Adaptive Optics spectro-imaging of starburst galaxies

As part of an ongoing program started at the Canada{France{Hawaii Telescope, we have observed Arp 299 and NGC 7469 in broad and narrow bands with PUEO, the facility adaptive optics system. Locating precisely the regions where starburst activity occurs can help to understand the events that may have led to enhanced star formation. Previous results Rouan, 1998a], Lai etal, 1998a] have shown that starburst activity is fragmented, either in very dense star clusters or in well deened regions such as rings or interface regions. We report on new images of Arp 299 and NGC 7469 obtained in narrow band lters (H 2 , Br, both redshifted at z=0.01). Such an attempt to obtain spectral information at high angular resolution allows us to identify the contribution of each hot spot in terms of star formation { more accurately than broad band color-color diagrams (chromatography): does the ux come from a population of hot recently-formed young stars? from ionized gas? from an older population of stars? More importantly, are there global similarities amongst these very diierent galaxies? In other words, are these high angular resolution images starting to hint at some fundamental and characteristic features of starburst galaxies? 1 Arp 299 1.1 Fact sheet Figure 1: R band image (3600 seconds) obtained at the UH88" Hibbard & Yun, 1995]. The eld of view is 6'5'. The tidal tails show violent signs of interaction. Arp 299 (11h23m37s +58 51'14" (1950)) is the merging of two galaxies, NGC 3690 to the west and IC 694 to the east ((gure 1). The distance of Arp 299 is 41 Mpc (z=0.01) which provides a linear scale of 200pc/arcsecond. This