Friday 21 March 2025
A team of astronomers has made a fascinating discovery about a mysterious region in space, known as CTB 87. Located in the constellation Cygnus X-1, this composite supernova remnant (SNR) is emitting radiation across the entire electromagnetic spectrum, from radio waves to gamma rays.
The researchers used data collected by NASA’s Fermi Gamma-Ray Space Telescope and other observatories to study the region. They found that CTB 87 contains two distinct sources of gamma-ray emission, which they dubbed PsA and PsB. The first source has a soft gamma-ray spectrum, meaning it produces radiation with lower energies, while the second source has a hard gamma-ray spectrum, producing radiation with higher energies.
The team believes that PsA is likely caused by interactions between the SNR shock and molecular clouds (MCs) in the surrounding environment. This type of interaction can produce gamma rays through hadronic processes, where high-energy particles collide with each other or with the surrounding material.
On the other hand, PsB has a hard gamma-ray spectrum that aligns with the TeV (teraelectron volt) spectrum of VER J2016+371, a previously detected source. This suggests that PsB could be the GeV counterpart of VER J2016+371. The researchers propose that PsB is actually a pulsar wind nebula (PWN), which is a dynamic and energetic structure powered by the rotational energy of a pulsar.
The pulsar at the center of CTB 87, known as PSR J2016+3711, has been spinning down rapidly since its formation. This rapid spin-down could be responsible for the observed gamma-ray emission from PsB. The team used a leptonic model, which assumes that electrons are responsible for producing the radiation, to simulate the data and found that it matched the observations remarkably well.
The researchers also explored the possibility of radiative losses affecting the electron spectrum, but their simulations suggest that this is not the case. Instead, they propose that the break in the electron spectrum is intrinsic to the injection process, rather than being caused by radiation losses.
CTB 87 is an intriguing region of space that offers insights into the complex processes involved in supernova explosions and pulsar formation. The discovery of PsA and PsB provides new opportunities for studying these phenomena and understanding their role in shaping the surrounding environment.
Cite this article: “Gamma-Ray Emission from CTB 87: Unveiling Pulsar Wind Neblae”, The Science Archive, 2025.
Supernova Remnant, Cygnus X-1, Gamma Rays, Fermi Gamma-Ray Space Telescope, Pulsar Wind Nebula, Leptonic Model, Electron Spectrum, Radiation Losses, Psa, Psb
