Halo abundances within the cosmic web
We investigate the dependence of the mass function of dark-matter haloes on their environment within the cosmic web of large-scale structure. A dependence of the halo mass function on large-scale mean density is a standard element of cosmological theory, allowing mass-dependent biasing to be underst...
| Main Authors: | , , |
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| Format: | Journal article |
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Oxford University Press
2015
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| _version_ | 1826281045597618176 |
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| author | Alonso, D Eardley, E Peacock, J |
| author_facet | Alonso, D Eardley, E Peacock, J |
| author_sort | Alonso, D |
| collection | OXFORD |
| description | We investigate the dependence of the mass function of dark-matter haloes on their environment within the cosmic web of large-scale structure. A dependence of the halo mass function on large-scale mean density is a standard element of cosmological theory, allowing mass-dependent biasing to be understood via the peak-background split. On the assumption of a Gaussian density field, this analysis can be extended to ask how the mass function depends on the geometrical environment: clusters, filaments, sheets and voids, as classified via the tidal tensor (the Hessian matrix of the gravitational potential). In linear theory, the problem can be solved exactly, and the result is attractively simple: the conditional mass function has no explicit dependence on the local tidal field, and is a function only of the local density on the filtering scale used to define the tidal tensor. There is nevertheless a strong implicit predicted dependence on geometrical environment, because the local density couples statistically to the derivatives of the potential. We compute the predictions of this model and study the limits of their validity by comparing them to results deduced empirically from N-body simulations. We have verified that, to a good approximation, the abundance of haloes in different environments depends only on their densities, and not on their tidal structure. In this sense we find relative differences between halo abundances in different environments with the same density which are smaller than ∼13 per cent. Furthermore, for sufficiently large filtering scales, the agreement with the theoretical prediction is good, although there are important deviations from the Gaussian prediction at small, non-linear scales. We discuss how to obtain improved predictions in this regime, using the ‘effective-universe’ approach. |
| first_indexed | 2024-03-07T00:22:52Z |
| format | Journal article |
| id | oxford-uuid:7d2437ab-bc1b-4840-b87b-32f47eb18e67 |
| institution | University of Oxford |
| last_indexed | 2024-03-07T00:22:52Z |
| publishDate | 2015 |
| publisher | Oxford University Press |
| record_format | dspace |
| spelling | oxford-uuid:7d2437ab-bc1b-4840-b87b-32f47eb18e672022-03-26T21:01:44ZHalo abundances within the cosmic webJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:7d2437ab-bc1b-4840-b87b-32f47eb18e67Symplectic Elements at OxfordOxford University Press2015Alonso, DEardley, EPeacock, JWe investigate the dependence of the mass function of dark-matter haloes on their environment within the cosmic web of large-scale structure. A dependence of the halo mass function on large-scale mean density is a standard element of cosmological theory, allowing mass-dependent biasing to be understood via the peak-background split. On the assumption of a Gaussian density field, this analysis can be extended to ask how the mass function depends on the geometrical environment: clusters, filaments, sheets and voids, as classified via the tidal tensor (the Hessian matrix of the gravitational potential). In linear theory, the problem can be solved exactly, and the result is attractively simple: the conditional mass function has no explicit dependence on the local tidal field, and is a function only of the local density on the filtering scale used to define the tidal tensor. There is nevertheless a strong implicit predicted dependence on geometrical environment, because the local density couples statistically to the derivatives of the potential. We compute the predictions of this model and study the limits of their validity by comparing them to results deduced empirically from N-body simulations. We have verified that, to a good approximation, the abundance of haloes in different environments depends only on their densities, and not on their tidal structure. In this sense we find relative differences between halo abundances in different environments with the same density which are smaller than ∼13 per cent. Furthermore, for sufficiently large filtering scales, the agreement with the theoretical prediction is good, although there are important deviations from the Gaussian prediction at small, non-linear scales. We discuss how to obtain improved predictions in this regime, using the ‘effective-universe’ approach. |
| spellingShingle | Alonso, D Eardley, E Peacock, J Halo abundances within the cosmic web |
| title | Halo abundances within the cosmic web |
| title_full | Halo abundances within the cosmic web |
| title_fullStr | Halo abundances within the cosmic web |
| title_full_unstemmed | Halo abundances within the cosmic web |
| title_short | Halo abundances within the cosmic web |
| title_sort | halo abundances within the cosmic web |
| work_keys_str_mv | AT alonsod haloabundanceswithinthecosmicweb AT eardleye haloabundanceswithinthecosmicweb AT peacockj haloabundanceswithinthecosmicweb |