Chandra ACIS survey of M33: The Chandra view of NGC604
Ralph Tuellmann (SAO) , T. J. Gaetz (SAO), P. P. Plucinsky (SAO), W. P. Blair (JHU), D. Breitschwerdt (Vienna University, Austria), M. A. de Avillez (University of Evora, Portugal), P. Ghavamian (JHU), K. S. Long (STSCI), T. Pannuti (SSC, Morehead State University)
In the framework of the Chandra ACIS Survey of M33 (ChASeM33, Plucinsky et al. 2008), we present new results of the first detailed X-ray analysis of the giant HII-region NGC604. Our deep (300ks) high resolution (2") ACIS-I X-ray images show highly structured emission covering 700f the full extent of NGC604. The bubbles and cavities in NGC604 are filled with hot X-ray emitting gas, as evidenced by a morphological comparison of X-ray, FUV, optical, and FIR emission. X-ray spectra, extracted from the images, provide the first reliable constraints on electron densities, filling factors, gas temperatures, and ionized gas masses for the main bubbles and cavities. It is generally believed that NGC604 is a wind blown bubble powered by 200 OB/WR-stars in its center. The observed X-ray luminosity of 1.1x10E36 erg/s is most likely caused by a shocked stellar wind and is consistent with the above assumption. Moreover, the derived X-ray gas mass of 1500 can be readily explained by heavy mass loss from the central stars. Finally, we investigated the evolution of NGC604 for the case that the first generation of massive stars ended their lifes within a short period of time as SNe. A comparison with current superbubble models implies that NGC604 will be the origin of a superbubble, breaking out into the halo. Currently, M33 does not fulfill the empirical criteria to also form a multi-phase gaseous halo. However, the expected energy input should push M33 over the threshold to form such structures which are well known for late-type edge-on spirals with enhanced star formation. This work was supported by NASA Chandra award number GO6-7073A.