  We present preliminary results on the low-redshift Lyman alpha forest as
based on STIS spectra of 3C 273. A total of 121 intergalactic Lyman
alpha-absorbing systems were detected, of which 60 are above the 3.5 sigma
completness limit, log N(HI)~12.3. The median Doppler parameter, b=27 km/s, is
similar to that seen at high redshift. However the distribution of HI column
densities (dN/dN(HI) propto N(HI)^-beta) has a steeper slope, beta = 2.02 +-
0.21, than is seen at high redshift. Overall, the observed N(HI)-b distribution
is consistent with that derived from a Lambda CDM hydrodynamic simulation.
