SHARP – VI. Evidence for CO (1–0) molecular gas extended on kpc-scales in AGN star-forming galaxies at high redshift
SHARP – VI. Evidence for CO (1–0) molecular gas extended on kpc-scales in AGN star-forming galaxies at high redshift
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DOI：
10.1093/mnras/staa1342
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发表时间：
2019-05
影响因子：
4.8
通讯作者：
C. Spingola;C. Spingola;J. McKean;J. McKean;S. Vegetti;D. Powell;M. Auger;L. Koopmans;C. Fassnac
中科院分区：
文献类型：
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作者：
C. Spingola;C. Spingola;J. McKean;J. McKean;S. Vegetti;D. Powell;M. Auger;L. Koopmans;C. Fassnac
我们研究了引力透镜尘埃遮蔽的AGN MG J0751+2716和JVAS B1938+666的恒星宿主星系，CO（1-0）分子气体分布和AGN发射在50 - 500pc尺度上的红移分别为3.200和2.059。利用基于网格的透镜建模技术对透镜畸变进行校正，首次在源平面上对不同的发射区域进行了空间定位。这两个AGN宿主星系都有300 - 500pc级的大小，表面亮度与凸起/伪凸起一致，以及2 kpc级的AGN射电喷流，嵌入在5 - 20kpc级的扩展分子气藏中。CO（1-0）速度场显示的结构可能与圆盘（拉长的速度梯度）和相互作用的物体（离轴速度分量）有关。有证据表明，在宿主星系的位置CO（1-0）表面亮度下降，这可能表明来自AGN的辐射反馈，或偏移恒星形成。我们发现CO - h2转换因子约为αCO = 1.5±0.5 (K km s−1 pc2)−1，分子气体质量为bb3 × 1010 M⊙，动力质量为~ 1011 M⊙，气体组分约为60%。其内在CO线光度与未遮挡的AGN和类似红移的尘埃恒星形成星系相当，但红外光度较低，表明目标形成恒星的效率较低。因此，它们可能属于星系形成模型预测的AGN反馈阶段，因为考虑到它们大量的分子气体，它们不能有效地形成恒星。
We present a study of the stellar host galaxy, CO (1–0) molecular gas distribution and AGN emission on 50–500 pc-scales of the gravitationally lensed dust-obscured AGN MG J0751+2716 and JVAS B1938+666 at redshifts 3.200 and 2.059, respectively. By correcting for the lensing distortion using a grid-based lens modelling technique, we spatially locate the different emitting regions in the source plane for the first time. Both AGN host galaxies have 300–500 pc-scale size and surface brightness consistent with a bulge/pseudo-bulge, and 2 kpc-scale AGN radio jets that are embedded in extended molecular gas reservoirs that are 5–20 kpc in size. The CO (1–0) velocity fields show structures possibly associated with discs (elongated velocity gradients) and interacting objects (off-axis velocity components). There is evidence for a decrement in the CO (1–0) surface brightness at the location of the host galaxy, which may indicate radiative feedback from the AGN, or offset star formation. We find CO–H2 conversion factors of around αCO = 1.5 ± 0.5 (K km s−1 pc2)−1, molecular gas masses of >3 × 1010 M⊙, dynamical masses of ∼1011 M⊙, and gas fractions of around 60 per cent. The intrinsic CO line luminosities are comparable to those of unobscured AGN and dusty star-forming galaxies at similar redshifts, but the infrared luminosities are lower, suggesting that the targets are less efficient at forming stars. Therefore, they may belong to the AGN feedback phase predicted by galaxy formation models, because they are not efficiently forming stars considering their large amount of molecular gas.