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摘要
We present Atacama Large Millimeter/submillimeter Array observations of CO lines and dust continuum emission of the source RCSGA 032727-132609, a young z. =. 1.7 low-metallicity starburst galaxy. The CO(3-2) and CO (6-5) lines and continuum at rest-frame 450 aem are detected and show a resolved structure in the image plane. We use the corresponding lensing model to obtain a source plane reconstruction of the detected emissions revealing an intrinsic flux density of m = S-450(23.5+) mu m 8.1 26.8 aeJy and intrinsic CO luminosities LCo(3-2)' = 2.90(-0.23)(-0.21) x 10(8) km s(-1) pc2 and x L'(CO(6-5)) = 8.0(-1.3)(+1.4) x 10 K km s pc(2) . We used the resolved properties in the source plane to obtain molecular gas and star formation rate surface densities of Sigma(II2) = 16.2(-3.5)(+5.8) M pc(-2) Sigma(SFR) = 0.54(-0.27)(+0.89) and , respectively. The intrinsic properties of RCSGA 032727-132609 show an enhanced star formation activity compared to local spiral galaxies with similar molecular gas densities, supporting the ongoing merger-starburst phase scenario. RCSGA 032727-132609 also appears to be a low-density starburst galaxy similar to local blue compact dwarf galaxies, which have been suggested as local analogs to high-redshift low-metallicity starburst systems. Finally, the CO excitation level in the galaxy is consistent with having the peak at J similar to 5, with a higher excitation concentrated in the star-forming clumps.
- 出版日期2017-9-10
- 单位MIT
