Herschel SPIRE-FTS observations of RCW 120: Physical conditions towards triggered star forming regions
Annie Zavagno, Jean-Paul Baluteau, Loren Anderson, et al.
The expansion of galactic HII regions can trigger the formation of a new generation of stars. However, little is known about the physical conditions that prevail in those regions.
We investigate the physical conditions in specific areas towards the HII region RCW 120, which trace representative zones such as the photodissociation region (PDR), the ionized region and condensations with and without ongoing star formation.
We use the SPIRE Fourier Transform Spectrometer (FTS) on board Herschel to observe these regions. Continuum and lines are observed in the 290−670 micron range. Line intensities are obtained and used as diagnostics of the gas properties.
We determine the gas column density and temperature in the different parts of RCW 120. In addition, we model the line emission from the PDR, obtaining also the gas density. Lastly, we analyze our results in the framework of triggered star formation, contrasting with the expected conditions in each of the observed areas of RCW 120.