We propose to exploit the spectroscopic capabilities of PACS to describe the [C II] line emission in a unique and comprehensive sample of star-forming galaxies selected from the wide-field, parallel PACS+SPIRE H-ATLAS imaging survey.
The sample has exquisite optical spectra from GAMA and SDSS, allowing us to:
[1] describe [C II] line as a function of dust and stellar mass, metallicity, extinction, dust temperature, and many other physical parameters; [2] identify the parameters controlling the behaviour of [CII]/L(FIR) at log L(FIR)>11; [3] calibrate [CII] as a star-formation indicator [exploiting our accurate L(FIR) and L(Halpha)] and determine the range over which it is valid.
[CII] is potentially an unrivalled tracer of the total gas mass in galaxies (in theory better than CO), and it is therefore an increasingly important observable, e.g. for upcoming ALMA observations of distant galaxies. Our study will become the benchmark for the interpretation of high-z observations, with a legacy value that will survive well into the SPICA era.
Some of the key advantages of this proposal over previous Herschel studies such as SHINING and HerCULES are:
- we cover 10.2 < log L(FIR) < 11.5 and are unbiased towards powerful ULIRGs with complex merger morphologies; - our sample is selected blindly from H-ATLAS rather than from IRAS, and thus allows exploration of comprehensive parameter space and is much less biased towards galaxies with warm dust emission; - we know the spatial extent of the galaxies, allowing reliable flux measurements via a single pointing within 10 min/target.
We can thus achieve our goals in a systematic fashion, maximising the parameter space for the diagnostics of interest.
We stress that the scientific legacy of ISO and Spitzer has in large par...t been based on the wealth of data in their spectroscopic archives and the same will likely be true for Herschel.
Publication
VALES. II. The physical conditions of interstellar gas in normal star-forming galaxies up to z = 0.2 revealed by ALMA . Hughes T. M. et al. . Astronomy & Astrophysics, Volume 602, id.A49, 12 pp. . 602 . 10.1051\/0004-6361\/201629588 . 2017A&A...602A..49H , A multiwavelength exploration of the [C II]/IR ratio in H-ATLAS/GAMA galaxies out to z = 0.2 . Ibar E. et al. . Monthly Notices of the Royal Astronomical Society, Volume 449, Issue 3, p.2498-2513 . 449 . 10.1093\/mnras\/stv439 . 2015MNRAS.449.2498I ,
Instrument
PACS_PacsLineSpec_point
Temporal Coverage
2013-04-18T03:19:18Z/2013-04-28T09:26:56Z
Version
SPG v14.2.0
Mission Description
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.
European Space Agency, 2013, A Detailed Anaysis Of The Square_Bracket_Openciisquare_Bracket_Close Line Emission For A Large Sample Of Star-Forming Galaxies At Z&Amp;Lt;0.2, SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-bh90go9
