6. SUMMARY

Based on complementary high-resolution imaging and spectroscopic observations from Chandra, we have learned a great deal about various high-energy phenomena and processes in galaxies:

• The luminosity functions and their dependence on the stellar mass and star formation rate are nearly universal for essentially all major types of discrete X-ray sources in galaxies.

• A very hot component of the global ISM in the Galaxy has been revealed, and its global spatial, thermal, chemical, and kinetic properties have been characterized.

• Stringent upper limits have been obtained to the contents of the chemically-enriched CGM around our Galaxy and around other galaxies/groups along the sight lines toward several luminous AGNs.

• Detailed structures of the superwinds emanated from starburst galaxies are resolved, tracing strong interplay between the very hot outflowing gas and the presence of cool gas.

• Sporadic energy injections from AGNs are shown to play an important role in shaping the global hot gas in and around elliptical galaxies.

• Truly diffuse hot gas has also been mapped out for a few nearby normal galaxies, indicating that ongoing stellar feedback may play an important role in regulating the galactic eco-systems.

In conclusion, the existing work has demonstrated the power of Chandra observations in probing the stellar and AGN feedback and its effect on galaxy evolution as well as inventorying various kinds of high-energy sources in galaxies.

I thank the referee for constructive comments and the organizers of the Chandra's First Decade of Discovery conference for the invitation to give the talk that this paper is based on and am grateful to my students and collaborators for their contributions to the work described above, particularly Yangsen Yao who helped to produce Figures 1 and 2. The work is partly supported by NASA/CXC under grants G08-9088B and G08-9047A.