Relativistic jets are observed from all accreting compact objects throughout the visible Universe. These jets have a profound impact on their surroundings, yet their launch mechanism remains unknown. For accreting neutron stars, jet speeds can reveal the dominant launching mechanism, showing whether the jets are powered by magnetic fields anchored in the accretion flow or in the star itself. These objects can display bright explosions on their surface due to unstable thermonuclear burning of recently accreted material, called type-I X-ray bursts. The seconds to minutes long X-ray bursts greatly impact the accretion flow, altering the properties of both the disk and corona. Here, I will present an intensive X-ray and radio monitoring program focused on two known bursting neutron star X-ray binaries, aiming to detect the impact that type I X-ray bursts may have on the emitted jets. Remarkably, we discovered a clear radio enhancement in the minutes immediately after each X-ray burst, lasting tens of minutes. The ongoing presence of the jet suggests that the magnetic field structure in the accretion flow collapses more slowly than the gas, providing crucial constraints for magnetohydrodynamics calculations. Importantly, the jet flares allow us to robustly measure the speed of the neutron star's jet, finding them to be much slower than those from black holes at similar luminosities. This discovery provides a powerful and repeatable new tool in which we can determine the role that individual system properties have on the jet speed, revealing the dominant jet launching mechanism.
https://www.nature.com/articles/s41586-024-07133-5
16/04/2024
Speaker: Thomas Russell (INAF - IASF Palermo)
Tuesday 16 April 2024, 11:30 AM
Connect to the Google Meet room at the following link: meet.google.com/msi-nsxv-wra