Investigation of diffuse hard X-ray emission from the massive star-forming region NGC 6334.
EZOE Y., KOKUBUN M., MAKISHIMA K., SEKIMOTO Y. and MATSUZAKI K.
Abstract (from CDS):
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.
ISM: H II Regions - ISM: Individual: NGC Number: NGC 6334 - Stars: Early-Type - Stars: Formation - Stars: Winds, Outflows