Advancing space-based gravitational wave astronomy: Rapid parameter estimation via normalizing flows

Gravitational wave(GW) astronomy is witnessing a transformative shift from terrestrial to space-based detection, with missions like Taiji at the forefront. While the transition brings unprecedented opportunities for exploring massive black hole binaries(MBHBs), it also imposes complex challenges in data analysis, particularly in parameter estimation amidst confusion noise.Addressing this gap, we utilize scalable normalizing flow models to achieve rapid and accurate inference within the Taiji environment. Innovatively, our approach simplifies the data's complexity, employs a transformation mapping to overcome the year-period time-dependent response function, and unveils additional multimodality in the arrival time parameter. Our method estimates MBHBs several orders of magnitude faster than conventional techniques, maintaining high accuracy even in complex backgrounds. These findings significantly enhance the efficiency of GW data analysis, paving the way for rapid detection and alerting systems and enriching our ability to explore the universe through space-based GW observation.

Exploring the nature of black hole and gravity with an imminent merging binary of supermassive black holes

A supermassive binary black-hole candidate SDSS J1430+2303 reported recently motivates us to investigate an imminent binary of supermassive black holes as potential gravitational wave source, and the radiated gravitational waves at the end of the merger are shown to be in the band of space-borne detectors. We provide a general analysis on the required detecting sensitivity needed for probing such type gravitational wave sources and make a full discussion by considering two typically designed configurations of space-borne antennas. If a source is so close, it is possible to be detected with Taiji pathfinder-plus which is proposed to be an extension for the planned Taiji pathfinder by just adding an additional satellite to the initial two satellites. The gravitational wave detection on such kind of source enables us to explore the properties of supermassive black holes and the nature of gravity.

激光干涉引力波空间阵列核心问题的综合讨论

空间激光干涉引力波探测计划,例如欧洲航天局主导和美国参加的LISA(Laser Interferometer Space Antenna)计划[1]、中国的“太极”计划[2]和“天琴”计划[3]等,瞄准中低频段(0.1mHz^lHz)的引力波波源.这个频段的引力波事件被认为具有更重要的天文学、宇宙学以及物理学意义[4-6],其典型的波源包括超大(和中等)质量黑洞双星的并合、极端(和中等)质量比黑洞双星的绕转、银河系内数以百万计的致密双星系统以及随机引力波背景等.

Research on Telescope TTL Coupling Noise in Intersatellite Laser Interferometry

The detection mission of gravitational waves in space is that the accuracy of the long-baseline intersatellite laser interferometry on the million-kilometer order needs to reach the order of 8 pm/Hz.Among all noise sources that affect the interferometry accuracy,tilt-to-length(TTL)coupling noise is the second largest source of noise after shot noise.This paper focuses on studying the contribution of TTL coupling noise of the telescope system in the intersatellite scientific interferometer.By referring to the laser interferometer space antenna(LISA)’s noise budget,TTL coupling noise is required to be within±25μm/rad(±300μrad).Therefore,this paper focuses on studying both the mechanism of TTL coupling noise due to the noise sources of the telescope and the method of suppressing the TTL noise,which can lay a foundation for noise distribution and the development of engineering prototypes in subsequent tasks.