Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation
Most of the mass content of dark matter haloes is expected to be in the form of tidal debris. The density of debris is not constant, but rather can grow due to formation of caustics at the apocenters and pericenters of the orbit, or decay as a result of phase mixing. In the phase space, the debris...
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| Format: | Article |
| Idioma: | en_US |
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American Physical Society
2010
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| Accés en línia: | http://hdl.handle.net/1721.1/51762 https://orcid.org/0000-0003-2480-5973 |
| _version_ | 1826212260990681088 |
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| author | Afshordi, Niayesh Mohayaee, Roya Bertschinger, Edmund |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Afshordi, Niayesh Mohayaee, Roya Bertschinger, Edmund |
| author_sort | Afshordi, Niayesh |
| collection | MIT |
| description | Most of the mass content of dark matter haloes is expected to be in the form of tidal debris. The density
of debris is not constant, but rather can grow due to formation of caustics at the apocenters and pericenters
of the orbit, or decay as a result of phase mixing. In the phase space, the debris assemble in a hierarchy
that is truncated by the primordial temperature of dark matter. Understanding this phase structure can be
of significant importance for the interpretation of many astrophysical observations and, in particular, dark
matter detection experiments. With this purpose in mind, we develop a general theoretical framework to
describe the hierarchical structure of the phase space of cold dark matter haloes. We do not make any
assumption of spherical symmetry and/or smooth and continuous accretion. Instead, working with
correlation functions in the action-angle space, we can fully account for the hierarchical structure
(predicting a two-point correlation function ∝ΔJ[superscript -1.6] in the action space), as well as the primordial
discreteness of the phase space. As an application, we estimate the boost to the dark matter annihilation
signal due to the structure of the phase space within virial radius: the boost due to the hierarchical tidal
debris is of order unity, whereas the primordial discreteness of the phase structure can boost the total
annihilation signal by up to an order of magnitude. The latter is dominated by the regions beyond 20% of
the virial radius, and is largest for the recently formed haloes with the least degree of phase mixing.
Nevertheless, as we argue in a companion paper, the boost due to small gravitationally-bound substructure
can dominate this effect at low redshifts. |
| first_indexed | 2024-09-23T15:18:34Z |
| format | Article |
| id | mit-1721.1/51762 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:18:34Z |
| publishDate | 2010 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/517622022-10-02T02:04:39Z Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation Afshordi, Niayesh Mohayaee, Roya Bertschinger, Edmund Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research Bertschinger, Edmund Bertschinger, Edmund Most of the mass content of dark matter haloes is expected to be in the form of tidal debris. The density of debris is not constant, but rather can grow due to formation of caustics at the apocenters and pericenters of the orbit, or decay as a result of phase mixing. In the phase space, the debris assemble in a hierarchy that is truncated by the primordial temperature of dark matter. Understanding this phase structure can be of significant importance for the interpretation of many astrophysical observations and, in particular, dark matter detection experiments. With this purpose in mind, we develop a general theoretical framework to describe the hierarchical structure of the phase space of cold dark matter haloes. We do not make any assumption of spherical symmetry and/or smooth and continuous accretion. Instead, working with correlation functions in the action-angle space, we can fully account for the hierarchical structure (predicting a two-point correlation function ∝ΔJ[superscript -1.6] in the action space), as well as the primordial discreteness of the phase space. As an application, we estimate the boost to the dark matter annihilation signal due to the structure of the phase space within virial radius: the boost due to the hierarchical tidal debris is of order unity, whereas the primordial discreteness of the phase structure can boost the total annihilation signal by up to an order of magnitude. The latter is dominated by the regions beyond 20% of the virial radius, and is largest for the recently formed haloes with the least degree of phase mixing. Nevertheless, as we argue in a companion paper, the boost due to small gravitationally-bound substructure can dominate this effect at low redshifts. 2010-02-16T20:12:53Z 2010-02-16T20:12:53Z 2009-04 2008-11 Article http://purl.org/eprint/type/JournalArticle 1550-2368 1550-7998 http://hdl.handle.net/1721.1/51762 Afshordi, Niayesh, Roya Mohayaee, and Edmund Bertschinger. “Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation.” Physical Review D 79.8 (2009): 083526. © 2009 The American Physical Society https://orcid.org/0000-0003-2480-5973 en_US http://dx.doi.org/10.1103/PhysRevD.79.083526 Physical Review D Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Afshordi, Niayesh Mohayaee, Roya Bertschinger, Edmund Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation |
| title | Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation |
| title_full | Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation |
| title_fullStr | Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation |
| title_full_unstemmed | Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation |
| title_short | Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation |
| title_sort | hierarchical phase space structure of dark matter haloes tidal debris caustics and dark matter annihilation |
| url | http://hdl.handle.net/1721.1/51762 https://orcid.org/0000-0003-2480-5973 |
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