Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters
Hierarchical mergers are one of the distinctive signatures of binary black hole (BBH) formation through dynamical evolution. Here, we present a fast semi-analytic approach to simulate hierarchical mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs). Hierar...
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MDPI AG
2021-09-01
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| Series: | Symmetry |
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| Online Access: | https://www.mdpi.com/2073-8994/13/9/1678 |
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| author | Michela Mapelli Filippo Santoliquido Yann Bouffanais Manuel Arca Sedda Maria Celeste Artale Alessandro Ballone |
| author_facet | Michela Mapelli Filippo Santoliquido Yann Bouffanais Manuel Arca Sedda Maria Celeste Artale Alessandro Ballone |
| author_sort | Michela Mapelli |
| collection | DOAJ |
| description | Hierarchical mergers are one of the distinctive signatures of binary black hole (BBH) formation through dynamical evolution. Here, we present a fast semi-analytic approach to simulate hierarchical mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs). Hierarchical mergers are more common in NSCs than they are in both GCs and YSCs because of the different escape velocity. The mass distribution of hierarchical BBHs strongly depends on the properties of first-generation BBHs, such as their progenitor’s metallicity. In our fiducial model, we form black holes (BHs) with masses up to ∼<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>3</mn></msup></semantics></math></inline-formula> M<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mo>⊙</mo></msub></semantics></math></inline-formula> in NSCs and up to ∼<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>2</mn></msup></semantics></math></inline-formula> M<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mo>⊙</mo></msub></semantics></math></inline-formula> in both GCs and YSCs. When escape velocities in excess of 100 km s<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> are considered, BHs with mass ><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>3</mn></msup></semantics></math></inline-formula> M<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mo>⊙</mo></msub></semantics></math></inline-formula> are allowed to form in NSCs. Hierarchical mergers lead to the formation of BHs in the pair instability mass gap and intermediate-mass BHs, but only in metal-poor environments. The local BBH merger rate in our models ranges from ∼10 to ∼60 Gpc<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></semantics></math></inline-formula> yr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>; hierarchical BBHs in NSCs account for ∼<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mrow><mo>−</mo><mn>2</mn></mrow></msup></semantics></math></inline-formula>–<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.2</mn></mrow></semantics></math></inline-formula> Gpc<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></semantics></math></inline-formula> yr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>, with a strong upper limit of ∼10 Gpc<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></semantics></math></inline-formula> yr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>. When comparing our models with the second gravitational-wave transient catalog, we find that multiple formation channels are favored to reproduce the observed BBH population. |
| first_indexed | 2024-03-10T07:10:49Z |
| format | Article |
| id | doaj.art-a6f5a421dd024a8594444e6ed808bb43 |
| institution | Directory Open Access Journal |
| issn | 2073-8994 |
| language | English |
| last_indexed | 2024-03-10T07:10:49Z |
| publishDate | 2021-09-01 |
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| series | Symmetry |
| spelling | doaj.art-a6f5a421dd024a8594444e6ed808bb432023-11-22T15:28:23ZengMDPI AGSymmetry2073-89942021-09-01139167810.3390/sym13091678Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star ClustersMichela Mapelli0Filippo Santoliquido1Yann Bouffanais2Manuel Arca Sedda3Maria Celeste Artale4Alessandro Ballone5Physics and Astronomy Department Galileo Galilei, University of Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, ItalyPhysics and Astronomy Department Galileo Galilei, University of Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, ItalyPhysics and Astronomy Department Galileo Galilei, University of Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, ItalyAstronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstrasse 12–14, D-69120 Heidelberg, GermanyInstitut für Astro- und Teilchenphysik, Universität Innsbruck, Technikerstrasse 25/8, A-6020 Innsbruck, AustriaPhysics and Astronomy Department Galileo Galilei, University of Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, ItalyHierarchical mergers are one of the distinctive signatures of binary black hole (BBH) formation through dynamical evolution. Here, we present a fast semi-analytic approach to simulate hierarchical mergers in nuclear star clusters (NSCs), globular clusters (GCs) and young star clusters (YSCs). Hierarchical mergers are more common in NSCs than they are in both GCs and YSCs because of the different escape velocity. The mass distribution of hierarchical BBHs strongly depends on the properties of first-generation BBHs, such as their progenitor’s metallicity. In our fiducial model, we form black holes (BHs) with masses up to ∼<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>3</mn></msup></semantics></math></inline-formula> M<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mo>⊙</mo></msub></semantics></math></inline-formula> in NSCs and up to ∼<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>2</mn></msup></semantics></math></inline-formula> M<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mo>⊙</mo></msub></semantics></math></inline-formula> in both GCs and YSCs. When escape velocities in excess of 100 km s<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> are considered, BHs with mass ><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>3</mn></msup></semantics></math></inline-formula> M<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mo>⊙</mo></msub></semantics></math></inline-formula> are allowed to form in NSCs. Hierarchical mergers lead to the formation of BHs in the pair instability mass gap and intermediate-mass BHs, but only in metal-poor environments. The local BBH merger rate in our models ranges from ∼10 to ∼60 Gpc<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></semantics></math></inline-formula> yr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>; hierarchical BBHs in NSCs account for ∼<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mrow><mo>−</mo><mn>2</mn></mrow></msup></semantics></math></inline-formula>–<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.2</mn></mrow></semantics></math></inline-formula> Gpc<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></semantics></math></inline-formula> yr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>, with a strong upper limit of ∼10 Gpc<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></semantics></math></inline-formula> yr<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula>. When comparing our models with the second gravitational-wave transient catalog, we find that multiple formation channels are favored to reproduce the observed BBH population.https://www.mdpi.com/2073-8994/13/9/1678astrophysical black holesintermediate-mass black holesgravitational wavesstar clusters |
| spellingShingle | Michela Mapelli Filippo Santoliquido Yann Bouffanais Manuel Arca Sedda Maria Celeste Artale Alessandro Ballone Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters Symmetry astrophysical black holes intermediate-mass black holes gravitational waves star clusters |
| title | Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters |
| title_full | Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters |
| title_fullStr | Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters |
| title_full_unstemmed | Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters |
| title_short | Mass and Rate of Hierarchical Black Hole Mergers in Young, Globular and Nuclear Star Clusters |
| title_sort | mass and rate of hierarchical black hole mergers in young globular and nuclear star clusters |
| topic | astrophysical black holes intermediate-mass black holes gravitational waves star clusters |
| url | https://www.mdpi.com/2073-8994/13/9/1678 |
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