Submillimeter H2O Maser in Circinus Galaxy―a New Probe for the Circumnuclear Region of Active Galactic Nuclei
Submillimeter H2O Maser in Circinus Galaxy―a New Probe for the Circumnuclear Region of Active Galactic Nuclei
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圆规座星系亚毫米H2O脉泽——活动星系核核周区的新探测器
DOI：
10.1088/2041-8205/768/2/l38
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Shinji
中科院分区：
文献类型：
--
作者：
Hagiwara;Yoshiaki; Miyoshi;Makoto; Doi;Akihiro; Horiuchi;Shinji
利用阿塔卡马大型毫米波/亚毫米波阵列，我们首次探测到银河系外亚毫米波微波激射器在321千兆赫波段向circirus星系中心（附近的Type 2 Seyfert）过渡。我们发现探测到的321 GHz h2o脉泽的多普勒特征跨越了星系中已知的22 GHz h2o脉泽的光谱中所看到的系统速度。通过比较两个跃迁过程中微波激射器的速度特征，可以推断出321 GHz微波激射器发生在与22 GHz微波激射器相似的区域，其中22 GHz微波激射器的亚秒差尺度分布已经被早期的超长基线干涉测量观测所揭示。在~ 0 farcs 66 （~ 15 pc）的合成波束下，探测到的脉泽特征仍然无法确定，并且在小的不确定度内与321 GHz连续谱峰一致。我们还提出了对星系中最高速度特征（红移高达~ 635 km s−1）的初步探测。如果这个高速特征来自于在这个星系中建立的开普勒旋转盘，它位于半径为~ 0.018 pc （~ 1.2× 10.5史瓦西半径）的地方，它可能探测到离中心发动机最近的分子物质。
We present the first detection of extragalactic submillimeter H 2 O maser in the 321 GHz transition toward the center of Circinus galaxy, the nearby Type 2 Seyfert using the Atacama Large Millimeter/Submillimeter Array. We find that Doppler features of the detected 321 GHz H 2 O maser straddle the systemic velocity of the galaxy as seen in the spectrum of the known 22 GHz H 2 O maser in the galaxy. By comparing the velocities of the maser features in both transitions, it can be deduced that the 321 GHz maser occurs in a region similar to that of the 22 GHz maser, where the sub-parsec-scale distribution of the 22 GHz maser was revealed by earlier very long baseline interferometry observations. The detected maser features remain unresolved at the synthesized beam of∼ 0 farcs 66 (∼ 15 pc) and coincide with the 321 GHz continuum peak within small uncertainties. We also present a tentative detection of the highest velocity feature (redshifts up to∼ 635 km s− 1) in the galaxy. If this high-velocity feature arises from a Keplerian rotating disk well established in this galaxy, it is located at a radius of∼ 0.018 pc (∼ 1.2× 10 5 Schwarzschild radii), which might probe molecular material closest to the central engine.