Discovery and timing of pulsar J2016+3711 in supernova remnant CTB 87 with FAST

We report on our discovery of the radio pulsar, PSR J2016+3711, in supernova remnant (SNR) CTB 87, with a similar to 10.8 sigma significance of pulses, which confirms the compact nature of the X-ray point source in CTB 87. It is the first pulsar discovered in SNRs using Five-hundred-meter Aperture Spherical radio Telescope (FAST). Its integrated radio pulse profile can be well described by a single component, with a width at 50 per cent of the peak flux density of about 28.1(circle) and an effective width of about 32.2(circle). The mean flux density at 1.25 GHz is estimated to be about 15.5 mu Jy. Combined with the non-detection of the radio pulse at lower frequencies, the radio spectral index of the pulsar is constrained to be less than or similar to 2.3. We also present the timing solution based on 28 follow-up FAST observations. Our results reveal a period of 50.81 ms, period derivative of 7.2 x 10(-14) s s(-1), and dispersion measure of 428 pc cm(-3). The strength of the equatorial surface magnetic dipole magnetic field is inferred to be about 1.9 x 10(12) G. Using the ephemeris obtained from the radio observations, we searched Fermi-LAT data for gamma-ray pulsations but detected no pulsed signal. We also searched for radio pulses with FAST towards the X-ray counterpart of the gamma-ray binary HESS J1832-093 proximate to SNR G22.7-00.2 but found no signal.