SUPPRESSION OF STAR FORMATION IN NGC 1266
SUPPRESSION OF STAR FORMATION IN NGC 1266
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DOI：
10.1088/0004-637x/798/1/31
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发表时间：
2014-10
期刊：
影响因子：
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通讯作者：
K. Alatalo;M. Lacy;L. Lanz;T. Bitsakis;P. Appleton;K. Nyland;S. Cales;P. Chang;T. Davis;P. T. de Zeeuw;C. Lonsdale;S. Martín;D. Meier;P. Ogle
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文献类型：
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作者：
K. Alatalo;M. Lacy;L. Lanz;T. Bitsakis;P. Appleton;K. Nyland;S. Cales;P. Chang;T. Davis;P. T. de Zeeuw;C. Lonsdale;S. Martín;D. Meier;P. Ogle
NGC 1266是一个附近的透镜状星系，拥有大量由活动星系核（AGN）的机械能驱动的分子气体外流。据推测，这种外流阻碍了宿主星系中的星星形成（SF），为星系形成过程提供了一种反馈形式。然而，以前的研究表明，只有来自极其罕见的高功率类星体或射电星系的喷流才能对其宿主产生显著的反馈。在这里，我们提出了详细的观察气体和尘埃连续的NGC 1266在毫米波长。我们的观测表明，分子气体在yr−1时被赶出核区域，其中绝大多数无法逃离核。只有2 M yr−1实际上能够逃离星系。大多数残留的分子气体在形成恒星时效率很低。远红外辐射主要由一个超小型（150 pc）源控制，该源可以由活动星系核或超小型星暴提供动力。SF表面密度（SFSFR）与气体表面密度（）的比值表明，如果所有的气体都在形成恒星，SF与正常的恒星形成星系相比被抑制了150倍，如果中心区域由超紧凑的恒星爆发提供动力，则外围（98%）致密分子气体的SF被抑制了150倍。活动星系核驱动的大体积外流可以解释这种极端的抑制，因为它阻碍了通过湍流注入过程形成恒星所必需的碎裂和引力坍缩。这一结果表明，即使是相对常见的低功率活动星系核，当它们的黑洞生长到M-σ关系时，也能够改变它们的宿主星系的演化。
NGC 1266 is a nearby lenticular galaxy that harbors a massive outflow of molecular gas powered by the mechanical energy of an active galactic nucleus (AGN). It has been speculated that such outflows hinder star formation (SF) in their host galaxies, providing a form of feedback to the process of galaxy formation. Previous studies, however, indicated that only jets from extremely rare, high-power quasars or radio galaxies could impart significant feedback on their hosts. Here we present detailed observations of the gas and dust continuum of NGC 1266 at millimeter wavelengths. Our observations show that molecular gas is being driven out of the nuclear region at yr−1, of which the vast majority cannot escape the nucleus. Only 2 M☉ yr−1 is actually capable of escaping the galaxy. Most of the molecular gas that remains is very inefficient at forming stars. The far-infrared emission is dominated by an ultra-compact (≲ 50 pc) source that could either be powered by an AGN or by an ultra-compact starburst. The ratio of the SF surface density (ΣSFR) to the gas surface density () indicates that SF is suppressed by a factor of ≈50 compared to normal star-forming galaxies if all gas is forming stars, and ≈150 for the outskirt (98%) dense molecular gas if the central region is powered by an ultra-compact starburst. The AGN-driven bulk outflow could account for this extreme suppression by hindering the fragmentation and gravitational collapse necessary to form stars through a process of turbulent injection. This result suggests that even relatively common, low-power AGNs are able to alter the evolution of their host galaxies as their black holes grow onto the M–σ relation.