  In the context of next-generation spectroscopic galaxy surveys, new
statistics of the distribution of matter are currently being developed. Among
these, we investigated the angular redshift fluctuations (ARF), which probe the
information contained in the projected redshift distribution of galaxies.
Relying on the Fisher formalism, we show how ARF will provide complementary
cosmological information compared to traditional angular galaxy clustering. We
tested both the standard $\mathrm{\Lambda CDM}$ model and the $\mathrm{wCDM}$
extension. We find that the cosmological and galaxy bias parameters express
different degeneracies when inferred from ARF or from angular galaxy
clustering. As such, combining both observables breaks these degeneracies and
greatly decreases the marginalised uncertainties by a factor of at least two on
most parameters for the $\mathrm{\Lambda CDM}$ and $\mathrm{wCDM}$ models. We
find that the ARF combined with angular galaxy clustering provide a great way
to probe dark energy by increasing the figure of merit of the $w_0$-$w_{\rm a}$
parameter set by a factor of more than ten compared to angular galaxy
clustering alone. Finally, we compared ARF to the CMB lensing constraints on
the galaxy bias parameters. We show that a joint analysis of ARF and angular
galaxy clustering improves constraints by $\sim 40\%$ on galaxy bias compared
to a joint analysis of angular galaxy clustering and CMB lensing.
