J/A+A/699/A55 Candidate mpc separation massive BH binaries (Foustoul+, 2025)
A catalogue of candidate milliparsec-separation massive black hole binaries
from long-term optical photometric monitoring.
Foustoul V., Webb N.A., Mignon-Risse R., Kammoun E., Volonteri M.,
Dong-Paez C.A.
<Astron. Astrophys. 699, A55 (2025)>
=2025A&A...699A..55F 2025A&A...699A..55F (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical ; Galaxies, photometry ; Binaries, orbits ; QSOs
Keywords: black hole physics - gravitational waves - catalogs -
galaxy: evolution - galaxy: formation -
quasars: supermassive black holes
Abstract:
The role of mergers in the evolution of massive black holes is still
unclear,and their dynamical evolution, from the formation of pairs to
binaries and the final coalescence, carries large physical
uncertainties. The identification of the elusive population of close
massive binary black holes (MBBHs) is crucial to understand the
importance of mergers in the formation and evolution of supermassive
black holes. It has been proposed that MBBHs may display periodic
optical/ultra-violet variability. Optical surveys provide photometric
measurements of a large variety of objects, over decades and searching
for periodicities coming from galaxies in their long-term optical/UV
lightcurves may help identify new MBBH candidates. Using the Catalina
Real-Time Transient Survey (CRTS) and Zwicky TransientFacility (ZTF)
data, we studied the long-term periodicity of variable sources in the
centre of galaxies identified using the galaxy catalogue Glade+. We
report 36 MBBHs candidates, with sinusoidal variability with
amplitudes between 0.1 and 0.8 magnitudes over 3-5 cycles, through
fitting 15 years of data. The periodicities are also detected when
adding a red noise contribution to the sine model. Moreover, the
periodicities are corroborated through Generalized Lomb Scargle (GLS)
periodograms analysis, providing supplementary evidence for the
observed modulation. We also indicate 58 objects, that were previously
proposed to be MBBH candidates from analysis of CRTS data only. Adding
ZTF data clearly shows that the previously claimed modulation is due to
red noise. We also created a catalogue of 221 weaker candidates which
require further observations over the coming years to help validate
their nature. Based on our 36 MBBHs candidates, we expect
$∼$20MBBHs at $z<1$, which is commensurate with simulations. Further
observations will help confirm these results.
Description:
The Zwicky Transient Facility (ZTF) is a 48-inch Schmidt telescope at
the Palomar Observatory with a 47deg2 field of view. The Catalina
Real-Time Transient Survey (CRTS) is an optical survey using three
telescopes, the Mt Lemmon Survey, the Catalina Sky Survey and the
Siding Spring Survey. The ZTF and CRTS surveys cover approximately
30000 square degrees. Parameters of weak MBBH candidates found during
the CRTS and ZTF-g joint search are presented.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablec1.dat 72 221 Parameters of weak MBBH candidates found during
the CRTS and ZTF-g joint search
--------------------------------------------------------------------------------
See also:
J/ApJS/249/17 : SDSS QSO DR14 spectral properties (Rakshit+, 2020)
Byte-by-byte Description of file: tablec1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 I15 --- Name ZTF Object ID
17- 24 F8.4 deg RAdeg Right ascension (J2000)
26- 32 F7.4 deg DEdeg Declination (J2000)
34- 37 F4.2 --- z Redshift
39- 44 F6.1 d Per Fitted period
46- 50 F5.1 d e_Per Period error
52- 57 F6.2 [Msun] logMBH ? Log10 black hole mass (1)
59- 63 F5.2 [Msun] e_logMBH ? Log10 black hole mass error (1)
65- 68 F4.2 --- rchi2 Reduced chi square
70- 72 A3 --- CRTSobs [Yes No] Does the object has CRTS
observations?
--------------------------------------------------------------------------------
Note (1): Black hole masses from Rahskit et al. (2020ApJS..249...17R 2020ApJS..249...17R,
Cat. J/ApJS/249/17).
--------------------------------------------------------------------------------
Acknowledgements:
Vincent Foustoul, vincent.foustoul(at)irap.omp.eu
(End) Patricia Vannier [CDS] 17-May-2025