The Indo-Japanese collaboration InPTA recently published its second data release making high-precision dispersion measures and timing solutions available for 27 millisecond pulsars across a 7 year time baseline, spanning simultaneous frequency coverage of 300-500 MHz and 1260-1460 MHz uGMRT receivers. This data is being combined with global PTA datasets for the upcoming IPTA DR3. The talk...
Pulsars generally exhibit stable integrated pulse profiles, making them
powerful tools for precision timing experiments. While short-term vari-
ability, such as mode-changing and nulling, is known in young pulsars,
studies suggest that long-term profile changes may also occur, potentially
correlated with the spin-down rate. Millisecond pulsars (MSPs), typi-
cally more stable, have shown...
ARGOS-CDS is the design study phase for the planned ARGOS telescope, a leading-edge, low-cost radio interferometer to be built in Europe. It will perform continuous wide-field monitoring in between 1 GHz and 3 GHz, and high-cadence, high-SNR observations of all PTA pulsars as the most sensitive instrument in the EPTA.
The pulsar science pipeline, arpa, for ARGOS is being developed as new,...
Pulsar Timing Arrays (PTAs) are approaching the sensitivity required to make a 5-σ detection of the nanohertz stochastic gravitational wave background (GWB), making it crucial to develop a comprehensive understanding of our data and of the outcomes of our analysis pipelines. Thus, it becomes essential to understand a counterintuitive feature revealed in the recent results from the European...
Building on Iraci et al. (2024), we study the impact of our main modelling routines to mitigate the effects of the ionized interstellar medium during the search for the Gravitational Wave Background (GWB) with Pulsar Timing Arrays (PTAs). To this scope, we use synthetic PTA datasets and model the DM variations as Gaussian Processes (DM GP) using the Enterprise software to test the consistency...
In Pulsar Timing Array (PTA) data analysis, noise is typically assumed to be Gaussian, and the marginalized likelihood has a well-established analytical form derived within the framework of Gaussian processes. However, this Gaussianity assumption may break down for certain classes of astrophysical and cosmological signals, particularly for a gravitational wave background (GWB) generated by a...
In this talk, we will discuss on the recent updates on LOFAR and NenuFAR.
LOFAR’s beamformed mode enables diverse science cases and data collected in this mode proved to be fundamental for the latest EPTA data release, DR2low (Iraci and Chalumeau et al 2025).
However, polarization analysis in beamformed mode has remained largely out of reach due to the absence of a reliable polarization calibration framework.
Here, I will present our cutting-edge polarization...
Low-frequency radio data are highly valuable for studying propagation effects in pulsar signals, such as dispersion measure (DM) variations. In this work, we combine for the first time observations from LOFAR (100–200 MHz) and NenuFAR (30–90 MHz) with EPTA DR2new+ data to build a new dataset, the so-called DR2low. It consists of 12 pulsars observed over a time span of ∼11 years with radio...
The cold dark matter (CDM) model successfully describes the Universe on large scales, yet faces challenges at sub-galactic scales. Ultralight dark matter (ULDM), with particle masses around $10^{-22}$ eV, offers a promising solution to these small-scale issues. Pulsar timing arrays (PTAs), originally designed to detect nanohertz gravitational waves, also provide a sensitive probe for ULDM...
Accurate localisation of continuous gravitational waves (CGWs) from supermassive black hole binaries (SMBHBs) remains one of the key challenges in Pulsar Timing Array (PTA) data analysis. Traditional searches based on the $\mathcal{F}_e$ statistic provide a robust analytic framework, but the resulting sky maps are strongly affected by the PTA antenna pattern, which redistributes signal power...
The most plausible astrophysical sources for PTA experiments are supermassive black hole binaries (SMBHBs), which emit gravitational waves (GWs) that incoherently superpose to form a stochastic GW background (SGWB). Particularly massive and nearby SMBHBs produce strong signals that may stand out above the GWB. PTAs will observe the early inspiral of these systems at large orbital separations,...
We present a fully general relativistic formalism to study propagation delays in the radio signals of pulsars in binary systems, arising from the gravitational bending of light. This bending delay is a significant contribution in neutron star–neutron star systems and becomes even more pronounced in neutron star–black hole binaries. Applying our framework to hypothetical neutron star–black hole...
