Active Galactic Nuclei: Boon or Bane for Biota?

Abstract

Active Galactic Nuclei (AGNs) emit substantial fluxes of high-energy electromagnetic radiation, and have therefore attracted some recent attention for their negative impact on galactic habitability. In this paper, we propose that AGNs may also engender the following beneficial effects: (i) prebiotic synthesis of biomolecular building blocks mediated by ultraviolet (UV) radiation, and (ii) powering photosynthesis on certain free-floating planets and moons. We also reassess the harmful biological impact of UV radiation originating from AGNs, and find that their significance could have been overestimated. Our calculations suggest that neither the positive nor negative ramifications stemming from a hypothetical AGN in the Milky Way are likely to affect putative biospheres in most of our Galaxy. On the other hand, we find that a sizable fraction of all planetary systems in galaxies with either disproportionately massive black holes ($\sim 10^{9-10}{M}_{\odot }$) or high stellar densities (e.g., compact dwarf galaxies) might be susceptible to both the beneficial and detrimental consequences of AGNs, with the former potentially encompassing a greater spatial extent than the latter.

Published in The Astrophysical Journal; 11 pages; 1 figure

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Cited by in corpus (6)

• The Habitability of the Galactic Bulge
• The impact of AGN outflows on the surface habitability of terrestrial planets in the Milky Way
• What Would Happen If We Were About 1 pc Away from a Supermassive Black Hole?
• Constraints on the abundance of $0.01c$ stellar engines in the Milky Way
• Gamma Ray Bursts: Not so Much Deadlier than We Thought
• On possible life-dispersal patterns beyond the Earth