We have detected a strong deflection of radio waves from the pulsar PSR B0834+06 in scintillation observations. Interference between the undeflected pulsar image and deflected subimages allows single-dish interferometry of the interstellar medium with submilliarcsecond resolution. We infer the presence of scattering structure(s) similar to those that are thought to cause extreme scattering events in quasar flux monitoring programs: size ～0.2 AU (an angular size of 0.1 mas) with an electron overdensity of approx >10~3 compared to the warm ionized medium. The deflectors are nearly stationary in a scattering screen that is thin (approx< 5% of the pulsar-observer distance in extent), is located 70% of the way from the Earth to the pulsar, and has been seen consistently in observations dating back 20 years. The pulsar scans the scattering screen at a velocity of 110 km s~(-1) with a detection radius of 15 mas. Pulsar observations such as these—particularly with a new generation of low-frequency radio telescopes with large collecting areas—hold promise for improving constraints on the poorly understood physical characteristics and space density of the deflecting structures. Such observations may also prove useful in correcting deviations that the deflectors produce in high-precision timing of millisecond pulsars.
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机译：在闪烁观测中，我们已经检测到脉冲星PSR B0834 + 06产生的无线电波强烈偏转。未偏转的脉冲星图像和偏转的子图像之间的干涉允许以亚毫秒级的分辨率对星际介质进行单碟干涉测量。我们推断存在类似于在类星通量监测程序中会引起极端散射事件的散射结构：大小约为0.2 AU（角大小为0.1 mas），电子超密度约为10〜3到温暖的电离介质。偏转器在薄的散射屏中几乎是静止的（大约小于脉冲星与观察者距离的5％），位于从地球到脉冲星的距离的70％处，并且可以追溯到早先的观测中20年。脉冲星以110 km s〜（-1）的速度扫描散射屏，探测半径为15 mas。诸如此类的脉冲星观测（尤其是在具有大收集面积的新一代低频射电望远镜中）有望改善对人们不了解的偏转结构的物理特性和空间密度的约束。这样的观察也可能被证明对校正偏转器在毫秒脉冲星的高精度定时中产生的偏差有用。
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