  A dipole anisotropy in ultra-high-energy cosmic ray (UHECR) arrival
directions, of extragalactic origin, is now firmly established at energies E >
8 EeV. Furthermore, the UHECR angular power spectrum shows no power at smaller
angular scales than the dipole, apart from hints of possible individual hot or
warm spots for energy thresholds $\gtrsim$40 EeV. Here, we exploit the
magnitude of the dipole and the limits on smaller-scale anisotropies to place
constraints on two quantities: the extragalactic magnetic field (EGMF) and the
number density of UHECR sources or the volumetric event rate if UHECR sources
are transient. We also vary the bias between the extragalactic matter and the
UHECR source densities, reflecting whether UHECR sources are preferentially
found in over- or under-dense regions, and find that little or no bias is
favored. We follow Ding et al. (2021) in using the Cosmic Flows 2 density
distribution of the local universe as our baseline distribution of UHECR
sources, but we improve and extend that work by employing an accurate and
self-consistent treatment of interactions and energy losses during propagation.
Deflections in the Galactic magnetic field are treated using both the full JF12
magnetic field model, with random as well as coherent components, or just the
coherent part, to bracket the impact of the GMF on the dipole anisotropy. This
Large Scale Structure (LSS) model gives good agreement with both the direction
and magnitude of the measured dipole anisotropy and forms the basis for
simulations of discrete sources and the inclusion of EGMF effects.
