Artificial Broadcasts as Galactic Populations: I. A Point Process Formalism for Extraterrestrial Intelligences and Their Broadcasts

Abstract

Artificial broadcasts from extraterrestrial intelligences (ETIs) are a hypothetical class of celestial phenomena. Unlike known astrophysical objects, the societies that generate them may be able to replicate on galactic scales through interstellar travel. Different galaxies could thus have drastically different populations, with abundance variations of many orders of magnitude. I present a probabilistic formalism to treat this shared history, in which societies and their broadcasts are described by distributions over basic properties like lifespan and energy released. The framework contains a hierarchy of objects related by a tree structure. Discrete societies, the sources of broadcasts, are organized into potentially interstellar "metasocieties." The population of each type of object is represented by a random point process in an abstract parameter hyperspace, a "haystack." When a selection like an observation draws a sample, the point process is thinned. Given assumptions of interchangeability and independence, observables are modeled with compound Poisson random variables. I present an example of how selection bias can favor sampling longer-lived objects. I rederive the Drake Equation for societies in the limit of no expansion. When interstellar replication is present, however, the mean number of detected broadcasts can depend quadratically on stellar mass, suggesting a search strategy favoring large galaxies.

Published in ApJ; 51 pages, 9 figures, 10 tables, 3 appendices

References in corpus (74)

• The ages and metallicities of galaxies in the local universe
• The Galactic disk mass function: reconciliation of the HST and nearby determinations
• Giant Planet Occurrence in the Stellar Mass-Metallicity Plane
• Social physics
• PRIMUS: Constraints on Star Formation Quenching and Galaxy Merging, and the Evolution of the Stellar Mass Function From z=0-1
• The Galactic Habitable Zone and the Age Distribution of Complex Life in the Milky Way
• Dynamical Formation of Close Binary Systems in Globular Clusters
• The Habitability of Planets Orbiting M-dwarf Stars
• A Dying Universe: The Long Term Fate and Evolution of Astrophysical Objects
• Early-Type Galaxy Archeology: Ages, Abundance Ratios, and Effective Temperatures from Full-Spectrum Fitting
• The Galactic Habitable Zone I. Galactic Chemical Evolution
• An Increase in the Mass of Planetary Systems around Lower-Mass Stars
• An Overabundance of Transient X-ray Binaries within 1 pc of the Galactic Center
• A Comprehensive Search for Dark Matter Annihilation in Dwarf Galaxies
• The Breakthrough Listen Search for Intelligent Life: 1.1-1.9 GHz observations of 692 Nearby Stars
• The Breakthrough Listen Search for Intelligent Life: Observations of 1327 Nearby Stars over 1.10-3.45 GHz
• The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. III. The Reddest Extended Sources in WISE
• The Breakthrough Listen Search for Intelligent Life: Target Selection of Nearby Stars and Galaxies
• The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. I. Background and Justification
• Transit Lightcurve Signatures of Artificial Objects
• The Ĝ Search for Extraterrestrial Civilizations with Large Energy Supplies. IV. The Signatures and Information Content of Transiting Megastructures
• Galactic Gradients, Postbiological Evolution and the Apparent Failure of SETI
• How Much SETI Has Been Done? Finding Needles in the n-Dimensional Cosmic Haystack
• Detecting industrial pollution in the atmospheres of earth-like exoplanets
• Extragalactic SETI: The Tully-Fisher relation as a probe of Dysonian astroengineering in disk galaxies
• How Rare Are Extraterrestrial Civilizations and When Did They Emerge?
• Scintillation-Induced Intermittency in SETI
• The Breakthrough Listen Search For Intelligent Life Near the Galactic Center I
• A Stochastic Process Approach of the Drake Equation Parameters
• The Steppenwolf: A proposal for a habitable planet in interstellar space
• The Non-homogeneous Poisson Process for Fast Radio Burst Rates
• The Case for Technosignatures: Why They May Be Abundant, Long-lived, Highly Detectable, and Unambiguous
• A Search for Laser Emission with Megawatt Thresholds from 5600 FGKM Stars
• Fast Radio Bursts from Extragalactic Light Sails
• Choosing a Maximum Drift Rate in a SETI Search: Astrophysical Considerations
• Analysis of the Breakthrough Listen signal of interest blc1 with a technosignature verification framework
• New SETI Sky Surveys for Radio Pulses
• A VLA Search for Radio Signals from M31 and M33
• Homogeneous cosmology with aggressively expanding civilizations
• Extending the Breakthrough Listen nearby star survey to other stellar objects in the field
• Searching for extraterrestrial intelligence signals in astronomical spectra, including existing data
• The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record?
• The Fermi Paradox and the Aurora Effect: Exo-civilization Settlement, Expansion and Steady States
• The habitability of the Milky Way during the active phase of its central supermassive black hole
• A probabilistic analysis of the Fermi paradox in terms of the Drake formula: the role of the L factor
• The quest for cradles of life: using the fundamental metallicity relation to hunt for the most habitable type of galaxy
• Globular Clusters as Cradles of Life and Advanced Civilizations
• Active Galactic Nuclei: Boon or Bane for Biota?
• SETI with Gaia: The observational signatures of nearly complete Dyson spheres
• The Breakthrough Listen Search for Intelligent Life: MeerKAT Target Selection
• On the search for artificial Dyson-like structures around pulsars
• The application of the Mid-IR radio correlation to the $\hat{G}$ sample and the search for advanced extraterrestrial civilisations
• Design for minimum energy in starship and interstellar communication
• Astrobiological Effects of Gamma-Ray Bursts in the Milky Way Galaxy
• Propulsion of Spacecrafts to Relativistic Speeds Using Natural Astrophysical Sources
• End-to-end interstellar communication system design for power efficiency
• Investigating Nearby Exoplanets via Interstellar Radar
• Contact Inequality -- First Contact Will Likely Be With An Older Civilization
• Prior Indigenous Technological Species
• Project Hephaistos I. Upper limits on partial Dyson spheres in the Milky Way
• Longevity is the key factor in the search for technosignatures
• A SETI Survey of the Vela Region using the Murchison Widefield Array: Orders of Magnitude Expansion in Search Space
• Searching for Exoplanets Around X-Ray Binaries with Accreting White Dwarfs, Neutron Stars, and Black Holes
• The Application of Autocorrelation SETI Search Techniques in an ATA Survey
• Power Beaming Leakage Radiation as a SETI Observable
• Jumping the energetics queue: Modulation of pulsar signals by extraterrestrial civilizations
• On the visible size and geometry of aggressively expanding civilizations at cosmological distances
• Searching for Kardashev Type III civilisations from High $q$-Value Sources in the LoTSS-DR1 Value-added Catalogue
• The Galactic Club, or Galactic Cliques? Exploring the limits of interstellar hegemony and the Zoo Hypothesis
• The Search for Extra-Galactic Intelligence Signal Synchronized with a Binary Neutron Star Merger
• Lens Flare: Magnified X-Ray Binaries as Passive Beacons in SETI
• Synchronized SETI - The Case for "Opposition"
• Sunscreen: Photometric Signatures of Galaxies Partially Cloaked in Dyson Spheres
• A Stationary Drake Equation Distribution as a Balance of Birth-Death Processes

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• Artificial Broadcasts as Galactic Populations: II. Comparing Individualist and Collective Bounds on Broadcast Populations in Single Galaxies
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• Artificial Broadcasts as Galactic Populations: III. Constraints on Radio Broadcasts from the Cosmic Population of Inhabited Galaxies