A new method to cleanly separate hot and cool populations using just Gaia and 2MASS photometry
Year: 2026
Type: preprint
Abstract: We have developed a photometric method that produces clean hot (intrinsically blue) populations using Gaia and 2MASS photometry alone with [a] a very small (false positives < 1%) contamination from cool (intrinsically red) luminous sources, [b] independent of extinction (limited only by S/N), and [c] with only small losses (false negatives < 10%) of real OB stars. Applying the method to Gaia DR3 data we are able to recover extinguished OB stars down to E(G_BP-G_RP) = 5, producing a catalog of ~2x10^5 candidate OB stars that reaches beyond the Scutum-Centaurus arm. This method can potentially extend the sample of known OB stars by an order of magnitude, which would yield a large leap in our knowledge of the populations of compact-object progenitors, including gravitational-wave sources.
Source: arXiv (Cornell University)
Institution: Centro de Astrobiología
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213248510