论文标题
Magnetar XTE J1810-197：平均无线电发射的光谱时间演变
Magnetar XTE J1810-197: Spectro-temporal evolution of average radio emission
论文作者
论文摘要
We present the long-term spectro-temporal evolution of the average radio emission properties of the magnetar XTE J1810-197 (PSR J1809-1943) following its most recent outburst in late 2018. We report the results from two and a half years of monitoring campaign with the upgraded Giant Metrewave Radio Telescope carried out over the frequency range of 300 - 1450 MHz.我们的观察结果表明，平均轮廓宽度，磁通密度，光谱指数和宽带光谱形状的时间变化很有趣。尽管在后期时期的平均轮廓宽度似乎逐渐减小，但通量密度在我们的监测过程中显示出多次无线电重新亮相。我们的系统监测观察结果表明，随着时间的流逝，无线电光谱从类似磁力的频谱变为较高的脉冲样光谱。一个更详细的分析表明，无线电频谱的营业率有一个营业额，并且随着时间的推移，这种营业额向较低的频率转移。我们介绍了分析的细节，导致这些结果，并在磁场无线电发射机制的背景下讨论我们的发现以及中间介质的潜在表现。我们还简要讨论了不断发展的光谱转移是否可能是无线电磁铁的无处不在特性。
We present the long-term spectro-temporal evolution of the average radio emission properties of the magnetar XTE J1810-197 (PSR J1809-1943) following its most recent outburst in late 2018. We report the results from two and a half years of monitoring campaign with the upgraded Giant Metrewave Radio Telescope carried out over the frequency range of 300 - 1450 MHz. Our observations show intriguing time variability in the average profile width, flux density, spectral index and the broadband spectral shape. While the average profile width appears to gradually decrease at later epochs, the flux density shows multiple episodes of radio re-brightening over the course of our monitoring. Our systematic monitoring observations reveal that the radio spectrum has steepened over time, resulting in evolution from a magnetar-like to a more pulsar-like spectrum. A more detailed analysis reveals that the radio spectrum has a turnover, and this turnover shifts towards lower frequencies with time. We present the details of our analysis leading to these results, and discuss our findings in the context of magnetar radio emission mechanisms as well as potential manifestations of the intervening medium. We also briefly discuss whether an evolving spectral turnover could be an ubiquitous property of radio magnetars.
