WoU-MMA: Linear and Circular Polarization as a Probe of the Relativistic Jets of Blazars

该项目将研究宇宙中最明亮、寿命最长的天体--blazar。来自恒星的物质和星际气体云坠落到一些星系中心的超大质量黑洞中，为耀星提供了能量。下落的物质和黑洞的自转产生了高能粒子和磁场的喷射，它们以接近光速的速度向外流动。该项目将有助于解释(1)喷流是如何形成和加速的，(2)辐射粒子是主要是“正常”物质还是等量的物质和反物质，以及(3)喷流中包含了多少能量。该项目将利用不同波长的多信使观测来探测近40个blazar喷流中的物理条件。该项目将提高我们对宇宙中极端条件的理解。它还将通过在图书馆和高中发表演讲来促进公众对科学的欣赏。它还将通过以下方式促进对学生的科学培训：美国原住民学生参观波士顿大学的珀金斯望远镜，本科生参与数据分析和解释，提供由PI编写的关于银河系外天文学和宇宙学的免费教科书，以及为大学一级的天文学入门课程开发练习。该奖项致力于解决/推进宇宙之窗的宏大构想的目标。Blazar是由磁化的高能等离子体的相对论喷流形成的星系核，这些高能等离子体是由超大质量黑洞主动吸积而产生的。这项研究将提供描述blazar喷流中磁场模式所需的详细信息，这与喷流的动力学直接相关。这将通过在43 GHz和86 GHz的微波频率下测量极高分辨率图像中的blazar喷流的偏振，以及在可见光和X射线频率下测量整个喷流的偏振来实现。对从毫米波到X射线波长的blazar的线性偏振的交叉比较将跟踪从大约10秒到亚秒尺度的磁场模式，并测试关于导致blazar极端亮度和可变性的粒子加速过程的假设。将43 GHz和86 GHz的线极化和圆极化与计算机模拟进行比较，将有助于确定反物质(正电子)的相对数量和喷流的总动能，这控制了喷流对其银河系环境的影响。反物质的数量决定了喷流中的粒子是在喷流底部靠近黑洞的地方产生的，还是从喷流外部注入的。该项目将培训STEM本科生进行科学数据分析和解释，提供由PI编写的关于河外天文学和宇宙学的免费教科书，并为大学级别的天文学入门课程开发练习。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will study blazars, the most luminous long-lived objects in the universe. Blazars are powered by matter from stars and interstellar gas clouds falling toward super-massive black holes at the centers of some galaxies. The infalling matter and rotation of the black hole create jets of high-energy particles and magnetic fields that flow outward at nearly the speed of light. The project will help to explain (1) how the jets are formed and accelerated, (2) whether the radiating particles are mostly "normal" matter or equal amounts of matter and anti-matter, and (3) how much energy is contained in the jets. The project will utilize multi-messenger observations at different wavelengths to probe the physical conditions in the jets of nearly 40 blazars. The project will improve our understanding of extreme conditions in the universe. It also will contribute to public appreciation of science through presentations at libraries and high schools. It will also advance the scientific training of students through visits of Native-American school students to Boston University’s Perkins Telescope, involvement of undergraduate students in the data analysis and interpretation, availability of a free textbook on extragalactic astronomy and cosmology written by the PI, and development of an exercise for college-level introductory astronomy classes. This award addresses/advances the goals of the Windows on the Universe Big Idea. Blazars are galactic nuclei with relativistic jets of magnetized, high-energy plasma produced by actively accreting super-massive black holes. The study will provide detailed information needed to characterize the magnetic field pattern in blazar jets, which is directly related to the dynamics of the jets. This will be accomplished by measuring the polarization of blazar jets both in extremely high-resolution images at microwave frequencies of 43 and 86 GHz, and from the entire jet at visible and X-ray frequencies. Cross-comparison of the linear polarization of blazars from millimeter-wave to X-ray wavelengths will trace the magnetic field pattern from about 10 parsecs to sub-parsec scales and test hypotheses regarding the particle acceleration processes that cause the extreme luminosities and variability of blazars. Comparison of the 43 and 86 GHz linear and circular polarization with computer simulations will facilitate a determination of both the relative amount of anti-matter (positrons) and the total kinetic power of the jets, which controls the impact that the jet can have on its galactic environment. The amount of anti-matter determines whether the particles in the jet are produced at the base of the jet near the black hole or injected from outside the jet. The project will train undergraduate STEM students in scientific data analysis and interpretation, make available a free textbook on extragalactic astronomy and cosmology written by the PI, and develop an exercise for college-level introductory astronomy classes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.