Final Report Summary - TRANSIENT-SKY (Transient-Sky)
Astronomical transients provide a unique opportunity for probing fundamental physics via the study of both spectral and temporal domains. Transient sources are often accompanied with collimated outflows, namely jets. The ultimate scientific goal of this proposal is to revolutionize our understanding of the transient sky by investigating the spectral, temporal, radiative and some other signatures (such as polarization, neutrinos) expected from collimated outflows, i.e. jets from transient sources, and their connection to the inflow (accreting material). The project focuses on three key questions: (I) where and how are jets launched, accelerated and collimated? (II) What are the composition, magnetization and kinetic and radiative power of jets, and how are these related to the properties of the accretion disks? (III) What are the internal dynamics and physical conditions inside transient jets? Which source fulfills the conditions that enable the acceleration of cosmic rays to ultra-high energies?
The objectives have been tackled with a multi-disciplinary approach, working simultaneously on both observations and theory, in order to maximize the scientific exploitation of the method. The project evolved smoothly and very successfully. The PI of the project was hired with a permanent position at the host institution. Two Ph.D. students were hired to work on this project; each one had an independent task that addressed one of the key questions outlines above. The first student, Mr. M. O’Riordan combines radiative calculations with dynamical general-relativistic magneto-hydrodynamics (GR-MHD) code, to calculate unique signature that emerges from launching of jets. For this task, this student worked in close collaboration with Prof. J. McKinney (UMD), who wrote the GR-MHD code HARM. As a result of this collaboration, we published 4 papers in the Astrophysical Journal. The second student, Mr. D. Riordan is working on a novel model of particle acceleration in shock waves. The results of his work on the validity of the popular “Bohm diffusion” are in final stages of preparation for publication. In addition, two summer students were hired to work on a data analysis task that is part of this project as well. The outcome of their work was also published. A third student worked on a different aspect of this project in his final year project, whose results were also published earlier this year.
Several international collaborators have been invited to work with the team on the various aspects of the projects. In addition to guiding the students, and in collaboration with the international visitors, the P.I. worked on including radiative calculations in models of magnetic reconnection, and continue his fruitful collaborations on analyzing data (mainly of gamma-ray bursts [GRBs], but also on X-ray binaries) and finding novel ways of interpreting it. Overall, I published 22 refereed journal papers, two review article, a book chapter and eleven conference proceedings, all treat subjects that are part of this proposal. Additional 4 publications are in final stages of preparation.
The objectives have been tackled with a multi-disciplinary approach, working simultaneously on both observations and theory, in order to maximize the scientific exploitation of the method. The project evolved smoothly and very successfully. The PI of the project was hired with a permanent position at the host institution. Two Ph.D. students were hired to work on this project; each one had an independent task that addressed one of the key questions outlines above. The first student, Mr. M. O’Riordan combines radiative calculations with dynamical general-relativistic magneto-hydrodynamics (GR-MHD) code, to calculate unique signature that emerges from launching of jets. For this task, this student worked in close collaboration with Prof. J. McKinney (UMD), who wrote the GR-MHD code HARM. As a result of this collaboration, we published 4 papers in the Astrophysical Journal. The second student, Mr. D. Riordan is working on a novel model of particle acceleration in shock waves. The results of his work on the validity of the popular “Bohm diffusion” are in final stages of preparation for publication. In addition, two summer students were hired to work on a data analysis task that is part of this project as well. The outcome of their work was also published. A third student worked on a different aspect of this project in his final year project, whose results were also published earlier this year.
Several international collaborators have been invited to work with the team on the various aspects of the projects. In addition to guiding the students, and in collaboration with the international visitors, the P.I. worked on including radiative calculations in models of magnetic reconnection, and continue his fruitful collaborations on analyzing data (mainly of gamma-ray bursts [GRBs], but also on X-ray binaries) and finding novel ways of interpreting it. Overall, I published 22 refereed journal papers, two review article, a book chapter and eleven conference proceedings, all treat subjects that are part of this proposal. Additional 4 publications are in final stages of preparation.