Planck's dusty GEMS IV. Star formation and feedback in a maximum starburst at z=3 seen at 60-pc resolution
Artikel i vetenskaplig tidskrift, 2017

We present an analysis of high-resolution ALMA interferometry of CO(4-3) line emission and dust continuum in the "Ruby" (PLCK_G244.8+54.9), a bright, gravitationally lensed galaxy at z = 3.0 discovered with the Planck all-sky survey. The Ruby is the brightest of Planck's dusty GEMS, a sample of 11 of the brightest gravitationally lensed high-redshift galaxies on the extragalactic sub-mm sky. We resolve the high-surface-brightness continuum and CO line emission of the Ruby in several extended clumps along a partial, nearly circular Einstein ring with 1.4 '' diameter around a massive galaxy at z = 1.5. Local star-formation intensities are up to 2000 M-circle dot yr(-1) kpc(-2), amongst the highest observed at high redshift, and clearly in the range of maximal starbursts. Gas-mass surface densities are a few x10(4) M-circle dot pc(-2). The Ruby lies at, and in part even above, the starburst sequence in the Schmidt-Kennicutt diagram, and at the limit expected for star formation that is self-regulated through the kinetic energy injection from radiation pressure, stellar winds, and supernovae. We show that these processes can also inject sufficient kinetic energy and momentum into the gas to explain the turbulent line widths, which are consistent with marginally gravitationally bound molecular clouds embedded in a critically Toomre-stable disk. The star-formation efficiency is in the range 1-10% per free-fall time, consistent with the notion that the pressure balance that sets the local star-formation law in the Milky Way may well be universal out to the highest star-formation intensities. AGN feedback is not necessary to regulate the star formation in the Ruby, in agreement with the absence of a bright AGN component in the infrared and radio regimes.

galaxies: high-redshift

Ultraluminous Infrared Galaxies


galaxies: starburst

Formation Law


Dense Gas Disk

galaxies: star

Lensed Submillimeter Galaxy

Forming Galaxies



Conversion Factor

submillimeter: galaxies

galaxies: evolution



R. Canameras

Universite Paris-Sud XI

N. Nesvadba

Universite Paris-Sud XI

R. Kneissl

European Southern Observatory Santiago

Atacama Large Millimeter-submillimeter Array

B. Frye

University of Arizona

R. Gavazzi

Universite Pierre et Marie Curie

Sabine König

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

E. Le Floc'H

CNRS Centre National de la Recherche Scientifique

M. Limousin

Laboratoire d'Astrophysique de Marseille

I. Oteo

European Southern Observatory

University of Edinburgh

D. Scott

The University of British Columbia

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 604 Article no A117 - A117


Astronomi, astrofysik och kosmologi