论文标题
Lofar 144-MHz GW170817的随访观察结果
LOFAR 144-MHz follow-up observations of GW170817
论文作者
论文摘要
我们提出了2017GFO（GW170817的电磁对应物）对2017GFO的低频率随访，这是第一次由高级Ligo-Virgo检测到的二进制中子星合并。通过低频阵列Lofar获得了这些数据，中央频率为144 MHz。当使用Lofar观察时，目标的最大升高仅为13.7度，这使得我们的观察值特别具有挑战性地校准并显着限制了可实现的灵敏度。合并事件发生后的130-138和371-374天的时间尺度，我们分别获得3 $σ$上限的余波组件，分别为6.6和19.5 mjy beam $^{ - 1} $。使用我们的最佳上限和先前发表的同时性高频无线电数据，我们对610和144 MHz之间的无线电光谱的任何潜在陡峭进行了限制：两点光谱指数$α^{610} _ {144} _ {144} \ gtrsim -2.5 $。我们还表明，Lofar可以检测出在更有利的海拔处发生的未来二进制中子星星合并事件的余辉。
We present low-radio-frequency follow-up observations of AT 2017gfo, the electromagnetic counterpart of GW170817, which was the first binary neutron star merger to be detected by Advanced LIGO-Virgo. These data, with a central frequency of 144 MHz, were obtained with LOFAR, the Low-Frequency Array. The maximum elevation of the target is just 13.7 degrees when observed with LOFAR, making our observations particularly challenging to calibrate and significantly limiting the achievable sensitivity. On time-scales of 130-138 and 371-374 days after the merger event, we obtain 3$σ$ upper limits for the afterglow component of 6.6 and 19.5 mJy beam$^{-1}$, respectively. Using our best upper limit and previously published, contemporaneous higher-frequency radio data, we place a limit on any potential steepening of the radio spectrum between 610 and 144 MHz: the two-point spectral index $α^{610}_{144} \gtrsim -2.5$. We also show that LOFAR can detect the afterglows of future binary neutron star merger events occurring at more favourable elevations.
