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We report on a 40ks Chandra observation of the TeV emitting high mass X-raybinary HESS J0632+057 performed in February 2011 during a high-state of X-rayand TeV activity. We have used the ACIS-S camera in Continuos Clocking mode tosearch for a possible X-ray pulsar in this system. Furthermore, we compare theemission of the source during this high state, with its X-ray properties duringa low state of emission, caught by a 47ks XMM-Newton observation on September2007. We did not find any periodic or quasi-periodic signal in any of the twoobservations. We derived an average pulsed fraction 3sigma upper limit for thepresence of a periodic signal of ~35% and 25% during the low and high emissionstate, respectively (although this limit is strongly dependent on the frequencyand the energy band). Using the best X-ray spectra derived to date for HESSJ0632+057, we found evidence for a significant spectral change between the lowand high X-ray emission states, with the absorption value and the photon indexvarying between Nh ~ 2.1-4.3x10^{21} cm^{-2} and Gamma ~ 1.18-1.61. At variancewith what observed in other TeV binaries, it seems that in this source thehigher the flux the softer the X-ray spectrum.

The TeV binary HESS J0632+057 in the low and high X-ray state