AI 中文总结
本研究通过蛇夫座星团的能量平衡与冷锋约束，检验各向同性热传导作为冷核加热机制，发现其需强烈各向异性或次主导，从而否定其普遍主导作用。
AI 中文摘要
热传导可以作为冷核团簇的一种加热机制，然而同样的输运过程必然会侵蚀其所穿越的任何温度不连续面。蛇夫座星团使得这两种效应可以在同一大气中进行检验。其温度从最内层核心的约1 keV上升到r~30 kpc处的9 keV，使得传导加热尤为有利，而两个清晰分辨的冷锋则独立地约束了相同的输运过程。我们基于去投影的Chandra密度和温度廓线，结合基于XRISM的湍流加热限制和亚声速内流贡献，构建了稳态径向能量平衡。仅用亚Spitzer系数即可闭合该能量平衡——在25 kpc处为Ftwentyfive，在内冷锋和外冷锋处分别为Finner和Fouter——因此传导在能量上可以提供缺失的热量。然而，将相同的系数垂直于冷锋表面应用，会在Tinner和Touter百万年内将锋面展宽至其观测宽度极限，这相对于产生和维持此类界面的特征晃动时标而言是短暂的。对于具有代表性的200百万年停留时间，能量平衡所要求的径向传导率超过锋面存活所允许的跨锋传导率约三倍，所需各向异性在99.9%和98.8%的接受模型中超过1。这一结果留下了两个广泛的机制区间：热传导在蛇夫座中要么是次主导的，要么贡献显著但强烈各向异性，其中跨冷锋的热输运相对于径向方向受到抑制。两者共同不利于局部各向同性传导作为冷核中普遍的主导加热机制。
英文摘要
Thermal conduction can act as a heating mechanism for cool-core clusters, yet the same transport must erode any temperature discontinuity it crosses. Ophiuchus permits both effects to be tested in the same atmosphere. Its temperature rises from about $1$ keV in the innermost core to $9$ keV at $r\sim30$ kpc, making conductive heating especially favorable, while two sharply resolved cold fronts independently constrain the same transport. \textcolor{black}{We construct a steady radial energy balance from deprojected \textit{Chandra} density and temperature profiles, with XRISM-based limits on turbulent heating and a subsonic inflow contribution.} Closing the balance with conduction requires only sub-Spitzer coefficients --- \Ftwentyfive\ at 25 kpc and \Finner\ and \Fouter\ at the inner and outer cold fronts --- so conduction can energetically supply the missing heat. Yet the same coefficients, applied normal to the cold-front surfaces, would broaden the fronts to their observed width limits within \Tinner\ and \Touter\ Myr, short compared to the characteristic sloshing timescales that generate and sustain such interfaces. For a representative 200 Myr residence time, the radial conductivity demanded by the energy balance exceeds the cross-front conductivity permitted by front survival by roughly a factor of three, with the required anisotropy exceeding unity in 99.9\% and 98.8\% of accepted models. The result leaves two broad regimes. Thermal conduction is either subdominant in Ophiuchus or contributes substantially but is strongly anisotropic, with heat transport suppressed across the cold fronts relative to the radial direction. Together they disfavor locally isotropic conduction as a dominant heating mechanism in cool cores generally.
Comments11 pages, 3 figures, Submitted to AAS journal, Comments are welcome
