论文标题
AGN对CO线探测的银河中心中分子气的影响
AGN impact on the molecular gas in galactic centers as probed by CO lines
论文作者
论文摘要
我们对35个本地样本（$ z \ leq 0.15 $），Active（$ L_X \ geq 10^{42} $ ERG S $^{ - 1} $）进行了X射线，红外和一氧化碳（CO）排放的详细分析。我们的目标是从恒星形成（SF）（SF）和从活性银河系核（AGN）中推断出远硫酸酯（FUV）辐射的贡献，从而产生了光解离区（PDRS）和X射线统治区（XDR），从而贡献X射线辐射。为此，我们利用了由Herschel所追踪的CO光谱线能分布（CO雪橇），并补充了来自低J线的单次望远镜的数据，以及Mid-J CO发射区域的高分辨率ALMA图像。通过将我们的结果与Schmidt-Kennicutt的关系进行比较，我们没有发现AGN对KPC尺度的冷和低密度气体影响的证据。在核（r = 250 pc）尺度上，我们发现CO线比与FUV或X射线通量之间的弱相关性：这可能表明SF和AGN辐射都不统治气体激发，至少在R = 250 PC时。从将CO线比与PDR和XDR模型进行比较，我们发现PDR只能在存在极高的气体密度（$ n> 10^5 $ cm $^{ - 3} $）的情况下重现观测值。相反，在XDR情况下，模型建议中等密度（$ n \ of 10^{2-4} $ cm $^{ - 3} $）。我们得出的结论是，必须将两种机制（MID-J，XDR的PDR或高J的冲击）的混合物解释为解释活性星系中观察到的CO激发。
We present a detailed analysis of the X-ray, infrared, and carbon monoxide (CO) emission for a sample of 35 local ($z \leq 0.15$), active ($L_X \geq 10^{42}$ erg s$^{-1}$) galaxies. Our goal is to infer the contribution of far-ultraviolet (FUV) radiation from star formation (SF), and X-ray radiation from the active galactic nuclei (AGN), respectively producing photodissociation regions (PDRs) and X-ray dominated regions (XDRs), to the molecular gas heating. To this aim, we exploit the CO spectral line energy distribution (CO SLED) as traced by Herschel, complemented with data from single-dish telescopes for the low-J lines, and high-resolution ALMA images of the mid-J CO emitting region. By comparing our results to the Schmidt-Kennicutt relation, we find no evidence for AGN influence on the cold and low-density gas on kpc-scales. On nuclear (r = 250 pc) scales, we find weak correlations between the CO line ratios and either the FUV or X-ray fluxes: this may indicate that neither SF nor AGN radiation dominates the gas excitation, at least at r = 250 pc. From a comparison of the CO line ratios with PDR and XDR models, we find that PDRs can reproduce observations only in presence of extremely high gas densities ($n > 10^5$ cm$^{-3}$). In the XDR case, instead, the models suggest moderate densities ($n \approx 10^{2-4}$ cm$^{-3}$). We conclude that a mix of the two mechanisms (PDR for the mid-J, XDR or possibly shocks for the high-J) is necessary to explain the observed CO excitation in active galaxies.
