  Absorption lines in front of distant quasars are quite rare in the millimeter
domain. They can however bring a very useful and complementary information to
emission lines.
  We report here the detection with NOEMA of CO(1-0) and CN(1-0) lines in
absorption, and confirmation of CO emission in the quasar/galaxy pair
Q0248+430/G0248+430. The system G0248+430 corresponds to two merging galaxies
(a Seyfert and a LINER) at z=0.0519 with a tidal tail just on the line of sight
to the background quasar Q0248+430 at z = 1.313.
  Optical (CaII, NaI), HI-21cm and OH-1667 MHz absorption lines associated with
the tidal tail of the foreground system have previously been detected toward
the quasar, while four CO lines at different rotation J levels have been
detected in emission from the foreground galaxies.
  New HI 21-cm line observations with the upgraded GMRT array are presented.
  We discuss the molecular content of the merging galaxies, and the physical
conditions in the absorbing interstellar medium of the tidal tail.
