PACS observations of the [CII] 158 micron emission line are proposed for 56 luminous, dusty galaxies to determine if there are starbursts so obscured by dust that the starbursts are weak or invisible in the mid-infrared PAH features observed with the Spitzer Infrared Spectrograph (IRS). Are there LIRGs and ULIRGs classified as AGN which really are heavily obscured starbursts? Because of the much smaller extinction affecting the [CII] feature, large f([CII])-f(PAH) ratios would show the presence of such obscured starbursts. Sources proposed include 18 "pure" starbursts to improve the f([CII])-f(PAH) calibration for these, 32 sources classified as AGN-starburst composites, and 6 sources with weak PAH and very strong silicate absorption. This proposal builds on the success of our OT1 program for which a summary is given of the excellent [CII] detections so far obtained and analyzed for a variety of luminous sources with IRS starburst-AGN classifications.
Star Formation Rates from [C II] 158 ?m and Mid-infrared Emission Lines for Starbursts and Active Galactic Nuclei . Sargsyan L. et al. . The Astrophysical Journal, Volume 790, Issue 1, article id. 15, 12 pp. (2014). . 790 . 10.1088\/0004-637X\/790\/1\/15 . 2014ApJ...790...15S ,
Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.