GMRT detections of low-mass young stars at 323 and 608 MHz
GMRT detections of low-mass young stars at 323 and 608 MHz
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323 和 608 MHz 低质量年轻恒星的 GMRT 探测
DOI：
10.1093/mnras/stw708
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发表时间：
2016
影响因子：
4.8
通讯作者：
Ainsworth R
中科院分区：
文献类型：
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作者：
Ainsworth R
我们目前的结果进行了一个探路者项目的巨型米波射电望远镜（GMRT），以调查在低无线电频率的原恒星系统。这些研究的目标是找到自由-自由光谱中光学深度等于1的突破点，以限制这些系统的物理参数，例如这些年轻恒星周围电离气体的质量。我们检测所有三个目标源，L1551 IRS 5（I类），T Tau和DG Tau（II类），频率为323和608 MHz（波长分别为90和50 cm）。这是第一次在如此低的频率下探测到低质量的年轻恒星。我们结合联合收割机这些新的GMRT数据与档案信息，以构建每个系统的光谱能量分布，并找到一个延续的光学薄自由自由光谱外推从更高的无线电频率为323 MHz的每个目标。我们用这些结果来限制与这些年轻的系统上的尺度为1000 Au的电离气体和平均电子密度的质量。未来的观测需要在较低频率下具有更高的角分辨率，以进一步约束这些物理参数。
We present the results of a pathfinder project conducted with the Giant Metrewave Radio Telescope (GMRT) to investigate protostellar systems at low radio frequencies. The goal of these investigations is to locate the break in the free–free spectrum where the optical depth equals unity in order to constrain physical parameters of these systems, such as the mass of the ionized gas surrounding these young stars. We detect all three target sources, L1551 IRS 5 (Class I), T Tau and DG Tau (Class II), at frequencies 323 and 608 MHz (wavelengths 90 and 50 cm, respectively). These are the first detections of low-mass young stellar objects at such low frequencies. We combine these new GMRT data with archival information to construct the spectral energy distributions for each system and find a continuation of the optically thin free–free spectra extrapolated from higher radio frequencies to 323 MHz for each target. We use these results to place limits on the masses of the ionized gas and average electron densities associated with these young systems on scales of ∼1000 au. Future observations with higher angular resolution at lower frequencies are required to constrain these physical parameters further.