OzDES Reverberation Mapping of Active Galactic Nuclei: Final Data Release, Black-Hole Mass Results, & Scaling Relations

H. McDougall, T. M. Davis, Z. Yu, P. Martini, C. Lidman, U. Malik, A. Penton, G. F. Lewis, B. E. Tucker, B. J. S. Pope, S. Allam, F. Andrade-Oliveira, J. Asorey, D. Bacon, S. Bocquet, D. Brooks, A. Carnero Rosell, D. Carollo, A. Carr, J. Carretero, T. Y. Cheng, L. N. da Costa, M. E. da Silva Pereira, J. De Vicente, H. T. Diehl, P. Doel, S. Everett, J. García-Bellido, K. Glazebrook, D. Gruen, G. Gutierrez, K. Herner, S. R. Hinton, D. L. Hollowood, D. J. James, A. G. Kim, K. Kuehn, S. Lee, M. March, J. L. Marshall, J. Mena-Fernández, F. Menanteau, R. Miquel, J. Myles, R. L. C. Ogando, A. Porredon, E. Sanchez, D. Sanchez Cid, R. Sharp, M. Smith, E. Suchyta, M. E. C. Swanson, C. To, D. L. Tucker, A. R. Walker, N. Weaverdyck

First listed 2025-12-01 | Last updated 2026-02-19

Abstract

Over the last decade, the Australian Dark Energy (OzDES) collaboration has used Reverberation Mapping to measure the masses of high redshift supermassive black holes. Here we present the final review and analysis of this OzDES reverberation mapping campaign. These observations use 6-7 years of photometric and spectroscopic observations of 735 Active Galactic Nuclei (AGN) in the redshift range 0.13-3.85 and bolometric luminosity range 44.3 - 47.5 erg/s. Both photometry and spectra are observed in visible wavelengths, allowing for the physical scale of the AGN broad line region to be estimated from reverberations of the H\b{eta}, MgII and CIV emission lines. We successfully use reverberation mapping to constrain the masses of 62 super-massive black holes, and combine with existing data to fit a power law to the lag-luminosity relation for the H\b{eta} and MgII lines with a scatter of ~0.25 dex, the tightest yet identified, fit specifically for consistency with high redshift AGN. We fit a similarly constrained relation for CIV, resolving a tension with the low luminosity literature AGN by accounting for selection effects arising from finite survey length. We also examine the impact of emission line width and luminosity (related to accretion rate) in reducing the scatter of these scaling relationships and find no significant improvement over the lag-only approach for any of the three lines. Using these relations, we further estimate the masses and accretion rates of 246 AGN with single epoch methods. We also use these relations to estimate the relative sizes of the H\b{eta}, MgII and CIV emitting regions. In short, we provide a comprehensive benchmark of high redshift AGN reverberation mapping at the close of this most recent generation of surveys, including light curves, time-delays, and a set of significantly improved radius-luminosity relations for use with high-redshift populations.

Short digest

OzDES delivers its final reverberation-mapping release: 6–7 years of optical photometry and spectroscopy for 735 AGN (0.13<z<3.85), yielding 62 black-hole masses and updated radius–luminosity relations for Hβ, Mg II, and C IV. Combining OzDES with literature, they achieve ~0.25 dex scatter for Hβ and Mg II and a similarly constrained C IV relation once finite survey-length selection effects are modeled, removing the prior low-luminosity tension. Line-width or luminosity terms do not improve scatter beyond lag-only fits; the calibrations enable single-epoch masses and accretion rates for 246 AGN and indicate Mg II may arise at larger radii than Hβ. These results provide a high‑redshift mass-calibration benchmark with released light curves, lags, and catalogs.

Key figures to inspect

• Radius–luminosity (lag–luminosity) planes for Hβ, Mg II, and C IV with OzDES+literature points: inspect slopes, intercepts, and intrinsic scatter, and how OzDES extends to high L and z (~0.25 dex scatter for Hβ/Mg II).
• C IV selection-function/finite-baseline test: the figure showing how survey length biases detectable lags and how correcting for this shifts the C IV fit to resolve the low-luminosity tension.
• Representative multi-year light curves and ICCF/JAVELIN lag posteriors for a high‑z Mg II or C IV source: check cadence, S/N, and lag credibility intervals that underpin mass estimates.
• Relative-scale comparison (lag ratios R_MgII/R_Hβ and R_CIV/R_Hβ vs luminosity): evaluate evidence that Mg II emission originates farther out than Hβ.
• Distributions of recovered lags and SMBH masses (62 RM) and derived single‑epoch masses (246): verify redshift and luminosity coverage (L_bol ≈10^44.3–10^47.5 erg s⁻¹).