Eva Hackmann
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View article: Testing Gravity with Binary Pulsars in the SKA Era
Testing Gravity with Binary Pulsars in the SKA Era Open
Binary (and trinary) radio pulsars are natural laboratories in space for understanding gravity in the strong field regime, with many unique and precise tests carried out so far, including the most precise tests of the strong equivalence pr…
View article: Galactic Centre Pulsars with the SKAO
Galactic Centre Pulsars with the SKAO Open
The detection of a pulsar closely orbiting our Galaxy’s supermassive black hole - Sagittarius A* - is one of the ultimate prizes in pulsar astrophysics. The relativistic effects expected in such a system could far exceed those currently ob…
Null integrability and photon phenomenology in the accelerated Schwarzschild black hole Open
In this study we analyse null geodesics in an accelerated Schwarzschild black hole sustained by a cosmic string/strut (C-metric) in the sub-extremal regime. Using dimensionless variables and a Mino-type parameter we cast the equations into…
Frequency shifts due to relativistic effects and retardation in continuous variable quantum key distribution Open
Space-based quantum communication naturally involves satellites and ground stations exchanging optical signals at high altitudes and large relative velocities. Starting from general relativistic considerations, we systematically separate t…
Non-Keplerian Charged Accretion Disk Orbiting a Black Hole Pulsar Open
Recent studies have focused on how spinning black holes (BHs) within a binary system containing a strongly magnetized neutron star, then immersed in external magnetic fields, can acquire charge through mechanisms like the Wald process and …
General relativity and geodesy Open
Mass redistribution on Earth due to dynamic processes such as ice melting and sea-level rise leads to a changing gravitational field, observable by geodetic techniques. Monitoring this change over time allows us to learn more about our pla…
Gravitational field recovery via inter-satellite redshift measurements Open
Satellite gravimetry is a common tool to monitor global changes in the Earth system, generally utilising accelerometers aboard satellites to measure acting forces along the orbits. In contrast, high-precision atomic clocks are used in firs…
General Relativistic Chronometry from Ground and in Space Open
Geodesy's primary objective lies in the determination of Earth's gravity field through ground and space-based measurements. General relativity and, thus, relativistic geodesy, introduce a novel perspective, leveraging high-precision clock …
Stability of rotating, charged fluids: Generalization of the Høiland conditions in Newtonian nonconductive case Open
We study the conditions for stability of electrically charged, non-conductive\nperfect fluid tori with respect to linear perturbations. To this end we employ\nLagrangian perturbation formalism and we assume a system where the fluid orbits\…
View article: Gravitomagnetic Clock Effect: Using GALILEO to explore General Relativity
Gravitomagnetic Clock Effect: Using GALILEO to explore General Relativity Open
All experiments to date are in remarkable agreement with the predictions of Einstein's theory of gravity, General Relativity. Besides the classical tests, involving light deflection, orbit precession, signal delay, and the gravitational re…
General Relativistic Chronometry with Clocks on Ground and in Space Open
One of geodesy's main tasks is to determine the gravity field of the Earth. High precision clocks have the potential to provide a new tool in a global determination of the Earth's gravitational potential based on the gravitational redshift…
Kerr geodesics in terms of Weierstrass elliptic functions Open
We derive novel analytical solutions describing timelike and null geodesics in the Kerr spacetime. The solutions are parametrized explicitly by constants of motion---the energy, the angular momentum, and the Carter constant---and initial c…
Equivalence of Active and Passive Gravitational Mass Tested with Lunar Laser Ranging Open
Lunar Laser Ranging (LLR) measures the distance between observatories on Earth and retro-reflectors on the Moon since 1969. In this Letter, we study the possible violation of the equivalence of passive and active gravitational mass (ma/mp)…
Kerr Geodesics in Terms of Weierstrass Elliptic Functions Open
We derive novel analytical solutions describing timelike and null geodesics in the Kerr spacetime. The solutions are parameterized explicitly by constants of motion -- the energy, the angular momentum, and the Carter constant -- and initia…
Chronometry: On the redshift and relativistic gravity potential determination in GR Open
We derive exact expressions for the relativistic redshift and timing between observers in various configurations in stationary spacetimes for the purpose of chronometry, i.e., relativistic gravimetry based on clocks. These observers are as…
Equivalence of Active and Passive Gravitational Mass Tested with Lunar Laser Ranging Open
LLR measures the distance between observatories on Earth and retro-reflectors on Moon since 1969. In this paper, we study the possible violation of the equality of passive and active gravitational mass ($m_{a}/m_{p}$), for Aluminium (Al) a…
Thick accretion disk configurations in the Born-Infeld teleparallel gravity Open
The main goal of this paper is to investigate one of the important astrophysical systems, namely Thick accretion disks, in the background of the spherically symmetric solution in Born-Infeld teleparallel gravity to examine observable predi…
The Framework of Relativistic Geodesy: What do we know? Open
Conventional geodesy builds on (the concepts of) Newtonian gravity. Thus, at the level of a relativistic theory of gravity, the underlying framework needs to be extended and basic notions need to be generalized. This opens an entirely new …
Relativistic propagation and frame dragging time delay in the timing of a pulsar orbiting the supermassive black hole SgrA* Open
Timing a pulsar in a close orbit around the supermassive black hole SgrA* at the center of the Milky Way would open the window for an accurate determination of the black hole parameters and for new tests of General Relativity and alternati…
Schwarzschild black hole surrounded by quintessential matter field as an accelerator for spinning particles Open
We study the collision of two massive particles with non-zero intrinsic spin\nmoving in the equatorial plane in the background of a Schwarzschild black hole\nsurrounded by quintessential matter field (SBHQ). For the quintessential matter\n…
Relativistic geoid: Gravity potential and relativistic effects Open
The Earth's geoid is one of the most essential and fundamental concepts to\nprovide a gravity field-related height reference in geodesy and associated\nsciences. To keep up with the ever-increasing experimental capabilities and to\nconsist…
Fundamental Notions in Relativistic Geodesy - physics of a timelike Killing vector field Open
The Earths geoid is one of the most important fundamental concepts to provide a gravity field- related height reference in geodesy and associated sciences. To keep up with the ever-increasing experimental capabilities and to consistently i…
Thin accretion disk around the distorted Schwarzschild black hole Open
We construct the relativistic standard steady, optically thick, cold and geometrically thin accretion disk around a distorted Schwarzschild black hole. The distortion of this static and axially symmetric black hole solution, is connected t…
Charged fluid structures around a rotating compact object with a magnetic dipole field Open
We study stationary, electrically charged fluid structures encircling a rotating compact object with a dipole magnetic field oriented along the rotation axis. This situation is described in an idealized way by the Kerr metric and a magneti…
Equilibrium configurations of a charged fluid around a Kerr black hole Open
Equilibrium configurations of electrically charged perfect fluid surrounding a central rotating black hole endowed with a test electric charge and embedded in a large-scale asymptotically uniform magnetic field are presented. Following our…
Redshift and frequency comparison in Schwarzschild spacetime Open
We derive exact expressions for the relativistic redshift between an Earth-bound observer, that is meant to model a standard clock on the Earth's surface, and various (geodesic) observers in the Schwarzschild spacetime. We assume that the …