MOLECULAR GAS IN INFRARED ULTRALUMINOUS QSO HOSTS
MOLECULAR GAS IN INFRARED ULTRALUMINOUS QSO HOSTS
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DOI：
10.1088/0004-637x/750/2/92
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发表时间：
2012-02
期刊：
影响因子：
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通讯作者：
X. Xia;Y. Gao;C. Hao;Q. Tan;S. Mao;A. Omont;B. O. Flaquer;S. Léon;P. Cox
中科院分区：
文献类型：
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作者：
X. Xia;Y. Gao;C. Hao;Q. Tan;S. Mao;A. Omont;B. O. Flaquer;S. Léon;P. Cox
我们报道了用IRAM 30米望远镜观测到的19个红外超发光类星体(IR QSO)主机中的17个探测到了CO。区内冷分子气藏的分布范围为(0.2~2.1)×10 10M☉(采用CO/H2转换因子αCO=0.8M☉(K KM S−1PC2)−1)。我们发现IR类星体的分子气体性质，如分子气体质量、恒星形成效率(LFIR/L‘Co)和CO(1-0)谱线宽度，与局域超发光红外星系(ULIRGs)没有什么区别。对CO探测的低红移和高红移类星体的比较表明，对于所有的类星体，LFIR与L的Co(1-0)有很好的相关性。这表明，与ULIRG类似，所有类星体的远红外辐射主要来自恒星形成而不是活动星系核(AGN)加热的尘埃，证实了斯皮策中红外光谱观测的类似发现。活动星系核相关的测辐射光度和CO谱线光度之间的相关性表明，恒星形成和活动星系核来自同一个储气库，∼kpc尺度上的恒星形成与小得多尺度上的中心黑洞吸积过程之间存在联系。
We report CO detections in 17 out of 19 infrared ultraluminous QSO (IR QSO) hosts observed with the IRAM 30 m telescope. The cold molecular gas reservoir in these objects is in a range of (0.2–2.1) × 1010 M☉ (adopting a CO-to-H2 conversion factor αCO = 0.8 M☉ (K km s−1 pc2)−1). We find that the molecular gas properties of IR QSOs, such as the molecular gas mass, star formation efficiency (LFIR/L′CO), and CO (1–0) line widths, are indistinguishable from those of local ultraluminous infrared galaxies (ULIRGs). A comparison of low- and high-redshift CO-detected QSOs reveals a tight correlation between LFIR and L′CO(1-0) for all QSOs. This suggests that, similar to ULIRGs, the far-infrared emissions of all QSOs are mainly from dust heated by star formation rather than by active galactic nuclei (AGNs), confirming similar findings from mid-infrared spectroscopic observations by Spitzer. A correlation between the AGN-associated bolometric luminosities and the CO line luminosities suggests that star formation and AGNs draw from the same reservoir of gas and there is a link between star formation on ∼kpc scale and the central black hole accretion process on much smaller scales.