标题： 宇宙射线伪装成冷核心：冷核心簇辐射的逆康普顿起源 显示英文标题

标题： Cosmic Rays Masquerading as Cool Cores: An Inverse-Compton Origin for Cool Core Cluster Emission

摘要： X射线明亮的冷却核心（CC）团块包含发光的无线电源，在极高的速率下加速宇宙射线（CR）电子。 在加速区域附近，高能电子产生同步辐射（微型）晕和有时可观察到的伽马射线，但这些电子寿命很短，因此无法远离源地传播，除非得到某种再生。 然而，低能 （~0.1-1 GeV）CR应能存活超过Gyr，可能在通过逆康普顿（IC）散射CMB光子损失能量至keV X射线能量之前，达到~100 kpc，具有显著的热X射线谱。 在星系团/群中，这将类似于星系团核心相对“冷”的气体（即。 CCs）。 在低质量（例如。 银河系/M31）晕中，类似的CR IC辐射将表现为外层CGM半径处的热（超virial）气体，解释了最近的弥漫X射线观测结果。 我们表明，对于合理的（无线电/伽马射线观测到的）电子注入速率，CR-IC辐射可能对CC中的X射线表面亮度（SB）有显著贡献，这意味着CC气体密度可能被高估，并缓解了冷却流问题。 CC团块中弥漫X射线辐射的显著IC贡献也解释了X射线“冷却光度”与AGN/腔室/喷流功率之间的紧密相关性，因为明显的CC辐射本身是由无线电源驱动的。 比较CC中$\ll 100$ kpc处观测到的Sunyaev Zeldovich效应与X射线推导的压力代表了对该情景的干净测试，现有数据似乎支持显著的CR-IC。 显著的IC贡献还意味着， X射线推导的气相金属丰度在CC中被低估了，可能解释了附近CC中心~10 kpc范围内X射线（亚太阳）与光学/紫外 （超太阳）观测金属丰度之间的差异。 我们还讨论了该模型与观测到的团块中多相气体的联系。 显示英文摘要

摘要： X-ray bright cool-core (CC) clusters contain luminous radio sources accelerating cosmic ray (CR) leptons at prodigious rates. Near the acceleration region, high-energy leptons produce synchrotron (mini)halos and sometimes observable gamma rays, but these leptons have short lifetimes and so cannot propagate far from sources without some rejuvenation. However, low-energy (~0.1-1 GeV) CRs should survive for >Gyr, potentially reaching ~100 kpc before losing energy via inverse-Compton (IC) scattering of CMB photons to keV X-ray energies, with remarkably thermal X-ray spectra. In groups/clusters, this will appear similar to relatively 'cool' gas in cluster cores (i.e. CCs). In lower-mass (e.g. Milky Way/M31) halos, analogous CR IC emission will appear as hot (super-virial) gas at outer CGM radii, explaining recent diffuse X-ray observations. We show that for plausible (radio/gamma-ray observed) lepton injection rates, the CR-IC emission could contribute significantly to the X-ray surface brightness (SB) in CCs, implying that CC gas densities may have been overestimated and alleviating the cooling flow problem. A significant IC contribution to diffuse X-ray emission in CC clusters also explains the tight correlation between the X-ray 'cooling luminosity' and AGN/cavity/jet power, because the apparent CC emission is itself driven by the radio source. Comparing observed Sunyaev Zeldovich to X-ray inferred pressures at $\ll 100$ kpc in CCs represents a clean test of this scenario, and existing data appears to favor significant CR-IC. A significant IC contribution also implies that X-ray inferred gas-phase metallicities have been underestimated in CCs, potentially explaining the discrepancy between X-ray (sub-Solar) and optical/UV (super-Solar) observed metallicities in the central ~10 kpc of nearby CCs. We also discuss the model's connection to observations of multiphase gas in clusters.