An analytic surface density profile for $\Lambda$CDM halos and gravitational lensing studies
Autor: | Lazar, Alexandres, Bullock, James S., Nierenberg, Anna, Moustakas, Leonidas, Boylan-Kolchin, Michael |
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Rok vydání: | 2023 |
Předmět: | |
Druh dokumentu: | Working Paper |
Popis: | 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, $\Sigma_{-1}$, 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. Comment: 15 pages, 13 figures, Accepted to MNRAS |
Databáze: | arXiv |
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