Abstract

We have obtained the spectrum of a middle-aged PSR B0656+14 in the 4300-9000 Å range with the ESO/VLT/FORS2. Preliminary results show that at 4600-7000 Å the spectrum is almost featureless and flat with a spectral index α ν ≃-0.2 that undergoes a change to a positive value at longer wavelengths. Combining with available multiwavelength data suggests two wide, red and blue, flux depressions whose frequency ratio is about 2 and which could be the 1st and 2nd harmonics of electron/positron cyclotron absorption formed at magnetic fields ∼108 G in upper magnetosphere of the pulsar. © Springer Science+Business Media B.V. 2007.