J/A+A/709/A62 Gaia DR3 dormant compact-object binaries (Mueller-Horn+, 2026)
Dormant black hole candidates from Gaia DR3 summary diagnostics.
Mueller-Horn J., Rix H.-W., El-Badry K., Pennell B., Green M., Li J.,
Seeburger R.
<Astron. Astrophys. 709, A62 (2026)>
=2026A&A...709A..62M 2026A&A...709A..62M (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, cataclysmic ; Black holes ; Stars, dwarfs ;
Stars, giant ; Stars, masses ; Stars, diameters ; Optical
Keywords: astrometry - binaries: close - binaries: spectroscopic -
stars: black holes - stars: neutron
Abstract:
We present a rigorous identification of candidates for dormant black
holes (BHs) and neutron stars (NSs) in binaries using summary
statistics from Gaia Data Release 3 (DR3), rather than full orbital
solutions. Although Gaia astrometric orbits have already revealed a
small sample of compact object binaries, many systems remain
undetected due to stringent quality cuts imposed on the published
orbits. Using a forward-modelling framework that simulates Gaia
observables, in particular the re-normalised unit weight error (ruwe)
and radial velocity (RV) scatter, we infer posterior distributions for
companion mass and orbital period via Markov chain Monte Carlo (MCMC)
sampling, marginalising over nuisance orbital parameters. We validate
our approach by comparing the predicted masses and periods against
full orbit solutions from DR3, and by successfully recovering known
compact object binaries as promising candidates. The method is best
suited for systems with red giant primaries, which have more reliable
Gaia RV scatter and a light centroid more likely dominated by one
component, compared to main-sequence stars, and they are less likely
to be triples with short-period inner binaries, which produce
confounding signatures. We applied the method to three million giants
and identify 389 systems with best-fit companion masses ≳3M☉.
Recovery simulations suggest our selection method is substantially
more sensitive than the DR3 non-single-star catalogue, particularly
for binaries with periods below 1 year and above ∼6 years. These
candidates represent promising targets for spectroscopic follow-up and
Gaia DR4 analysis to confirm the presence of compact objects and build
a more complete census of the Galactic BH and NS population. Candidate
main-sequence stars with massive companions face a larger set of
confounding effects. Therefore, we present an analogous catalogue of
279 additional main-sequence candidates only as an appendix.
Description:
We provide two catalogues of candidate dormant compact-object binaries
selected from Gaia DR3 summary diagnostics. Companion-mass and
orbital- period posteriors are inferred by forward-modelling Gaia
observables (RUWE and RV scatter), while marginalising over nuisance
orbital parameters.
The catalogues target red-giant-branch (RGB) and main-sequence (MS)
primaries, respectively. Each catalogue contains all analysed sources,
together with Gaia DR3 astrometric and photometric quantities, adopted
stellar properties, inferred binary parameters, and quality flags for
selecting the most promising BH and NS candidates.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 531 21028 Red giant branch (RGB) sample
table2.dat 531 19664 Main-sequence (MS) sample
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 28 A28 --- Name Gaia DR3 designation (designation)
30- 48 I19 --- GaiaDR3 Gaia DR3 source id (source_id)
50- 69 F20.16 deg RAdeg Right ascension (ICRS) at Ep=2016.0 (ra)
71- 90 F20.16 deg DEdeg Declination (ICRS) at Ep=2016.0 (dec)
92-110 F19.16 mas plx Parallax (parallax)
112-123 F12.10 mas e_plx Parallax uncertainty (parallax_error)
125-149 F25.20 mas/yr pmRA Proper motion in RA (pmra)
151-171 F21.16 mas/yr pmDE Proper motion in Dec (pmdec)
173-182 F10.7 --- RUWE Gaia DR3 RUWE (ruwe)
184-193 F10.6 km/s RVamp Robust RV amplitude (rvamplituderobust)
195-210 F16.11 km/s RV Gaia DR3 radial velocity (radial_velocity)
212-222 F11.8 km/s e_RV RV uncertainty (radialvelocityerror)
224-226 I3 --- o_RV Number of RV transits (rvnbtransits)
228-237 F10.7 mag Gmag Mean G magnitude (photgmean_mag)
239-248 F10.7 mag BPmag Mean BP magnitude (photbpmean_mag)
250-259 F10.7 mag RPmag Mean RP magnitude (photrpmean_mag)
261-272 F12.6 --- RFG G flux / flux error
(photgmeanfluxover_error)
274-277 I4 --- o_Gmag Number of G observations (photgn_obs)
279-296 F18.16 Msun Mass Primary-star mass (mass) (1)
298-316 F19.16 Rsun Radius Primary-star radius (radius) (1)
318-337 F20.15 d fitPer Inferred orbital period (fit_period)
339-359 F21.16 d E_fitPer Upper period error (fitperioderrup)
361-381 F21.16 d e_fitPer Lower period error (fitperioderrlow)
383-401 F19.16 Msun fitcpMass Inferred companion mass
(fitcompanionmass) (2)
403-421 F19.16 Msun E_fitcpMass Upper mass error (fitcompanionmass_errup)
423-440 F18.16 Msun e_fitcpMass Lower mass error (fitcompanionmass_errlow)
442-459 F18.16 --- fitcosi cos(i) (fit_cosi)
461-478 F18.16 --- e_fitcosi Error on cos(i) (fitcosierr)
480-501 E22.1 --- MassSigni Posterior P(M2>3Msun) (mass_significance)
503-507 A5 --- fRV RV outlier flag (True/False) (flag_rv)
509-513 A5 --- fPlx Parallax flag (True/False) (flag_parx)
515-519 A5 --- fPhot Photometric flag (True/False) (flag_phot)
521-525 A5 --- fNSS NSS flag (True/False) (flag_nss)
527-531 A5 --- fQual Final quality flag (True/False)
(flag_quality)
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Note (1): Primary-star parameters differ by sample.
RGB sample: mass and radius inferred from XGBoost estimates.
MS sample: mass and radius from SED/isochrone-based estimates.
Note (2): A high-priority BH candidate selection can be obtained with
fitcompanionmass > 3 and flag_quality ≡ True.
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Acknowledgements:
Johanna Mueller-Horn, mueller-horn(at)mpia.de
License: CC-BY-4.0 [see https://spdx.org/licenses/]
(End) Patricia Vannier [CDS] 24-Mar-2026