Binary black hole signatures in polarized light curves
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
Standard
Binary black hole signatures in polarized light curves. / Dotti, Massimo; Bonetti, Matteo; D'Orazio, Daniel J.; Haiman, Zoltan; Ho, Luis C.
I: Monthly Notices of the Royal Astronomical Society, Bind 509, Nr. 1, 08.11.2021, s. 212-223.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - Binary black hole signatures in polarized light curves
AU - Dotti, Massimo
AU - Bonetti, Matteo
AU - D'Orazio, Daniel J.
AU - Haiman, Zoltan
AU - Ho, Luis C.
PY - 2021/11/8
Y1 - 2021/11/8
N2 - Variable active galactic nuclei showing periodic light curves have been proposed as massive black hole binary (MBHB) candidates. In such scenarios, the periodicity can be due to relativistic Doppler-boosting of the emitted light. This hypothesis can be tested through the timing of scattered polarized light. Following the results of polarization studies in type I nuclei and of dynamical studies of MBHBs with circumbinary discs, we assume a coplanar equatorial scattering ring, whose elements contribute differently to the total polarized flux, due to different scattering angles, levels of Doppler boost, and line-of-sight time delays. We find that in the presence of an MBHB, both the degree of polarization and the polarization position angle have periodic modulations. The polarization angle oscillates around the semiminor axis of the projected MBHB orbital ellipse, with a frequency equal either to the binary's orbital frequency (for large scattering screen radii), or twice this value (for smaller scattering structures). These distinctive features can be used to probe the nature of periodic MBHB candidates and to compile catalogues of the most promising sub-pc MBHBs. The identification of such polarization features in gravitational-wave (GW) detected MBHBs would enormously increase the amount of physical information about the sources, allowing the measurement of the individual masses of the binary components, and the orientation of the line of nodes on the sky, even for monochromatic GW signals.
AB - Variable active galactic nuclei showing periodic light curves have been proposed as massive black hole binary (MBHB) candidates. In such scenarios, the periodicity can be due to relativistic Doppler-boosting of the emitted light. This hypothesis can be tested through the timing of scattered polarized light. Following the results of polarization studies in type I nuclei and of dynamical studies of MBHBs with circumbinary discs, we assume a coplanar equatorial scattering ring, whose elements contribute differently to the total polarized flux, due to different scattering angles, levels of Doppler boost, and line-of-sight time delays. We find that in the presence of an MBHB, both the degree of polarization and the polarization position angle have periodic modulations. The polarization angle oscillates around the semiminor axis of the projected MBHB orbital ellipse, with a frequency equal either to the binary's orbital frequency (for large scattering screen radii), or twice this value (for smaller scattering structures). These distinctive features can be used to probe the nature of periodic MBHB candidates and to compile catalogues of the most promising sub-pc MBHBs. The identification of such polarization features in gravitational-wave (GW) detected MBHBs would enormously increase the amount of physical information about the sources, allowing the measurement of the individual masses of the binary components, and the orientation of the line of nodes on the sky, even for monochromatic GW signals.
KW - techniques: polarimetric
KW - galaxies: interactions
KW - CIRCUMBINARY ACCRETION DISCS
KW - BROAD-LINE REGION
KW - OPTICAL POLARIZATION
KW - EQUATORIAL SCATTERING
KW - VARIABLE QUASARS
KW - UV POLARIZATION
KW - EVOLUTION
KW - SPECTROPOLARIMETRY
KW - EMISSION
KW - MERGERS
U2 - 10.1093/mnras/stab2893
DO - 10.1093/mnras/stab2893
M3 - Journal article
VL - 509
SP - 212
EP - 223
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
IS - 1
ER -
ID: 301351263