Theoretical estimates of integrated Sachs–Wolfe effect detection through the Australian Square Kilometre Array Pathfinder’s Evolutionary Map of the Universe (ASKAP- EMU) survey, with confusion, position uncertainty, shot noise, and signal-to-noise ratio analysis

Abstract

Detection of the late time integrated Sachs-Wolfe effect (ISW) is an active area of study related to Large Scale Structures (LSS).The ISW effect can be studied by observing the nonzero cross-correlation between cosmic microwave background (CMB) anisotropies with tracers of mass field, such as galaxy survey data. We plan to study this effect by crosscorrelating the CMB data and related cosmological parameters as delineated by the Wilkinson microwave anisotropy probe (WMAP) with the upcoming evolutionary map of the universe (EMU) survey planned for Australian square kilometer array Pathfinder(ASKAP). EMU-ASKAP is planned to conduct a deep radio continuum survey with rms 10µJy/beam. The survey is planned to cover the entire southern sky, extending to North + 30 degree declination. To infer the expected redshift distribution (dN/dz) and differential source count (S) of the survey that can be extracted from the EMU galaxies, we use data from Scubed simulation of extra-galactic radio continuum (S 3 -SEX) for square kilometer array design studies (SKADS). We also calculate various parameters including galaxy survey shot noise, rms confusion uncertainty, and position uncertainty for the survey which can help in understanding the accuracy and analyzing the results of the data. We also discuss Signal to noise ratios over range of maximum redshifts and maximum multipole values with some discussion on constraints over ΩΛ and Ωb.

Number Counts, Confusion, Mapping Issues, and Sky Coverage Analysis for Radio Continuum Surveys through Emu Early Science, EMU-ASKAP, and WODAN Especially for Cosmology Science Goals

“…As a northern sky survey, with similar sensitivity as of EMU-ASKAP and coverage of >+30 degrees declination coverage, Westerbork Observations of the Deep APERTIF Northern sky (WODAN) will be well suited to complement the full EMU-ASKAP survey ([9], [21]). WODAN is going to cover about 25% (1π steradians) of the sky on the northern hemisphere ( [9], [21]). It will have an expected resolution of about 15 arcseconds.…”

“…In order to calculate the rms confusion limit, we can fit the power law curve for the differential source count of the continuum survey ([1], [2], [3], [4], [5], [6], [8], [9], [40], [41], and [42]). We can obtain the differential source count power law probability distribution ([9], [42]) in −1 −1 as:…”

“…We first use SKADS (S3-SEX) ( [39]) to get the differential source counts for 1. We also estimated power law distributions using SKADS and obtained results as given in , [2], [3], [4], [5], [6], [8], [9], [40], and [41])…”

“…With advances in antenna technologies, imaging techniques, and powerful computing machines, it has become possible to look deeper into our sky, a lot more than was imaginable few decades ago (see: [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15] and [16]). These developments provided hope for understanding some of the most important questions about our universe and its cosmic history especially in settling questions related to the correct values for dark energy density parameters and expansion rate( read ref: [8], [9], [17], [18], [19] and [20]). We now have the capability to observe millions of galaxies with highly sensitive telescopes ( [8], [21], [22]).…”

“…While there were previous studies ( [4], [9], [18]) which dealt with the cosmology from upcoming radio continuum surveys, there is still a gap in the literature where key technical and mapping issues are discussed in relation to their effects on major science goals especially when it comes to looking at the combine effects of shot-noise, confusion, redshift range, sky coverage and maximum multipole range.…”