An analytic surface density profile for $Λ$CDM halos and gravitational lensing studies
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arXiv
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| Autori principali: | , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866914627606020096 |
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| author | Lazar, Alexandres Bullock, James S. Nierenberg, Anna Moustakas, Leonidas Boylan-Kolchin, Michael |
| author_facet | Lazar, Alexandres Bullock, James S. Nierenberg, Anna Moustakas, Leonidas Boylan-Kolchin, Michael |
| contents | We introduce an analytic surface density profile for dark matter halos that accurately reproduces the structure of simulated halos of mass $M_{\rm vir} = 10^{7-11}\ M_\odot$, making it useful for modeling line-of-sight perturbers in strong gravitational lensing models. The two-parameter function has an analytic deflection potential and is more accurate than the projected Navarro, Frenk & White (NFW) profile commonly adopted at this mass scale for perturbers, especially at the small radii of most relevant for lensing perturbations. Using a characteristic radius, $R_{-1}$, where the log slope of surface density is equal to $-1$, and an associated surface density, $Σ_{-1}$, we can represent the expected lensing signal from line-of-sight halos statistically, for an ensemble of halo orientations, using a distribution of {\em projected concentration} parameters, $\mathcal{C}_{\rm vir} := r_{\rm vir}/ R_{-1}$. Though an individual halo can have a projected concentration that varies with orientation with respect to the observer, the range of projected concentrations correlates with the usual three-dimensional halo concentration in a way that enables ease of use. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2304_11177 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | An analytic surface density profile for $Λ$CDM halos and gravitational lensing studies Lazar, Alexandres Bullock, James S. Nierenberg, Anna Moustakas, Leonidas Boylan-Kolchin, Michael Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies We introduce an analytic surface density profile for dark matter halos that accurately reproduces the structure of simulated halos of mass $M_{\rm vir} = 10^{7-11}\ M_\odot$, making it useful for modeling line-of-sight perturbers in strong gravitational lensing models. The two-parameter function has an analytic deflection potential and is more accurate than the projected Navarro, Frenk & White (NFW) profile commonly adopted at this mass scale for perturbers, especially at the small radii of most relevant for lensing perturbations. Using a characteristic radius, $R_{-1}$, where the log slope of surface density is equal to $-1$, and an associated surface density, $Σ_{-1}$, we can represent the expected lensing signal from line-of-sight halos statistically, for an ensemble of halo orientations, using a distribution of {\em projected concentration} parameters, $\mathcal{C}_{\rm vir} := r_{\rm vir}/ R_{-1}$. Though an individual halo can have a projected concentration that varies with orientation with respect to the observer, the range of projected concentrations correlates with the usual three-dimensional halo concentration in a way that enables ease of use. |
| title | An analytic surface density profile for $Λ$CDM halos and gravitational lensing studies |
| topic | Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2304.11177 |