Gravity  
  Volume 41 Issue 5 Pages 055003 - 21pp  
  Keywords bumblebee gravity; metric affine formalism; shadows  
  Abstract This work explores various manifestations of bumblebee gravity within the metric-affine formalism. We investigate the impact of the Lorentz violation parameter, denoted as X, on the modification of the Hawking temperature. Our calculations reveal that as X increases, the values of the Hawking temperature attenuate. To examine the behavior of massless scalar perturbations, specifically the quasinormal modes, we employ the Wentzel-Kramers-Brillouin method. The transmission and reflection coefficients are determined through our calculations. The outcomes indicate that a stronger Lorentz-violating parameter results in slower damping oscillations of gravitational waves. To comprehend the influence of the quasinormal spectrum on time-dependent scattering phenomena, we present a detailed analysis of scalar perturbations in the time-domain solution. Additionally, we conduct an investigation on shadows, revealing that larger values of X correspond to larger shadow radii. Furthermore, we constrain the magnitude of the shadow radii using the EHT horizon-scale image of SgrA* . Finally, we calculate both the time delay and the deflection angle.  
  Address [Araujo Filho, A. A.] Univ Valencia, CSIC, Dept Fis Teor, Ctr MIxto Univ Valencia, Burjassot 46100, Valencia, Spain, Email: dilto@fisica.ufc.br  
  Corporate Author Thesis  
  Publisher IOP Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0264-9381 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001152994800001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5925  
Permanent link to this record
 

 
Author Arrechea, J.; Delhom, A.; Jimenez-Cano, A. url  doi
openurl 
  Title Inconsistencies in four-dimensional Einstein-Gauss-Bonnet gravity Type Journal Article
  Year 2021 Publication Chinese Physics C Abbreviated Journal Chin. Phys. C  
  Volume 45 Issue 1 Pages 013107 - 8pp  
  Keywords alternative theories of gravity; singularities; Einstein-Gauss-Bonnet  
  Abstract We attempt to clarify several aspects concerning the recently presented four-dimensional Einstein-Gauss-Bonnet gravity. We argue that the limiting procedure outlined in [Phys. Rev. Lett. 124, 081301 (2020)] generally involves ill-defined terms in the four dimensional field equations. Potential ways to circumvent this issue are discussed, alongside remarks regarding specific solutions of the theory. We prove that, although linear perturbations are well behaved around maximally symmetric backgrounds, the equations for second-order perturbations are ill-defined even around a Minkowskian background. Additionally, we perform a detailed analysis of the spherically symmetric solutions and find that the central curvature singularity can be reached within a finite proper time.  
  Address [Arrechea, Julio] CSIC, Inst Astrofis Andalucia, Granada, Spain, Email: arrechea@iaa.es;  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1674-1137 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000606026400001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 4676  
Permanent link to this record
 

 
Author Babichev, E.; Fabbri, A. url  doi
openurl 
  Title A class of charged black hole solutions in massive (bi)gravity Type Journal Article
  Year 2014 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 07 Issue 7 Pages 016 - 10pp  
  Keywords Classical Theories of Gravity; Black Holes  
  Abstract We present a new class of solutions describing charged black holes in massive (bi)gravity. For a generic choice of the parameters of the massive gravity action, the solution is the Reissner-Nordstrom-de Sitter metric written in the Eddington-Finkelstein coordinates for both metrics. We also study a special case of the parameters, for which the space of solutions contains an extra symmetry.  
  Address [Babichev, Eugeny] Univ Paris 11, CNRS, LPT, UMR 8627, F-91405 Orsay, France, Email: eugeny.babichev@th.u-psud.fr;  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1029-8479 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000339110500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1847  
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