Modeling the Galactic Compact Binary Neutron Star Population and Studying the Double Pulsar System
Abstract
In this dissertation, we estimate the population of different classes of BNS systems that are visible to gravitationalwave observatories. Given that no ultracompact BNS systems have been discovered in pulsar radio surveys, we place a 95\% confidence upper limit of $\sim$850 and $\sim$1100 ultracompact neutron starwhite dwarf and double neutron star (DNS) systems that are beaming towards the Earth, respectively. We show that among all of the current radio pulsar surveys, the ones at the Arecibo radio telescope have the best chance of detecting an ultracompact BNS system. We also show that adopting a survey integration time of $t_{\rm int} \sim 1$~min will maximize the signaltonoise ratio, and thus, the probability of detecting an ultracompact BNS system. Similarly, we use the sample of nine observed DNS systems to derive a Galactic DNS merger rate of $\mathcal{R}_{\rm MW} = 37^{+24}_{11}$~Myr$^{1}$, where the errors represent 90\% confidence intervals. Extrapolating this rate to the observable volume for LIGO, we derive a merger detection rate of $\mathcal{R} = 1.9^{+1.2}_{0.6} \times \left(D_{\rm r}/100 \ \rm Mpc \right)^3 \rm yr^{1}$, where $D_{\rm r}$ is the range distance for LIGO. This rate is consistent with that derived using the DNS mergers observed by LIGO. Finally, we measure the sense of rotation of the older millisecond pulsar, pulsar A, in the DNS J07373039 system and find that it rotates prograde with respect to its orbit. This is the first direct measurement of the sense of rotation of a pulsar and a direct confirmation of the rotating lighthouse model for pulsars. This result confirms that the spin angular momentum vector is closely aligned with the orbital angular momentum, suggesting that kick of the supernova producing the second born pulsar J07373039B was small.
 Publication:

arXiv eprints
 Pub Date:
 August 2020
 arXiv:
 arXiv:2008.03842
 Bibcode:
 2020arXiv200803842P
 Keywords:

 Astrophysics  High Energy Astrophysical Phenomena
 EPrint:
 PhD Dissertation (West Virginia University, 2020), 137 pages, 33 figures, 4 tables. Go to https://researchrepository.wvu.edu/etd/7691 for original version. Text overlap with: arxiv:1811.04086 (Chapter 2), arxiv:2002.10225 (Chapter 2), arxiv:1712.04360 (Chapter 4). Chapter 3 in peer review