The magnetic field and turbulence of the cosmic web measured using a brilliant fast radio burst
The magnetic field and turbulence of the cosmic web measured using a brilliant fast radio burst
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DOI：
10.1126/science.aaf6807
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发表时间：
2016-11
期刊：
影响因子：
56.9
通讯作者：
V. Ravi;R. Shannon;M. Bailes;K. Bannister;S. Bhandari;N. Bhat;S. Burke-Spolaor;M. Caleb;
中科院分区：
文献类型：
--
作者：
V. Ravi;R. Shannon;M. Bailes;K. Bannister;S. Bhandari;N. Bhat;S. Burke-Spolaor;M. Caleb;
探测星系际磁场快速射电爆发（FRB）是天文无线电波的强大闪光，持续时间只有几毫秒，其起源存在争议。拉维等人。发现了一个异常明亮的快速射电暴（参见 Kaspi 的透视图）。这使他们能够测量信号的偏振如何随波长变化（法拉第旋转）。将其与不同波长的闪光的时间延迟相结合，揭示了沿视线的平均磁场。假设快速射电暴起源于同位星系，其结果会限制星系间磁场，并将为星系形成和宇宙学模型提供信息。科学，本期第 14 页。 1249；另见 p. 1230 快速射电爆发使天文学家能够限制星系际磁场。快速射电爆发（FRB）是持续时间为毫秒的事件，被认为起源于银河系之外。爆发源周围的不确定性及其通过介入等离子体的传播限制了它们作为宇宙学探测器的用途。我们报告了一种轻度分散（分散测量为每立方厘米 266.5 ± 0.1 秒差距）、异常强烈（120 ± 30 janskys）、线性偏振、闪烁爆发（FRB 150807），我们直接将其定位于 9 方弧分。基于低法拉第旋转（每平方米 12.0 ± 0.7 弧度），我们推断环爆发等离子体中的磁化强度可以忽略不计，并将沿该视线的宇宙网的净磁化强度限制为 <21 纳高斯，与视线平行。爆发性闪烁表明电离星际介质中存在微弱的湍流。
Probing the intergalactic magnetic field Fast radio bursts (FRBs) are powerful flashes of astronomical radio waves that last just milliseconds and whose origins are a matter of debate. Ravi et al. discovered a FRB that is exceptionally bright (see the Perspective by Kaspi). This allowed them to measure how the polarization of the signal varies with wavelength (Faraday rotation). Combining this with the time delay of the flash at different wavelengths revealed the mean magnetic field along the line of sight. Assuming that the FRB originates from a colocated galaxy, the results constrain the intergalactic magnetic field and will inform models of galaxy formation and cosmology. Science, this issue p. 1249; see also p. 1230 A fast radio burst allows astronomers to constrain the intergalactic magnetic field. Fast radio bursts (FRBs) are millisecond-duration events thought to originate beyond the Milky Way galaxy. Uncertainty surrounding the burst sources, and their propagation through intervening plasma, has limited their use as cosmological probes. We report on a mildly dispersed (dispersion measure 266.5 ± 0.1 parsecs per cubic centimeter), exceptionally intense (120 ± 30 janskys), linearly polarized, scintillating burst (FRB 150807) that we directly localize to 9 square arc minutes. On the basis of a low Faraday rotation (12.0 ± 0.7 radians per square meter), we infer negligible magnetization in the circum-burst plasma and constrain the net magnetization of the cosmic web along this sightline to <21 nanogauss, parallel to the line-of-sight. The burst scintillation suggests weak turbulence in the ionized intergalactic medium.