Published papers
- Smith, R.J., Glover, S.C.O, Klessen, R.S., 2014, submitted to MNRAS
On the nature of star-forming filaments: I. Filament morphologies - Goodman, A.A., Alves, J., Beaumont, C.N., Benjamin, R.A., Borkin, M.A., Burkert, A., Dame, T.M., Jackson, J., Kauffmann, J, Robitaille, T., Smith, R.J., 2014, ApJ, in press
The Bones of the Milky Way - Peters, T., Schleicher, D.R.G.,Smith, R.J., Schmidt, W., Klessen, R.S., 2014, MNRAS, 442, 3112
Low-metallicity star formation: Relative impact of metals and magnetic fields - Smith, R.J., Glover, S.C.O, Clark, P.C., Klessen, R.S., Springel, V., 2014, MNRAS, 441, 1628
CO-dark gas and molecular filaments in Milky Way type galaxies - Chira R-A, Smith, R.J., Klessen, R.S., Stutz, A.M., Shetty, R., 2014, MNRAS, in press
Line Profiles of Cores within Clusters. III. What is the most reliable tracer of core collapse in dense clusters? - Smith, R.J., Shetty, R., Beuther, H., Klessen, R., Bonnell, I.A., 2013, ApJ, 771, 24
Line Profiles of Cores within Clusters: II Signatures of Dynamical Collapse during High Mass Star Formation - Zernickel, A., Schilke, P.,Smith, R.J., 2013, A&A, 554, L2
The global velocity field of the filament in NGC 6334* - Beuther, H., Linz, H., Tackenberg, J., Henning, Th., Krause, O., Ragan, R., Nielbock, M., Launhardt, R., Bihr, S., Schmiedeke, A., Schuller, F., Smith, R.J., A&A, 2013, 553, 115
Fragmentation and dynamical collapse of the starless high-mass star-forming region IRDC18310-4 - Walker-Smith S.L., Richer J.S., Buckle J.V., Smith, R.J., Greaves J.S., Bonnell I.A., 2013, MNRAS, 429, 3252
The structure and kinematics of dense gas in NGC 2068 - Bonnell, I.A., Dobbs, C.A. & Smith, R.J., 2013, MNRAS, 430, 1790
Shocks, cooling and the origin of star formation rates in spiral galaxies - Smith, R.J., Iocco, F., Schleicher, D., Glover, S.C.O, Klessen, R.S., Hirano, S., & Yoshida, N., 2012, ApJ, 761, 154
WIMP DM and first stars: suppression of fragmentation in primordial star formation - Peters, T., Schleicher, D. R. G., Klessen, R. S., Banerjee, R., Federrath, C., Smith, R. J., Sur S., 2012, ApJL, 760, 28
The impact of thermodynamics on gravitational collapse: filament formation and magnetic field amplification - Smith, R.J., Shetty, R., Stutz, A., Klessen, R.S. 2012, ApJ, 750, 64
Line Profiles of Cores within Clusters: I. The Anatomy of a Filament - Greif, Thomas H.; Bromm, Volker; Clark, Paul C.; Glover, Simon C. O.; Smith, Rowan J.; Klessen, Ralf S.; Yoshida, Naoki; Springel, Volker, 2012, MNRAS 424, 399
Formation and evolution of primordial protostellar systems - Smith, R.J., Hosokawa, T., Clark, Omukai, K., Glover, S.C.O., Klessen, R.S. 2012, MNRAS, 424, 457
Variable Accretion Rates and Fluffy First Stars - Smith, R.J., Glover, S.C.O., Clark, P.C., Greif, T.H., Klessen, R.S. 2011, MNRAS, 414, 3633
The effects of accretion luminosity upon fragmentation in the early universe - Greif, T.H., Springel, V., White, S.D.H., Glover, S.C.O., Clark, P.C., Smith, R.J., Klessen, R.S., Bromm, V., 2011, ApJ, 737, 75
Simulations on a Moving Mesh: The Clustered Formation of Population III Protostars - Clark, P.C., Glover, S.C.O.,Smith, R.J., Greif, T.H., Klessen, R.S., Bromm, V., 2011, Science, 331, 1040
The Formation and Fragmentation of Disks around Primordial Protostars - Smith, R.J., Glover, S.C.O., Bonnell, I.A., Clark, P.C., Klessen, R.S., 2011, MNRAS, 411, 1354
A quantification of the non-spherical geometry and accretion of collapsing cores - Dale, J.E., Wunsch, R.,Smith, R.J.,Whitworth, A., Palous, J, 2011, MNRAS, 411, 2230
The fragmentation of expanding shells III: Oligarchic accretion and the mass spectrum of fragments - Bonnell, I.A. ,Smith, R.J.,Clark, P.C., Bate, M.R., 2011, MNRAS, 410, 2339
The efficiency of star formation in clustered and distributed regions - Smith, R.J., Longmore, S., Bonnell, I.A., 2009, MNRAS, 400, 1775-1784
The simultaneous formation of massive stars and stellar clusters - Smith, R.J., Clark, P.C., Bonnell, I.A., 2009, MNRAS, 396, 830-841
Fragmentation in molecular clouds and its connection to the IMF - Smith, R.J., Clark, P.C., Bonnell, I.A., 2008, MNRAS, 391, 1091-1099
The structure of molecular clouds and the universality of the clump mass function
PhD Thesis
The Earliest Fragmentation in Molecular Clouds and its connection to Star Fomrnation
Abstract
Stars are born from dense cores of gas within molecular clouds. The exact nature of the connection between these gas cores and the stars they form is an important issue in the field of star formation. In this thesis I use numerical simulations of molecular clouds to trace the evolution of cores into stars. The CLUMPFIND method, commonly used to identify gas structures is tested. I find that the core boundaries it yields are unreliable, but in spite of this, the same profile is universally found for the mass function. To facilitate a more robust definition of a core, a modified clumpfind algorithm which uses gravitational potential instead of density is introduced. This allows the earliest fragmentation in a simulated molecular cloud to be identified. The first bound cores have a mass function that closely resembles the stellar IMF, but there is a poor correspondence between individual core masses and the stellar masses formed from them. From this, it is postulated that environmental factors play a significant part in a cores evolution. This is particularly true for massive stars, as massive cores are prone to further fragmentation. In these simulations, massive stars are formed simultaneously with stellar clusters, and thus the evolution of one can affect the other. In particular, the global collapse of the forming cluster aids accretion by the precursors of the massive stars. By tracing the evolution of the massive stars, I find that most of the material accreted by them comes from diffuse gas, rather than from a well-defined stellar core.
Thesis [ 13.7MB pdf ]
Proceedings
- Bonnell, I.A., Smith, R.J., 2011, Proceedings of "Computational Star Formation, Proceedings of the International Astronomical Union, IAU Symposium"
The Formation of Massive Stars - Smith, R.J., Clark, P. C., Glover S.C.O., Klessen, R.S. 2010, Proceedings of "The First Stars and Galaxies: Challenges for the Next Decade"
The Effects of Accretion Luminosity on the Environment of the First Stars - Smith, R.J., Clark, P. C., Glover S.C.O., Greif, T., Klessen, R.S. 2010, Proceedings of "Cosmic Radiation Fields: Sources in the early Universe (CRF 2010)"
The effects of accretion luminosity from Pop III protostars - Smith, R.J., Clark, P.C, Glover, S.C.O, Bonnell, I.A., Klessen, R.S. 2010, Proceedings of "UP2010, Have Observations Revealed a Variable Upper End of the Initial Mass Function?"
The Effect of Environment on Massive Star Formation