Diagnosing shock temperature with NH$_3$ and H$_2$O profiles
  In a previous study of the L1157 B1 shocked cavity, a comparison between
NH$_3$(1$_0$-$0_0$) and H$_2$O(1$_{\rm 10}$--1$_{\rm 01}$) transitions showed a
striking difference in the profiles, with H$_2$O emitting at definitely higher
velocities. This behaviour was explained as a result of the high-temperature
gas-phase chemistry occurring in the postshock gas in the B1 cavity of this
outflow. If the differences in behaviour between ammonia and water are indeed a
consequence of the high gas temperatures reached during the passage of a shock,
then one should find such differences to be ubiquitous among chemically rich
outflows. In order to determine whether the difference in profiles observed
between NH$_3$ and H$_2$O is unique to L1157 or a common characteristic of
chemically rich outflows, we have performed Herschel-HIFI observations of the
NH$_3$(1$_0$-0$_0$) line at 572.5 GHz in a sample of 8 bright low-mass outflow
spots already observed in the H$_2$O(1$_{\rm 10}$--1$_{\rm 01}$) line within
the WISH KP. We detected the ammonia emission at high-velocities at most of the
outflows positions. In all cases, the water emission reaches higher velocities
than NH$_3$, proving that this behaviour is not exclusive of the L1157-B1
position. Comparisons with a gas-grain chemical and shock model confirms, for
this larger sample, that the behaviour of ammonia is determined principally by
the temperature of the gas.
