A high-resolution radio study of the L1551 IRS 5 and L1551 NE jets
A high-resolution radio study of the L1551 IRS 5 and L1551 NE jets
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L1551 IRS 5 和 L1551 NE 喷气机的高分辨率无线电研究
DOI：
10.1051/0004-6361/202346737
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发表时间：
2023
影响因子：
6.5
通讯作者：
Feeney-Johansson A
中科院分区：
文献类型：
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作者：
Feeney-Johansson A
利用e-Merlin和Karl G.Jansky超大型阵列的观测，加上阿塔卡马大毫米/亚毫米阵列的档案数据，我们获得了两个双星YSO的高分辨率射电图像：L1551IRS5和L1551NE，覆盖从5到336千兆赫的广泛频率范围，并在仅∼15 Au的尺度上分辨射电喷流的发射。通过将这些观测结果与前一个时期的观测结果进行比较，结果表明，这些源的喷流的自由-自由辐射具有高度的变异性。特别是L1551IRS5的北部分量，其通量密度的一个因子∼5显著降低，表明该源的自由辐射几乎消失了。通过对源的谱进行拟合，得到了喷流的电离质量损失率，结果表明，在∼20年的时间尺度上，存在高达∼6倍的显著变化。利用辐射传输模式，我们还获得了L1551IRS5南分量急流的模式图像，以帮助研究电离高密度急流的内部区域。这些发现有利于从非常小的最里面区域发射的X-WIND模型。
Using observations with e-MERLIN and theKarl G. JanskyVery Large Array (VLA), together with archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), we obtain high-resolution radio images of two binary YSOs: L1551 IRS 5 and L1551 NE, covering a wide range of frequencies from 5 to 336 GHz, and resolving emission from the radio jet on scales of only ∼15 au. By comparing these observations to those from a previous epoch, it is shown that there is a high degree of variability in the free-free emission from the jets of these sources. In particular, the northern component of L1551 IRS 5 shows a remarkable decline in flux density of a factor of ∼5, suggesting that the free-free emission of this source has almost disappeared. By fitting the spectra of the sources, the ionised mass-loss rates of the jets were derived and it was shown that there is significant variability of up to a factor of ∼6 on timescales of ∼20 years. Using radiative transfer modelling, we also obtained a model image for the jet of the southern component of L1551 IRS 5 to help study the inner region of the ionised high-density jet. The findings favour the X-wind model launched from a very small innermost region.