Searching for Kardashev Type III civilisations from High $q$-Value Sources in the LoTSS-DR1 Value-added Catalogue

Abstract

Kardashev Type III civilisations have by definition energy requirements that are likely to generate strong excess emission in the mid-infrared (MIR) that is associated with the waste heat they generate. For those civilisations that capture starlight via Dyson sphere like constructions, the Optical to MIR flux ratio of the host galaxies is also expected to be unusually low. Since a wide range of galaxy types adhere to the infrared-radio correlation (IRC), galaxies hosting Type III civilisations should also strongly deviate from this relation. Radio data can therefore play a crucial role in breaking the degeneracy between the effects of dust obscuration in a galaxy and the signature of an energy-intensive civilisation. We have used the newly released LoTSS-DR1 value-added catalogue to create a sample of 16,367 $z<0.2$ sources with radio and MIR flux densities, optical photometry and (photometric) redshifts. We calculated the IRC parameter $q_{150\mathrm{MHz}}^{22\mu \mathrm{m}}$ = log($S_{150\mathrm{MHz}}$/$S_{22\mu \mathrm{m}}$) and identified 21 sources with exceptionally high values of $q_{150\mathrm{MHz}}^{22\mu \mathrm{m}}$, an indication of MIR emission enhanced by a factor of $\sim$ 10. Out of the 21 high $q$-value sources, 4 sources have very red MIR colors, and appear to have relatively low optical/MIR ratios. Two of the 4 sources are not well known in the literature, they are considered as potential hosts of Type III civilisations. These sources deserve further study and investigation. Finally, we note that extending our analysis to the full LoTSS survey area can place very strong constraints on the incidence of Type III civilisations in the universe.

arXiv comment10 pages, 7 figures

References in corpus (42)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• LOFAR: The LOw-Frequency ARray
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Mass assembly in quiescent and star-forming galaxies since z=4 from UltraVISTA
• The Pan-STARRS1 Photometric System
• Radio Properties of Infrared Selected Galaxies in the IRAS 2 Jy Sample
• The Pan-STARRS1 Surveys
• The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
• The LOFAR Two-metre Sky Survey - II. First data release
• The Bulk of the Cosmic Infrared Background Resolved by ISOCAM
• A Comprehensive Study of 2 000 Narrow Line Seyfert 1 Galaxies from the Sloan Digital Sky Survey: I. The Sample
• The contribution of starbursts and normal galaxies to infrared luminosity functions at z < 2
• Groups of Galaxies in the Two Micron All-Sky Redshift Survey
• Strongly star forming galaxies in the local Universe with nebular He II 4686 emission
• The 2M++ galaxy redshift catalogue
• Galaxies with Wolf-Rayet signatures in the low-redshift Universe - A survey using the Sloan Digital Sky Survey
• A strong redshift dependence of the broad absorption line quasar fraction
• VLA-COSMOS 3GHz Large Project: The infrared-radio correlation of star-forming galaxies and AGN to $z\lesssim 6$
• The far-infrared/radio correlation and radio spectral index of galaxies in the SFR-M* plane up to z 2
• The LOFAR Two-metre Sky Survey (LoTSS) III. First Data Release: optical/IR identifications and value-added catalogue
• The LOFAR window on star-forming galaxies and AGN - curved radio SEDs and IR-radio correlation at $0<z<2.5$
• Active Galactic Nucleus Pairs from the Sloan Digital Sky Survey. I. The Frequency on ~ 5-100 kpc Scales
• Unveiling a Population of X-ray Non-Detected AGN
• The FIR/Radio correlation of high redshift galaxies in the HDF-N
• Radio faint AGN: a tale of two populations
• A New Catalogue of Type 1 AGN and its Implication on the AGN Unified Model
• A Uniformly Selected Sample of Low-mass Black Holes in Seyfert 1 Galaxies
• The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. III. The Reddest Extended Sources in WISE
• The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. I. Background and Justification
• The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. II. Framework, Strategy, and First Result
• Luminosity and Redshift Dependence of the Covering Factor of AGNs viewed with WISE and SDSS
• The LOFAR Two-metre Sky Survey IV. First Data Release: Photometric redshifts and rest-frame magnitudes
• IRAS-based whole-sky upper limit on Dyson Spheres
• The Far-Infrared Radio Correlation at low radio frequency with LOFAR/H-ATLAS
• A LOFAR-IRAS cross-match study: the far-infrared radio correlation and the 150-MHz luminosity as a star-formation rate
• AEGIS: Radio and Mid-Infrared Selection of Obscured AGN Candidates
• Star Formation in Nearby Early-Type Galaxies: The Radio Continuum Perspective
• The application of the Mid-IR radio correlation to the $\hat{G}$ sample and the search for advanced extraterrestrial civilisations
• Dissection of Halpha Emitters : Low-z Analogs of z>4 Star-Forming Galaxies
• Radio continuum and X-ray emission from the most extreme FIR-excess galaxy NGC 1377: An extremely obscured AGN revealed
• Radio-Infrared Correlation for Local Dusty Galaxies and Dusty AGNs from the AKARI All Sky Survey

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