With the help of the FAST radio telescope with an aperture of 500 meters, astronomers from Nankinsk University and their colleagues from other countries discovered radiopulsars in the remnant of the supernova CTB 87. This radiotelescope is the largest in the world, and its use allows studying cosmic objects with high resolving power and improved sensitivity.
Pulsars are a special type of neutron star, which rotate around their axis at high speed and have strong magnetic fields. They emit regular pulses of radio waves, similar to a lighthouse that lights up in the sky. However, not all pulsars appear only in the radio range. Some of them are also excited in the optical, X-ray and gamma-diazones.
CTB 87 — this is a single supernova, which formed as a result of the explosion of a star. The remnant of the supernova CTB 87 has been studied in various wavelengths, including X-rays. However, no interactions of pulsar emissions with the atmosphere have yet been detected.
A group of astronomers led by Professor Tian-Chen Liu from Nanjing University established a point source of X-ray radiation under the designation CXOU J201609.2+371110 in the remnant supernova CTB 87. With the help of the FAST radio telescope they detected radio impulses from this point source. The pulsar, named PSR J2016+3711, is located at a distance of about 43 400 light years from us and has a rotation period of 50.8 milliseconds and a mean dispersion of about 428 pc/cm3. The age of the pulsar is estimated at 11 100 years.
Interestingly, this is the first pulsar detected in the remnant supernova CTB 87 by the FAST radio telescope. Researchers also noted that the field of view from which this pulsar’s radio beam emanates is most likely narrow and may be associated with its magnetic polar cap.
Considering that some pulsars also emit gamma-rays, the team of astronomers analyzed data from the space gamma-telescope «Fermi», to verify the presence of pulsations of gamma-rays from PSR J2016+3711. However in this case pulsations of gamma-emission were not detected. The authors of the study note that additional observations over a longer period of time are necessary to obtain more accurate results and to definitively rule out a link between the pulsar and gamma radiation.
«Subsequent radio observations, covering several years, would have been useful for obtaining more accurate data, which could have been used to combine gamma-emission data and search for pulsations», — concluded the authors of the research.