Speaker
Description
The Lofar Two-meter Sky Survey (LoTSS) had its second data release (DR2) published in 2022. It provides the largest radio sources catalogue to date, including 4.4 million sources and covering 5600 square degrees of the sky, and therefore an excellent opportunity for studies of the large-scale structure of the Universe. In this talk, I will present the results based on one-point correlation function. This statistic, also known as counts-in-cells, offers insights into the spatial distribution of radio sources. I will show that the distribution of the radio sources is non-Poisson which is likely due to multiple physical components of individual sources. Employing Cox process, I utilize both compound Poisson and negative binomial distributions to model the distribution of the sources. Through statistical tests in both frequentist and Bayesian frameworks, I evaluate which distribution fit better to the observed source distribution.
In the second part of the talk, I will use statistical measures from counts-in-cells to calculate the two-point correlation function. It's widely known that the variance of counts-in-cells is directly linked to the angular two-point correlation function. By analyzing the variance of counts-in-cells in various cell sizes within the Healpix pixelization scheme, I will fit it to a single power-law model representing the angular two-point correlation function. This helps us determine the amplitude and exponent of the power-law by a computationally very cheaper method.
