Estimating black hole masses in active, star-forming galaxies (2015)
Undergraduates: Ashley Bittner, Elaine Snyder
Faculty Advisor: Sheila Kannappan
Department: Physics & Astronomy
Most galaxies follow an evolutionary track that begins with their formation as spiral galaxies along the ¿¿¿blue sequence¿¿¿, named for the blue color seen from star-forming galaxies. As galaxies exhaust their dense gas, a necessity for star formation, they become redder spheroids as their internal stars age. The galaxy type investigated in this project, ¿¿¿blue sequence spheroids¿¿¿ deviate from this track due to a period of late star formation. This ¿¿¿starburst¿¿¿ is due to a concentration of gas in the galactic center, often thought to be the consequence of a merger of two galaxies. This central gas may fuel two types of nuclear activity; starbursts or Active Galactic Nuclei (AGN), a term used to describe mass accretion by the black hole. While nuclear starbursts may explain our observations of increased star formation and depleted gas reserves, some of the gas depletion observed might be due to AGN activity. In an attempt to probe the effects of AGN activity on galaxy evolution, we estimate central black-hole masses and measure properties related to the central BH and its possible AGN activity. BH-mass values can be estimated based on a correlation with the typical orbital velocities of stars in the galaxy. These velocities are obtained by using a public code on spectroscopic data available for the galaxies in the RESOLVE survey. In future work, we aim to pinpoint a detectable signature of AGN activity through a literature review and search for this signature in our sample.