Detection of X-Ray Emission from the Unidentified TeV Gamma-Ray Source TeV J2032+4130

AbstractWe observed the first unidentified TeV γ-ray source TeV J2032+4130 with Suzaku. Owing to Suzaku’shigh sensitivity for detection of diffuse X-ray emission, we found two small structures in the TeV emittingregion. One of them is coincident with a γ-ray pulsar PSR J2032+4127, which was discovered by the FermiGamma-ray Space Telescope. By subtracting contribution of point sources estimated by Chandra data,we obtained diffuse X-ray spectrum. The X-ray spectrum can be reproduced by a power-law model with aphoton index of ∼ 2, and an X-ray flux of 2×10 −13 erg s −1 cm −2 . The ratio of the γ-ray flux to the X-rayflux is about 10. If the origin of the TeV γ-ray is inverse Compton scattering of microwave backgroundby high energy electrons, the ratio corresponds to the magnetic field strength of ∼ 1 µG. However, thesmaller size of the X-ray emission than that of the TeV emission suggests that energy loss of the electronscan explain the large ratio of the γ-ray flux with a reasonable magnetic field strength of a few µG.Key words: acceleration of particles — X-rays: individual (TeV J2032+4130) — X-rays: ISM —pulsars: individual (PSR J2032+4127)1. IntroductionThe stereoscopic technique of atmospheric Cerenkovtelescopes improved the angular resolution for detectingTeV γ-rays and thus increased the number of TeV γ-raysources. Some of new TeV objects have no counterparts atother wavelengths and are called unidentified TeV γ-rayobjects. These objects provide key information in the in-vestigationofthe originofhigh-energycosmicrays. Multi-wavelength observations of these objects are very impor-tant in elucidating the emission mechanism and successfulidentification of them.TeV J2032+4130 was the first unidentified TeV γ-raysource discovered by HEGRA (Aharonian et al. 2002).The TeV emission exhibits a significant extension witha radius of 6.