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Astron. Astrophys. 357, 1020-1030 (2000)

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The NGC 6334 IV massive star formation site: a cluster in the making? *

P. Persi 1, M. Tapia 2 and M. Roth 3

1 Istituto Astrofisica Spaziale, CNR, Area di Ricerca Tor Vergata, Via del Fosso del Cavaliere, 00133 Roma, Italy (persi@saturn.ias.rm.cnr.it)
2 Instituto de Astronomia, UNAM, Apartado Postal 877, Ensenada, Baja California, CP 22830, Mexico
3 Las Campanas Observatory, Carnegie Institution of Washington, Casilla 601, La Serena, Chile

Received 24 November 1999 / Accepted 17 February 2000


Sub-arcsecond JHK images of the star formation region NGC 6334 IV covering 14.7 sq arcmin have been obtained. These were supplemented by H2 and Br[FORMULA] images of the central 2 sq arcmin. A total of 1238 sources brighter than [FORMULA] were detected. Due to the very high extinction in this region, only 685 of these are brighter at 1.2 [FORMULA] than our limit, [FORMULA]. Only less than 5% of the sources exhibit excess emission at [FORMULA] and they are scattered over the whole area covered. No evidence of a developed stellar cluster was found, but a small number of luminous (O-B2) young stellar objects were detected. These are embedded in the densest part of the molecular cloud that is at the centre of a giant bipolar structure seen in the radio and the infrared. This morphology is the result of the effect of massive stellar winds originating from the centre of a dense molecular toroid which collimates the outflow material giving rise to two lobes of thermal gas and dust emission. We confirm that the extinction is higher toward the southern lobe than toward the northen one but both are less reddened than their immediate surroundings. A new centre of active massive star formation is reported to the east of the central region. Close to a (sub)millimeter emission peak, a large infrared nebula with several point-like sources was found at 2.2 [FORMULA]. The discovery of a small embedded low-luminosity bipolar object in the vicinity of one of the giant lobes is also reported.

Key words: stars: formation – ISM: clouds – ISM: dust, extinction – ISM: H ii regions – infrared: stars

* The complete list of the detected sources including their positions and photometry is available in electronic form at the CDS

Send offprint requests to: P. Persi

Correspondence to: Istituto Astrofisica Spaziale, CNR, Area di Ricerca Tor Vergata, Via del Fosso del Cavaliere, 00133, Roma, Italy

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© European Southern Observatory (ESO) 2000

Online publication: June 5, 2000