Starburst in NGC 6090 Junzhi Wang Purple mountain observatory Collaborators: Qizhou Zhang, Zhong Wang, Giovanni G. Fazio, Paul T. P. Ho (CFA) Yuefang Wu (PKU), Yu Gao (PMO)

Motivation To find the star forming gas and the dust emission distribution in galaxy-galaxy mergers to determine the starburst distribution in these galaxies The starburst distribution will help us to understand the trigger of the starburst during merging process NGC 6090 was one of the mergers selected for such study, because of the amount of the molecular gas and the strong IR emission

NGC 6090: A mid-stage merger Distance: 122 Mpc Project separation: 3.2 kpc (5.4") L IR : 3×10 11 L sun M H 2 :3×10 10 M sun

HST near-IR image (Dinshaw et al. 1999) NGC6090E NGC6090W Overlap region

Observations CO 2-1 & 3-2 with the SMA (2003) Ks and H band images with MMT (2004) Mid-IR images with the IRAC

View of the SMA in the direction of Mauna Loa (Ho et al. 2004) The first and the only interferometer working at sub-mm now Resolution: from several arcseconds to sub-arcsecond Frequency:230GHz(1.3mm), 345GHz(0.85mm), 690GHz(0.43mm)…

Red contour: CO 2-1 Green contour: CO 3-2 Grey scale: Ks Two stars: 20cm peaks Both CO 2-1 and CO 3-2 peaking at the overlap region! Wang, J., et al.,2004, ApJ, 616, L67

3.6 µm 8.0µm Grey scale:Ks Contour: IRAC data NGC6090E NGC6090W SDSS G bandMMT Ks band

20cm radio continuum (contour,VLA) on the 8.0 µm (grey scale, IRAC)

H  (blue, Sugai et al. 2004), CO 3-2 (green) CO 2- 1 (red) on the Ks band image (Grey scale)

Summary Warm molecular gas distribution: peaking at the overlap region The different properties of the two galaxies: one gas rich and the other gas poor Most of the mid-IR emission comes from the face-on galaxy NGC 6090E, just similar to the 20cm radio continuum Starburst was found in several regions