New molecular species at redshift z=0.89
  We present the first detections of CH3SH, C3H+, C3N, HCOOH, CH2CHCN, and H2CN
in an extragalactic source. Namely the spiral arm of a galaxy located at z=0.89
on the line of sight to the radio-loud quasar PKS 1830-211. OCS, SO2, and NH2CN
were also detected, raising the total number of molecular species identified in
that early time galaxy to 54, not counting isotopologues. The detections were
made in absorption against the SW quasar image, at 2 kpc from the galaxy
centre, over the course of a Q band spectral line survey made with the Yebes 40
m telescope (rest-frame frequencies: 58.7-93.5 GHz). We derived the rotational
temperatures and column densities of those species, which are found to be
subthermally excited. The molecular abundances, and in particular the large
abundances of C3H+ and of several previously reported cations, are
characteristic of diffuse or translucent clouds with enhanced UV radiation or
strong shocks.
