The study of the angular and spatial distribution of radio-selected AGNs and star-forming galaxies in the ELAIS N1 field

Abstract

The cosmic evolution of bias of different source populations with underlying dark matter density field in post reionization era can shed light on large scale structures. Studying the angular and spatial distribution of different compact sources using deep radio catalogue at lowfrequency is essential to understand the matter distribution of the present Universe. Here, we investigate the relationship of luminous matter with their host dark matter haloes by measuring the angular and spatial clustering of sources (two-point statistics), using deep radio observation of ELAIS N1 (EN1) field with upgraded Giant Metrewave Radio Telescope (uGMRT) at 300-500 MHz. We also analyze the 612 MHz GMRT archival data of the same field to understand the cosmic evolution of clustering of different source populations. We classify the sources as star-forming galaxies (SFGs) and active galactic nuclei (AGN) based on their radio luminosity. We find that the spatial clustering length and bias to the dark matter density field of SFGs are smaller than AGNs at both frequencies. This proves that AGNs are mainly hosted by massive haloes and hence strongly clustered. However, a small decrease in the bias for both kind of sources at higher frequency indicates that we are most likely tracing the faint objects residing in less massive haloes at higher frequencies. Our results are in excellent agreement with previous findings at radio and multi-frequency surveys. However, comparison with SKADS simulation suggests that the halo mass for different populations used in the simulation is systematically lower. This work quantifies the spatial distribution of extragalactic compact objects in EN1 field.

New constraints on the 1.4 GHz source number counts and luminosity functions in the Lockman Hole field

“…This has motivated many clustering studies at various radio frequencies and to different depths (e.g. Lindsay et al 2014;Magliocchetti et al 2017;Hale et al 2018;Rana & Bagla 2019;Chakraborty et al 2020).…”

“…larger than the maximum angular separation used to identify multicomponent sources). We have also added, for comparison, the best-fitting w(θ ) reported by other studies: Lindsay et al (2014),Hale et al (2018), Rana & Bagla (2019), and Chakraborty et al (2020. The results for 'SFG' and 'AGN' byHale et al (2018) are the fits given in their table 1.…”

New constraints on the 1.4 GHz source number counts and luminosity functions in the Lockman Hole field

“…This has motivated many clustering studies at various radio frequencies and to different depths (e.g. Lindsay et al 2014;Magliocchetti et al 2017;Hale et al 2018Hale et al , 2019Rana & Bagla 2019;Chakraborty et al 2020).…”

“…larger than the maximum angular separation used to identify multi-component sources). We have also added, for comparison, the best fit w(θ) reported by other studies:Lindsay et al (2014),Hale et al (2018),Hale et al (2019), Rana & Bagla (2019 andChakraborty et al (2020). The results for "SFG" and "AGN" byHale et al (2018) are the fits given in their Table1.…”

Using strong gravitational lensing to probe the post reionization \HI power spectrum

“…These are usually referred to as foreground contamination to the signal and have several orders of magnitude higher amplitude (Trott, 2016) compared to the signal itself. A majority of work (Datta et al, 2010;Ghosh et al, 2011;Choudhuri et al, 2016) over the last decade towards the H I power spectrum estimation focuses on better detection, mitigation and avoidance of these foreground contaminations (Choudhuri et al, 2017;Chakraborty et al, 2019a,b;Chakraborty et al, 2020).…”