Abstract

Abstract Wave dark matter (WaveDM) has recently gained attention as a viable candidate to account for the dark matter content of the universe. In this paper we explore the extent to which, and under what conditions, dark matter halos in this model are able to reproduce strong-lensing systems. First, we explore analytically the lensing properties of the model, finding that a pure WaveDM density profile, the soliton profile, produces a weaker lensing effect than similar cored profiles. Then, we analyze models with a soliton embedded within a Navarro, Frenk, and White (NFW) profile, as has been found in numerical simulations of structure formation. We use a benchmark model with a boson mass of m a = 10−22 eV, for which we see that there is a bimodality in the contribution of the external NFW part of the profile, and some of the free parameters associated with it are not well constrained. We find that for configurations with boson masses 10−23 to 10−22 eV, a range of masses preferred by dwarf galaxy kinematics, the soliton profile alone can fit the data, but its size is incompatible with the luminous extent of the lens galaxies. Likewise, boson masses of the order of 10−21 eV, which would be consistent with Lyα constraints and consist of more compact soliton configurations, necessarily require the NFW part in order to reproduce the observed Einstein radii. We then conclude that lens systems impose a conservative lower bound m a > 10−24 eV and that the NFW envelope around the soliton must be present to satisfy the observational requirements.

Highlights

  • The ΛCDM model is the most successful theoretical framework in modern cosmology to explain the process of structure formation in the universe on large scales

  • We have studied the properties of the so-called Wave dark matter (WaveDM) density profile, assuming that it constitutes the total dark matter (DM)

  • We have adapted the standard lens equations to the particular features of the WaveDM, in that we took into account its soliton core together with its NFW envelope, which is the complete form suggested by numerical simulations of cosmological structure under the WaveDM hypothesis

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Summary

Introduction

The ΛCDM model is the most successful theoretical framework in modern cosmology to explain the process of structure formation in the universe on large scales. Using information obtained from the strong-lensed galaxies, it is possible to test the gravitational weak field, through the post-Newtonian parameter γ, where the parameterization of the profiles to describe is sensitive to the total mass distribution This can be used to test the validity of general relativity on large scales. For the description of lensing systems, several mass distribution profiles exist that have been successful enough to represent observed data; the most popular, which include the SIS and SIE (see, e.g., Keeton 2001), follow a power-law distribution These are very successful in describing the observed data for lensing geometry and stellar dynamics when considering the total matter contents (luminous+DM; Bolton et al 2008a, 2008b; Auger et al 2009; Cao et al 2012, 2015; Suyu et al 2014). Some analytic solutions of the lens equations used in the text are shown in the Appendix

General Lensing Equations
Combined Density Profile of WaveDM
Gravitational Lensing
Data Analysis
Soliton Core Profile
Complete Profile
General Results
Conclusions
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