A Foundation for Gravitational-Wave Population Inference within the LISA Global Fit
Vanderbilt University(范德堡大学);Fisk University(菲斯克大学);Northwestern University(西北大学);Monash University(蒙纳士大学);University of Toronto(多伦多大学);NASA Marshall Space Flight Center(美国国家航空航天局马歇尔太空飞行中心);Universities Space Research Association(大学空间研究协会);University of Alabama in Huntsville(亨茨维尔阿拉巴马大学)
Alexander W. Criswell, Sharan Banagiri, Vera Delfavero, Maria Jose Bustamante-Rosell, Stephen R. Taylor, Robert Rosati
Population inference in gravitational-wave astronomy allows us to connect individual detections to the astrophysics of compact objects and their environments. Current approaches employed for population inference with LIGO-Virgo-KAGRA data approximate evaluation of the hierarchical population likelihood via post-processing of individual-event posteriors. However, the case of the Laser Interferometer Space Antenna (LISA) will be more complex for two main reasons: the transdimensional "global fit" approach to LISA data analysis which models all signals and noise simultaneously, and the presence of both individually-resolved signals and the unresolved stochastic ``Galactic foreground" arising from the Galactic binary population, which induces a circular dependence between the resolved and unresolved systems and our ability to detect the former. These challenges are not without opportunity; LISA's data will contain every mHz compact binary in the Milky Way -- either individually or within the Galactic foreground -- with great potential for Galactic and stellar astrophysics. We therefore propose an alternative approach: direct evaluation of the full hierarchical population likelihood within the LISA global fit. We develop a statistical formalism for joint inference of individually-resolved gravitational-wave sources, an unresolved stochastic foreground, and a shared, underlying astrophysical population, present PELARGIR, a prototype GPU-accelerated population inference module for the LISA global fit, demonstrate the formalism and PELARGIR via a toy model analysis, and lay out a roadmap towards an astrophysically-motivated LISA global fit with embedded population inference. While we apply the formalism here to the population of LISA Galactic binaries, it is applicable across the gravitational-wave spectrum with use cases in pulsar timing and next-generation terrestrial observatories.
Università di Milano-Bicocca(米兰比可卡大学);INFN, Sezione di Milano-Bicocca(意大利国家核物理研究所米兰比可卡分部);Max Planck Institute for Gravitational Physics (Albert Einstein Institute)(马克斯·普朗克引力物理研究所(爱因斯坦研究所))
Inferring the population properties of galactic binaries from LISA's stochastic foreground
Universitá degli Studi di Milano-Bicocca(米兰-比可卡大学);INFN, Sezione di Milano-Bicocca(意大利国家核物理研究所米兰-比可卡分部);Max Planck Institute for Gravitational Physics (Albert Einstein Institute)(马克斯·普朗克引力物理研究所(爱因斯坦研究所));Aristotle University of Thessaloniki(萨洛尼加亚里士多德大学);Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens(雅典国立天文台天文学、天体物理学、空间应用与遥感研究所)
PTA-Compatible Domain Walls at LISA and Taiji: Bayesian Reconstruction and Multiband Inference
Nanjing Normal University(南京师范大学);Scuola Superiore Meridionale, Università degli studi di Napoli “Federico II”(那不勒斯费德里科二世大学南方高等学院);INFN - Sezione di Napoli(意大利国家核物理研究所那不勒斯分部)