Supermassive Black Hole and Broad-line Region in NGC 5548: 2023 Reverberation Mapping Results
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| Auteurs principaux: | , , , , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866911255526113280 |
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| author | Xi, Wen-Zhe Lu, Kai-Xing Bai, Jin-Ming Yue, Zhang Yi, Weimin Xu, Liang Li, Sha-Sha Feng, Hai-Cheng Wang, Jian-Guo |
| author_facet | Xi, Wen-Zhe Lu, Kai-Xing Bai, Jin-Ming Yue, Zhang Yi, Weimin Xu, Liang Li, Sha-Sha Feng, Hai-Cheng Wang, Jian-Guo |
| contents | We present the results of the 2023 spectroscopic reverberation mapping (RM) campaign for active galactic nuclei (AGN) of NGC 5548, continuing our long-term monitoring program. Using the Lijiang 2.4-meter telescope, we obtained 74 spectra with a median cadence of 1.9 days. Through detailed spectral decomposition, we measured the light curves of the optical continuum at 5100~Å and the broad He~{\sc ii}, He~{\sc i}, H$γ$, and H$β$ emission lines. The time lags of these lines relative to the continuum are measured as $1.3^{+1.6}_{-0.6}$, $2.3^{+1.5}_{-2.1}$, $10.0^{+2.0}_{-1.8}$, and $15.6^{+2.6}_{-2.9}$ days (rest-frame), respectively. Velocity-resolved lag profiles for H$γ$ and H$β$ were constructed. Combined with data from previous seasons (2015$-$2021), we find that the radial ionization stratification of the broad-line region (BLR) is stable; the average virial mass of the supermassive black hole in NGC~5548 is $(2.6\pm1.1)\times 10^{8}M_{\odot}$, consistent with the $M_{\rm BH}-σ_*$ relation; the broad He~{\sc ii} line exhibits the largest responsivity, followed by broad He~{\sc i} (or H$γ$) and H$β$ lines; the BLR kinematics show significant temporal evolution, transitioning from virialized motions to signatures of inflow and outflow. Furthermore, an analysis of 35 years of historical data confirms a 3.5-year time lag between variations in the optical luminosity and the BLR radius, potentially implicating the role of radiation pressure or dynamical structure changes in the inner accretion disk. Long-term campaign demonstrates that the BLR in NGC 5548 is a robust yet dynamically evolving entity, providing crucial insights into AGN structure and accretion physics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_05851 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Supermassive Black Hole and Broad-line Region in NGC 5548: 2023 Reverberation Mapping Results Xi, Wen-Zhe Lu, Kai-Xing Bai, Jin-Ming Yue, Zhang Yi, Weimin Xu, Liang Li, Sha-Sha Feng, Hai-Cheng Wang, Jian-Guo Astrophysics of Galaxies We present the results of the 2023 spectroscopic reverberation mapping (RM) campaign for active galactic nuclei (AGN) of NGC 5548, continuing our long-term monitoring program. Using the Lijiang 2.4-meter telescope, we obtained 74 spectra with a median cadence of 1.9 days. Through detailed spectral decomposition, we measured the light curves of the optical continuum at 5100~Å and the broad He~{\sc ii}, He~{\sc i}, H$γ$, and H$β$ emission lines. The time lags of these lines relative to the continuum are measured as $1.3^{+1.6}_{-0.6}$, $2.3^{+1.5}_{-2.1}$, $10.0^{+2.0}_{-1.8}$, and $15.6^{+2.6}_{-2.9}$ days (rest-frame), respectively. Velocity-resolved lag profiles for H$γ$ and H$β$ were constructed. Combined with data from previous seasons (2015$-$2021), we find that the radial ionization stratification of the broad-line region (BLR) is stable; the average virial mass of the supermassive black hole in NGC~5548 is $(2.6\pm1.1)\times 10^{8}M_{\odot}$, consistent with the $M_{\rm BH}-σ_*$ relation; the broad He~{\sc ii} line exhibits the largest responsivity, followed by broad He~{\sc i} (or H$γ$) and H$β$ lines; the BLR kinematics show significant temporal evolution, transitioning from virialized motions to signatures of inflow and outflow. Furthermore, an analysis of 35 years of historical data confirms a 3.5-year time lag between variations in the optical luminosity and the BLR radius, potentially implicating the role of radiation pressure or dynamical structure changes in the inner accretion disk. Long-term campaign demonstrates that the BLR in NGC 5548 is a robust yet dynamically evolving entity, providing crucial insights into AGN structure and accretion physics. |
| title | Supermassive Black Hole and Broad-line Region in NGC 5548: 2023 Reverberation Mapping Results |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2511.05851 |