Double Neutron Stars Formed in Globular Clusters: Simulating an Evolutionary Route
Abstract
As extremely dense objects generating intense gravitational fields, double neutron star (DNS) systems are integral to many tests of general relativity. While their orbital precessions have been used as a direct strong field test, they can also be used more indirectly as probes for gravitational waves, and tests of well timed pulsar systems could eventually lead to direct observations of gravitational waves from distant supermassive black hole binaries. Even so, very few DNS systems are known, totalling only 19 systems out of nearly 3000 known pulsars. While future surveys will almost certainly reveal more systems of this nature, optimizing these surveys using theoretical information on the evolutionary paths of DNS systems could greatly expedite the process. One possible formation route is through interactions of neutron stars with main sequence stars in globular clusters. As these stars orbit, the neutron star accretes material and angular momentum from its main sequence companion. This increases the neutron star rotation, sometimes up to millisecond periods, and potentially causes its companion to undergo a supernova explosion and collapse into a neutron star. The velocity kick given to the system by the second companion's supernova could jettison the system out of the cluster, leaving it with a small final velocity as it slowly begins to fall into a path set by the gravitational potential of the galaxy. We modeled a population of DNS systems of this nature, evolving their spin and trajectory forward from formation to the present day. By running simulated surveys on these systems and comparing the resulting population to the known population of DNS systems using Kolmogorov Smirnov tests, we draw conclusions about the possibility of globular clusters serving as birth locations for DNS systems.
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23510211C