1. INTRODUCTION

2. DATA HOMOGENIZATION OF OBSERVATIONS AND SIMULATIONS
2.1. X-ray Measurements from the Chandra Sample
2.2. Massive Disc Galaxies from the Literature
2.3. Numerical Simulations

3. COMPARISON BETWEEN OBSERVATION AND THEORY
3.2. Comparison between Observations and Simulations

4. DISCUSSION
4.1. Effects of Missing AGN Feedback
4.2. Role of SF in the Coronal X-ray Emission
4.3. Differences between Low and High Mass Galaxies

5. SUMMARY AND PROSPECTS