论文标题
通过突破性收听，对外乳外发射器的限制
Constraints on extragalactic transmitters via Breakthrough Listen
论文作者
论文摘要
突破性的聆听计划以银河系的方式开始了对附近恒星的全面调查，该调查优于以前的努力，这是由广泛的不同指标所衡量的。 SETI调查传统上忽略了这样一个事实，即除前景目标星外，它们对许多背景对象敏感。为了更好地欣赏和利用视野中的伴乳外物体的存在，采用Aladin Sky Atlas和Ned进行了对外层次物体进行基本的人口普查，这些物体在100 m GreenBank望远镜观察1.1-1.9 GHz时偶然观察到。对于469个目标场（假设径向视野为4.2弧形），NED确定了总计143024个外层状物体，包括各种天体物理exotica，例如，例如。各种类型的AGN，射电星系，相互作用的星系和一个已确认的重力透镜系统。确定了附近的几个星系，星系组和星系簇，允许SETI调查探测的参数空间显着扩展。假设它遵循一个简单的功率定律，并限制了与这些庞大的恒星系统相关的非常强大的外星发射器的限制，也确定了潜在外星发射器的亮度功能的约束。已经证明，最近的突破性聆听计划，以及实际上许多以前的SETI无线电调查，对遥远宇宙中外星智能的普遍性更为强大，而不是经常被完全欣赏。
The Breakthrough Listen Initiative has embarked on a comprehensive SETI survey of nearby stars in the Milky Way that is vastly superior to previous efforts as measured by a wide range of different metrics. SETI surveys traditionally ignore the fact that they are sensitive to many background objects, in addition to the foreground target star. In order to better appreciate and exploit the presence of extragalactic objects in the field of view, the Aladin sky atlas and NED were employed to make a rudimentary census of extragalactic objects that were serendipitously observed with the 100-m Greenbank telescope observing at 1.1-1.9 GHz. For 469 target fields (assuming a FWHM radial field-of-view of 4.2 arcminutes), NED identified a grand total of 143024 extragalactic objects, including various astrophysical exotica e.g. AGN of various types, radio galaxies, interacting galaxies, and one confirmed gravitational lens system. Several nearby galaxies, galaxy groups and galaxy clusters are identified, permitting the parameter space probed by SETI surveys to be significantly extended. Constraints are placed on the luminosity function of potential extraterrestrial transmitters assuming it follows a simple power law and limits on the prevalence of very powerful extraterrestrial transmitters associated with these vast stellar systems are also determined. It is demonstrated that the recent Breakthrough Listen Initiative, and indeed many previous SETI radio surveys, place stronger limits on the prevalence of extraterrestrial intelligence in the distant Universe than is often fully appreciated.
