Abstract
Young massive clusters (M ≥ 104Mʘ) are proposed modern-day analogues of the globular clusters that were products of extreme star formation in the early Universe1,2,3,4. The exact conditions and mechanisms under which young massive clusters form remain unknown4,5—a fact further complicated by the extreme radiation fields produced by their numerous young stars6,7,8,9. Here, we show that massive clusters are naturally produced in radiation-hydrodynamic simulations of isolated 107Mʘ giant molecular clouds with properties typical of the local Universe, even under the influence of radiative feedback. In all cases, these massive clusters grow to globular cluster masses within 5 million years (Myr) via a roughly equal combination of filamentary gas accretion and mergers with less massive clusters. Lowering the heavy-element abundance of the molecular cloud by a factor of ten reduces the opacity of the gas and better represents the high-redshift Universe10,11. This results in higher gas accretion, leading to a mass increase of the largest cluster by a factor of around four. When combined with simulations of less massive molecular clouds12 (104–6Mʘ), a clear relation emerges between the maximum cluster mass and the mass of the host cloud13. Our results indicate that young massive clusters—and potentially globular clusters—are simple power-law extensions of local cluster formation, and are insensitive to star formation thresholds. A universal picture emerges without the need for exotic formation scenarios13–15.
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References
Kruijssen, J. M. D. Globular clusters as the relics of regular star formation in ‘normal’ high-redshift galaxies. Mon. Not. R. Astron. Soc. 454, 1658–1686 (2015).
Longmore, S. N. et al. in Protostars and Planets VI 291–314 (Univ. Arizona Press, Tucson, AZ, 2014).
Portegies Zwart, S. F., McMillan, S. L. W. & Gieles, M. Young massive star clusters. Annu. Rev. Astron. Astrophys. 48, 431–493 (2010).
Bastian, N. in Stellar Clusters: Benchmarks of Stellar Physics and Galactic Evolution – EES2015 Vol. 80–81 (eds Moraux, E., Lebreton, Y. & Charbonnel, C.) 5–37 (EDP Sciences, Les Ulis, 2016).
Walker, D. L. et al. Comparing young massive clusters and their progenitor clouds in the Milky Way. Mon. Not. R. Astron. Soc. 457, 4536–4545 (2016).
Dale, J. E., Bonnell, I. A., Clark, C. J. & Bate, M. R. Photoionizing feedback in star cluster formation. Mon. Not. R. Astron. Soc. 358, 291–304 (2005).
Krumholz, M. R. & Matzner, C. D. The dynamics of radiation-pressure-dominated H II regions. Astrophys. J. 703, 1352–1362 (2009).
Murray, N., Quataert, E. & Thompson, T. A. The disruption of giant molecular clouds by radiation pressure and the efficiency of star formation in galaxies. Astrophys. J. 709, 191–209 (2010).
Dale, J. E., Ercolano, B. & Bonnell, I. A. Ionizing feedback from massive stars in massive clusters—II. Disruption of bound clusters by photoionization. Mon. Not. R. Astron. Soc. 424, 377–392 (2012).
Erb, D. K. et al. The mass–metallicity relation at z ~2. Astrophys. J. 644, 813–828 (2006).
Maiolino, R. et al. AMAZE. I. The evolution of the mass–metallicity relation at z 3. Astron. Astrophys. 488, 463–479 (2008).
Howard, C. S., Pudritz, R. E. & Harris, W. E. Simulating radiative feedback and star cluster formation in GMCs—II. Mass dependence of cloud destruction and cluster properties. Mon. Not. R. Astron. Soc. 470, 3346–3358 (2017).
Moore, B., Diemand, J., Madau, P., Zemp, M., & Stadel, J. Globular clusters, satellite galaxies and stellar haloes from early dark matter peaks. Mon. Not. R. Astron. Soc. 368, 563–570 (2006).
Renzini, A. et al. The Hubble space telescope UV legacy survey of galactic globular clusters—V. Constraints on formation scenarios. Mon. Not. R. Astron. Soc. 454, 4197–4207 (2015).
D’Ercole, A., D’Antona, F., & Vesperini, E. Accretion of pristine gas and dilution during the formation of multiple-population globular clusters. Mon. Not. R. Astron. Soc. 461, 4088–4098 (2016).
Fukui, Y. & Kawamura, A. Molecular clouds in nearby galaxies. Annu. Rev. Astron. Astrophys. 48, 547–580 (2010).
Heyer, M. & Dame, T. M. Molecular clouds in the Milky Way. Annu. Rev. Astron. Astrophys. 53, 593–629 (2015).
Lada, C. J. & Lada, E. A. Embedded clusters in molecular clouds. Annu. Rev. Astron. Astrophys. 41, 57–115 (2003).
Fall, M. S. & Chandar, R. Similarities in populations of star clusters. Astrophys. J. 752, 96 (2012).
Brodie, J. P. & Strader, J. Extragalactic globular clusters and galaxy formation. Annu. Rev. Astron. Astrophys. 44, 193–267 (2006).
Harris, W. E. Massive star clusters in galaxies. Philos. Trans. R. Soc. A 386, 889–906 (2010).
Vanzella, E. et al. Paving the way for the JWST: witnessing globular cluster formation at z > 3. Mon. Not. R. Astron. Soc. 467, 4303–4321 (2017).
Bouwens, R. J. et al. Very low-luminosity galaxies in the early universe have observed sizes similar to single star cluster complexes. Preprint at https://arxiv.org/abs/1711.02090 (2017).
Lada, C. J., Forbrich, L., Lombardi, M. & Alves, J. F. Star formation rates in molecular clouds and the nature of the extragalactic scaling relations. Astrophys. J. 745, 190 (2012).
Shapiro, K. L., Genzel, R., Förster, S. & Natascha, M. Star-forming galaxies at z ~ 2 and the formation of the metal-rich globular cluster population. Mon. Not. R. Astron. Soc. Lett. 403, L36–L40 (2010).
Rogers, H. & Pittard, J. M. Feedback from winds and supernovae in massive stellar clusters—I. Hydrodynamics. Mon. Not. R. Astron. Soc. 431, 1337–1351 (2013).
Sabbi, E. et al. Hubble tarantula treasury project. III. Photometric catalog and resulting constraints on the progression of star formation in the 30 Doradus region. Astrophys. J. Supp. 222, 11 (2016).
Reina-Campos, M. & Kruijssen, J. M. D. A. A unified model for the maximum mass-scales of molecular clouds, stellar clusters, and high-redshift clumps. Mon. Not. R. Astron. Soc. 469, 1282–1298 (2017).
Elmegreen, B. G. Globular cluster formation at high density: a model for elemental enrichment with fast recycling of massive-star debris. Astrophys. J. 836, 80 (2017).
Agertz, O. & Kravstov, A. V. On the interplay between star formation and feedback in galaxy formation simulations. Astrophys. J. 804, 18 (2015).
Fryxwell, B. et al. FLASH: an adaptive mesh hydrodynamics code for modeling astrophysical thermonuclear flashes. Astrophys. J. Suppl. Ser. 131, 273–334 (2000).
MacNeice, P., Olson, K. M., Mobarry, C. M., de Fainchtein, R. & Packer, C. PARAMESH: a parallel adaptive mesh refinement community toolkit. Comput. Phys. Commun. 126, 330–354 (2000).
Banerjee, R. & Pudritz, R. E. Outflows and jets from collapsing magnetized cloud cores. Astrophys. J. 641, 949–960 (2006).
Neufeld, D. A.., Lepp, S. & Melnick, G. J. Thermal balance in dense molecular clouds: radiative cooling rates and emission-line luminosities. Astrophys. J. Suppl. Ser. 100, 132 (1995).
Goldsmith, P. F. Molecular depletion and thermal balance in dark cloud cores. Astrophys. J. 557, 736–746 (2001).
Federrath, C., Banerjee, R., Clark, P. C. & Klessen, R. S. Modeling collapse and accretion in turbulent gas clouds: implementation and comparison of sink particles in AMR and SPH. Astrophys. J. 713, 269–290 (2010).
Howard, C. S., Pudritz, R. E., & Harris, W. E. Cluster formation in molecular clouds—I. Stellar populations, star formation rates and ionizing radiation. Mon. Not. R. Astron. Soc. 438, 1305–1317 (2014).
Krumholz, M. R. & McKee, C. F. A general theory of turbulence-regulated star formation, from spirals to ultraluminous infrared galaxies. Astrophys. J. 630, 250–268 (2005).
Padoan, P. & Nordlund, Å. The star formation rate of supersonic magnetohydrodynamic turbulence. Astrophys. J. 730, 40 (2011).
Chabrier, G. in The Initial Mass Function 50 Years Later Vol. 327 (eds Corbelli, E., Palla, F. & Zinnecker, H.) 41–50 (Springer, Dordrecht, 2005).
Tout, C. A., Pols, O. R., Eggleton, P. P. Han, Z. Zero-age main-sequence radii and luminosities as analytic functions of mass and metallicity. Mon. Not. R. Astron. Soc. 281, 257–262 (1996).
Rijkhorst, E. J., Plewa, T., Dubey, A., Mellema, G. Hybrid characteristics: 3D radiative transfer for parallel adaptive mesh refinement hydrodynamics. Astron. Astrophys. 452, 907–920 (2006).
Peters, T. et al. H ii regions: witnesses to massive star formation. Astrophys. J. 711, 1017–1028 (2010).
Frank, A. & Mellema, G. A. A radiation-gasdynamical method for numerical simulations of ionized nebulae: radiation-gasdynamics of PNe I. Astron. Astrophys. 289, 937–945 (1994).
Pollack, J. B. et al. Composition and radiative properties of grains in molecular clouds and accretion disks. Astrophys. J. 421, 615–639 (1994).
Li, A. & Draine, B. T. Infrared emission from interstellar dust. II. The diffuse interstellar medium. Astrophys. J. 554, 778–802 (2001).
Rémy-Ruyer, A. et al. Gas-to-dust mass ratios in local galaxies over a 2 dex metallicity range. Astron. Astrophys. 563, A31 (2014).
Girichidis, P., Federrath, C., Banerjee, R., Klessen, R. S. Importance of the initial conditions for star formation—I. Cloud evolution and morphology. Mon. Not. R. Astron. Soc. 413, 2741–2759 (2011).
Howard, C. S., Pudritz, R. E. & Harris, W. E. Simulating radiative feedback and star cluster formation in GMCs—I. Dependence on gravitational boundedness. Mon. Not. R. Astron. Soc. 461, 2953–2974 (2016).
Georgy, C. et al. Grids of stellar models with rotation III. Models from 0.8 to 120 M at a metallicity Z = 0.002. Astron. Astrophys. 558, A103 (2013).
Rathborne, J. M. et al. Turbulence sets the initial conditions for star formation in high-pressure environments. Astrophys. J. 795, L24 (2014).
Bigiel, F. et al. The EMPIRE survey: systematic variations in the dense gas fraction and star formation efficiency from full-disk mapping of M51. Astrophys. J. 822, L26 (2016).
Turk, M. J. et al. YT: a multi-code analysis toolkit for astrophysical simulation data. Astrophys. J. Suppl. Ser. 192, 9 (2011).
Acknowledgements
This research was financially supported by the Natural Sciences and Engineering Research Council through a postgraduate scholarship and Discovery Grants. Computations were performed on the GPC supercomputer at the SciNet HPC Consortium. SciNet is funded by the Canada Foundation for Innovation under the auspices of Compute Canada; Government of Ontario; the Ontario Research Fund: Research Excellence; and the University of Toronto.
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C.S.H. carried out the simulations and completed the data analysis and figure production. All authors contributed to the interpretation of the results and were involved in writing the final manuscript.
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Supplementary Information
Supplementary Figures 1–5, Supplementary Video captions 1–6, Supplementary discussion
Supplementary Video 1
Full cloud visualization of the column density and cluster movement for the solar metallicity (Zʘ) simulation
Supplementary Video 2
Zoomin of the central 35 pc region showing only the clusters that merge to the young massive cluster (1 Zʘ simulation)
Supplementary Video 3
Full cloud visualization of the column density and cluster movement for the 0.1 Zʘ simulation
Supplementary Video 4
Zoom-in of the central 35 pc region showing only the clusters that merge to the young massive cluster (0.1 Zʘ simulation)
Supplementary Video 5
The density and gas flow rate of a 5 pc spherical region centered on the 1 Zʘ young massive cluster
Supplementary Video 6
The density and gas flow rate of a 5 pc spherical region centered on the 0.1 Zʘ young massive cluster
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Howard, C.S., Pudritz, R.E. & Harris, W.E. A universal route for the formation of massive star clusters in giant molecular clouds. Nat Astron 2, 725–730 (2018). https://doi.org/10.1038/s41550-018-0506-0
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DOI: https://doi.org/10.1038/s41550-018-0506-0
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