Extragalactic Radio Sources: Jet/Lobe Internal Pressure and Consequences

In this work, we use analytical methods to describe expansion of Extragalactic Radio Sources (EGRS). Result shows that source size expansion depends on the following parameters: age of the source, lobe internal pressure, ambient medium density, and angle of observation. Moreover, from the analyses, we have shown that the obtained results, and , suggestively implies that and . This shows that since , jet internal pressure exceeds the lobe’s internal pressure. Therefore, for a typical EGRS, this simply indicates that ambient medium density is higher in the jet region than in the region of the lobe. This is expected since the ambient density thins out from the central core to the region where lobe is located. It is in consonance with the notion that for large extended EGRS, lobes are located outside the host galaxies rather than within the host galaxies. Moreover, we can conclude from these results that compact steep spectrum sources have denser ambient medium than their more extended counterparts.

Cosmological effects on Size Evolution of some Extragalactic Radio Sources and Quasar/Galaxy Unification

We use analytical methods to develop a mathematical model that expresses the relationship between the linear size of some extragalactic radio sources (EGRS) and their redshift . Result shows that , where . For the purpose of obtaining an empirical relation of similar form, we carry out simple linear regression analyses of the observed linear sizes of these EGRS in our sample against their respective observed redshifts. We obtain an empirical relation of the form, , where and for radio-loud quasars and radio galaxies respectively, with correlation coefficients given by, for each of the sources. The correlation is marginal/slight. Comparing the theoretical and empirical relations, we find that the data show an inverse correlation which is similar to the theory. This suggestively indicates presence of cosmological effects on the size evolution of the radio sources. Moreover, we find that similarity in the behavior of the two sources in the plane, simply supports quasar/galaxy unification scheme in which the different observable properties that characterize these two subclasses of radio sources are aspect-dependent.

Tables of physical and morphological properties of nearby extended radio galaxies

It is brought the physical and morphological data of 267 nearby radio galaxies identified with elliptical galaxies brighter than 18th magnitude (sample 1) and for 280 extragalactic radio sources with known position angles between the integrated intrinsic radio polarization and radio axes (sample 2).

FIGARO simulation: FIlaments & GAlactic RadiO simulation

We produce the first low to mid-frequency radio simulation that incorporates both traditional extragalactic radio sources as well as synchrotron cosmic web emission. The FIlaments & GAlactic RadiO (FIGARO) simulation includes 10 unique 4° × 4° fields, incorporating active galactic nucleii (AGNs), star-forming galaxies (SFGs), and synchrotron cosmic web emission out to a redshift of z = 0.8 and over the frequency range 100–1 400 MHz. To do this, the simulation brings together a recent 1003 Mpc3 magnetohydrodynamic simulation (Vazza et al. 2019, A&A, 627, A5), calibrated to match observed radio relic population statistics, alongside updated ‘T-RECS’ code for simulating extragalactic radio sources (Bonaldi et al. 2019, MNRAS, 482, 2). Uniquely, the AGNs and SFGs are populated and positioned in accordance with the underlying matter density of the cosmological simulation. In this way, the simulation provides an accurate understanding of the apparent morphology, angular scales, and brightness of the cosmic web as well as—crucially—the clustering properties of the cosmic web with respect to the embedded extragalactic radio population. We find that the synchrotron cosmic web does not closely trace the underlying mass distribution of the cosmic web, but is instead dominated by shocked shells of emission surrounding dark matter halos and resembles a large, undetected population of radio relics. We also show that, with accurate kernels, the cosmic web radio emission is clearly detectable by cross-correlation techniques and this signal is separable from the embedded extragalactic radio population. We offer the simulation as a public resource towards the development of techniques for detecting and measuring the synchrotron cosmic web.

On the Magnetic Fields of Galaxies

We bring results of some our investigations of magnetic field of our Galaxy and extragalactic radio sources. For the study were used data of Faraday rotation of pulsars and extragalactic radio sources as well as data of physical and morphological properties of more than 500 radio galaxies of different morphological classes.