Relativistic jets that move at 0.99 of the speed of light (or even faster) are a central ingredient in many of the most exciting and fascinating astronomical objects. These include gamma-ray bursts, Active galactic nuclei, binary neutron star mergers, Supernovae, and Tidal Disruption events. This project aims to explore the conditions in which such jets are formed and the observational impacts of these jets on their surroundings. The goals of this project is to examine relativistic jets in different configurations and to study different observational aspects that haven't been realized so far. With those, we hope to understand better how relativistic jets are accelerated and, on the other hand, to explore observational signatures of jets that are not directly identified. Along these lines, the project is built on a unique combination of exploration of different features of relativistic jets in different astronomical systems. The research is along the following four main projects: (i) A unique feature of all relativistic jets is that their acceleration (and subsequent deceleration) leads to a unique gravitational waves signal we coined Jet-GWs. These gravitational waves, which are extremely hard to detect, can provide unique information about the engines that power relativistic jets. The project deals with two different aspects of the phenomena: First, constructing a new computational scheme that is capable of calculating the resulting gravitational wave. Second, participating in the design of a Moon-based gravitational radiation detector that will be capable of detecting these Jet-GW signals. (ii) Relativistic jets arise in binary neutron star mergers in particular, the late radio and X-ray observations of the afterglow of the binary merger GW 170817 revealed the existence of such a jet in this world-famous event with the first detection of gravitational waves from a merger by LIGO Virgo this event was followed by more astronomers than any other one so far. The unique observations of GW 170817 revealed a kilonova - the signature of mass ejected from the merger. This mass was composed mostly of rare heavy metals, confirming the idea that mergers are the furnaces in which our universe produces these rare elements, including, for example, gold. Within our project, we explore the propagation of relativistic jets through this matter and the interaction between the two. (iii) Relativistic jets also exist in Supernova. When they emerge from the envelope of the collapsing star, we observe a gamma-ray burst. At times, the jets are choked within the stellar atmosphere and don’t emerge. We explore the conditions for choking and the observational signatures of such choked jets. (iv) A tidal disruption event (TDE) occurs when a star wanders near a supermassive black hole and is shredded to pieces by the enormous gravitational field of the black hole. These events last from a few weeks to a few years. Jets arise in some but not all TDEs. Exploring TDEs, we study the process of jet formation from beginning to end.
