  Deep NuSTAR observation of X-ray pulsar A 0535+262, performed at a very low
luminosity of $\sim7\times10^{34}$ 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 $E_{\rm cyc}=47.7\pm0.8$ 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.
