arXiv subjects

Maria J. Rodriguez

Publications and source records attributed to Maria J. Rodriguez.

At least 19 recordsLinked to original sources

arXiv2026

Precessing Black Hole Jets and Galactic Fossils

The Galactic Center gamma-ray excess (GCE) -- a surplus of gamma-ray radiation around SgrA$^{\star}$ -- has remained without a consensus interpretation for more than fifteen years. Dark-matter annihilation and unresolved millisecond-pulsar populations remain the leading candidates, yet neither connects the excess to the past activity of SgrA$^{\star}$ traced by the Fermi and eROSITA bubbles. We propose a common-origin scenario in which a contribution to the GCE arises as a fossil hadronic imprint of the same SgrA$^{\star}$ outburst associated with the bubbles. We develop a model of SgrA$^{\star}$ with a precessing paraboloidal Blandford-Znajek (BZ) jet launched from a tilted, magnetically arrested accretion disc during a ~ 7.5 Myr active phase ending ~2.6 Myr ago. In this picture, the jet drives the bipolar expansion of the Fermi/eROSITA bubbles -- contributing, alongside wider-angle outflows, to their observed extent -- and injects hadronic cosmic rays at the Galactic Center. We couple the analytic BZ injection to a two-zone diffusion numerical solver to compute the resulting GCE surface brightness and verify internal consistency: the proton Larmor radius remains small compared to the jet coherence scale, ensuring magnetic confinement of the cosmic-ray population, while attenuation of the produced $\gamma$ rays in the interstellar medium is negligible, leaving the medium effectively transparent. Isolating the jet contribution alone yields a spin-dependent, irreducible hadronic floor: for a SgrA$^{\star}$ spin of a$^{\star} = 0.9$, we find a robust floor at the few-percent to $\sim 10\%$ level of the observed GCE surface brightness across the inner ten degrees, highlighting a previously unexplored component relevant for comprehensive models of the GCE.

astro-ph.HE↗

arXiv2025

Clines and the Analytic Structure of Black Hole Perturbations

We revisit black hole perturbations through Heun differential equations, focusing on Frobenius power-series solutions near regular singularities and their connection formulas. Central to our approach is the notion of a cline in the complex plane, which organizes singular points of the differential equations and remain invariant under M\"obius transformations. Building on the cline structure we identified in black hole horizons, we carry out a systematic reduction and relocation of poles in the differential equation to obtain explicit representations of the solutions. We illustrate our approach by extracting the scalar perturbation solutions for the 7-dimensional Myers-Perry black hole and deriving the static scalar tidal Love numbers. These results suggest that clines expose a M\"obius-invariant order within black hole perturbations, rendering black hole perturbation problems remarkably tractable.

gr-qc↗

arXiv2025

Dynamical Tidal Response of Schwarzschild Black Holes

Dynamical Love numbers capture the conservative response of an object to a time-dependent external tidal gravitational field. We compute the dynamical Love numbers of Schwarzschild black holes in general relativity within a point-particle effective field theory framework. In addition to the known logarithmic running, we compute the finite scheme-dependent contributions to the Love number couplings. We do this by matching the renormalized one-point function in the effective theory to the classical field profile computed in general relativity. On the general relativity side, we solve the Regge-Wheeler and Zerilli equations perturbatively in a small frequency expansion. In order to match on the effective field theory side we include gravitational interactions using the Born series and employ dimensional regularization to obtain a renormalized field profile.

gr-qc↗

arXiv2024

Higher-Dimensional Black Holes and Effective Field Theory

We study the scalar tidal responses of spinning higher-dimensional black holes, and their effective field theory description. After constructing the effective field theory of a spinning point particle in general dimension, we apply this theory to match the scalar responses of a variety of black hole solutions. In addition to the five-dimensional Myers--Perry black hole, we derive the scalar responses of spinning black holes in the large $D$ limit, and also study the responses of black holes in the ultra-spinning regime. We find that in the most generic case, the static responses of higher-dimensional spinning black holes do not vanish, but for special cases we find a pattern of zeroes in the responses, similar to other known examples. Further, we observe various interesting relations between the responses.

hep-th↗

arXiv2024

Love Numbers for Extremal Kerr Black Hole

We perform a detailed study of the gravitational tidal Love numbers of extremal zero-temperature Kerr black holes. These coefficients are finite and exhibit the dissipative nature of these maximally spinning black holes. Upon considering the dynamical behavior of the tidal deformations of the extremal Kerr black holes, we provide explicit expressions of the Love numbers at low frequencies. Their calculation is simplified to specific formulas, which are directly derived using the Leaver-MST methods.

hep-th↗

arXiv2024

Thermodynamics of Kerr Effective Black Hole Geometries

We uncover the thermodynamical properties of a class of non-asymptotically flat geometries, referred here as the Kerr effective geometries, that realize the hidden symmetries of Kerr black hole spacetimes via Teukolsky's equation in the theory of linear gravitational perturbations. While the thermodynamic properties, such as entropy, remain the same as those of Kerr black holes, the asymptotic charges, as we will demonstrate, are different. In this new framework with the ambient flat asymptotic boundary removed, we derive the mass and angular momentum of the Kerr effective geometries using the regulated Komar integral and the Brown-York prescription. We also obtain explicit expressions for the corresponding gauge potentials and electric charges. By deriving the asymptotic charges, we demonstrate that both the first law of black hole mechanics and the Smarr law hold.

hep-th↗

arXiv2024

Kerr Effective Black Hole Geometries in Supergravity

We derive the explicit embedding of the effective Kerr spacetimes, which are pertinent to the vanishing of static Love numbers, soft hair descriptions of Kerr black holes, and low-frequency scalar-Kerr scattering amplitudes, as solutions within N = 2 supergravity. These spacetimes exhibit a hidden $SL(2, R) \times U (1)$ or $SO(4, 2)$ symmetry resembling the so called subtracted geometries with $SL(2, R) \times SL(2, R)$ symmetry, which accurately represent the near-horizon geometry of Kerr black holes and, as we will argue most accurately represents the internal structure of the Kerr black hole. To quantify the differences among the effective Kerr spacetimes, we compare their physical quantities, internal structures, and geodesic equations. Although their thermodynamic properties, including entropy, match those of Kerr, our study uncovers significant differences in the interiors of these effective Kerr solutions. A careful examination of the internal structure of the spacetimes highlights the distinctions between various effective Kerr geometries and their quasinormal spectra.

hep-th↗

arXiv2023

Dynamical Love Numbers for Kerr Black Holes

While static Love number vanish identically for Kerr black holes, we show that the corresponding dynamical tidal coefficients are generically non-zero and exhibit logarithmic behavior. The computational method employs a related but simpler scheme consistent with CFT descriptions, low-frequency regimes and post-Newtonian results. These coefficients are illustrated with a numerical examples.

gr-qc↗

arXiv2023

Blandford-Znajek jets in MOdified Gravity

General relativity (GR) will be imminently challenged by upcoming experiments in the strong gravity regime, including those testing the energy extraction mechanisms for black holes. Motivated by this, we explore magnetospheric models and black hole jet emissions in MOdified Gravity (MOG) scenarios. Specifically, we construct new power emitting magnetospheres in a Kerr-MOG background which are found to depend non-trivially on the MOG deformation parameter. This may allow for high-precision tests of GR. In addition, a complete set of analytic solutions for vacuum magnetic field configurations around static MOG black holes are explicitly derived, and found to comprise exclusively Heun polynomials.

gr-qc↗

arXiv2023

Love Numbers for Rotating Black Holes in Higher Dimensions

We compute the tidal Love numbers and static response coefficients associated to several rotating black holes in higher dimensions, including Myers-Perry black holes, black rings, and black strings. These coefficients exhibit a rich and complex structure as a function of the black hole parameters and multipoles. Our results agree in limiting cases with known and new expressions for various lower-dimensional black holes. In particular, we provide an alternative approach to the computation of the static response of Kerr black holes as a limiting case of the boosted black string.

hep-th↗

arXiv2022

CFT Duals for Black Rings and Black Strings

Holographic dualities between certain gravitational theories in four and five spacetime dimensions and 2D conformal field theories (CFTs) have been proposed based on hidden conformal symmetry exhibited by the radial Klein-Gordon (KG) operator in a so-called near-region limit. In this paper, we examine hidden conformal symmetry of black rings and black strings solutions, thus demonstrating that the presence of hidden conformal symmetry is not linked to the separability of the KG-equation (or the existence of a Killing-Yano tensor). Further, we will argue that these classes of non-extremal black holes have a dual 2D CFT. New revised monodromy techniques are developed to encompass all the cases we consider.

hep-th↗

arXiv2022

Signatures of Extra Dimensions in Black Hole Jets

One of the leading mechanisms powering relativistic black hole jets is the Blandford-Znajek (BZ) process. Inspired by its success we construct energy extracting models for black holes in five space-time dimensions. Here, we find solutions to the force-free electrodynamic equations representing plasma-magnetospheres for slowly rotating Myers-Perry black holes. Both, energy and angular momentum fluxes are computed for these solutions realizing power extraction from black holes in higher dimensions. Comparisons of the main features of the five-dimensional BZ models with lower four-dimensional counterparts are discussed.

hep-th↗

arXiv2022

CFT duals of Kerr-Taub-NUT and beyond

The duality relating the four-dimensional Kerr-Taub-NUT black hole to a thermal two-dimensional CFT with central charges $c_L=c_R=12 J_0$ is analyzed in detail, generalizing an argument given recently for Kerr within the soft-hair approach. The hidden conformal symmetry is realized in the form of $Vir_L \times Vir_R$ diffeomorphisms which act non-trivially on the black hole horizon. Semiclassical formulae are derived for the temperature and central charges of the dual CFT. Assuming the applicability of the Cardy formula, these CFT quantities precisely reproduce the macroscopic Bekenstein-Hawking area law. Various further generalizations including the complete family of black holes in four dimensions are discussed.

hep-th↗

arXiv2021

First Law for Kerr Taub-NUT AdS Black Holes

The first law of black hole mechanics, which relates the change of energy to the change of entropy and other conserved charges, has been the main motivation for probing the thermodynamic properties of black holes. In this work, we investigate the thermodynamics of Kerr Taub-NUT AdS black holes. We present geometric Komar definitions for the black hole charges, that by construction satisfy the Smarr formula. Further, by a scaling argument based on Euler's theorem, we establish the first law for the Kerr Taub-NUT AdS black holes. The corresponding first law includes variations in the cosmological constant, NUT charges and angular momenta. The key new ingredient in the construction are the independent variations of both angular momenta, the black hole and Misner string angular momenta. Employing the Brown-York quasilocal charge definitions we show that our expression for the mass and spin coincide with our generalized Komar expressions. We indicate the relevance of these results to the thermodynamics of rotating AdS black holes, including the proper choice of time-like Killing vector to produce the correct thermodynamic mass.

hep-th↗

arXiv2020

Central Charges for AdS Black Holes

Nontrivial diffeomorphisms act on the horizon of a generic 4D black holes and create distinguishing features referred to as soft hair. Amongst these are a left-right pair of Virasoro algebras with associated charges that reproduce the Bekenstein-Hawking entropy for Kerr black holes. In this paper we show that if one adds a negative cosmological constant, there is a similar set of infinitesimal diffeomorphisms that act non-trivially on the horizon. The algebra of these diffeomorphisms gives rise to a central charge. Adding a boundary counterterm, justified to achieve integrability, leads to well-defined central charges with cL = cR. The macroscopic area law for Kerr-AdS black holes follows from the assumption of a Cardy formula governing the black hole microstates.

hep-th↗

arXiv2020

Electro-Magnetic Energy Extraction from Rotating Black Holes in AdS

Force-Free Electrodynamics for black holes in Anti de Sitter is considered. We present new, energy extracting solutions of Force-Free Electrodynamics in Anti de Sitter - Near Horizon Extremal Kerr and Super-Entropic Near Horizon Extremal Kerr geometries. The relevant equations of motion are derived from an action for force-free plasma surrounding spinning black holes with generic asymptotics. We consider the energy flux of electrodynamic fields in rotating frames to argue that the correct measure for energy extraction is the energy flux measured by a rotating observer in the near horizon region. We illustrate this procedure by application to near horizon solutions in Kerr, AdS-Kerr and BTZ.

hep-th↗

arXiv2020

Emergent Black Hole Thermodynamics from Monodromy

We argue that the equations of motion of quantum field theories in curved backgrounds encode new fundamental black hole thermodynamic relations. We define new entropy variation relations. These `emerge' through the monodromies that capture the infinitesimal changes in the black hole background produced by the field excitations. This raises the possibility of new thermodynamic relations defined as independent sums involving entropies, temperatures and angular velocities defined at every black hole horizon. We present explicit results for the sum of all horizon entropy variations for general rotating black holes, both in asymptotically at and asymptotically anti-de Sitter spacetimes in four and higher dimensions. The expressions are universal, and in most cases add up to zero. We also find that these thermodynamic summation relations apply in theories involving multi-charge black holes.

gr-qc↗

arXiv2019

Generalized Near Horizon Extreme Binary Black Hole Geometry

We present a new vacuum solution of Einstein's equations describing the near horizon region of two neutral, extreme (zero-temperature), co-rotating, non-identical Kerr black holes. The metric is stationary, asymptotically near horizon extremal Kerr (NHEK), and contains a localized massless strut along the symmetry axis between the black holes. In the deep infrared, it flows to two separate throats which we call "pierced-NHEK" geometries: each throat is NHEK pierced by a conical singularity. We find that in spite of the presence of the strut for the pierced-NHEK geometries the isometry group SL(2,R)xU(1) is restored. We find the physical parameters and entropy.

hep-th↗