Exploring the gamma-ray emission processes in accreting X-ray pulsars

• Applicant: Dr. Lorenzo Ducci
• Subject Area: Astrophysics and Astronomy
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 549824807

There is a group of approximately 11 accreting neutron stars (or black holes) in X-ray binaries (XRBs) that has recently been discovered, which surprisingly emits gamma-rays and whose production mechanism is still unknown and poorly explored. The number of gamma-ray detections in this type of source is constantly growing, and in the coming years, it is expected to increase further thanks to the advent of new facilities that will operate in the gamma-ray band, having better sensitivity and angular resolution than the current ones. The study of gamma-ray emission from accreting XRBs is of fundamental importance because it provides crucial insights into the physical processes involving relativistic particles and their interaction with energetic photons in environments characterized by high magnetic field and strong gravity. Additionally, sizing up this population is crucial to estimate their contribution to the total gamma-ray emission from our Galaxy. The aim of this project is to provide theoretical models to understand the mechanism that produces gamma-ray emission in these sources and its properties, such as intensity, spectral shape, and temporal variability. This approach will also provide tools to estimate the size of the population of accreting XRBs that emit gamma rays. The developed models will also be able to predict the transient emission of neutrinos from these sources. The results of this work will consist of theoretical models and grids of ready-to-use solutions designed to be compared to observational properties of XRBs in gamma-rays. The tools and results provided by this work will be of fundamental importance, especially in view of the start of scientific operations of the Cherenkov Telescope Array Observatory and other facilities that in the near future will observe the Universe in gamma-rays and neutrinos, with unprecedented sensitivity

• DFG Programme: Research Grants
• International Connection: Italy
• Cooperation Partners: Patrizia Romano, Ph.D.; Stefano Vercellone, Ph.D.