PHY480: 4th Year Projects in Physics & Astronomy

#1: Supermassive Black Hole Mass Measurements
and the Importance of Data Quality

The masses of supermassive black holes can be estimated via the analysis of broad emission lines (e.g. MgII, CIV, H-beta). However, discrepancies are often observed between the masses derived from different lines, which may reflect more complicated physics in the vicinity of the black hole. Alternatively, there may be systematic errors between the results from different lines due to model degeneracies, which are particularly sensitive to the quality of the observational data used.

In this project, the student will produce idealised spectra of broad emission lines for a range of different black hole masses, and then investigate the impact of degrading them to match the observational characteristics of commonly used instrumentation, before fitting and re-extracting the input model parameters.

Possible questions to be addressed within this project include:
  1. What impact do adjacent spectral features have on the results for the different emission lines?
  2. How do blue-shifted line components due to gas outflows affect the masses obtained?
  3. Are the masses derived from emission line width and velocity dispersion equally sensitive to data quality?
  4. At what noise levels/spectral resolutions do modelling degeneracies make a dataset worthless?
  5. What are the best-case errors on model fits to real data?

If you are interested in this project, feel free to come and have a chat - my office is F29 and my student drop-in hours are 9.30-11.00 on Mondays, Tuesdays and Fridays, and 13.00-14.00 on Wednesdays.

Dr. Katherine J. Inskip

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