  Low density regions are less affected by the nonlinear structure formation
and baryonic physics. They are ideal places for probing the nature of dark
energy, a possible explanation for the cosmic acceleration. Unlike void
lensing, which requires identifications of individual voids, we study the
stacked lensing signals around the low-density-positions (LDP), defined as
places that are devoid of foreground bright galaxies in projection. The method
allows a direct comparison with numerical results by drawing correspondence
between the bright galaxies with halos. It leads to lensing signals that are
significant enough for differentiating several dark energy models. In this
work, we use the CFHTLenS catalogue to define LDPs, as well as measuring their
background lensing signals. We consider several different definitions of the
foreground bright galaxies (redshift range \& magnitude cut). Regarding the
cosmological model, we run six simulations: the first set of simulations have
the same initial conditions, with $\rm{w_{de}=-1,-0.5,-0.8,-1.2}$; the second
set of simulations include a slightly different $\Lambda$CDM model and a w(z)
model from \cite{2017NatAs...1..627Z}. The lensing results indicate that the
models with $\rm{w_{de}=-0.5,-0.8}$ are not favored, and the other four models
all achieve comparable agreement with the data.

Cosmology and Nongalactic Astrophysics;Astrophysics of Galaxies