Keywords: galaxies: SMBH growth: active — galaxies: nuclei — quasars: general

1. INTRODUCTION

2. MULTI-WAVELENGTH SED OF H1821+643

2.1. ALLWISE Catalog

2.2. IRAS Catalogs

2.3. AKARI Point Source Catalogs

2.4. Spitzer and ISO IR spectra

2.5. UV, Optical and X-ray bands

3. SED FITTING OF H1821+643

3.1. Host Galaxy Component

3.2. AGN Component

3.3. AGN X-ray Emission

4. RESULTS

4.1. SFR and stellar mass

4.2. AGN luminosity and BH accretion rate

5. DISCUSSION

5.1. Energy Balance between Cooling and Heating in the Central 100 kpc of H1821

5.2. FIR Fine Structure Line: Cooling Path to Star-Formation

5.3. Molecular Gas: Immediate Proceeding into Star-Formation

5.4. Inverse Compton Cooling is not an Effective Cooling Path for H1821

5.5. Possible Growth Pathways for the SMBH in H1821

6. CONCLUSION