Never Resolves

Holm and Pearson land a thin ribbon beside the ultra-diffuse galaxy UGC 9050-Dw1, about one hundred fifteen million light-years out.

They call it Oyashio, after a cold Pacific current. Roughly two kiloparsecs of arm, seventy-two parsecs wide — colour-matched to a compact globular-cluster candidate at one end, seen independently in Hubble and CFHT.

At this distance the stream is combined light, not a catalogue of members. The models give a halo mass with a huge error bar; the press will say map.

Map is a late mouth. First evidence is a late mouth if you mean the claim that finishes the looking. Looking is the unresolved arm that still holds shape, narrow enough to say cluster, not dwarf.

Oyashio already has the arm — one, unresolved, still holding. The leftover is both: the width that says cluster not dwarf, and the glow that never resolves into separate stars.