The following document lists the file abstract/PVDWERF_SHOCKS.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
===================================================================== ===================================================================== The SWS and LWS will be used to measure the brightest cooling lines of shocked neutral gas in the prototypical ultraluminous infrared galaxies (ULIRGs) Arp220 and NGC6240. In ground-based observations, we have found that the H2 emission peaks between the two remnant stellar nuclei of the merging galaxies. This is a result of dissipation in shocks in the gas, which makes the gas components merge before the dissipationless stellar components merge. The shock-excited line emission is the direct signature of this dissipation and can be used to trace the flow of molecular gas towards the bottom of the potential well. ULIRGs are suspected to harbour dust-embedded quasars, formed in their dusty centers. The immense concentrations of dissipative material, in a deep potential well, may form ideal birth places for active nuclei, by building up a massive black hole, or by fueling a pre-existing seed black hole. Aim of the SWS/LWS observations is a determination of the total energy radiated away in line emission by the shocks, thereby measuring the rate at which mechanical energy is being dissipated. In addition the shock velocities involved will be determined. This will allow us to measure the rate at which the molecular gas flows towards the bottom of the potential well. The line cooling is dominated by H2, CO, H2O and OH rotational lines and H2 vibrational lines. Of these, only the vibrational lines can be measured from the ground. Our proposal is to measure the brightest rotational lines of the 4 species listed above with ISO. Since the central regions of ULIRGs will form the birth places of extreme starbursts or luminous active nuclei, the programme will have implications on the formation of active nuclei and extreme starbursts in general.