hot-star selection (for SDSS-V) addendum

This is a revised attempt to select massive stars, based on the dereddened color
(J-K) - 0.25*(G-K); which should be < 0.03, along with absK<0.

The query is here:

SELECT        top 1500000 g.source_id,g.ra,g.dec,g.l,g.b,g.parallax,g.parallax_error,g.pmra,g.pmra_error,g.pmdec,
              g.pmdec_error,g.astrometric_n_good_obs_al,g.astrometric_excess_noise,g.astrometric_chi2_al
              ,g.phot_g_mean_mag,g.phot_bp_mean_mag,g.phot_rp_mean_mag,g.phot_variable_flag,g.teff_val,g.a_g_val,
              tm.j_m,tm.j_msigcom,tm.h_m,tm.h_msigcom,tm.ks_m,tm.ks_msigcom,g.phot_g_mean_mag - tm.h_m AS g_min_h,
 sqrt(g.phot_g_n_obs)/g.phot_g_mean_flux_over_error as variability,
 sqrt( g.astrometric_chi2_al / ( g.astrometric_n_good_obs_al - 5)) as astrometric_quality
FROM gaiadr2.gaia_source AS g
INNER JOIN gaiadr1.tmass_best_neighbour AS xmatch
 ON g.source_id = xmatch.source_id
INNER JOIN gaiadr1.tmass_original_valid AS tm
 ON tm.tmass_oid = xmatch.tmass_oid
WHERE  b between -15 and 15
and
( (tm.j_m - tm.ks_m - 0.25*(g.phot_g_mean_mag - tm.ks_m) < 0.03) or (g.phot_g_mean_mag - tm.ks_m < 1.5) )
and
g.phot_g_mean_mag < 18.
and
g.parallax+g.parallax_error < power(10.,(10.-tm.ks_m)/5.)
and
tm.ks_m < 12.




the basic sample file is here:
  https://www.dropbox.com/s/ayryeaqfo5jrz8l/massive_star_selection_2MASS.fits?dl=0

and the color-selection is presented below

the (observed) color vs. absmag distribution

shows that we are still missing nearby blue objects (when compared to the literature); this must be a query problem:

I cleaned via: good_astrometry (eliminates many), non-variable (at <0.02) and parallax SNR > 2


Some plots:

Let's look at the distribution in (observed) color vs distance?

compared to the literature (in blue)

What are the reddened stars in the bulge region?

B.t.w. there are some funny variables:

that only occur in the bar/bulge?

this smells like a data artifact; some other time...

and another footnote:

there's an artifact for stars at G=11mag