1996A&A...308L...1M

Spectra (3700-10000A) and continuum + line images of NGC4945 at optical (V,R,Z,[OIII],Hα+[NII]) and IR (J,H,K,L,H2,Brγ) wavelengths reveal a conical wind-blown cavity. The Brγ and L band images trace a starburst disc or ring with no morphological similarity to the more extended H₂ emission which shows the cavity and indicates that it is confined by molecular material heated by shocks or X-rays. The spectra reveal significant bulk motions (<600km/s); line ratios typical of LINERS and the discovery of prominent [CI] which is very weak in Seyferts 1-2 while strong in supernova remnants, including the X-ray excited filaments of the Crab. Shock excitation at the surface of the cavity provides a likely explanation for the line emission although photoionization by X-rays associated with the superwind or the suspected Seyfert nucleus detected in hard X-rays cannot be excluded.