We present results of the multiwavelength campaign on the TeV blazar Mkn 501 performed in 2006 July , including MAGIC for the very-high-energy ( VHE ) \gamma -ray band and Suzaku for the X-ray band .
A VHE \gamma -ray signal was clearly detected with an average flux above 200 GeV of \sim 20 % of the Crab Nebula flux , which indicates a low state of source activity in this energy range .
No significant variability has been found during the campaign .
The VHE \gamma -ray spectrum can be described by a simple power-law from 80 GeV to 2 TeV with a photon index of 2.8 \pm 0.1 , which corresponds to one of the steepest photon indices observed in this energy range so far for this object .
The X-ray spectrum covers a wide range from 0.6 to 40 keV , and is well described by a broken power law , with photon indices of 2.257 \pm 0.004 and 2.420 \pm 0.012 below and above the break energy of 3.24 ^ { +0.13 } _ { -0.12 } keV .
No apparent high-energy cut off is seen above the break energy .
Although an increase of the flux of about 50 % is observed in the X-ray band within the observation , the data indicate a consistently low state of activity for this source .
Time-resolved spectra show an evidence for spectral hardening with a flux level .
A homogeneous one-zone synchrotron self-Compton ( SSC ) model can adequately describe the spectral energy distribution ( SED ) from the X-ray to the VHE \gamma -ray bands with a magnetic field intensity B = 0.313 G and a Doppler beaming factor \delta = 20 , which are similar to the values in the past multiwavelength campaigns in high states .
Based on our SSC parameters derived for the low state , we are able to reproduce the SED of the high state by just changing the Lorentz factor of the electrons corresponding to the break energy in the primary electron spectrum .
This suggests that the variation of the injected electron population in the jet is responsible for the observed low-high state variation of the SED .