Cyclotron emission, absorption, and the two faces of X-ray pulsar A 0535+262
Another nice, NuSTAR result where we follow-up our earlier work on GX 304-1. The latest discovery pretty much confirms our earlier interpretation and seals the deal. Just in time for my Birthday :)
Deep NuSTAR observation of X-ray pulsar A 0535+262, performed at a very low luminosity of ∼7×\(10^{34}\) erg s\(^{-1\), revealed the presence of two spectral components. We argue that the high-energy component is associated with cyclotron emission from recombination of electrons collisionally excited to the upper Landau levels. The cyclotron line energy of Ecyc = 47.7 ± 0.8 keV was measured at the luminosity of almost an order of magnitude lower than what was achieved before. The data firmly exclude a positive correlation of the cyclotron energy with the mass accretion rate in this source