Dr Seamus Clarke

I'm an astrophysicist focusing on the problem of star formation and am a postdoctoral research fellow at Academia Sinica Institute of Astronomy and Astrophysics. I am both a theorist and an observer interested in star-forming filaments, synthetic observations, numerical methods and the application of statistical and machine learning techniques to astrophysical data.

Research interests

My research is split into three main topics: (magneto-)hydrodynamic simulations of filament evolution and fragmentation to determine how filament geometry affects star formation, synthetic observations of my simulations to compare to and interpret real observations, and continuum and molecular line observations of giant molecular filaments to study their kinematics and fragmentation. I am also interested in larger-scale problems such as the formation of molecular clouds and the effects of supernovae on dense molecular gas, as well as smaller-scale problems such as disk and outflow physics, and hot-core chemistry.

For more details on my recent work

Code development

During the course of my research I have developed and contributed to a number of analysis codes. As I believe in open science I have made these public for use by the wider star formation community.

  • RJ-plots is a Python module which builds upon the earlier J-plots module to automatically classify 2D structures using their moments of inertia. It approximately separates a structure's elongation from its central concentration, allowing easy interpretation and analysis.

    • RJ-plots Github

  • FragMent is a Python/C module which combines a number of fragmentation analysis techniques and model selection tools to characterise the fragmentation of filaments. While it was designed specifically for filament fragmentation it can be applied to study any form of fragmentation.

    • FragMent Github

  • BTS is a Python module designed to fit optically thin spectral line emission. It is fully-automated and can deal with multiple velocity components, allowing for the quick and easy fitting of data cubes containing 10,000s of complex spectra.

    • BTS Github

  • J-plots is a Python module written by Dr Sarah Jaffa which quantifies the 2D and 3D morphology of pixelated structures using their moments of inertia. This technique can be applied to volume density cubes, column density maps or molecular line emission.

    • J-plots Github

  • FilChaP is a Python module written by Dr Sümeyye Suri which allows for the easy characterisation of filament properties, such as their width and length, in 2D and 3D.

    • FilChaP Github

Publications

Here is a list of my recent publications. Below one can find a complete list of my publications, a link to NASA ADS, and a copy of my thesis.

GMF G214.5-1.8 as traced by CO: I - cloud-scale CO freeze-out as a result of a low cosmic-ray ionisation rate:
Clarke, S. D. ; Makeev, V. A. ; Sánchez-Monge, Á. ; Williams, G. M. ; Tang, Y.-W. ; Walch, S. ; Higgins, R. ; Nürnberger, P. C. ; Suri, S.
Published 02/2024 MNRAS.

Filamentary Network and Magnetic Field Structures Revealed with BISTRO in the High-mass Star-forming Region NGC 2264: Global Properties and Local Magnetogravitational Configurations
Wang, J.-W. ; Koch, P. M. ; Clarke, S. D. ; Fuller, G. ; Peretto, N. ; Tang, Y.-W. ; Yen, H.-W. ; Lai, S.-P. ;
Ohashi, N. ; Arzoumanian, D. ; Johnstone, D. ; Furuya, R. ; Inutsuka, S. ; Lee, C. W. ; Ward-Thompson, D. ; BISTRO consortium
Published 02/2024 ApJ.

SILCC-Zoom: the dynamic balance in molecular cloud substructures:
Ganguly, S. ; Walch, S. ; Clarke, S. D. ; Seifried, D.
Published 02/2024 MNRAS.

Unravelling the structure of magnetised molecular clouds with SILCC-zoom: sheets, filaments and fragmentation:
Ganguly, S. ; Walch, S. ; Seifried, D. ; Clarke, S. D. ; Weis, M.
Published 10/2023 MNRAS.

From bubbles and filaments to cores and disks: Gas gathering and growth of structure leading to the formation of stellar systems:
Pineda, J. E.; Arzoumaninan, D.; Andre, Ph.; Friesen, R. K.; Zavagno, A.; Clarke, S. D.; Inoue, T.; Chen, C.-Y.; Lee, Y.-N.; Soler, J. D.; Kuffmeier, M.
Published 07/2023 PPVII ASPCS

A complete list of publications NASA ADS search My PhD. Thesis

Contact

Dr Seamus Clarke
Academia Sinica, Institute of Astronomy and Astrophysics,
Office 1103, 11F of Astronomy-Mathematics Building, AS/NTU,
No.1, Sec. 4, Roosevelt Rd,
Taipei 10617,
Taiwan, R.O.C.

sclarke at asiaa.sinica.edu.tw
https://github.com/SeamusClarke
ORCID: 0000-0001-9751-4603