Jet-driven AGN feedback on molecular gas and low star-formation efficiency in a massive local spiral galaxy with a bright X-ray halo
Jet-driven AGN feedback on molecular gas and low star-formation efficiency in a massive local spiral galaxy with a bright X-ray halo
复制标题
喷射驱动的 AGN 对分子气体的反馈和具有明亮 X 射线晕的巨大局部螺旋星系中低恒星形成效率
DOI：
10.1051/0004-6361/202140544
复制
发表时间：
2021
影响因子：
6.5
通讯作者：
Bicknell G.
中科院分区：
文献类型：
--
作者：
Nesvadba N. P. H.;Wagner A. Y.;Mukherjee D.;Mandal A.;Janssen R. M. J.;Zovaro H.;Neumayer N.;Bagchi J.;Bicknell G.
长期以来，人们一直怀疑强大的射电源可能会降低恒星由其所在星系中的分子气体形成的效率，然而，到目前为止，还没有排除其他机制，特别是与其所在星系大质量凸起中的恒星质量分布有关的机制。我们提出了新的弧秒分辨率阿塔卡马大毫米阵列CO(1−0)干涉测量方法，它探测了附近(z= 0.08)、大质量(Mstella= 4 × 1011m⊙)、孤立的晚期螺旋星系2MASSX J23453269−044925中空间分辨的冷分子气体，它因拥有两对强大的巨型射电喷流和明亮的X射线光晕而出类拔萃。分子气体位于一个大质量(MGAs= 2.0kpc× 1010m⊙)、24kpc宽的快速旋转的环中，它与内恒星盘有关。宽阔的(半高宽= 70−180公里S−1)发射线与射电源相关，具有复杂的轮廓，在环中的大片区域可以看到，这表明气体速度足够高，足以防止原本略微稳定的气体分裂成引力约束的恒星形成的云。为这些运动提供动力大约需要1−2%的喷流动能。由星系演化探测器和广域红外巡天探测器得到的恒星形成速率表面密度比标准肯尼库特-施密特定律的预期低30−70倍，接近气体丰富的早期类型星系，其恒星形成的特征通过喷流反馈降低。我们认为射电活动星系核(AGN)反馈是解释该星系低恒星形成率的唯一可能机制。之前的作者已经注意到，J2345−0449的X射线晕暗示着重子比例接近宇宙平均水平，对于星系来说，这是非常高的。我们将这一发现与其他同等质量、同样富含重子的螺旋星系进行了对比，这些星系没有显著的射电源。这些星系中的大部分重子都在恒星中，而不是在光晕中。我们还讨论了我们的结果对于我们对大质量星系中活动星系核反馈的一般理解的影响。
It has long been suspected that powerful radio sources may lower the efficiency with which stars form from the molecular gas in their host galaxy, however so far, alternative mechanisms, in particular related to the stellar mass distribution in the massive bulges of their host galaxies, have not been ruled out. We present new, arcsecond-resolution Atacama Large Millimeter Array (ALMA) CO(1−0) interferometry, which probes the spatially resolved, cold molecular gas in the nearby (z= 0.08), massive (Mstellar= 4 × 1011M⊙), isolated, late-type spiral galaxy 2MASSX J23453269−044925, which is outstanding for having two pairs of powerful, giant radio jets, and a bright X-ray halo of hot circumgalactic gas. The molecular gas is in a massive (Mgas= 2.0 × 1010M⊙), 24 kpc wide, rapidly rotating ring, which is associated with the inner stellar disk. Broad (FWHM= 70−180 km s−1) emission lines with complex profiles associated with the radio source are seen over large regions in the ring, indicating gas velocities that are high enough to keep the otherwise marginally Toomre-stable gas from fragmenting into gravitationally bound, star-forming clouds. About 1−2% of the jet kinetic energy is required to power these motions. Resolved star-formation rate surface densities derived from Galaxy Evolution Explorer and Wide-Field Infrared Survey Explorer fall by factors of 30−70 short of expectations from the standard Kennicutt–Schmidt law of star-forming galaxies, and near gas-rich early-type galaxies with signatures of star formation that are lowered by jet feedback. We argue that radio Active Galactic Nucleus (AGN) feedback is the only plausible mechanism to explain the low star-formation rates in this galaxy. Previous authors have already noted that the X-ray halo of J2345−0449 implies a baryon fraction that is close to the cosmic average, which is very high for a galaxy. We contrast this finding with other, equally massive, and equally baryon-rich spiral galaxies without prominent radio sources. Most of the baryons in these galaxies are in stars, not in the halos. We also discuss the implications of our results for our general understanding of AGN feedback in massive galaxies.