arXiv subjects

Vladimir Lenok

Publications and source records attributed to Vladimir Lenok.

4 recordsLinked to original sources

arXiv2026

Wigner interferometry

Aims. This work aims to introduce a new method of interferometric measurements based on correlation of Wigner functions constructed for the fields from a distant source. Methods. This work presents theoretical studies of correlation of the Wigner functions. Numerical simulations support the findings. Results. It is shown that in comparison to the correlation of the fields, a correlation of their Wigner functions samples twice higher spatial frequencies of the source intensity distribution and has about twice smaller scale of the spatial pattern. This opens a fundamental possibility to improve the angular resolution of interferometric measurements by a factor of two.

astro-ph.IM↗

arXiv2025

Bertrand's Representation of the Optimal Detector

It is shown how the optimal detector of Gaussian signals can be represented in terms of Bertrand's class of time-frequency distributions. In this representation, the detector is a correlation between the corresponding time-frequency distributions. Since Bertrand's class is related to the power-law chirp signals, the new representation can be useful for their detection. The new approach is shown to be more effective then other time-frequency methods for the case of phase-insensitive detection. The finding provides a complementary representation to Cohen's class representation in the time-frequency domain already known in the literature.

physics.data-an↗

arXiv2022

A Probabilistic Model for the Efficiency of Cosmic-Ray Radio Arrays

Digital radio detection of cosmic-ray air showers has emerged as an alternative technique in high-energy astroparticle physics. Estimation of the detection efficiency of cosmic-ray radio arrays is one of the few remaining challenges regarding this technique. To address this problem, we developed a model based on the explicit probabilistic treatment of key elements of the radio technique for air showers: the footprint of the radio signal on ground, the detection of the signal in an individual antenna, and the detection criterion on the level of the entire array. The model allows for estimation of sky regions of full efficiency and can be used to compute the aperture of the array, which is essential to measure the absolute flux of cosmic rays. We also present a semi-analytical method that we apply to the generic model, to calculate the efficiency and aperture with high accuracy and reasonable calculation time. The model in this paper is applied to the Tunka-Rex array as example instrument and validated against Monte Carlo simulations. The validation shows that the model performs well, in particular, in the prediction of regions with full efficiency. It can thus be applied to other antenna arrays to facilitate the measurement of absolute cosmic-ray fluxes and to minimize a selection bias in cosmic-ray studies.

astro-ph.IM↗

arXiv2021

Reconstruction of radio signals from air-showers with autoencoder

The Tunka Radio Extension (Tunka-Rex) is a digital antenna array (63 antennas distributed over 1km^2) co-located with the TAIGA observatory in Eastern Siberia. Tunka-Rex measures radio emission of air-showers induced by ultra-high energy cosmic rays in the frequency band of 30-80 MHz. Air-shower signal is a short (tens of nanoseconds) broadband pulse. Using time positions and amplitudes of these pulses, we reconstruct parameters of air showers and primary cosmic rays. The amplitudes of low-energy event (E<10^17 eV) cannot be used for successful reconstruction due to the domination of background. To lower the energy threshold of the detection and increase the efficiency, we use autoencoder neural network which removes noise from the measured data. This work describes our approach to denoising raw data and further reconstruction of air-shower parameters. We also present results of the low-energy events reconstruction with autoencoder.

astro-ph.IM↗