Application of the FRADO model of broad line region formation to Seyfert galaxy NGC 5548 and a first step toward determining the Hubble constant - 2025
galaxies: active; galaxies: Seyfert; Accretion discs; Accretion rate; Broad line region; Dynamical structure; Galaxies active; Galaxy:seyfert; Geometric structure; Hubble constant; Seyfert galaxies; Time-delays; Astronomy and Astrophysics; Space and Planetary Science
Abstract :
[en] Context. The dynamical and geometric structures of broad line region (BLRs) and the origins of continuum time delays in active galaxies remain topics of ongoing debate. Aims. In this study, we aim to reproduce the observed broadband spectrum, the Hβ line delay, and the continuum time delays using our newly developed model for the source NGC 5548. Methods. We adopted the standard accretion disk model, with the option of an inner hot flow, and employed the lamp-post model to account for disk irradiation. Additionally, we modeled the BLR structure based on radiation pressure acting on dust. The model is parameterized by the black hole mass, MBH (which is fixed), the accretion rate, the viewing angle, the height of the lamp-post, the cloud density, and the cloud covering factor. The resulting continuum time delays arise from a combination of disk reprocessing and the reprocessing of a fraction of the radiation by the BLR. Results. Our model can reasonably reproduce the observed broadband continuum, Hβ time delay, and continuum inter-band time delays measured during the observational campaign. When the accretion rate is not constrained by the known distance to the source, our approach allows for a direct estimation of the distance. The resulting Hubble constant, H0 = 66.9+10.6−2.1 km s−1 Mpc−1, represents a significant improvement over previously reported values derived from continuum time delays in the literature. Conclusions. This pilot study demonstrates that with sufficient data coverage, it is possible to disentangle the time delays originating from the accretion disk and the BLR. This paves the way for efficient applications of inter-band continuum time delays as a method for determining the Hubble constant. Additionally, these findings provide strong support for the adopted model for the formation of the Hβ line.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Jaiswal, Vikram Kumar; Center for Theoretical Physics, Polish Academy of Sciences, Warsaw, Poland
Mandal, Amit Kumar ; Center for Theoretical Physics, Polish Academy of Sciences, Warsaw, Poland
Prince, Raj; Center for Theoretical Physics, Polish Academy of Sciences, Warsaw, Poland ; Department of Physics, Institute of Science, Banaras Hindu University, Varanasi, India
Pandey, Ashwani ; Center for Theoretical Physics, Polish Academy of Sciences, Warsaw, Poland ; Department of Physics and Astronomy, University of Utah, Salt Lake City, United States
Naddaf Moghaddam, Mohammad Hassan ; Université de Liège - ULiège > Unités de recherche interfacultaires > Space sciences, Technologies and Astrophysics Research (STAR)
Czerny, Bożena ; Center for Theoretical Physics, Polish Academy of Sciences, Warsaw, Poland
Panda, Swayamtrupta; International Gemini Observatory, NSF NOIRLab, La Serena, Chile
Pozo Nuñez, Francisco ; Astroinformatics, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
Language :
English
Title :
Application of the FRADO model of broad line region formation to Seyfert galaxy NGC 5548 and a first step toward determining the Hubble constant
We thank the anonymous referee for valuable commentsand suggestions. This project has received funding from the European ResearchCouncil (ERC) under the European Union\u2019s Horizon 2020 research and innovation program (grant agreement No. [951549]). VKJ acknowledges the OPUSLAP/GA CR-LA bilateral project (2021/43/I/ST9/01352/OPUS 22 and GF2304053L). MHN also acknowledges the financial support by the University of Liege under Special Funds for Research, IPD-STEMA Program. SP is supportedby the international Gemini Observatory, a program of NSF NOIRLab, which ismanaged by the Association of Universities for Research in Astronomy (AURA)under a cooperative agreement with the U.S. National Science Foundation, onbehalf of the Gemini partnership of Argentina, Brazil, Canada, Chile, the Republic ofKorea,andtheUnitedStatesofAmerica.BCacknowledgesthesupportfromCOSTAction CA21136\u2013 Addressing observational tensions in cosmology withsystematics and fundamental physics (CosmoVerse), supported by COST (European Cooperation in Science and Technology). FPN gratefully acknowledges thegenerous and invaluable support of the Klaus Tschira Foundation. We thank Dr.Missagh Mehdipour for sharing the broadband SED data points with us.We thank the anonymous referee for valuable comments and suggestions. This project has received funding from the European Research Council (ERC) under the European Union\u2019s Horizon 2020 research and innovation program (grant agreement No. [951549]). VKJ acknowledges the OPUS-LAP/GA CR-LA bilateral project (2021/43/I/ST9/01352/OPUS 22 and GF23-04053L). MHN also acknowledges the financial support by the University of Liege under Special Funds for Research, IPD-STEMA Program. SP is supported by the international Gemini Observatory, a program of NSF NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the U.S. National Science Foundation, on behalf of the Gemini partnership of Argentina, Brazil, Canada, Chile, the Republic of Korea, and the United States of America. BC acknowledges the support from COST Action CA21136 \u2013 Addressing observational tensions in cosmology with systematics and fundamental physics (CosmoVerse), supported by COST (European Cooperation in Science and Technology). FPN gratefully acknowledges the generous and invaluable support of the Klaus Tschira Foundation. We thank Dr. Missagh Mehdipour for sharing the broadband SED data points with us.
