Research

Research Interests

My research focuses on disentangling the complexities of Active Galactic Nuclei (AGN) using optical spectroscopy. I mainly use spectra from the Six-degree Field Galaxy Survey (6dFGS: 2001–2009), along with modern spectra from the ANU 2.3m Wide Field Spectrograph (WiFeS) to compare changes in the Hβ/[OIII] line ratios on a 15–20 year timescale.

Understanding AGN Sub-Types

My Ph.D. project aims to unravel the physical distinctions among AGN sub-types and examine their correlations with the orientation of the AGN and host galaxy, the accretion rate of the AGN, and the dust obscuration of the host galaxy. Specifically, my work entails a comprehensive exploration of variations in the Hβ and [OIII] emission line ratios over two epochs. By analysing these ratios, I aim to infer the transient properties of AGN.

Changing Look AGN

The [OIII] emission line is a tracer of host galaxy star formation along with AGN narrow-line emission, and is not expected to change on short timescales. In contrast, the broad Hβ emission line traces the accretion rate of the AGN and is expected to vary on short timescales. Therefore, the Hβ/[OIII] ratio is expected to vary accordingly. However, certain AGN exhibit extreme fluctuations — including the abrupt appearance or disappearance of the broad Hβ component within just a few months. Such phenomena are classified as Changing Look AGN (CLAGN). For my Honours Thesis, I focused on identifying CLAGN through the analysis of light curves.

A Complete Spectroscopic Atlas and Catalogue of AGN

I am releasing a comprehensive spectroscopic atlas and catalogue of AGN, including all objects used in the projects described above. The atlas is complete to K < 12.65 mag at z < 0.1, covering the Southern Sky while avoiding the Galactic Plane. It comprises approximately 1,000 spectra of ~900 AGN obtained with the ANU 2.3m Wide Field Spectrograph (WiFeS). The catalogue is designed as a reference resource for studies of AGN transients, variability, and multi-wavelength populations, and is intended to complement major surveys such as LSST, SDSS-V, and 4MOST. It includes derived spectroscopic properties such as emission-line fluxes, widths, and ratios, as well as AGN–host galaxy decomposition products. Data products are currently available upon request (via email) and will be publicly released following submission of the accompanying paper (target: June 2026).