A fast test for the identification and confirmation of massive black hole binaries

Fuente: arXiv
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Main Authors: Dotti, Massimo, Rigamonti, Fabio, Rinaldi, Stefano, Del Pozzo, Walter, Decarli, Roberto, Buscicchio, Riccardo
Format: Preprint
Published: 2023
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author Dotti, Massimo
Rigamonti, Fabio
Rinaldi, Stefano
Del Pozzo, Walter
Decarli, Roberto
Buscicchio, Riccardo
author_facet Dotti, Massimo
Rigamonti, Fabio
Rinaldi, Stefano
Del Pozzo, Walter
Decarli, Roberto
Buscicchio, Riccardo
contents We present a new observational test to identify massive black hole binaries in large multi-epoch spectroscopical catalogues and to probe the real nature of already proposed binary candidates. The test is tailored for binaries with separations large enough to allow each black hole to retain its own broad line region. In this limit the fast AGN variability typically observed over months cannot be associated to the much longer binary period, and it is assumed (as for the case of single black holes) to be the consequence of the evolution of the innermost regions of the two accretion discs. A simple analysis of the cross-correlation between different parts of individual broad emission lines can therefore identify the presence of two massive black holes whose continua vary independently of each other. Our analysis indicates that to be less affected by the noise in the spectra the broad lines should be divided in two close-to-equal-flux parts. This ensures that in the single massive black hole scenario the cross-correlation will always be high. With monitoring campaigns similar to those performed for reverberation mapping studies, on the other way, a binary can show any value of the cross-correlation and can therefore be distinguished from a standard AGN. The new test can be performed over timescales orders of magnitude shorter than the alternative tests already discussed in literature, and can be a powerful complement to the massive black hole binary search strategies already in place.
format Preprint
id arxiv_https___arxiv_org_abs_2310_06896
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A fast test for the identification and confirmation of massive black hole binaries
Dotti, Massimo
Rigamonti, Fabio
Rinaldi, Stefano
Del Pozzo, Walter
Decarli, Roberto
Buscicchio, Riccardo
High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
We present a new observational test to identify massive black hole binaries in large multi-epoch spectroscopical catalogues and to probe the real nature of already proposed binary candidates. The test is tailored for binaries with separations large enough to allow each black hole to retain its own broad line region. In this limit the fast AGN variability typically observed over months cannot be associated to the much longer binary period, and it is assumed (as for the case of single black holes) to be the consequence of the evolution of the innermost regions of the two accretion discs. A simple analysis of the cross-correlation between different parts of individual broad emission lines can therefore identify the presence of two massive black holes whose continua vary independently of each other. Our analysis indicates that to be less affected by the noise in the spectra the broad lines should be divided in two close-to-equal-flux parts. This ensures that in the single massive black hole scenario the cross-correlation will always be high. With monitoring campaigns similar to those performed for reverberation mapping studies, on the other way, a binary can show any value of the cross-correlation and can therefore be distinguished from a standard AGN. The new test can be performed over timescales orders of magnitude shorter than the alternative tests already discussed in literature, and can be a powerful complement to the massive black hole binary search strategies already in place.
title A fast test for the identification and confirmation of massive black hole binaries
topic High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2310.06896