A5004777579- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- Cosmology and Gravitation Theories
- Superconducting Materials and Applications
- Advanced Frequency and Time Standards
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Seismic Waves and Analysis
- Statistical and numerical algorithms
- Black Holes and Theoretical Physics
- Scientific Research and Discoveries
- Astrophysical Phenomena and Observations
- Inertial Sensor and Navigation
Max Planck Institute for Radio Astronomy
2023-2025
Aarhus University
2021
We present the results of search for an isotropic stochastic gravitational wave background (GWB) at nanohertz frequencies using second data release European Pulsar Timing Array (EPTA) 25 millisecond pulsars and a combination with first Indian (InPTA). analysed (i) full 24.7-year EPTA set, (ii) its 10.3-year subset based on modern observing systems, (iii) set InPTA ten commonly timed pulsars, (iv) data. These combinations allowed us to probe contributions instrumental noise interstellar...
Pulsar timing arrays offer a probe of the low-frequency gravitational wave spectrum (1 - 100 nanohertz), which is intimately connected to number markers that can uniquely trace formation and evolution Universe. We present dataset results analysis from second data release European Timing Array (EPTA). The contains high-precision pulsar 25 millisecond pulsars collected with five largest radio telescopes in Europe, as well Large for Pulsars. forms foundation search waves by EPTA, presented...
The European Pulsar Timing Array (EPTA) and Indian (InPTA) collaborations have measured a low-frequency common signal in the combination of their second first data releases, respectively, with correlation properties gravitational wave background (GWB). Such may its origin number physical processes including cosmic population inspiralling supermassive black hole binaries (SMBHBs); inflation, phase transitions, strings, tensor mode generation by non-linear evolution scalar perturbations early...
The European Pulsar Timing Array (EPTA) and Indian (InPTA) collaborations have measured a low-frequency common signal in the combination of their second first data releases respectively, with correlation properties gravitational wave background (GWB). Such may its origin number physical processes including cosmic population inspiralling supermassive black hole binaries (SMBHBs); inflation, phase transitions, strings tensor mode generation by non-linear evolution scalar perturbations early...
Aims. The nanohertz gravitational wave background (GWB) is expected to be an aggregate signal of ensemble waves emitted predominantly by a large population coalescing supermassive black hole binaries in the centres merging galaxies. Pulsar timing arrays (PTAs), which are ensembles extremely stable pulsars at approximately kiloparsec distances precisely monitored for decades, most precise experiments capable detecting this background. However, subtle imprints that GWB induces on pulsar data...
Abstract The Australian, Chinese, European, Indian, and North American pulsar timing array (PTA) collaborations recently reported, at varying levels, evidence for the presence of a nanohertz gravitational-wave background (GWB). Given that each PTA made different choices in modeling their data, we perform comparison GWB individual noise parameters across results reported from PTAs constitute International Pulsar Timing Array (IPTA). We show despite making choices, there is no significant...
Pulsar Timing Array experiments probe the presence of possible scalar or pseudoscalar ultralight dark matter particles through decade-long timing an ensemble galactic millisecond radio pulsars. With second data release European Array, we focus on most robust scenario, in which interacts only gravitationally with ordinary baryonic matter. Our results show that masses 10^{-24.0} eV≲m≲10^{-23.3} eV cannot constitute 100% measured local density, but can have at density ρ≲0.3 GeV/cm^{3}.
We present the results of a search for continuous gravitational wave signals (CGWs) in second data release (DR2) European Pulsar Timing Array (EPTA) Collaboration. The most significant candidate event from this has frequency 4–5 nHz. Such signal could be generated by supermassive black hole binary (SMBHB) local Universe. follow-up analysis using both Bayesian and frequentist methods. gives Bayes factor 4 favour presence CGW over common uncorrelated noise process. In contrast, estimates...
We present the results of search for an isotropic stochastic gravitational wave background (GWB) at nanohertz frequencies using second data release European Pulsar Timing Array (EPTA) 25 millisecond pulsars and a combination with first Indian (InPTA). analysed (i) full 24.7-year EPTA set, (ii) its 10.3-year subset based on modern observing systems, (iii) set InPTA ten commonly timed pulsars, (iv) data. These combinations allowed us to probe contributions instrumental noise interstellar...
We present the results of a search for continuous gravitational wave signals (CGWs) in second data release (DR2) European Pulsar Timing Array (EPTA) collaboration. The most significant candidate event from this has frequency 4-5 nHz. Such signal could be generated by supermassive black hole binary (SMBHB) local Universe. follow-up analysis using both Bayesian and frequentist methods. gives Bayes factor 4 favor presence CGW over common uncorrelated noise process, while estimates p-value to...
The Australian, Chinese, European, Indian, and North American pulsar timing array (PTA) collaborations recently reported, at varying levels, evidence for the presence of a nanohertz gravitational wave background (GWB). Given that each PTA made different choices in modeling their data, we perform comparison GWB individual noise parameters across results reported from PTAs constitute International Pulsar Timing Array (IPTA). We show despite making choices, there is no significant difference...
We search for a stochastic gravitational wave background (SGWB) generated by network of cosmic strings using six millisecond pulsars from Data Release 2 (DR2) the European Pulsar Timing Array (EPTA). perform Bayesian analysis considering two models string loops, and compare it to simple power-law model which is expected population supermassive black hole binaries. Our main strong assumption that previously reported common red noise process SGWB. find one-parameter slightly favored over...
ABSTRACT Propagation effects are one of the main sources noise in high-precision pulsar timing. For pulsars below an ecliptic latitude 5°, ionized plasma solar wind can introduce dispersive delays order $100\, \mu \mathrm{s}$ around conjunction at observing frequency 300 MHz. A common approach to mitigate this assumes a spherical with time-constant amplitude. However, has been shown be insufficient describe wind. We present linear, Gaussian-process piecewise Bayesian fit time-variable...
Ultralight axionlike particles (ALPs) can be a viable solution to the dark matter problem. The scalar field associated with ALPs, coupled electromagnetic acts as an active birefringent medium, altering polarization properties of light through which it propagates. In particular, oscillations axionic induce monochromatic variations plane linearly polarized radiation astrophysical signals. radio emission millisecond pulsars provides excellent tool search for such manifestations, given their...
Pulsar timing array (PTA) collaborations recently reported evidence for the presence of a gravitational wave background (GWB) in their datasets. The main candidate that is expected to produce such GWB population supermassive black hole binaries. Some analyses showed recovered signal may exhibit time-dependent properties, i.e., nonstationarity. In this paper, we propose an approximated nonstationary Gaussian process model obtained from perturbation stationary processes. presented method...
The origin and fate of magnetars (young, extremely magnetized neutron stars, NSs) remain unsolved. Probing their evolution is therefore crucial for investigating possible links to other species isolated NSs, such as the X-ray dim NSs (XDINSs) rotating radio transients (RRATs). Here we investigate spin magnetars. Two avenues are considered: one with exponentially decaying B-fields, sub- super-exponential decay. Using Monte Carlo methods, synthesize magnetar populations using different input...
The nanohertz gravitational wave background (GWB) is expected to be an aggregate signal of ensemble waves emitted predominantly by a large population coalescing supermassive black hole binaries in the centres merging galaxies. Pulsar timing arrays, ensembles extremely stable pulsars, are most precise experiments capable detecting this background. However, subtle imprints that GWB induces on pulsar data obscured many sources noise. These must carefully characterized increase sensitivity GWB....
ABSTRACT In this work, we investigated the presence of strictly periodic, as well quasi-periodic signals, in timing 25 millisecond pulsars (MSPs) from European Pulsar Timing Array Second Data Release data set. This is especially interesting context recent hints a gravitational wave background these data, and necessary further study red noise processes, which are known to behave quasi-periodically some normal pulsars. We used Bayesian models developed through run_enterprise pipeline: strict...
Propagation effects are one of the main sources noise in high-precision pulsar timing. For pulsars below an ecliptic latitude $5^\circ$, ionised plasma solar wind can introduce dispersive delays order 100 microseconds around conjunction at observing frequency 300 MHz. A common approach to mitigate this assumes a spherical with time-constant amplitude. However, has been shown be insufficient describe wind. We present linear, Gaussian-process piecewise Bayesian fit time-variable amplitude,...
Pulsar Timing Array (PTA) collaborations recently reported evidence for the presence of a gravitational wave background (GWB) in their datasets. The main candidate that is expected to produce such GWB population supermassive black hole binaries (SMBHB). Some analyses showed recovered signal may exhibit time-dependent properties, i.e. non-stationarity. In this paper, we propose an approximated non-stationary Gaussian process (GP) model obtained from perturbation stationary processes....
In this work, we investigated the presence of strictly periodic, as well quasi-periodic signals, in timing 25 millisecond pulsars from EPTA DR2 dataset. This is especially interesting context recent hints a gravitational wave background these data, and necessary further study red-noise processes, which are known to behave quasi-periodically some normal pulsars. We used Bayesian models developed through run_enterprise pipeline: strict periodicity was modelled influence planetary companion on...