Chinese Astronomers Detect Radio Pulsar in Supernova Remnant Using FAST Telescope
Chinese astronomers, in collaboration with researchers from Nanjing University and beyond, have made a significant discovery utilizing the Five-hundred-meter Aperture Spherical radio Telescope (FAST). They have identified a radio pulsar within the supernova remnant CTB 87, as detailed in a paper released on February 1 via the arXiv pre-print server.
Pulsars, characterized by highly magnetized rotating neutron stars emitting electromagnetic radiation beams, are typically observed through short bursts of radio emission, alongside detections via optical, X-ray, and gamma-ray telescopes.
CTB 87 represents a plerionic supernova remnant (SNR) with an X-ray luminosity nearly 100 times weaker than the Crab Nebula in the 0.15−3 keV band. The supernova remnant (SNR) contains a pulsar wind nebula (PWN) exhibiting trailing morphology evident in X-ray imaging.Notably, no such object had been identified within this SNR until now.
The team, led by Qian-Cheng Liu of Nanjing University, focused on a point-like X-ray source within CTB 87, designated CXOU J201609.2+371110. Through FAST observations, they detected radio pulses emanating from this source, confirming its compact nature.
The researchers detailed their discovery of the radio pulsar, PSR J2016+3711, within CTB 87, with pulses exhibiting a significance of approximately 10.8σ. Situated approximately 43,400 light years away, PSR J2016+3711 boasts a spin period of 50.8 milliseconds and a dispersion measure of about 428 pc/cm^3. Its spin down luminosity is measured at 22 undecillion erg/s, with a characteristic age estimated at 11,100 years, marking it as the first pulsar in an SNR detected using FAST.
The equatorial surface dipole magnetic field strength of PSR J2016+3711 was determined to be approximately 1.9 TG. Additionally, the study revealed that the radio pulse profile of this pulsar is narrow, lacking broad wings, indicating either an intrinsically narrow radio beam starting near the magnetic polar cap or a line of sight sweeping just across a small segment of a broad beam.
Despite the potential for gamma-ray emission from pulsars, analysis of data from NASA’s Fermi spacecraft did not reveal gamma-ray pulsation from PSR J2016+3711. The researchers emphasized the necessity for further observations spanning years to refine the timing solution, facilitating a comprehensive search for gamma-ray pulsation.
In conclusion, this discovery underscores the capabilities of FAST and highlights the ongoing pursuit of understanding pulsar behavior and their implications within supernova remnants.