Studying galaxy troughs and ridges using Weak Gravitational Lensing with the Kilo-Degree Survey

Understand

We study projected underdensities in the cosmic galaxy density field known as 'troughs', and their overdense counterparts, which we call 'ridges'.

• We identify these regions using a bright sample of foreground galaxies from the photometric Kilo-Degree Survey (KiDS), specifically selected to mimic the spectroscopic Galaxy And Mass Assembly survey (GAMA).
• Using background galaxies from KiDS, we measure the weak gravitational lensing profiles of the troughs/ridges.
• We quantify the amplitude of their lensing strength $A$ as a function of galaxy density percentile rank $P$ and galaxy overdensity $\delta$, and find that the skewness in the galaxy density distribution is reflected in the total mass distribution measured by weak lensing.