Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z similar to 2-4 as probed by multi-J CO lines

doi:10.1051/0004-6361/201731391

	Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z similar to 2-4 as probed by multi-J CO lines
	Yang, C.1,2,3,4,5; Omont, A.4,5; Beelen, A.2; Gao, Y.1 ; van der Werf, P.6; Gavazzi, R.4,5; Zhang, Z. -Y.7,8; Ivison, R.7,8; Lehnert, M.4,5; Liu, D.9
刊名	ASTRONOMY & ASTROPHYSICS
	2017-12-15
卷号	608 页码:41
关键词	galaxies: high-redshift galaxies: ISM infrared: galaxies submillimeter: galaxies radio lines: ISM ISM: molecules
ISSN号	1432-0746
DOI	10.1051/0004-6361/201731391
通讯作者	Yang, C.(yangcht@pmo.ac.cn)
英文摘要	We present the IRAM-30m observations of multiple-J CO (J(up) mostly from 3 up to 8) and [CI](P-3(2) -> P-3(1)) ([CI](2-1) hereafter) line emission in a sample of redshift similar to 2-4 submillimeter galaxies (SMGs). These SMGs are selected among the brightest-lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Forty-seven CO lines and 7 [CI](2-1) lines have been detected in 15 lensed SMGs. A non-negligible effect of differential lensing is found for the CO emission lines, which could have caused significant underestimations of the linewidths, and hence of the dynamical masses. The CO spectral line energy distributions (SLEDs), peaking around J(up) similar to 5-7, are found to be similar to those of the local starburst-dominated ultra-luminous infrared galaxies and of the previously studied SMGs. After correcting for lensing amplification, we derived the global properties of the bulk of molecular gas in the SMGs using non-LTE radiative transfer modelling, such as the molecular gas density n(H2) similar to 10(2.5)-10(4.1) cm(-3) and the kinetic temperature T-k similar to 20-750 K. The gas thermal pressure P-th ranging from similar to 10(5) Kcm(-3) to 10(6) Kcm(-3) is found to be correlated with star formation efficiency. Further decomposing the CO SLEDs into two excitation components, we find a low-excitation component with n(H2) similar to 10(2.8)-10(4.6) cm(-3) and T-k similar to 20-30 K, which is less correlated with star formation, and a high-excitation one (n(H2) similar to 10(2.7)-10(4.2) cm(-3), T-k similar to 60-400 K) which is tightly related to the on-going star-forming activity. Additionally, tight linear correlations between the far-infrared and CO line luminosities have been confirmed for the J(up) >= 5 CO lines of these SMGs, implying that these CO lines are good tracers of star formation. The [C I](2-1) lines follow the tight linear correlation between the luminosities of the [C I](2-1) and the CO(1-0) line found in local starbursts, indicating that [C I] lines could serve as good total molecular gas mass tracers for high-redshift SMGs as well. The total mass of the molecular gas reservoir, (1-30) x 10(10) M circle dot, derived based on the CO(3-2) fluxes and alpha(CO(1-0)) = 0.8 M circle dot (K km s(-1) pc(2))(-1), suggests a typical molecular gas depletion time t(dep) similar to 20-100 Myr and a gas to dust mass ratio delta(GDR) similar to 30-100 with similar to 20%-60% uncertainty for the SMGs. The ratio between CO line luminosity and the dust mass L'(CO)/M-dust appears to be slowly increasing with redshift for high-redshift SMGs, which need to be further confirmed by a more complete SMG sample at various redshifts. Finally, through comparing the linewidth of CO and H2O lines, we find that they agree well in almost all our SMGs, confirming that the emitting regions of the CO and H2O lines are co-spatially located.
WOS关键词	STAR-FORMING GALAXIES ; DEEP-FIELD-SOUTH ; ULTRALUMINOUS INFRARED GALAXIES ; HIGH-REDSHIFT GALAXIES ; INTERSTELLAR-MEDIUM ; CONVERSION FACTOR ; NUMBER COUNTS ; ATOMIC CARBON ; PIXELATED RECONSTRUCTION ; CLOVERLEAF QUASAR
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	EDP SCIENCES S A
WOS记录号	WOS:000418460000010
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/22106]
专题	中国科学院紫金山天文台
通讯作者	Yang, C.
作者单位	1.Chinese Acad Sci, Purple Mt Observ, Key Lab Radio Astron, Nanjing 210008, Jiangsu, Peoples R China 2.Univ Paris 11, Univ Paris Saclay, CNRS, Inst Astrophys Spatiale, Bat 121, F-91405 Orsay, France 3.Grad Univ Chinese Acad Sci, 19A Yuquan Rd, Beijing 10049, Peoples R China 4.CNRS, UMR 7095, Inst Astrophys Paris, F-75014 Paris, France 5.UPMC, Univ Paris 06, UMR 7095, Inst Astrophys Paris, F-75014 Paris, France 6.Leiden Univ, Leiden Observ, POB 513, Leiden, Netherlands 7.Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland 8.European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching, Germany 9.Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany 10.Univ Alcala De Henares, Dept Fis & Matemat, Campus Univ,28871 Alcala Henares, Madrid, Spain
推荐引用方式 GB/T 7714	Yang, C.,Omont, A.,Beelen, A.,et al. Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z similar to 2-4 as probed by multi-J CO lines[J]. ASTRONOMY & ASTROPHYSICS,2017,608:41.
APA	Yang, C..,Omont, A..,Beelen, A..,Gao, Y..,van der Werf, P..,...&Smail, I..(2017).Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z similar to 2-4 as probed by multi-J CO lines.ASTRONOMY & ASTROPHYSICS,608,41.
MLA	Yang, C.,et al."Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z similar to 2-4 as probed by multi-J CO lines".ASTRONOMY & ASTROPHYSICS 608(2017):41.