The prevalence of core emission in faint radio galaxies in the SKA Simulated Skies

Abstract

Empirical simulations based on extrapolations from well-established low-frequency ($<5$ GHz) surveys fail to accurately model the faint, high frequency ($>10$~GHz) source population; they under-predict the number of observed sources by a factor of two below $S_{18\mathrm{GHz}}=10$ mJy and fail to reproduce the observed spectral index distribution. We suggest that this is because the faint radio galaxies are not modelled correctly in the simulations and show that by adding a flat-spectrum core component to the FRI sources in the SKA Simulated Skies, the observed 15-GHz source counts can be reproduced. We find that the observations are best matched by assuming that the fraction of the total 1.4-GHz flux density which originates from the core varies with 1.4-GHz luminosity; sources with 1.4-GHz luminosities $<10^{25}\mathrm{W}\mathrm{H}{\mathrm{z}}^{-1}$ require a core fraction $\sim 0.3$, while the more luminous sources require a much smaller core fraction of $5\times 10^{-4}$. The low luminosity FRI sources with high core fractions which were not included in the original simulation may be equivalent to the compact `FR0' sources found in recent studies.

arXiv comment6 pages, 5 figures, accepted for publication in MNRAS

References in corpus (28)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• A semi-empirical simulation of the extragalactic radio continuum sky for next generation radio telescopes
• A sample of radio-loud AGN in the Sloan Digital Sky Survey
• The radio luminosity function from the low-frequency 3CRR, 6CE & 7CRS complete samples
• Radio and Millimeter Continuum Surveys and their Astrophysical Implications
• Predictions for high-frequency radio surveys of extragalactic sources
• Total and Jet Blandford-Znajek Power in Presence of Accretion Disk
• The Arcminute Microkelvin Imager
• Accretion Disk Model of Short-Timescale Intermittent Activity in Young Radio Sources
• Systematic properties of decelerating relativistic jets in low-luminosity radio galaxies
• A pilot study of the radio-emitting AGN population: the emerging new class of FR0 radio-galaxies
• High--frequency predictions for number counts and spectral properties of extragalactic radio sources. New evidences of a break at mm wavelengths in spectra of bright blazar sources
• The local radio-galaxy population at 20 GHz
• 9C: A Survey of Radio Sources at 15 GHz with the Ryle Telescope
• A Comprehensive Study of the Radio Properties of Brightest Cluster Galaxies
• An infrared-radio simulation of the extragalactic sky: from the Square Kilometer Array to Herschel
• 10C Survey of Radio Sources at 15.7 GHz: I - Observing, mapping and source extraction
• What governs the bulk velocity of the jet components in active galactic nuclei?
• 10C Survey of Radio Sources at 15.7 GHz: II - First Results
• A 610-MHz survey of the Lockman Hole with the Giant Metrewave Radio Telescope - I. Observations, data reduction and source catalogue for the central 5 square degrees
• Is there really a dichotomy in AGN jet power?
• The faint source population at 15.7 GHz - I. The radio properties
• 9C continued: a radio-source survey at 15 GHz
• The faint source population at 15.7 GHz - III. A high-frequency study of HERGs and LERGs
• 10C continued: a deeper radio survey at 15.7 GHz
• The faint radio source population at 15.7 GHz - II. Multi-wavelength properties
• Further GMRT observations of the Lockman Hole at 610 MHz
• GMRT 610-MHz observations of the faint radio source population - and what these tell us about the higher-radio-frequency sky

Cited by in corpus (17)

• A Quick Look at the $3$GHz Radio Sky I. Source Statistics from the Very Large Array Sky Survey
• The LoTSS view of radio AGN in the local Universe. The most massive galaxies are always switched on
• Radio-loud AGN in the first LoTSS data release: The lifetimes and environmental impact of jet-driven sources
• FRII{\sl{CAT}}: A FIRST catalog of FR~II radio galaxies
• FR0CAT: a FIRST catalog of FR0 radio galaxies
• High-resolution VLA observations of FR0 radio galaxies: properties and nature of compact radio sources
• Nowhere to Hide: Radio-faint AGN in the GOODS-N field. I. Initial catalogue and radio properties
• Completing the Census of AGN in GOODS-S/HUDF: New Ultra-Deep Radio Imaging and Predictions for JWST
• Determining the core radio luminosity function of radio AGNs via copula
• Linear radio size evolution of $\mu$Jy populations
• An insight into the extragalactic transient and variable microJy radio sky across multiple decades
• The role of environment in the observed Fundamental Plane of radio Active Galactic Nuclei
• The faint radio source population at 15.7 GHz -- IV. The dominance of core emission in faint radio galaxies
• AMI-LA Observations of the SuperCLASS Super-cluster
• Observations of compact sources in galaxy clusters using MUSTANG2
• Confusion noise due to clustered extragalactic point sources. Application of logarithmic cumulants for parameter estimation
• MIGHTEE: total intensity radio continuum imaging and the COSMOS / XMM-LSS Early Science fields