| Records |
| Author |
Guerrero, M.; Olmo, G.J.; Rubiera-Garcia, D.; Saez-Chillon Gomez, D. |
| Title |
Multiring images of thin accretion disk of a regular naked compact object |
Type |
Journal Article |
| Year |
2022 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
106 |
Issue |
4 |
Pages |
044070 - 13pp |
| Keywords |
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| Abstract |
We discuss the importance of multiring images in the optical appearance of a horizonless spherically symmetric compact object, when illuminated by an optically thin accretion disk. Such an object corresponds to a subcase of an analytically tractable extension of the Kerr solution dubbed as the “eye of the storm” by Simpson and Visser in [J. Cosmol. Astropart. Phys. 03 (2022) 011], which merits in removing curvature singularities via an asymptotically Minkowski core, while harboring both a critical curve and an infinite potential barrier at the center for null geodesics. This multiring structure is induced by light rays winding several times around the object, and whose luminosity is significantly boosted as compared to the Schwarzschild solution by the modified shape of the potential. Using three toy profiles for the emission of an infinitely thin disk, truncated at its inner edge (taking its maximum value there) and having different decays with the distance, we discuss the image created by up to eight rings superimposed on top of the direct emission of the disk as its edge is moved closer to the center of the object. Our results point to the existence of multiring images with a non-negligible luminosity in shadow observations when one allows for the existence of other compact objects in the cosmic zoo beyond the Schwarzschild solution. Such multiring images could be detectable within the future projects on very long baseline interferometry. |
| Address |
[Guerrero, Merce; Rubiera-Garcia, Diego] Univ Complutense Madrid, Dept Fis Teor, IPARCOS, Madrid 28040, Spain, Email: merguerr@ucm.es; |
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Thesis |
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| Publisher |
Amer Physical Soc |
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| Language |
English |
Summary Language |
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ISSN  |
2470-0010 |
ISBN |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000850772800006 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5352 |
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| Author |
Silva, J.E.G.; Maluf, R.V.; Olmo, G.J.; Almeida, C.A.S. |
| Title |
Braneworlds in f(Q) gravity |
Type |
Journal Article |
| Year |
2022 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
106 |
Issue |
2 |
Pages |
024033 - 15pp |
| Keywords |
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| Abstract |
We propose a braneworld scenario in a modified symmetric teleparallel gravitational theory, where the dynamics for the gravitational field is encoded in the nonmetricity tensor rather than in the curvature. Assuming a single real scalar field with a sine-Gordon self-interaction, the generalized quadratic nonmetricity invariant Q controls the brane width while keeping the shape of the energy density. By considering power corrections of the invariant Q in the gravitational Lagrangian, the sine-Gordon potential is modified exhibiting new barriers and false vacuum. As a result, the domain wall brane obtains an inner structure, and it undergoes a splitting process. In addition, we also propose a nonminimal coupling between a bulk fermion field and the nonmetricity invariant Q. Such geometric coupling leads to a massless chiral fermion bound to the 3-brane and a stable tower of nonlocalized massive states. |
| Address |
[Silva, J. E. G.] Univ Fed do Cariri UFCA, Ave Tenente Raimundo Rocha,Cidade Universitaria, BR-63048080 Juazeiro do Norte, CE, Brazil, Email: euclides.silva@ufca.edu.br; |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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| ISSN |
2470-0010 |
ISBN |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000880673200004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5410 |
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| Author |
Magalhaes, R.B.; Maso-Ferrando, A.; Olmo, G.J.; Crispino, L.C.B. |
| Title |
Asymmetric wormholes in Palatini f (R) gravity: Energy conditions, absorption, and quasibound states |
Type |
Journal Article |
| Year |
2023 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
108 |
Issue |
2 |
Pages |
024063 - 20pp |
| Keywords |
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| Abstract |
We investigate the scalar absorption spectrum of wormhole solutions constructed via the recently developed thin-shell formalism for Palatini f(R) gravity. Such wormholes come from the matching of two Reissner-Nordstrom spacetimes at a timelike hypersurface (shell), which, according to the junction conditions in Palatini f(R), can be stable and have either positive or negative energy density. In particular, we identified a new physically interesting configuration made out of two overcharged Reissner-Nordstrom spacetimes, whose absorption profile departs from that of black holes and other previously considered wormholes in the whole range of frequencies. Unlike in symmetric wormhole solutions, the asymmetry of the effective potential causes the dilution of the resonances associated to the quasibound states for the high -frequency regime. Therefore, slight asymmetries in wormhole space-times could have a dramatic impact on the observable features associated to resonant states. |
| Address |
[Magalhaes, Renan B.; Crispino, Luis C. B.] Univ Fed, Programa Pos Graduacao Fis, BR-66075110 Belem, PA, Brazil, Email: renan.batalha@ext.uv.es; |
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Thesis |
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| Publisher |
Amer Physical Soc |
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| Language |
English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2470-0010 |
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:001055237800002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5629 |
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| Author |
Dias da Silva, L.F.; Lobo, F.S.N.; Olmo, G.J.; Rubiera-Garcia, D. |
| Title |
Photon rings as tests for alternative spherically symmetric geometries with thin accretion disks |
Type |
Journal Article |
| Year |
2023 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
108 |
Issue |
8 |
Pages |
084055 - 18pp |
| Keywords |
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| Abstract |
The imaging by the Event Horizon Telescope (EHT) of the supermassive central objects at the heart of the M87 and Milky Way (Sgr A*) galaxies, has marked the first step into peering at the photon rings and central brightness depression that characterize the optical appearance of black holes surrounded by an accretion disk. Recently, Vagnozzi et al. [arXiv:2205.07787] used the claim by the EHT that the size of the shadow of Sgr A* can be inferred by calibrated measurements of the bright ring enclosing it, to constrain a large number of spherically symmetric space-time geometries. In this work we use this result to study some features of the first and second photon rings of a restricted pool of such geometries in thin accretion disk settings. The emission profile of the latter is described by calling upon three analytic samples belonging to the family introduced by Gralla, Lupsasca, and Marrone, in order to characterize such photon rings using the Lyapunov exponent of nearly bound orbits and discuss its correlation with the luminosity extinction rate between the first and second photon rings. We finally elaborate on the chances of using such photon rings as observational discriminators of alternative black hole geometries using very long baseline interferometry. |
| Address |
[Dias da Silva, Luis F.; Lobo, Francisco S. N.] Univ Lisbon, Inst Astrofis & Ciencias Espaco, Fac Ciencias, Edificio C8, P-1749016 Lisbon, Portugal, Email: fc53497@alunos.fc.ul.pt; |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2470-0010 |
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:001093442700002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5779 |
| Permanent link to this record |
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| Author |
Maluf, R.V.; Olmo, G.J. |
| Title |
Vacuum polarization and induced Maxwell and Kalb-Ramond effective action in very special relativity |
Type |
Journal Article |
| Year |
2023 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
108 |
Issue |
9 |
Pages |
095022 - 13pp |
| Keywords |
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| Abstract |
This work investigates the implications of very special relativity (VSR) on the calculation of vacuum polarization for fermions in the presence of Maxwell and Kalb-Ramond gauge fields in four-dimensional spacetime. We derive the SIM(2)-covariant gauge theory associated with an Abelian antisymmetric twotensor and its corresponding field strength. We demonstrate that the free VSR-Kalb-Ramond electrodynamics is equivalent to a massive scalar field with a single polarization. Furthermore, we determine an explicit expression for the effective action involving Maxwell and Kalb-Ramond fields due to fermionic vacuum polarization at one-loop order. The quantum corrections generate divergences free of nonlocal terms only in the VSR-Maxwell sector. At the same time, we observe UV/IR mixing divergences due to the entanglement of VSR-nonlocal effects with quantum higher-derivative terms for the Kalb-Ramond field. However, in the lower energy limit, the effective action can be renormalized like in the Lorentz invariant case. |
| Address |
[Maluf, Roberto, V; Olmo, Gonzalo J.] Univ Fed Ceara UFC, Dept Fis, Campus Pici,CP 6030, BR-60455760 Fortaleza, CE, Brazil, Email: r.v.maluf@fisica.ufc.br; |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
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 |
2470-0010 |
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:001111823400003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5863 |
| Permanent link to this record |
