Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1S018

Does the Galactic centre cloud G0.253+0.016 violate star formation relations?

Johnston, Katharine (Max Planck Institute for Astronomy)
Beuther, Henrik (Max Planck Institute for Astronomy)
Longmore, Steven (Liverpool John Moores University)
Rathborne, Jill (CSIRO)
Ragan, Sarah (Max Planck Institute for Astronomy)

The massive infrared dark cloud G0.253+0.016 near the Galactic centre contains 10^5 Msun of dense gas whilst being mostly devoid of observed star formation tracers. Thus G0.253+0.016 violates the recently proposed ”star formation law” of Lada et al. (2010), which suggests a relation between the mass above a column density threshold of 0.024 gcm^−2 and the observed star formation rate. In fact, a recent study by Longmore et al. (2013) has shown that the SFR over the Galactic centre region appears to be an order of magnitude lower than predicted by the mass of dense gas. To scrutinize the gas properties of G0.253+0.016, we have carried out a concerted SMA and IRAM 30m study of this enigmatic cloud in dust continuum, CO isotopologues as low-density tracers, and CH3OH, SO, SiO and HNCO as shock tracers. In this poster, we discuss 1) how our results suggest that G0.253+0.016 is colliding with another cloud, which could affect its final star-forming fate, 2) the density structure of the cloud with relation to whether star formation is currently ongoing, and 3) whether it is possible to reconcile the lack of star formation in G0.253+0.016 and the Galactic centre with the density threshold for star formation, found for the Milky Way disk and external galaxies, by considering the effects of turbulent support.

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