Scientific Articles

Click here to see the full publication list on NASA/ADS.

Click here to download the publication list in PDF format.


35. Gaches, B.A.L., Bisbas, T.G., and Bialy, S. 2022, A&A, 658, 151

The Impact of Cosmic-Ray Attenuation on the Carbon Cycle Emission in Molecular Clouds


34. Bisbas, T.G., Tan, J.C. and Tanaka, K.E.I., 2021, MNRAS, 502, 2701

Photodissociation Region Diagnostics Across Galactic Environments


33. Lim, W. Nakamura F., Wu, B., Bisbas, T.G., Tan J.C., et al., 2021, PASJ, 73, S239

Star Cluster Formation in Orion A


32. Seifried, D., Haid, S., Walch, S., Borchert, E.M., Bisbas, T.G., 2020, MNRAS, 492, 1465

SILCC-Zoom: H2 and CO-dark gas in molecular clouds — The Impact of feedback and magnetic fields


31. Gaches, B. A. L., Offner, S. S. R., Bisbas, T.G., 2019, ApJ, 883, 190

The Astrochemical Impact of Cosmic Rays in Protoclusters II: CI-to-H2 and CO-to-H2 conversion factors


30. Gaches, B. A. L., Offner, S. S. R., Bisbas, T. G., 2019, ApJ, 878, 105

The Astrochemical Impact of Cosmic Rays in Protoclusters I: Molecular Cloud Chemistry


29. Bisbas, T. G., Schruba, A. & van Dishoeck, E.F., 2019, MNRAS, 485, 3097

Simulating the atomic and molecular content of molecular clouds using probability distributions of physical parameters


28. Williams, R. J. R., Bisbas, T. G., Haworth, T. J., Mackey, J., 2018, MNRAS, 479, 2018.

The classical D-type expansion of spherical HII regions


27. Banerji, M., Jones, G. C., Wagg, J., Carilli, C. L., Bisbas, T. G., Hewett, P. C., 2018, MNRAS, 479, 1154.

The interstellar medium properties of heavily reddened quasars and companions at z~2.5 with ALMA and JVLA


26. Haworth, T. J., Glover S. C. O., Koepferl, C. M., Bisbas, T. G., Dale, J. E., 2018, New Astronomy Reviews, 82, 1.

Synthetic observations of star formation and the interstellar medium [Review article]


25. Papadopoulos, P. P., Bisbas, T. G., Zhang Z-Y., 2018, MNRAS, 478, 1716.

New places and phases of CO-poor/CI-rich molecular gas in the Universe


24. Bisbas, T. G., Tan, J. C., Csengeri, T., Wu, B., Lim, W., and 4 co-authors, 2018, MNRAS, 478L, 54.

The inception of star cluster formation revealed by [CII] emission around an Infrared Dark Cloud


23. Li, Q., Tan, J. C., Christie, D., Bisbas, T. G., & Wu, B., 2017, PASJ, 70, 56.

The interstellar medium and star formation of galactic disks. I. Interstellar medium and giant molecular cloud properties with diffuse far-ultraviolet and cosmic-ray backgrounds


22. Bisbas, T. G., Tanaka, K. E. I., Tan, J. C., Wu, B., & Nakamura, F., 2017, ApJ, 850, 23.

GMC Collisions as Triggers of Star Formation. V. Observational Signatures


21. Bothwell, M. S., Aguirre, J. E., Aravena, M., Bethermin, M., Bisbas, T. G., et al., 2017, MNRAS, 466, 2825.

ALMA observations of atomic carbon in z~4 dusty star-forming galaxies


20. Bisbas, T. G., van Dishoeck, E. F., Papadopoulos, P. P., Szücs, L., Bialy, S., & Zhang, Z-Y, 2017, ApJ, 839, 90.

Cosmic-ray Induced Destruction of CO in Star-forming Galaxies


19. Accurso, G., Saintonge, A., Bisbas, T. G., & Viti, S., 2017, MNRAS, 464, 3315.

Radiative transfer meets Bayesian statistics: where does a galaxy’s [CII] emission come from?


18. Haworth, T. J., Boubert, D., Facchini, S., Bisbas, T. G., & Clarke, C. J., 2016, MNRAS, 463, 3616.

Photochemical-dynamical models of externally FUV irradiated protoplanetary discs


17. Krips, M., Martín, S., Sakamoto, K., Aalto, S., Bisbas, T.G., et al., 2016, A&A, 592, L3.

ACA [CI] observations of the starburst galaxy NGC 253


16. Facchini, S., Clarke, C. J., & Bisbas, T. G. 2016, MNRAS, 457, 3593.

External photoevaporation of protoplanetary discs in sparse stellar groups: the impact of dust growth


15. Bisbas, T. G., Haworth, T. J., Barlow, M. J., Viti, S., and 3 co-authors, 2015 , MNRAS, 454, 2828.

TORUS-3DPDR: a self-consistent code treating three-dimensional photoionization and photodissociation regions


14. Haworth, T. J., Harries, T. J., Acreman, D. M., & Bisbas, T. G., 2015, MNRAS, 453, 2277.

On the relative importance of different microphysics on the D-type expansion of galactic H II regions


13. Bisbas, T. G., Haworth, T. J., Williams, R. J. R., Mackey, J., and 15 co-authors, 2015, MNRAS, 453, 1324.

STARBENCH: the D-type expansion of an HII region


12. Walch, S., Whitworth, A. P., Bisbas, T. G., Hubber, D. A., Wünsch, R. 2015, MNRAS, 452, 2794.

Comparing simulations of ionization triggered star formation and observations in RCW 120


11. Bisbas, T. G., Papadopoulos, P. P., & Viti, S. 2015, ApJ, 803, 37.

Effective Destruction of CO by Cosmic Rays: Implications for Tracing H2 Gas in the Universe


10. Gaches, B. A. L., Offner, S. S. R., Rosolowsky, E. W., & Bisbas, T. G., 2015, ApJ, 799, 235.

Astrochemical Correlations in Molecular Clouds


9. Bisbas, T. G., Bell, T. A., Viti, S., Barlow, M.J., Yates, J.A., & Vasta, M., 2014, MNRAS, 443, 111.

A photodissociation region study of NGC 4038


8. Offner, S. S. R., Bisbas, T. G., Bell, T. A., & Viti, S. 2014, MNRAS, 440, L81.

An alternative accurate tracer of molecular clouds: the ‘XCI-factor’


7. Walch, S., Whitworth, A. P., Bisbas, T. G., Wünsch, R., & Hubber, D. A. 2013, MNRAS, 435, 917.

Clumps and triggered star formation in ionized molecular clouds


6. Offner, S. S. R., Bisbas, T. G., Viti, S., & Bell, T. A. 2013, ApJ, 770, 49.

Modeling the atomic-to-molecular Transition and Chemical Distributions of Turbulent Star-forming Clouds


5. Bisbas, T. G., Bell, T. A., Viti, S., Yates, J., & Barlow, M. J. 2012, MNRAS, 427, 2100.

3D-PDR: a new three-dimensional astrochemistry code for treating photodissociation regions

Click here to visit the code website


4. Walch, S. K., Whitworth, A. P., Bisbas, T., Wünsch, R., & Hubber, D. 2012, MNRAS, 427, 625.

Dispersal of molecular clouds by ionizing radiation


3. Bisbas, T. G., Wünsch, R., Whitworth, A. P., Hubber, D. A., & Walch, S. 2011, ApJ, 736, 142.

Radiation-driven Implosion and Triggered Star Formation


2. Bisbas, T. G., Wünsch, R., Whitworth, A. P., & Hubber, D. A. 2009, A&A, 497, 649.

Smoothed particle hydrodynamics simulations of expanding HII regions. I. Numerical method and applications


1. Stamatellos, D., Whitworth, A. P., Bisbas, T.G., & Goodwin, S. 2007, A&A, 475, 37.

Radiative transfer and the energy equation in SPH simulations of star formation


I have written the book “The Interstellar Medium, Expanding Nebulae and Triggered Star Formation; theory and simulations”, published by Springer (Springer Briefs in Astronomy).


The book brings together the theoretical aspects of star formation and ionized regions with the most up-to-date simulations and observations. Beginning with the basic theory of star formation, the physics of expanding HII regions are reviewed in detail and a discussion on how a massive star can give birth to tens or hundreds of other stars follows. The theoretical description of star formation is shown in simplified and state-of-the-art numerical simulations, describing in a more clear way how feedback from massive stars can trigger star and planet formation. This is also combined with spectacular images of nebulae taken by talented amateur astronomers. The latter is very likely to stimulate the reader to observe the structure of nebulae from a different point of view, and to better understand the associated star formation therein.


Ph.D. Thesis

Click here to download my PhD Thesis (2009, Cardiff University)


Abstract: This thesis deals with numerical simulations of expanding ionized regions, known as HII regions. We implement a new three dimensional algorithm in Smoothed Particle Hydrodynamics for including the dynamical effects of the interaction between ionizing radiation and the interstellar medium. This interaction plays a crucial role in star formation at all epochs. We study the influence of ionizing radiation in spherically symmetric clouds. In particular, we study the spherically symmetric expansion of an HII region inside a uniform-density, non-self-gravitating cloud. We examine the ability of our algorithm to reproduce the known theoretical solution and we find that the agreement is very good. We also study the spherically symmetric expansion inside a uniform-density, self-gravitating cloud. We propose a new differential equation of motion for the expanding shell that includes the effects of gravity. Comparing its numerical solution with the simulations, we find that the equation predicts the position of the shell accurately. We also study the expansion of an off-centre HII region inside a uniform-density, non- self-gravitating cloud. This results in an evolution known as the rocket effect, where the ionizing radiation pushes and accelerates the cloud away from the exciting star leading to its dispersal. During this evolution, cometary knots appear as a result of Rayleigh-Taylor and Vishniac instabilities. The knots are composed of a dense head with a conic tail behind them, a structure that points towards the ionizing source. Our simulations show that these knots are very reminiscent of the observed structures in planetary nebula, such as in the Helix nebula. The last part of this thesis is dedicated to the study of cores ionized by an exciting source which is placed outside and far away from them. The evolution of these cores is known as radiation driven compression (or implosion). We perform simulations and compare our findings with results of other workers and we find that they agree very well. Using stable Bonnor-Ebert spheres, we extend our study to modelling triggered star formation within these cores as they are overrun and compressed by the incident ionizing flux. We construct a parameter space diagram and we map regions where star formation is expected to be observed. All the above results indicate that the algorithm presented in this thesis works well for treating the propagation of ionizing radiation. This new algorithm provides the means to explore and evaluate the role of ionizing radiation in regulating the efficiency and statistics of star formation.