Probing binary supermassive black hole in quasars tough spectropolarimetry
Abstract
Nearly all galaxies are believed to host a supermassive black hole at their center. In the context of galaxy mergers, the SMBHs from the progenitor galaxies are expected to form a bound binary system. Given the high frequency of such mergers throughout cosmic time, binary SMBHs should be relatively common in active galactic nuclei (AGNs). Yet, their direct detection remains a major observational challenge, with most candidates inferred only through indirect signatures. The quasar Markarian 231 presents unique ultraviolet-optical properties, including an atypical drop in the total flux around 2500 A and a strong wavelength-dependent polarization. In this work, we explore the potential of spectropolarimetry as a tool to detect and characterize SMBH binaries in AGNs. We construct a simple analytical model in order to reproduce the spectral energy distribution (SED) of Mrk 231 taking into account a binary SMBHs scenario and we compute the resulting total and polarized flux. Our goal is to test if the presence of two distinct sources can reproduce the unique ultraviolet-optical properties observed in Markarian 231. Such investigations support the case for future high-sensitivity UV spectropolarimeters in order to probe the inner structure of quasars. In particular, the next-generation instrument POLLUX, proposed for the Habitable Worlds Observatory, would be particularly suited to provide new insights into AGNs physics and supermassive black hole binaries in quasars.
Related
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BibTeX
@misc{biedermann2026probing,
title = {{Probing binary supermassive black hole in quasars tough spectropolarimetry}},
author = {J. Biedermann and F. Marin},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.29441},
eprint = {2609.29441},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.29441},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Probing binary supermassive black hole in quasars tough spectropolarimetry
AU - J. Biedermann
AU - F. Marin
PY - 2026
DA - 2026/09/24
PB - arXiv
DO - 10.48550/arxiv.2609.29441
UR - https://arxiv.org/abs/2609.29441
AB - Nearly all galaxies are believed to host a supermassive black hole at their center. In the context of galaxy mergers, the SMBHs from the progenitor galaxies are expected to form a bound binary system. Given the high frequency of such mergers throughout cosmic time, binary SMBHs should be relatively common in active galactic nuclei (AGNs). Yet, their direct detection remains a major observational challenge, with most candidates inferred only through indirect signatures. The quasar Markarian 231 presents unique ultraviolet-optical properties, including an atypical drop in the total flux around 2500 A and a strong wavelength-dependent polarization. In this work, we explore the potential of spectropolarimetry as a tool to detect and characterize SMBH binaries in AGNs. We construct a simple analytical model in order to reproduce the spectral energy distribution (SED) of Mrk 231 taking into account a binary SMBHs scenario and we compute the resulting total and polarized flux. Our goal is to test if the presence of two distinct sources can reproduce the unique ultraviolet-optical properties observed in Markarian 231. Such investigations support the case for future high-sensitivity UV spectropolarimeters in order to probe the inner structure of quasars. In particular, the next-generation instrument POLLUX, proposed for the Habitable Worlds Observatory, would be particularly suited to provide new insights into AGNs physics and supermassive black hole binaries in quasars.
ER -