Background Contamination of the Project Hephaistos Dyson Spheres Candidates

TL;DR

The study suggests that dust-obscured galaxies can contaminate Dyson Sphere candidate identifications around M-dwarfs, leading to misclassification due to mid-infrared flux contributions.

Contribution

It demonstrates that background galaxies, specifically Hot DOGs, can cause false positives in Dyson Sphere searches around stars.

Findings

Radio sources offset from stellar positions suggest background galaxy contamination.

Dust-obscured galaxies can account for the IR flux attributed to Dyson Sphere candidates.

Misidentification of candidates due to background galaxy contamination is likely common.

Abstract

Project Hephaistos recently identified seven M-dwarfs as possible Dyson Spheres (DS) candidates. We have cross-matched three of these candidates (A, B \& G) with radio sources detected in various all-sky surveys. The radio sources are offset from the Gaia stellar positions by $\sim 4.9$, $\sim 0.4$ and $\sim 5.0$ arcseconds for candidates A, B, and G respectively. We propose that DOGs (Dust obscured galaxies) lying close to the line-of-sight of these M-dwarf stars significantly contribute to the measured WISE mid-IR flux densities in the WISE W3 and W4 wavebands. These three stars have therefore been misidentified as DS candidates. We also note that with an areal sky density of $9 \times 10^{-6}$ per square arcsecond, Hot DOGs can probably account for the contamination of all 7 DS candidates drawn from an original sample of 5 million stars.