Dynamical Accretion Flows (PhD Thesis)

Modelling the Star Forming Efficiency of Dense Clumps

My Masters’ project was titled ‘Modelling the star forming efficiency of dense clumps’ and completed under the supervision of Dr James Urquhart. This was a 20-week project assessed with a written report, viva and presentation. In this project I used a Monte-Carlo approach to model the possible distributions of clusters for a particular luminosity and mass with the main goal being to estimate the range of star formation efficiencies as a function of the initial clump mass and use this to estimate the Galactic Star Formation Rate. This was done by creating 1000s of clusters randomly from the IMF and producing a probability density plot of the SFE as a function of clump mass.

Determining the Statistical Lifetimes of High Mass Stars

In Summer 2019 I completed an 8-week paid internship with Dr James Urquhart. During this internship I completed a research project titled ‘Determining the statistical lifetimes of high mass stars’. This involved classifying the sources in the ATLASGAL catalogue by looking at the different wavelengths they appear it, 70, 24 or 8 microns, into four distinct subsets; Quiescent, Protostellar, YSO or HII Regions. These classifications were used, along with respective densities and free fall times, to calculate the amount of time a source spends in each of these 4 stages of evolution: the statistical lifetime. At the end of the internship L/M graphs were plotted as a cumulative distribution function with free fall times; effectively showing a clock of the evolution of the sources in terms of L/M. As a result of this internship I am a co-author on a published paper ‘SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency Across the Galactic Disk’ and I am currently writing up my results for publication.


J S Urquhart, C Figura, J R Cross, M R A Wells , T J T Moore, D J Eden, S E Ragan, A R Pettitt, A Duarte-Cabral, D Colombo, F Schuller, T Csengeri, M Mattern, H Beuther, K M Menten, F Wyrowski, L D Anderson, P J Barnes, M T Beltrán, S J Billington, L Bronfman, A Giannetti, J Kainulainen, J Kauffmann, M-Y Lee, S Leurini, S-N X Medina, F M Montenegro, M Riener, A J Rigby, A Sánchez-Monge, P Schilke, E Schisano, A Traficante, M Wienen, SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency Across the Galactic Disk, Monthly Notices of the Royal Astronomical Society, DOI

J S Urquhart, M R A Wells , T Pillai, S Leurini, A Giannetti, T J T Moore, M A Thompson, C Figura, D Colombo, A Y Yang, C König, F Wyrowski, K M Menten, A J Rigby, D J Eden, S E Ragan ATLASGAL-Evolutionary trends in high-mass star formation, Monthly Notices of the Royal Astronomical Society, DOI

Hubble Sees a Horsehead of a Different Color. Backlit wisps along the Horsehead Nebula upper ridge are being illuminated by Sigma Orionis, a young five-star system just off the top of this image from the Hubble Space Telescope.