Standardizing reverberation-mapped Hα and Hβ active galactic nuclei using radius-luminosity relations involving monochromatic and broad Hα luminosities
| Authors | |
|---|---|
| Year of publication | 2025 |
| Type | Article in Periodical |
| Magazine / Source | Physical review D |
| MU Faculty or unit | |
| Citation | |
| web | |
| Doi | http://dx.doi.org/10.1103/PhysRevD.111.083545 |
| Keywords | Cosmological parameters; Cosmology; Dark energy; Galactic nuclei and quasars |
| Description | We test the standardizability of a homogeneous sample of 41 lower-redshift (0.00415 <= z <= 0.474) active galactic nuclei (AGNs) reverberation-mapped (RM) using the broad Ha and H/3 emission lines. We find that these sources can be standardized using four radius-luminosity (R - L) relations incorporating Ha and H/3 time delays and monochromatic and broad Ha luminosities. Although the R - L relation parameters are well-constrained and independent of the six cosmological models considered, the resulting cosmological constraints are weak. The measured R - L relations exhibit slightly steeper slopes than predicted by a simple photoionization model and steeper than those from previous higher-redshift H/3 analyses based on larger datasets. These differences likely reflect the absence of high-accreting sources in our smaller, lower-redshift sample, which primarily comprises lower-accreting AGNs. The inferred cosmological parameters are consistent within 26 (or better) with those from better-established cosmological probes. This contrasts with our earlier findings using a larger, heterogeneous sample of 118 H/3 AGNs, which yielded cosmological constraints differing by greater than or similar to 26 from better-established cosmological probes. Our analysis demonstrates that sample homogeneity-specifically, the use of a consistent time-lag determination method-is crucial for developing RM AGNs as a cosmological probe. |
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