An ALMA view of the interstellar medium of the z=4.77 lensed starburst SPT-S J213242-5802.9

作者：Bethermin M^*; De Breuck C; Gullberg B; Aravena M; Bothwell M S; Chapman S C; Gonzalez A H; Greve T R; Litke K; Ma J; Malkan M; Marrone D P; Murphy E J; Spilker J S; Stark A A; Strandet M; Vieira J D; Weiss A; Welikala N

来源：Astronomy & Astrophysics, 2016, 586: L7.

DOI：10.1051/0004-6361/201527739

• galaxies: starburst
• galaxies: ISM
• galaxies: high-redshift
• galaxies: star formation
• submillimeter: galaxies

We present ALMA detections of the [NII] 205 mu m and CO(12-11) emission lines, and the tentative detection of [CI] P-3(1)-P-3(0) for the strongly lensed (mu = 5.7 +/- 0.5) dusty, star-forming galaxy SPT-S J213242-5802.9 (hereafter SPT2132-58) at z = 4.77. The [NII] and CO(12-11) lines are detected at 11.5 and 8.5 sigma levels, respectively, by our band 6 observations. The [CI] line is detected at 3.2 sigma after a reanalysis of existing band 3 data. The [CI] luminosity implies a gas mass of (3.8 +/- 1.2) x 10(10) M-circle dot, and, consequently, a very short depletion timescale of 34 +/- 13 Myr and a CO luminosity to gas mass conversion factor alpha(CO) of 1.0 +/- 0.3 M-circle dot (K km s(-1) pc(2))(-1). SPT2132-58 is an extreme starburst with an intrinsic star formation rate of 1100 +/- 200 M-circle dot/yr. We find a [CII]/[NII] ratio of 26 +/- 6, which is the highest ratio reported at z > 4. This suggests that SPT2132-58 hosts an evolved interstellar medium (0.5 Z(circle dot) < Z < 1.5 Z(circle dot)), which may be dominated by photodissociation regions. The CO(2-1) and CO(5-4) transitions have lower CO to far-infrared ratios than local and high-redshift samples, while CO(12-11) is similar to these samples, suggesting the presence of an additional very excited component or an active galactic nucleus.

• 出版日期2016-2