Derivation of Active Galactic Nuclei Mass by Gravitational Redshift

Manager: AKI HASEGAWA-JOHNSON, isba keshwani


Learning Objectives: Python (Astropy), Extragalactic Astrophysics, Observational Cosmology

Utilizing Georgia State’s database of AGN distances measured with the reverberation method, we determined the value of both cosmological redshift and doppler redshift of light emitted from the AGNs. We used NASA’s AGN database containing total redshifts of various AGNs, as well as the multiplicative sum equation for combining different sources of redshifts to solve for the portion of the total redshift that is caused by gravitational redshift. Utilizing the relativistic gravitational redshift equation we solved for the mass of an AGN that has data in both databases.

In order to verify that the calculated mass is accurate, or at least accurate enough to be acceptable, a mass vs. luminosity graph for the AGNs used in the project was plotted. The luminosity was calculated from the electromagnetic flux data from the SDSS.  The relationship between luminosity and mass is a linear relationship. The relationship that we found in this experiment agreed with the accepted relationship found using other known methods; this proves that the method of calculation we used is viable, and the masses we calculated are accurate. 

Another part of our project will be to use the raw data of AGN’s to classify the AGN in their respective groups. AGN classifications have to do with how luminous they are, the width of their emission lines, and their radioactivity.