The structure behind the Galactic bar traced by red clump stars in the
  VVV survey
  Red clump stars are commonly used to map the reddening and morphology of the
inner regions of the Milky Way. We use the new photometric catalogues of the
VISTA Variables in the V\'ia L\'actea survey to achieve twice the spatial
resolution of previous reddening maps for Galactic longitudes
$-10^{\circ}<l<10^{\circ}$ and latitudes $-1.5^{\circ}<b<1.5^{\circ}$. We use
these de-reddened catalogues to construct the $K_{s}$ luminosity function
around the red clump in the Galactic plane. We show that the secondary peak
(fainter than the red clump) detected in these regions does not correspond to
the bulge red-giant branch bump alone, as previously interpreted. Instead, this
fainter clump corresponds largely to the over-density of red clump stars
tracing the spiral arm structure behind the Galactic bar. This result suggests
that studies aiming to characterise the bulge red-giant branch bump should
avoid low galactic latitudes ($|b|< 2^{\circ}$), where the background red clump
population contributes significant contamination. It furthermore highlights the
need to include this structural component in future modelling of the Galactic
bar
