Nikolaos Karnesis
A5075267136- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- Cosmology and Gravitation Theories
- Gamma-ray bursts and supernovae
- Advanced Frequency and Time Standards
- Computational Physics and Python Applications
- Particle physics theoretical and experimental studies
- Scientific Measurement and Uncertainty Evaluation
- Scientific Research and Discoveries
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Astronomical Observations and Instrumentation
- Gaussian Processes and Bayesian Inference
- Advanced Electrical Measurement Techniques
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Particle Detector Development and Performance
- Superconducting and THz Device Technology
- Superconducting Materials and Applications
- Particle Accelerators and Free-Electron Lasers
- Ionosphere and magnetosphere dynamics
- Soil Moisture and Remote Sensing
- Dark Matter and Cosmic Phenomena
Aristotle University of Thessaloniki
2021-2025
Université Paris Cité
2014-2024
Laboratoire AstroParticule et Cosmologie
2014-2024
Centre National de la Recherche Scientifique
2018-2024
Institut d'Astrophysique de Paris
2024
University of Insubria
2023
Délégation Paris 7
2018-2021
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2018-2021
Royal Observatory
2018-2020
Sorbonne Paris Cité
2018-2020
Following the selection of The Gravitational Universe by ESA, and successful flight LISA Pathfinder, Consortium now proposes a 4 year mission in response to ESA's call for missions L3. observatory will be based on three arms with six active laser links, between identical spacecraft triangular formation separated 2.5 million km. is an all-sky monitor offer wide view dynamic cosmos using Waves as new unique messengers unveil Universe. It provides closest ever infant at TeV energy scales, has...
We report the first results of LISA Pathfinder in-flight experiment. The demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with relative acceleration noise square root power spectral density 5.2±0.1 fm s^{-2}/sqrt[Hz], or (0.54±0.01)×10^{-15} g/sqrt[Hz], g standard gravity, frequencies between 0.7 and 20 mHz. This value is lower than requirement by more factor 5 within 1.25...
In the months since publication of first results, noise performance LISA Pathfinder has improved because reduced Brownian due to continued decrease in pressure around test masses, from a better correction noninertial effects, and calibration electrostatic force actuation. addition, availability numerous long measurement runs, during which no perturbation is purposely applied allowed with good statistics down 20 μHz. The Letter presents measured differential acceleration figure, at...
ABSTRACT Realistic models of the Galactic double white dwarf (DWD) population are crucial for testing and quantitatively defining science objectives Laser Interferometer Space Antenna (LISA), a future European Agency’s gravitational-wave observatory. In addition to numerous individually detectable DWDs, LISA will also detect an unresolved confusion foreground produced by underlying population, which affect detectability all sources at frequencies below few mHz. So far, modelling DWD has been...
The large-scale analysis task of deciphering gravitational-wave signals in the LISA data stream will be difficult, requiring a large amount computational resources and extensive development methods. Its high dimensionality, multiple model types, complicated noise profile require global fit to all parameters input models simultaneously. In this work, we detail our algorithm, called “Erebor,” designed accomplish challenging task. It is capable analyzing current state-of-the-art datasets then...
The last century has seen enormous progress in our understanding of the Universe. We know life cycles stars, structure galaxies, remnants big bang, and have a general how Universe evolved. come remarkably far using electromagnetic radiation as tool for observing However, gravity is engine behind many processes Universe, much its action dark. Opening gravitational window on will let us go further than any alternative. Gravity own messenger: Gravitational waves, ripples fabric spacetime. They...
Measurements of electrostatic forces on free-falling test masses--2 kg metal cubes--are carried out for the first time in an environment constructed space-based gravitational wave detectors (a spacecraft 1.5 million km away from Earth).
The Laser Interferometer Space Antenna (LISA) mission, scheduled for launch in the early 2030s, is a gravitational wave observatory space designed to detect sources emitting millihertz band. In contrast present ground-based detectors, LISA data are expected be signal dominated, with strong and weak signals overlapping time frequency. Astrophysical population models predict sufficient number of band blend together form an irresolvable foreground noise. this work, we generic method...
Abstract We use the latest constraints on population of stellar origin binary black holes (SOBBH) from LIGO/Virgo/KAGRA (LVK) observations, to estimate stochastic gravitational wave background (SGWB) they generate in frequency band LISA. In order account for faint and distant binaries, which contribute most SGWB, we extend merger rate at high redshift assuming that it tracks star formation rate. adopt different methods compute SGWB signal: perform an analytical evaluation, Monte Carlo sums...
Abstract Detecting stochastic background radiation of cosmological origin is an exciting possibility for current and future gravitational-wave (GW) detectors. However, distinguishing it from other processes, such as instrumental noise astrophysical backgrounds, challenging. It even more delicate the space-based GW observatory LISA since cannot correlate its observations with detectors, unlike today's terrestrial network. Nonetheless, multiple measurements across constellation high accuracy...
ABSTRACT In recent years, methods for Bayesian inference have been widely used in many different problems physics where detection and characterization are necessary. Data analysis gravitational-wave astronomy is a prime example of such case. has very successful because this technique provides representation the parameters as posterior probability distribution, with uncertainties informed by precision experimental measurements. During last couple decades, specific advances proposed employed...
We present an in-depth analysis of the LISA Pathfinder differential acceleration performance over entire course its science operations, spanning approximately 500 days. find: (1) The evolution Brownian noise that dominates amplitude spectral density (ASD), for frequencies f≳1 mHz, is consistent with decaying pressure due to outgassing a single gaseous species. (2) Between f=36 μHz and 1 ASD shows 1/f tail in excess almost constant amplitude, ≃20% fluctuations period few days, no particular...
Abstract Stellar-mass black-hole binaries are the most numerous gravitational-wave sources observed to date. Their properties make them suitable for observation both by ground- and space-based detectors. Starting from synthetic catalogues constructed based on observational constraints ground-based detectors, we explore detection rates characteristic parameters of stellar-mass observable LISA during their inspiral, using signal-to-noise ratio thresholds as a criterion. We find that only...
In this paper, we describe the current status of LISA Pathfinder mission, a precursor mission aimed at demonstrating key technologies for future spacebased gravitational wave detectors, like LISA.Since much flight hardware has already been constructed and tested, will show that performance measurements analysis these components lead to an expected which is significant improvement over requirements, actually reaches requirements entire measurement band.
The science operations of the LISA Pathfinder mission have demonstrated feasibility sub-femto-g free fall macroscopic test masses necessary to build a gravitational wave observatory in space such as LISA. While main focus interest, i.e., optical axis or $x$-axis, has been extensively studied, it is also great importance evaluate stability spacecraft with respect all other degrees freedom (d.o.f.). current paper dedicated study: exhaustive and quantitative evaluation imperfections dynamical...
We report on the first subpicometer interferometer flown in space. It was part of ESA's Laser Interferometer Space Antenna (LISA) Pathfinder mission and performed fundamental measurement positional angular motion two free-falling test masses. The worked immediately, stably, reliably from switch until end with exceptionally low residual noise ${32.0}_{\ensuremath{-}1.7}^{+2.4}\text{ }\text{ }\mathrm{fm}/\sqrt{\mathrm{Hz}}$, significantly better than required. present an upper limit for sensor...
Abstract The science objectives of the LISA mission have been defined under implicit assumption a 4-years continuous data stream. Based on performance Pathfinder, it is now expected that will duty cycle $$\approx 0.75$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>≈</mml:mo> <mml:mn>0.75</mml:mn> </mml:mrow> </mml:math> , which would reduce effective span usable to 3 years. This paper reports results study by Science Group, was charged with assessing...
The LISA Pathfinder (LPF) mission succeeded outstandingly in demonstrating key technological aspects of future space-borne gravitational-wave detectors, such as the Laser Interferometer Space Antenna (LISA). Specifically, LPF demonstrated with unprecedented sensitivity measurement relative acceleration two free-falling cubic test masses. Although most disruptive nongravitational forces have been identified and their effects mitigated through a series calibration processes, some faint...
The coupling of an angular jitter into the interferometric phase readout is summarized under term tilt-to-length (TTL) coupling. This noise expected to be a major source in intersatellite interferometry for Laser Interferometer Space Antenna (LISA) space mission. Despite efforts reduce it by satellite construction, some remaining TTL will need removed postprocessing on Earth. Therefore, such procedure needs developed and validated ensure success LISA paper shows method calibrate subtract...
The Laser Interferometer Space Antenna (LISA) has two scientific objectives of cosmological focus: to probe the expansion rate universe, and understand stochastic gravitational-wave backgrounds their implications for early universe particle physics, from MeV Planck scale. However, range potential applications gravitational wave observations extends well beyond these objectives. This publication presents a summary state art in LISA cosmology, theory methods, identifies new opportunities use...
Future gravitational wave detectors, such as the Laser Interferometer Space Antenna (\textit{LISA}), will be able to resolve a significant number of ultra compact stellar-mass binaries in our own Galaxy and its neighborhood. These mostly double white dwarf (DWD) binaries, their underlying population characteristics can directly correlated different properties Galaxy. In particular, with \textit{LISA} we $\sim\mathcal{O}(10^4)$ while rest generate confusion foreground signal. Analogously how...
Extreme mass ratio inspirals (EMRIs) are among the primary targets for Laser Interferometer Space Antenna (LISA). The extreme ratios of these systems result in relatively weak gravitational wave signals, that can be individually resolved only cosmologically nearby sources (up to $z\ensuremath{\approx}2$). incoherent piling up signal emitted by unresolved EMRIs generate a confusion noise, formally treated as stochastic GW background (GWB). In this paper, we estimate level considering...