We study clusters in Warm Dark Matter (WDM) models of a thermally produced dark matter particle $0.5$ keV mass. show that, despite WDM cosmologies having similar density profiles as their Cold (CDM) counterparts, the internal properties, such amount substructure, shows marked differences. This result is surprising are at mass scales that {\em thousand times greater} than which structure formation suppressed. gain significantly more via smooth accretion and contain fewer substructures CDM...

The nature of the dark sector Universe remains one outstanding problems in modern cosmology, with search for new observational probes guiding development next generation facilities. Clues come from tension between predictions {\Lambda}CDM and observations gravitationally lensed galaxies. Previous studies showed that galaxy clusters are not strong enough to reproduce observed number arcs. This work aims constrain warm matter cosmologies by means lensing efficiency drawn these alternative...

The paper presents an overview of theoretical aspects small radio telescope antenna parameters. basic parameters include beamwidth, gain, aperture efficiency, and temperature. These should be carefully studied since they have vital effects on astronomical observations. simulations were carried out to assess the capability efficiency telescopes observe a point source at specific frequency. Two-dimensional numerical uniform circular are implemented different radii. diameter values chosen...

Warm Dark Matter (WDM) models offer an attractive alternative to the current Cold (CDM) cosmological model. We present a novel method differentiate between WDM and CDM cosmologies, namely using weak lensing; this provides unique probe as it is sensitive all "matter in beam", not just dark matter haloes galaxies that reside them, but also diffuse material haloes. compare lensing maps of clusters those model corresponding thermally produced $0.5$~keV particle. Our analysis clearly shows...

Baghdad University Radio Telescope (BURT) is a 3 meter radio telescope that was installed in the main campus of Jadiriyah. telescopes, general, offer wide range applications astronomy, which are usually used to detect neutral hydrogen emission line at wavelength 21 cm. One key BURT observe Milky Way galaxy and determine its rotation curve. However, performing such observations requires accurate determination appropriate observing time as well coordinates. This paper focuses on how...

This work aims to investigate the dependence of gravitational lensing properties on lens redshift and source redshift.
 The angular diameter distance hereafter referred as ADD has been determined using two different numerical integral methods, Simpson's rule, definite methods. Both those methods gave identical results. In addition, observational data Lensing systems have used find most probable value redshift. result showed that are more likely occur in ranges zL=0.2-0.6 zS=1-3,...

This research aims to investigate the color distribution of a huge sample 613654 galaxies from Sloan Digital Sky Survey (SDSS). Those are at redshift 0.001 - 0.5 and have magnitudes g = 17 20. Five subsamples redshifts (0.001 0.1), (0.1 0.2), (0.2 0.3), (0.3 0.4) (0.4 0.5) been extracted main sample. The distributions (u-g), (g-r) (u-r) produced analysed using Matlab code for as well all five subsamples. Then bimodal Gaussian fit data that carried out minimum chi-square in Microsoft Office...

Astronomical radio observations from a small telescope suffer various types of noise. Hence, astronomers continuously search for new techniques to eliminate or reduce such noise and obtain more accurate results. This research investigates the impact implementing Savitzky-Golay filter on enhancing observation signals retrieved Baghdad University Radio Telescope (BURT). Observations BURT were carried out different Galactic coordinates, then MATLAB code was written used implement collected...

The research involves examining the influence of partial solar eclipse on strength neutral hydrogen from Sun. Baghdad University Radio Telescope (BURT) was used to monitor 25th October, 2022. observations Sun were recorded 11:30 AM 03:36 PM. This means that HI emission before, during and after event. It noticed, at moment maximum eclipse, ~ 46% Sun’s disk covered by Moon. For purpose this research, radio wave intensity monitored flux density determined different times, i.e. eclipse. obtained...

Radio observations from astronomical sources like supernovae became one the most important of information about physical properties those objects. However, such radio are affected by various types noise as sky, background, receiver, and system itself. Therefore, it is essential to eliminate or reduce these undesired signals in order ensure accurate measurements analysis observations. One commonly used methods for reducing use a calibrator. In this study, 3-m Baghdad University Telescope...

This work aims to use the color distribution of galaxies differentiate between blue and red galaxies. The photometric data 300000 at redshift z = 0 – 0.15 were collected from Sloan Digital Sky Survey (SDSS). Three ranges considered for purpose this work: 100000 0-0.05, 0.05-0.1 0.1-0.15. distributions all determined. results have clearly shown that are bimodal. One two peaks corresponds (young star-forming galaxies), whereas other peak (old non-star-forming galaxies). Therefore, can be as an...

This work aims to study the physical properties of Neutron stars. The effect magnetic forces and ratio accelerations on surface layers are determined. Goldriech Julian model is considered. field evolution within light cylinder can contribute explain mechanism generating electromagnetic with other like gravitation centrifugal acceleration. between them will be determined for r ≫ R. terms neglected. would become comparable at r~10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...