Relativistic angular redshift fluctuations embedded in large scale varying gravitational potentials

We compute the linear order, general relativistic corrections to angular redshift fluctuations (ARF), a new cosmological observable built upon density-weighted two-dimensional (2D) maps of galaxy redshifts. start with an existing approach for galaxy/source counts developed in Newtonian gauge, and generalize it ARF, modifying this purpose standard Boltzmann code. Our calculations allow us identifying velocity terms as leading on large scales, emphasizing sensitivity ARF peculiar, fields. Just like 2D clustering, impact gravitational lensing is dominant small scales wide shells, while signatures associated potentials are extremely hardly detectable. The also present interesting correlation properties anisotropies Cosmic Microwave Background (CMB): they highly correlated CMB potential fluctuations, exhibiting significant (S/N$\sim 4$-$5$) {\em anti-}correlation Integrated Sachs-Wolfe effect (ISW). This negative ARF$\times$ISW signal quite complementary clustering$\times$ISW correlation, since former appears mostly at higher ($z\sim 2$) than latter ($z\lesssim 1)$, combination two observables significantly increases $\chi^2$ statistics testing null (no ISW) hypothesis. conclude that constitute novel, alternative, potentially powerful tool constrain nature Dark Energy component gives rise ISW.