We probe ultra-low-frequency gravitational waves (GWs) with statistics of spin-down rates of milli-second pulsars (thereafter MSPs) by a method proposed in our prevous work (Yonemaru et al. 2016). The considered frequency range is 10 −12 Hz f GW 10 −10 Hz . The effect of such low-frequency GWs appears as a bias to spin-down rates which has a quadrupole pattern in the sky. We use the skewness of the spin-down rate distribution and the number of MSPs with negative spin-down rates to search for the bias induced by GWs. Applying this method to 149 MSPs selected from the ATNF pulsar catalog, we derive upper bounds on the time derivative of the GW amplitudes of h < 6.2 × 10 −18 sec −1 and h < 8.1 × 10 −18 sec −1 in the directions of the Galactic Center and M87, respectively. Approximating the GW amplitude as h ∼ 2π f GW h, the bounds translate into h < 3 × 10 −8 and h < 4 × 10 −8 , respectively, for f GW = 1/(1000 yr). Finally, we give the implications to possible super-massive black hole binaries at these sites.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.