The Landscape of L-functions: degree 3 and conductor 1

We extend previous lists by numerically computing approximations to many L-functions of degree $d=3$, conductor $N=1$, and small spectral parameters. We sketch how previous arguments extend to say that for very small spectral parameters there are no such L-functions. Using the case $(d,N)=(3,1)$ as a guide, we explain how the set of all L-functions with any fixed invariants $(d,N)$ can be viewed as a landscape of points in a $(d-1)$-dimensional Euclidean space. We use Plancherel measure to identify the expected density of points for large spectral parameters for general $(d,N)$. The points from our data are close to the origin and we find that they have smaller density.