A star in Sagittarius brightened 2.6 times in September 2015, equally in Gaia and NEOWISE: a microlensing candidate

Found blind in Oddsky hunts H-0008/H-0009 (NEOWISE x2.7 on 2015 Sep 15). Gaia DR3 epoch photometry shows x2.6 nine days earlier and twenty days later, equal in G and RP. Gaia's own classifier labels the star MICROLENSING.

Claims

C1 [observed] NEOWISE on 2015 Sep 15: x2.7 in W1 and x2.75 in W2 against the star's median; every other visit quiet.
C2 [observed] Gaia DR3 epoch photometry: G x2.60 at -9 d and x2.57 at +20 d, RP the same (hunts/H-0009/reviews/claude-referee-atlas-2026-10-31.md).
C3 [observed] The Gaia DR3 classifier labels the star MICROLENSING (score 0.26); it is not in the Gaia DR3 microlensing catalogue.
C4 [computed] ATLAS's 2015 images at this position are too blurred (PSF 4 px) to measure the event.

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