Probing the Local Bubble with Diffuse Interstellar Bands. II. The DIB
  properties in the Northern hemisphere
  We present a new high signal to noise ratio spectroscopic survey of the
Northern hemisphere to probe the Local Bubble and its surroundings using the
$\lambda 5780$ \AA\ and $\lambda 5797$ \AA\ Diffuse Interstellar Bands (DIBs).
We observed 432 sightlines to a distance of 200 pc over a duration of 3 years.
In this study, we establish the $\lambda 5780$ and $\lambda 5797$ correlations
with Na I, Ca II and E(B-V), for both inside and outside the Local Bubble. The
correlations show that among all neutral and ionized atoms, the correlation
between Ca II and $\lambda5780$ is stronger than its correlation with
$\lambda5797$, suggesting that $\lambda5780$ is more associated with regions
where Ca$^{+}$ is more abundant. We study the $\lambda5780$ correlation with
$\lambda5797$, which shows a tight correlation within and outside the Local
Bubble. In addition we investigate the DIB properties in UV irradiated and UV
shielded regions. We find that, within and beyond the Local Bubble,
$\lambda5797$ is located in denser parts of clouds, protected from UV
irradiation, while $\lambda5780$ is located in the low density regions of
clouds.
