SIMBAD references

Chandra ACIS-I data of the molecular cloud and H II region complex NGC 6334 were analyzed. The hard X-ray clumps detected with ASCA (Sekimoto and coworkers) were resolved into 792 point sources. After removing the point sources, an extended X-ray emission component was detected over a 5x9 pc² region, with the 0.5-8 keV absorption-corrected luminosity of 2x10³³ ergs/s. The contribution from faint point sources to this extended emission was estimated as at most ∼20%, suggesting that most of the emission is diffuse in nature. The X-ray spectrum of the diffuse emission was observed to vary from place to place. In tenuous molecular cloud regions with hydrogen column density of (0.5-1)x10²²/cm2, the spectrum can be represented by a thermal plasma model with temperatures of several keV. The spectrum in dense cloud cores exhibits harder continuum, together with higher absorption of more than ∼3x10²²/cm2. In some of such highly obscured regions, the spectra show extremely hard continua equivalent to a photon index of ∼1, and favor a nonthermal interpretation. These results are discussed in the context of thermal and nonthermal emission, both powered by fast stellar winds from embedded young early-type stars through shock transitions.