论文标题
在射手座B2中发现非量子的氨气斯
Discovery of non-metastable ammonia masers in Sagittarius B2
论文作者
论文摘要
我们报告了在不可用的反转过渡中发现广泛的maser排放的NH $ _3 $向射手座B2 B2分子云/恒星形成区域建筑群的发现：我们在$ j，k = $（6,3），（7,4），（8,5）和（9,6）和（9,6）和（10,7,7,7,7,7,7）中检测Masers（Masers）。 B2（n），SGR B2（NS）中的NH $ _3 $（6,3）MASER，NH $ _3 $（7,4），（9,6），（9,6）和（10,7）Masers在SGR B2（S）中。使用Karl G. Jansky的高角度分辨率数据，非常大的阵列（JVLA）在A-configuration中，我们识别出18个Maser斑点。九个MASER斑点来自SGR B2（N），一个来自SGR B2（NS），SGR B2（M）的五个，SGR B2（S）中有3个。与我们的effelsberg单盘数据相比，JVLA数据表明没有丢失的通量。我们的JVLA观察结果无法解决所检测到的Maser斑点。亮度温度的下限为$> $ 3000〜K，最高可达几个10 $^5 $ 〜k，表现为线条的Maser性质。鉴于MASERS相对于相邻热分子核的速度差异和/或Uch {\ Scriptsize II}区域，有人认为，所有测得的氨Moser线可能与外流或由Uch {\ Scriptssize II}区域扩展引起的冲击有关。总体而言，SGR B2是独一无二的，因为它使我们能够同时测量许多NH $ _3 $ MASERS，这对于阐明其迄今为止鲜为人知的起源和激发至关重要。
We report the discovery of widespread maser emission in non-metastable inversion transitions of NH$_3$ toward various parts of the Sagittarius B2 molecular cloud/star forming region complex: We detect masers in the $J,K = $ (6,3), (7,4), (8,5), (9,6), and (10,7) transitions toward Sgr B2(M) and Sgr B2(N), an NH$_3$ (6,3) maser in Sgr B2(NS), and NH$_3$ (7,4), (9,6), and (10,7) masers in Sgr B2(S). With the high angular resolution data of the Karl G. Jansky Very Large Array (JVLA) in A-configuration we identify 18 maser spots. Nine maser spots arise from Sgr B2(N), one from Sgr B2(NS), five from Sgr B2(M), and three in Sgr B2(S). Compared to our Effelsberg single dish data, the JVLA data indicate no missing flux. The detected maser spots are not resolved by our JVLA observations. Lower limits to the brightness temperature are $>$3000~K and reach up to several 10$^5$~K, manifesting the lines' maser nature. In view of the masers' velocity differences with respect to adjacent hot molecular cores and/or UCH{\scriptsize II} regions, it is argued that all the measured ammonia maser lines may be associated with shocks caused either by outflows or by the expansion of UCH{\scriptsize II} regions. Overall, Sgr B2 is unique in that it allows us to measure many NH$_3$ masers simultaneously, which may be essential to elucidate their so far poorly understood origin and excitation.
