MAGIC Observations of the Unidentified γ-Ray Source TeV J2032+4130

We observed the first known very high energy (VHE) gamma-ray-emitting unidentified source, TeV J2032 + 4130, for 94 hr with the MAGIC telescope. The source was detected with a significance of 5.6 sigma. The flux, position, and angular extension are compatible with the previous ones measured by the HEGRA telescope system 5 years ago. The integral flux amounts to (4.5 +/- 0.3(stat)+/- 0.35(sys)) x 10 (- 13) photons cm(-2) s(-1) above 1 TeV. The source energy spectrum, obtained with the lowest energy threshold to date, is compatible with a single power law with a hard photon index of Gamma= - 2.0 +/- 0.3(stat)+/- 0.2(sys).