You will be presented with the full text of a science research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
within the field of quasar absorption lines , one long  standing question is how the halos and ism of earlier epoch galaxies compare or relate , in an evolutionary sense , to those of the present epoch . the look 
back time to @xmath1 covers well more than half the age of the universe .
furthermore , spectral and morphological properties of absorbing galaxies are accessible with present day ground  based and spaced  based observatories ( steidel , dickinson , & persson 1994 ; steidel 1998 ) .
thus , absorption line studies at intermediate redshifts provide an opportunity to examine the gaseous evolution of galaxies .
the ism and halos of local galaxies are comprised of many ionization phases , including diffused ionized gas , extended coronae , and denser low ionization regions often located in front of shock fronts ( e.g.dahlem 1998 ) . in absorption , simultaneous study of both the low and high ionization phases in our galaxy
have been required to constrain the ionization mechanisms , chemical abundance variations , and the dust properties ( e.g.  savage & sembach 1996 ) .    a significant obstacle in the face of rapid progress with studies employing absorption lines , however , is that the strongest transitions of the cosmologically most abundant elements lie in the far to near ultraviolet ( uv ) portion of the electromagnetic spectrum .
fortunately , at @xmath2 , the near uv transitions , which are most often associated with neutral and low ionization ions  ev .
] , are redshifted into the visible .
thus , they can be observed from the ground with large aperture telescopes .
however , the far uv transitions , associated with moderate and high ionization ions and @xmath3  ev and between @xmath4 and @xmath5  ev , respectively . ] , are redshifted to the near uv ; a study of the high ionization component requires a spaced  based telescope , i.e.  _ hst_. the _ hst _ archive is rich with @xmath6 fos spectra of quasars , the majority due to the qso absorption line key project ( bahcall et  al .
we used hires / keck spectra ( @xmath7  ) and archival fos/_hst _ spectra ( @xmath8  ) to place constraints on the ionization and multiphase distribution of absorbing gas at @xmath9 to @xmath1 . in figure  1 , we present  @xmath10 and the c0.1emiv  @xmath11 doublet for each of 40 systems ( note that the velocity scale for is 500   and for is 3000  ) . ticks above the hires spectra give the velocities of the voigt profile sub  components and ticks above the fos data give the expected location of these components for the doublet .
the labels `` d '' , `` l '' , and `` bl '' denote detection , limit , and blend , respectively .
the systems are presented in order of increasing kinematic spread from the upper left to lower right .    based upon a highly significant correlation between the equivalent widths and the kinematics
, it is inferred that most intermediate redshift galaxies have multiphase gaseous structures ( churchill et  al .   1999 , 2000 ) .
the low ionization gas is in multiple , narrow components , @xmath12  , and the high ionization gas is kinematically spread out with @xmath13   ( using the doublet ratio method ) .
this is an effective velocity dispersion , for the fos spectra are of too low resolution to resolve velocity splittings below @xmath14  .
the three systems at @xmath15 , @xmath16 , and @xmath17 along the line of sight to pg  @xmath18 exhibit complex kinematics and exceptionally strong , , and absorption .
we investigated the ionization and spatial distribution of these systems using detailed photoionization models ( cloudy ; ferland 1996 ) .    in the top panels of figure  2 ,
the hires / keck spectra of the @xmath19 transition and of the mg0.1emii  @xmath20 doublet are shown with a voigt profile model spectrum superimposed ; the ticks give the component centers .
the systemic redshifts of the three systems , a , b , and c , are labeled .
the lower two panels show the normalized fos/_hst _ spectrum ( histogram ) with tuned model predictions ( not fits ) superimposed ( see churchill & charton 1999 ) .
the dotted  line is a single  phase model , assuming all absorption arises due to ionization balance in the clouds ; a single phase of gas fails to account for the high ionization absorption strengths .
the solid spectrum is a two  phase model , which allows the higher ionization gas to reside in a separate phase .    based upon the photoionization modeling , a highly ionized phase , not seen in , is required to account for the observed , , and absorption
. an `` effective '' doppler width of @xmath21   is consistent with the complex , blended data .
the physical size of the high ionization component is less than 30  kpc , with the best values between 10 and 20  kpc .    based upon the sizes and effective doppler widths
, we infer that the highly ionized material is analogous to the galactic coronae ( savage et  al .
1997 ) , material stirred up by energetic mechanical processes , such as galactic fountains . in this scenario ,
the gas is concentrated around the individual galaxies which presumably provide a source of support , heating , and chemical enrichment .
we present 40 quasar absorption line systems at intermediate redshifts ( @xmath0 ) , with focus on one of the most kinematically complex known , as examples of how the unique capabilities of space  based and ground  based facilities can be combined to glean much broader insights into astrophysical systems .