DOI: 10.5281/zenodo.17271785
title: Dormant BH candidates from Gaia DR3 summary diagnostics -- supplementary material

description: Candidate dormant black hole and neutron star binaries identified using summary statistics from Gaia DR3.

Here, we provide the results from applying our forward-modelling framework of Gaia summary diagnostics to stars showing excess scatter in RV and position in DR3. For all candidates, we inferred posterior distributions for companion mass and orbital period by simulating and fitting Gaia observables, in particular the renormalised unit weight error (ruwe) and radial velocity (RV) scatter, marginalising over nuisance orbital parameters.

The sample is split into two catalogues; the main catalogue of 21,028 RGB stars and the supplementary catalogue of 19,664 MS stars. 

Each catalogue contains the inferred orbital periods and companion masses and quality flags to filter unreliable sources, as explained in more detail in Müller-Horn et al. (2025). The subset of the most promising BH canididates can be selected by requiring fit_companion_mass > 3.0 and flag_quality == True, yielding 556 RGB+BH candidates and 279 MS+BH candidates, respectively.

For all stars, we include the most relevant Gaia DR3 data as well as the assumed primary star masses and radii.







Parameter



Description





Fundamental Parameters

 


designation
Gaia DR3 designation


source_id
Gaia DR3 source identifier


ra, dec
Gaia DR3 right ascension and declination (deg)


parallax, parallax_error
Gaia DR3 parallax and uncertainty (mas)


pmra, pmdec
Gaia DR3 propoer motion in right ascension and declination (mas/yr)


phot_g_mean_mag
Gaia DR3 G-band magnitude


phot_g_mean_flux_over_error
Gaia DR3 G-band mean flux divided by its error


phot_g_n_obs
Gaia DR3 number of observations contributing to G photometry


phot_bp_mean_mag
Gaia DR3 BP-band magnitude


phot_rp_mean_mag
Gaia DR3 RP-band magnitude


ruwe
Gaia DR3 renormalised unit weight error


rv_amplitude_robust
Gaia DR3 total amplitude in the radial velocity time series after outlier removal (km/s)


radial_velocity, radial_velocity_error
Gaia DR3 radial velocity and uncertainty (km/s)


rv_nb_transits
Gaia DR3 number of transits used to compute the radial velocity


mass


Primary star mass (solar mass)



for RGB stars: inferred from XGBoost inference

for MS stars: SED based, from Li et al. 2025 




radius


Primary star radius (solar radius)



for RGB stars: inferred from XGBoost inference

for MS stars: isochrone radius, based on Li et al. 2025 






Results from binary model fit of summary diagnostics

 


fit_period, fit_period_errup, fit_period_errlow
Binary orbital period and uncertainties (days)


fit_companion_mass, fit_companion_mass_errup, fit_companion_mass_errlow
Companion mass and uncertainties (solar mass)


fit_cosi, fit_cosi_err
Cosine of orbital inclination and uncertainty




Quality flags

 


mass_significance
Fraction of posterior weight for companion mass exceeding three solar masses


flag_rv
Star removed as RV outlier? (Boolean)


flag_parx
Star removed because of unreliable parallax? (Boolean)


flag_phot
Star removed because of photometric variability? (Boolean)


flag_nss
Star removed becasue of existing NSS orbital solution? (Boolean)


flag_quality
Whether star remains in final cleaned sample. (Boolean)