A search for technosignatures toward the Galactic Centre at 150 MHz

Abstract

This paper is the fourth in a series of low-frequency searches for technosignatures. Using the Murchison Widefield Array over two nights, we integrate 7 h of data toward the Galactic Centre (centred on the position of Sagittarius $\mathrm{A}^{*}$ ) with a total field-of-view of $200\,\mathrm{deg}^{2}$ . We present a targeted search toward 144 exoplanetary systems, at our best yet angular resolution (75 arcsec). This is the first technosignature search at a central frequency of 155 MHz toward the Galactic Centre (our previous central frequencies have been lower). A blind search toward in excess of 3 million stars toward the Galactic Centre and Galactic bulge is also completed, placing an equivalent isotropic power limit $<\!1.1\times10^{19}\,\mathrm{W}$ at the distance to the Galactic Centre. No plausible technosignatures are detected.

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