Speaker: Sebastian Heinz, University of Wisconsin-Madison
Abstract: Neutron stars are nature's strongest magnets. At birth their fields are thought to exceed 1e8 Tesla and can reach up to 1e11 Tesla. Over time, these strong fields are believed to decay, but this process is expected to take millions of years. When a neutron star is born in a supernova explosion, it may stay bound to a stellar companion it was in orbit with before. In such a case, the companion can transfer mass to the neutron star and make it shine - we call this an X-ray binary. The nature of the accretion transport of matter can tell us a lot about the properties of a neutron star. For example, we can use X-ray binaries to probe whether the simple picture of young strong magnetized and old weakly magnetized neutron stars hold in nature. I will present results from an ongoing study of the neutron star X-ray binary Circinus X-1 that solve a number of outstanding puzzles about this source and show that even young neutron stars can be weakly magnetized.