Tuesday, January 10, 2023

Galaxies' border

ToughSF linked to Deason et al. 2020, on "the edge of [this] galaxy": 1.9 million lightyears. I wonder if ToughSF took inspiration from these RR Lyrae's: these stars orbit us (slowly!), 1+ MLY so almost halfway to Andromeda. Which is 2.5 MLY away. Er.

Deason cannot be implying that the border between us and Andromeda should be 1.9 MLY. Andromeda is, like, bigger than us. Did Deason intend stars opposite Andromeda? It wouldn't seem to follow a Lagrange pattern.

The distant RR Lyrae stars were found from Next Generation Virgo Cluster Survey data, which as the article notes was not a survey for RR Lyrae stars; so they were dug out of the dataset. The best sort of discovery!

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