Records |
Author |
Guerrero, M.; Olmo, G.J.; Rubiera-Garcia, D.; Saez-Chillon Gomez, D. |
Title |
Shadows and optical appearance of black bounces illuminated by a thin accretion disk |
Type |
Journal Article |
Year |
2021 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
08 |
Issue |
8 |
Pages |
036 - 19pp |
Keywords |
GR black holes; Wormholes; modified gravity; accretion |
Abstract |
We study the light rings and shadows of an uniparametric family of spherically symmetric geometries interpolating between the Schwarzschild solution, a regular black hole, and a traversable wormhole, and dubbed as black bounces, all of them sharing the same critical impact parameter. We consider the ray-tracing method in order to study the impact parameter regions corresponding to the direct, lensed, and photon ring emissions, finding a broadening of all these regions for black bounce solutions as compared to the Schwarzschild one. Using this, we determine the optical appearance of black bounces when illuminated by three standard toy models of optically and geometrically thin accretion disks viewed in face-on orientation. |
Address |
[Guerrero, Merce; Rubiera-Garcia, Diego] Univ Complutense Madrid, Dept Fis Teor, E-28040 Madrid, Spain, Email: merguerr@ucm.es; |
Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000686656000022 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
4943 |
Permanent link to this record |
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Author |
Maso-Ferrando, A.; Sanchis-Gual, N.; Font, J.A.; Olmo, G.J. |
Title |
Boson stars in Palatini f(R) gravity |
Type |
Journal Article |
Year |
2021 |
Publication |
Classical and Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
Volume |
38 |
Issue |
19 |
Pages |
194003 - 25pp |
Keywords |
boson stars; Palatini formalism; modified gravity |
Abstract |
We explore equilibrium solutions of spherically symmetric boson stars in the Palatini formulation of f (R) gravity. We account for the modifications introduced in the gravitational sector by using a recently established correspondence between modified gravity with scalar matter and general relativity with modified scalar matter. We focus on the quadratic theory f (R) = R + xi R-2 and compare its solutions with those found in general relativity, exploring both positive and negative values of the coupling parameter xi. As matter source, a complex, massive scalar field with and without self-interaction terms is considered. Our results show that the existence curves of boson stars in Palatini f (R) gravity are fairly similar to those found in general relativity. Major differences are observed for negative values of the coupling parameter which results in a repulsive gravitational component for high enough scalar field density distributions. Adding self-interactions makes the degeneracy between f (R) and general relativity even more pronounced, leaving very little room for observational discrimination between the two theories. |
Address |
[Maso-Ferrando, Andreu; Olmo, Gonzalo J.] Univ Valencia, Dept Fis Teor, Ctr Mixto Univ Valencia CSIC, Valencia 46100, Spain, Email: andreu.maso@uv.es |
Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0264-9381 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000695280300001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
4964 |
Permanent link to this record |
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Author |
Guerrero, M.; Mora-Perez, G.; Olmo, G.J.; Orazi, E.; Rubiera-Garcia, D. |
Title |
Charged BTZ-type solutions in Eddington-inspired Born-Infeld gravity |
Type |
Journal Article |
Year |
2021 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
11 |
Issue |
11 |
Pages |
025 - 23pp |
Keywords |
modified gravity; Exact solutions; black holes and black hole thermodynamics in GR and beyond; Wormholes |
Abstract |
We construct an axially symmetric solution of Eddington-inspired Born-Infeld gravity coupled to an electromagnetic field in 2 + 1 dimensions including a (negative) cosmological constant term. This is achieved by using a recently developed mapping procedure that allows to generate solutions in certain families of metric-affine gravity theories starting from a known seed solution of General Relativity, which in the present case corresponds to the electrically charged Banados-Teitelboim-Zanelli (BTZ) solution. We discuss the main features of the new configurations, including the modifications to the ergospheres and horizons, the emergence of wormhole structures, and the consequences for the regularity (or not) of these space-times via geodesic completeness. |
Address |
[Guerrero, Merce; Rubiera-Garcia, Diego] Univ Complutense Madrid, Dept Fis Teor, Plaza Ciencias S-N, E-28040 Madrid, Spain, Email: merguerr@ucm.es; |
Corporate Author |
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Thesis |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000727716400006 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5050 |
Permanent link to this record |
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Author |
Afonso, V.I.; Mora-Perez, G.; Olmo, G.J.; Orazi, E.; Rubiera-Garcia, D. |
Title |
An infinite class of exact rotating black hole metrics of modified gravity |
Type |
Journal Article |
Year |
2022 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
03 |
Issue |
3 |
Pages |
052 - 14pp |
Keywords |
Exact solutions; black holes and black hole thermodynamics in GR and beyond; Gauss-Bonnet-Lovelock-Horndeski-Palatini etc gravity theories; modified gravity |
Abstract |
We build an infinite class of exact axisymmetric solutions of a metric-affine gravity theory, namely, Eddington-inspired Born-Infeld gravity, coupled to an anisotropic fluid as a matter source. The solution-generating method employed is not unique of this theory but can be extended to other Ricci-Based Gravity theories (RBGs), a class of theories built out of contractions of the Ricci tensor with the metric. This method exploits a correspondence between the space of solutions of General Relativity and that of RBGs, and is independent of the symmetries of the problem. For the particular case in which the fluid is identified with non-linear electromagnetic fields we explicitly derive the corresponding axisymmetric solutions. Finally, we use this result to work out the counterpart of the Kerr-Newman black hole when Maxwell electrodynamics is set on the metric-affine side. Our results open up an exciting new avenue for testing new gravitational phenomenology in the fields of gravitational waves and shadows out of rotating black holes. |
Address |
[Afonso, Victor, I] Univ Fed Campina Grande, Unidade Academ Fis, BR-58429900 Campina Grande, Paraiba, Brazil, Email: viafonso@df.ufcg.edu.br; |
Corporate Author |
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Thesis |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000776994500002 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5185 |
Permanent link to this record |
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Author |
Delhom, A.; Mariz, T.; Nascimento, J.R.; Olmo, G.J.; Petrov, A.Y.; Porfirio, P.J. |
Title |
Spontaneous Lorentz symmetry breaking and one-loop effective action in the metric-affine bumblebee gravity |
Type |
Journal Article |
Year |
2022 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
Volume |
07 |
Issue |
7 |
Pages |
018 - 27pp |
Keywords |
gravity; modified gravity; quantum field theory on curved space; Quantum fields in curved spacetimes |
Abstract |
The metric-affine bumblebee model in the presence of fermionic matter minimally coupled to the connection is studied. We show that the model admits an Einstein frame representation in which the matter sector is described by a non-minimal Dirac action without any analogy in the literature. Such non-minimal terms involve unconventional couplings between the bumblebee and the fermion field. We then rewrite the quadratic fermion action in the Einstein frame in the basis of 16 Dirac matrices in order to identify the coefficients for Lorentz/CPT violation in all orders of the non-minimal coupling xi. The exact result for the fermionic determinant in the Einstein frame, including all orders in xi, is also provided. We demonstrate that the axial contributions are at least of second order in the perturbative expansion of xi. Furthermore, we compute the one-loop effective potential within the weak field approximation. |
Address |
[Delhom, Adria] Univ Tartu, Inst Phys, Lab Theoret Phys, W Ostwaldi 1, EE-50411 Tartu, Estonia, Email: adria.delhom@gmail.com; |
Corporate Author |
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Thesis |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Medium |
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Area |
|
Expedition |
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Conference |
|
Notes |
WOS:000834157900011 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5314 |
Permanent link to this record |