We study the galaxy number density ( smoothed on a 5 h ^ { -1 } Mpc scale ) around 18 low-redshift Lyman-alpha absorbers previously observed with HST .
The absorbers lie in the foregrounds of Mrk 335 , Mrk 421 , Mrk 501 , I Zw 1 , and 3C 273 , all within regions where there are now complete redshift surveys to m _ { Zw } = 15.5 .
We construct a smoothed galaxy number density field from the redshift survey data and determine the distribution of densities at the Lyman-alpha absorber locations .
We also find the distribution of galaxy number density for a variety of test samples : all galaxy locations within the Center for Astrophysics Redshift Survey ( CfA2 ) , CfA2 galaxy locations along randomly selected lines of sight , and randomly chosen redshifts along random lines of sight .

The Lyman-alpha absorbers are present in dense regions of the survey , but occur far more frequently in underdense regions than do typical luminous galaxies .
The distribution of smoothed galaxy density around the Lyman-alpha absorbers is inconsistent at the 4 \sigma level with the density distribution around survey galaxies .
It is highly consistent with a density distribution at randomly chosen redshifts along random lines of sight .
This supports earlier evidence that the nearby , low column density ( \log N _ { H \sc i } \lesssim 14 ) Lyman-alpha forest systems are spatially distributed at random ; they are not well correlated with the local large-scale structure .