The orbital-decay test of general relativity to the 2% level with 6-year VLBA astrometry of the double neutron star PSR J1537+1155

Understand

PSR J1537+1155, also known as PSR B1534+12, is the second discovered double neutron star (DNS) binary.

• More than 20 years of timing observations of PSR J1537+1155 have offered some of the most precise tests of general relativity (GR) in the strong-field regime.
• As one of these tests, the gravitational-wave emission predicted by GR has been probed with the significant orbital decay ($\dot{P}_\mathrm{b}$) of PSR J1537+1155.
• However, compared to most GR tests provided with the post-Keplerian parameters, the orbital-decay test was lagging behind in terms of both precision and consistency with GR, limited by the uncertain distance of PSR J1537+1155.