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首页> 外文期刊>The Astrophysical journal >DEEP CHANDRA OBSERVATIONS OF EDGES AND BUBBLES IN THE NGC?5846 GALAXY GROUP
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DEEP CHANDRA OBSERVATIONS OF EDGES AND BUBBLES IN THE NGC?5846 GALAXY GROUP

机译:NGC?5846银河系边缘和气泡的深层Chandra观测

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摘要

We use a combined 120?ks Chandra exposure to analyze X-ray edges produced by non-hydrostatic gas motions (sloshing) from galaxy collisions, and cavities formed by active galactic nucleus (AGN) activity. Evidence for gas sloshing is seen in the spiral morphology and multiple cold front edges in NGC?5846's X-ray surface brightness distribution, while the lack of spiral structure in the temperature map suggests that the perturbing interaction was not in the plane of the sky. Density and spectral modeling across the edges indicate that the relative motion of gas in the cold fronts is at most transonic. Evidence for AGN activity is seen in two inner bubbles at 0.6?kpc, filled with 5?GHz and 1.5?GHz radio plasma and coincident with Hα emission, and in a ghost bubble at 5.2?kpc west of NGC?5846's nucleus. The outburst energy and ages for the inner (ghost) bubbles are ~1055?erg and ~2?Myr (~5 × 1055?erg and 12?Myr), respectively, implying an AGN duty cycle of 10?Myr. The inner bubble rims are threaded with nine knots, whose total 0.5-2?keV X-ray luminosity is 0.3 × 1040?erg?s–1, a factor ~2-3 less than that of the surrounding rims, and 0.7?keV mean temperature is indistinguishable from that of the rims. We suggest that the knots may be transient clouds heated by the recent passage of a shock from the last AGN outburst. We also observe gas stripping from a cE galaxy, NGC?5846A, in a 0.5?kpc long (~105 M ☉) hot gas tail, as it falls toward NGC?5846.
机译:我们使用组合的120ks Chandra曝光量来分析由星系碰撞产生的非静液压气体运动(晃动)产生的X射线边缘,以及由活跃的银河核(AGN)活动形成的空腔。在NGC?5846的X射线表面亮度分布中,螺旋状形态和多个冷前边缘可见气体晃动的迹象,而温度图中缺乏螺旋状结构则表明扰动相互作用不在天空中。边缘的密度和光谱模型表明,冷锋处气体的相对运动最多为跨音速的。在NGC?5846原子核以西5.2?kpc处的两个幽灵气泡中,出现了两个0.6?kpc的内部气泡,充满了5?GHz和1.5?GHz的放射性等离子体并与Hα发射相吻合,这是AGN活性的证据。内部(鬼影)气泡的爆发能量和寿命分别为〜1055?erg和〜2?Myr(〜5×1055?erg和12?Myr),这意味着AGN占空比为10?Myr。气泡内圈有九个节,其总的0.5-2?keV X射线发光度为0.3×1040?erg?s–1,比周围的圈约低2-3倍,而0.7?keV平均温度与轮辋温度没有区别。我们建议,这些结可能是最近一次上一次AGN爆发引起的冲击传热而产生的短暂云。我们还观察到从一个0.5Ekpc长(〜105 M☉)的热气体尾巴中,一个cE星系NGC?5846A出现气体剥落,该气体向NGC?5846坠落。

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