Lomb-Scargle Recovery of Periodic Binary Signals across Black Hole Mass and Cadence
Abstract
Searches for periodic supermassive black hole binaries in quasar light curves rely on recovery fractions, the share of injected signals detected, which forecasts use as detection efficiencies. Lin, Charisi, & Haiman (2026) measured them for the Lomb-Scargle periodogram on damped-random-walk light curves matched to 12,400 bright, high-mass Palomar Transient Factory (PTF) quasars with Sloan Digital Sky Survey Data Release 7 (DR7) masses. To test them over four decades of mass, we inject their sinusoidal and sawtooth signals into light curves of mergers in the TNG100-1 cosmological simulation, with magnitudes drawn from DR7 quasars of similar mass (extrapolated at low mass). We apply their threshold in each frequency bin, set by 105 noise-only light curves per binary, on observed PTF cadences, one Stripe 82 cadence and an LSST-like cadence (Legacy Survey of Space and Time). At fixed absolute magnitude Mi=−23, sinusoid recovery falls toward high mass, and with DR7 magnitudes it climbs above about 108 M⊙, so the magnitude assignment sets the sign of the trend. Above 108 M⊙, where their sample lies, PTF sinusoid recovery is 39.8 against their 44.7 per cent. At LSST-like cadence sinusoid recovery is 76.9 per cent, about three times their 22.6 per cent, for reasons mostly unidentified. Denser sampling of the same PTF baselines did not lower recovery in any test. Even at LSST-like cadence we miss most sawtooth signals above 108 M⊙. We tabulate recovery per 0.5-dex mass bin and cadence, with low-mass values likely too high for a deeper survey.
Related
- Population of Binary Black Holes Inferred from One Hundred and Fifty Gravitational Wave Signals
- Detectability of bulk viscosity effects on post-merger gravitational wave signals from binary neutron star mergers
- Eccentricity in Disguise? Insights from GW231123 and Numerically Simulated Binary Black Hole Merger Signals
- Eccentricity in disguise? Insights from GW231123 and numerically simulated binary black hole merger signals
- An equal mass ratio supermassive binary black holes in Q J0158-4325 with periodic microlensing signature?
BibTeX
@misc{akbari2026lombscargle,
title = {{Lomb-Scargle Recovery of Periodic Binary Signals across Black Hole Mass and Cadence}},
author = {Karan Akbari and Sayantan Bhattacharya},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30772},
eprint = {2610.30772},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30772},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Lomb-Scargle Recovery of Periodic Binary Signals across Black Hole Mass and Cadence
AU - Karan Akbari
AU - Sayantan Bhattacharya
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2610.30772
UR - https://arxiv.org/abs/2610.30772
AB - Searches for periodic supermassive black hole binaries in quasar light curves rely on recovery fractions, the share of injected signals detected, which forecasts use as detection efficiencies. Lin, Charisi, & Haiman (2026) measured them for the Lomb-Scargle periodogram on damped-random-walk light curves matched to 12,400 bright, high-mass Palomar Transient Factory (PTF) quasars with Sloan Digital Sky Survey Data Release 7 (DR7) masses. To test them over four decades of mass, we inject their sinusoidal and sawtooth signals into light curves of mergers in the TNG100-1 cosmological simulation, with magnitudes drawn from DR7 quasars of similar mass (extrapolated at low mass). We apply their threshold in each frequency bin, set by 10^5 noise-only light curves per binary, on observed PTF cadences, one Stripe 82 cadence and an LSST-like cadence (Legacy Survey of Space and Time). At fixed absolute magnitude M_i=−23, sinusoid recovery falls toward high mass, and with DR7 magnitudes it climbs above about 10^8 M_⊙, so the magnitude assignment sets the sign of the trend. Above 10^8 M_⊙, where their sample lies, PTF sinusoid recovery is 39.8 against their 44.7 per cent. At LSST-like cadence sinusoid recovery is 76.9 per cent, about three times their 22.6 per cent, for reasons mostly unidentified. Denser sampling of the same PTF baselines did not lower recovery in any test. Even at LSST-like cadence we miss most sawtooth signals above 10^8 M_⊙. We tabulate recovery per 0.5-dex mass bin and cadence, with low-mass values likely too high for a deeper survey.
ER -