The PdBI Arcsecond Whirlpool Survey

The PdBI Arcsecond Whirlpool Survey (PAWS) is a Large Program that combines Plateau de Bure interferometer and 30m data to image at high angular resolution the emission from the molecular gas disk in the nearby grand-design spiral galaxy M51a (also known as the Whirlpool galaxy). PAWS is an international collaboration led by Eva Schinnerer (MPIA).

PAWS mapped the ¹²CO(1-0) emission from the central ~9 kpc of a massive spiral galaxy to allow for the study of the molecular gas properties as a function of galactic environment at the scale of Giant Molecular Clouds (GMCs, size ~ 40pc). The aim was to complement the existing superb imaging of M51 across the electro-magnetic spectrum to enable studies on the molecular gas structure, the formation and evolution of GMCs and subsequent star formation within a massive disk galaxy. 

New results based on the PAWS dataset include the finding that on cloud-scales the correspondence between CO emission and tracers of the cold ISM (e.g. optical extinction, PAH emission) is excellent and even holds for radio continuum emission while the correspondence to star formation tracers ranges from excellent to absent (strongly depending on galactic environment) (Schinnerer et al. 2013). Detailed analysis of the molecular gas structure reveals an additional thick molecular gas disk (Pety et al. 2013), a strong environmental dependance of the molecular gas structure function (Hughes et al. 2013a) as well as the properties and distribution of the GMCs (Colombo et al. 2013). Careful comparison to GMC properties in two local low-mass galaxies underlines the strong environmental dependance of GMC properties and identifies pressure as an important actor for GMC formation (Hughes et al. 2013b), in particular dynamical pressure is playing an important role in the dramatic changes observed (Meidt et al. 2013).

The official PAWS data repositories are at MPIA and IRAM.

Details on the survey and the data processing are given in Schinnerer et al. (2013) and Pety et al. (2013). The links above provide access to the PAWS data products: data cubes, integrated intensity maps ('moment 0'), velocity fields ('moment 1') and velocity dispersion maps ('moment 2') of a) the ¹²CO(1-0) emission line for the combined 30m+PdBI data at 1”, 3" and 6" resolution, and b) the ¹²CO(1-0) and ¹³CO(1-0) emission line for the 30m only data at 23” resolution.

Please do not hesitate to contact Eva Schinnerer and Jerome Pety to tell them about your use of the data for scientific analysis. The following acknowledgement would be appreciated: "This work made use of PAWS, 'The PdBI Arcsecond Whirlpool Survey' (Schinnerer et al. 2013, Pety et al. 2013)." Acknowledgement of the PAWS project is also appreciated if data are used in public presentations.

Last updated : June 2013