论文标题
太阳系尺度的干涉法可以在快速无线电爆发上以次级精度测量宇宙距离
Solar System-scale interferometry on fast radio bursts could measure cosmic distances with sub-percent precision
论文作者
论文摘要
距离d处的源的光在探测器时会在100个AU分离的探测器中，由于波前的曲率，由于波兰的曲率，该nanoseconds差异120（d/100 mpc）^{ - 1}纳米环。在Gigahertz频率下，可以确定到达时间差要比干涉测量法更好。如果探测器的时空位置已知几厘米，可以与很长的基线干涉仪基准和全球导航卫星系统（GNSS）地理位置的准确性相媲美，则纳米环境将允许竞争性的宇宙学约束。我们表明，在> 10 au的太阳半径处的四探测器星座可以测量具有次级精度的单个来源的距离，因此，宇宙学参数（例如，诸如Hubble常数）的距离。精度随着基线长度四次增加。 FRB是唯一已知的亮点外射线源，具有足够的点状。银河散射限制了<3 GHz的时序精度，而在较高频率下，精度是通过去除分散体设置的。此外，对于大于100 au的基线，夏皮罗时间延迟限制了精度，但是可以用另外两个探测器清洁其效果。可以通过每周类似GNSS样的三材料来纠正探测器位置的加速度（从太阳辐照度，灰尘碰撞和气体阻力的变化）的加速度。小行星的重力加速发生在更长的时间尺度上，因此具有精确加速度计的设置并校准了远处FRB的检测器位置也可能就足够了。所提出的干涉仪还将解决银河脉冲星的无线电发射区域，限制外部太阳系中的质量分布，并将有趣的敏感性达到〜0.01-100 micro-Hz引力波。
The light from a source at a distance d will arrive at detectors separated by 100 AU at times that differ by as much as 120 (d/100 Mpc)^{-1} nanoseconds because of the curvature of the wavefront. At gigahertz frequencies, the arrival time difference can be determined to better than a nanosecond with interferometry. If the space-time positions of the detectors are known to a few centimeters, comparable to the accuracy to which very long baseline interferometry baselines and global navigation satellite systems (GNSS) geolocations are constrained, nanosecond timing would allow competitive cosmological constraints. We show that a four-detector constellation at Solar radii of >10 AU could measure distances to individual sources with sub-percent precision and, hence, cosmological parameters such as the Hubble constant to this precision. The precision increases quadratically with baseline length. FRBs are the only known bright extragalactic radio source that are sufficiently point-like. Galactic scattering limits the timing precision at <3 GHz, whereas at higher frequencies the precision is set by removing dispersion. Furthermore, for baselines greater than 100 AU, Shapiro time delays limit the precision, but their effect can be cleaned with two additional detectors. Accelerations that result in ~1 cm uncertainty in detector positions (from variations in the Sun's irradiance, dust collisions and gaseous drag) could be corrected for with weekly GNSS-like trilaterations. Gravitational accelerations from asteroids occur over longer timescales, and so a setup with a precise accelerometer and calibrating the detector positions off of distant FRBs may also be sufficient. The proposed interferometer would also resolve the radio emission region of Galactic pulsars, constrain the mass distribution in the outer Solar System, and reach interesting sensitivities to ~0.01-100 micro-Hz gravitational waves.
