Letter | Published:

The nature of giant clumps in distant galaxies probed by the anatomy of the cosmic snake

Nature Astronomyvolume 2pages7682 (2018) | Download Citation


Giant stellar clumps are ubiquitous in high-redshift galaxies1,2. They are thought to play an important role in the build-up of galactic bulges3 and as diagnostics of star formation feedback in galactic discs4. Hubble Space Telescope (HST) blank field imaging surveys have estimated that these clumps have masses of up to 109.5 M and linear sizes of 1 kpc5,6. Recently, gravitational lensing has also been used to get higher spatial resolution7,8,9. However, both recent lensed observations10,11 and models12,13 suggest that the clumps’ properties may be overestimated by the limited resolution of standard imaging techniques. A definitive proof of this observational bias is nevertheless still missing. Here we investigate directly the effect of resolution on clump properties by analysing multiple gravitationally lensed images of the same galaxy at different spatial resolutions, down to 30 pc. We show that the typical mass and size of giant clumps, generally observed at ~1 kpc resolution in high-redshift galaxies, are systematically overestimated. The high spatial resolution data, only enabled by strong gravitational lensing using currently available facilities, support smaller scales of clump formation by fragmentation of the galactic gas disk via gravitational instabilities.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from $8.99

All prices are NET prices.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


  1. 1.

    Elmegreen, D. M., Elmegreen, B. G., Ravindranath, S. & Coe, D. A. Resolved galaxies in the Hubble ultra deep field: star formation in disks at high redshift. Astrophys. J. 658, 763–777 (2007).

  2. 2.

    Dekel, A., Sari, R. & Ceverino, D. Formation of massive galaxies at high redshift: cold streams, clumpy disks, and compact spheroids. Astrophys. J. 703, 785–801 (2009).

  3. 3.

    Bournaud, F. in Galactic Bulges (eds E. Laurikainen, R. Peletier & D. Gadotti) Vol. 418, 355–390 (Springer, 2016)

  4. 4.

    Mayer, L. et al. Clumpy disks as a testbed for feedback-regulated galaxy formation. Astrophys. J. 830, L13–L19 (2016).

  5. 5.

    Guo, Y., Giavalisco, M., Ferguson, H. C., Cassata, P. & Koekemoer, A. M. Multi-wavelength view of kiloparsec-scale clumps in star-forming galaxies at z2. Astrophys. J. 757, 120–141 (2012).

  6. 6.

    Elmegreen, B. G. et al. Massive clumps in local galaxies: comparisons with high-redshift clumps. Astrophys. J. 774, 86–99 (2013).

  7. 7.

    Adamo, A. et al. High-resolution study of the cluster complexes in a lensed spiral at redshift 1.5: constraints on the bulge formation and disk evolution. Astrophys. J. 766, 105–130 (2013).

  8. 8.

    Wuyts, E., Rigby, J. R., Gladders, M. D. & Sharon, K. A magnified view of the kinematics and morphology of RCSGA 032727-132609: zooming in on a merger at z = 1.7. Astrophys. J. 781, 61–77 (2014).

  9. 9.

    Johnson, T. L. et al. Star formation at z = 2.481 in the lensed galaxy SDSS J1110 + 6459: star formation down to 30 pc scales. Astrophys. J. Lett. 843, L21–L25 (2017).

  10. 10.

    Dessauges-Zavadsky, M., Schaerer, D., Cava, A., Mayer, L. & Tamburello, V. On the stellar masses of giant clumps in distant star-forming galaxies. Astrophys. J. Lett. 836, L22–L27 (2017).

  11. 11.

    Rigby, J. R. et al. Star formation at z = 2.481 in the lensed galaxy SDSS J1110 + 6459. II. What is missed at the normal resolution of the Hubble Space Telescope? Astrophys. J. 843, 79–87 (2017).

  12. 12.

    Tamburello, V. et al. Clumpy galaxies seen in H-alpha: inflated observed clump properties due to limited spatial resolution and sensitivity. Mon. Not. Roy. Astron. Soc 468, 4792–4800 (2017).

  13. 13.

    Behrendt, M., Burkert, A. & Schartmann, M. Clusters of small clumps can explain the peculiar properties of giant clumps in high-redshift galaxies. Astrophys. J. Lett. 819, L2–L6 (2016).

  14. 14.

    Ebeling, H. et al. A spectacular giant arc in the massive cluster lens MACSJ1206.2-0847. Mon. Not. Roy. Astron. Soc. 395, 1213–1224 (2009).

  15. 15.

    Wisnioski, E. et al. Scaling relations of star-forming regions: from kpc-sized clumps to HII regions. Mon. Not. Roy. Astron. Soc. 422, 3339–3355 (2012).

  16. 16.

    Fisher, D. B. et al. DYNAMO-HST survey: clumps in nearby massive turbulent discs and the effects of clump clustering on kiloparsec scale measurements of clumps. Mon. Not. Roy. Astron. Soc. 464, 491–507 (2017).

  17. 17.

    Postman, M. et al. The Cluster Lensing and Supernova survey with Hubble: an overview. Astrophys. J. Suppl. Ser. 199, 25–47 (2012).

  18. 18.

    Bolzonella, M., Miralles, J.-M. & Pelló, R. Photometric redshifts based on standard SED fitting procedures. Astronom. Astrophys. 363, 476–492 (2000).

  19. 19.

    Tamburello, V., Mayer, L., Shen, S. & Wadsley, J. A lower fragmentation mass scale in high-redshift galaxies and its implications on giant clumps: a systematic numerical study. Mon. Not. Roy. Astron. Soc. 453, 2490–2514 (2015).

  20. 20.

    Bolatto, A. D., Leroy, A. K., Rosolowsky, E., Walter, F. & Blitz, L. The resolved properties of extragalactic giant molecular clouds. Astrophys. J. 686, 948–965 (2008).

  21. 21.

    Overzier, R. A. et al. Local Lyman break galaxy analogs: the impact of massive star-forming clumps on the interstellar medium and the global structure of young, forming galaxies. Astrophys. J. 706, 203–222 (2009).

  22. 22.

    Förster Schreiber, N. M. et al. Constraints on the assembly and dynamics of galaxies. II. Properties of kiloparsec-scale clumps in rest-frame optical emission of z2 star-forming galaxies. Astrophys. J. 739, 45–69 (2011).

  23. 23.

    Soto, E. et al. Physical properties of sub-galactic clumps at 0.5 ≤ z ≤ 1.5 in the UVUDF. Astrophys. J. 837, 6–20 (2017).

  24. 24.

    Genzel, R. et al. The SINS survey of z ~ 2 galaxy kinematics: properties of the giant star-forming clumps. Astrophys. J. 733, 101–130 (2011).

  25. 25.

    Mandelker, N. et al. Giant clumps in simulated high-z galaxies: properties, evolution and dependence on feedback. Mon. Not. Roy. Astron. Soc. 464, 635–665 (2017).

  26. 26.

    Oklopčić, A. et al. Giant clumps in the FIRE simulations: a case study of a massive high-redshift galaxy. Mon. Not. Roy. Astron. Soc. 465, 952–969 (2017).

  27. 27.

    Egami, E. et al. The Spitzer Massive Lensing Cluster Survey. Astron. Soc. Pacific Conf. Ser. 357, 242 (2006).

  28. 28.

    Egami, E. et al. The Herschel Lensing Survey (HLS): overview. Astronom. Astrophys 518, L12 (2010).

  29. 29.

    Pérez-González, P. G. et al. The stellar mass assembly of galaxies from z = 0 to z = 4: analysis of a sample selected in the rest-frame near-infrared with Spitzer. Astrophys. J. 675, 234–261 (2008).

  30. 30.

    Barro, G. et al. UV-to-FIR analysis of Spitzer/IRAC sources in the extended groth strip. I. Multi-wavelength photometry and spectral energy distributions. Astrophys. J. Suppl. Ser. 193, 13 (2011).

  31. 31.

    Barro, G. et al. UV-to-FIR analysis of Spitzer/IRAC sources in the extended groth strip. II. Photometric redshifts, stellar masses, and star formation rates. Astrophys. J. Suppl. Ser. 193, 30 (2011).

  32. 32.

    Buck, T. et al. NIHAO XIII: clumpy discs or clumpy light in high redshift galaxies? Mon. Not. Roy. Astron. Soc. 468, 3628–3649 (2017).

  33. 33.

    Ryan, R. E. iGalFit: an interactive tool for GalFit. Preprint at https://arxiv.org/abs/1110.1090 (2011)

  34. 34.

    Peng, C. Y., Ho, L. C., Impey, C. D. & Rix, H.-W. Detailed decomposition of galaxy images. II. Beyond axisymmetric models. Astronom. J. 139, 2097–2129 (2010).

  35. 35.

    Schlafly, E. F. & Finkbeiner, D. P. Measuring reddening with Sloan Digital Sky Survey stellar spectra and recalibrating SFD. Astrophys. J. 737, 103 (2011).

  36. 36.

    Schaerer, D. & de Barros, S. On the physical properties of z 6–8 galaxies. Astronom. Astrophys 515, A73 (2010).

  37. 37.

    Bruzual, G. & Charlot, S. Stellar population synthesis at the resolution of 2003. Mon. Not. Roy. Astron. Soc 344, 1000–1028 (2003).

  38. 38.

    Pérez-Montero, E. et al. Physical properties of galaxies and their evolution in the VIMOS VLT Deep Survey. II. Extending the mass-metallicity relation to the range z ≈ 0.89-1.24. Astronom. Astrophys 495, 73–81 (2009).

  39. 39.

    Kewley, L. J. & Dopita, M. A. Using strong lines to estimate abundances in extragalactic HII regions and starburst galaxies. Astrophys. J. Suppl. Ser. 142, 35–52 (2002).

  40. 40.

    Salpeter, E. E. The luminosity function and stellar evolution. Astrophys. J. 121, 161 (1955).

  41. 41.

    Calzetti, D. et al. The dust content and opacity of actively star-forming galaxies. Astrophys. J. 533, 682–695 (2000).

  42. 42.

    Schaerer, D., de Barros, S. & Sklias, P. Properties of z 3-6 Lyman break galaxies. I. Testing star formation histories and the SFR-mass relation with ALMA and near-IR spectroscopy. Astronom. Astrophys 549, A4 (2013).

  43. 43.

    Biviano, A. et al. CLASH-VLT: the mass, velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 galaxy cluster MACS J1206.2-0847. Astronom. Astrophys. 558, A1 (2013).

  44. 44.

    Eichner, T. et al. Galaxy halo truncation and giant arc surface brightness reconstruction in the cluster MACSJ1206.2-0847. Astrophys. J. 774, 124 (2013).

  45. 45.

    Zitrin, A. et al. CLASH: new multiple images constraining the inner mass profile of MACS J1206.2-0847. Astrophys. J. 749, 97 (2012).

  46. 46.

    Christensen, L. et al. The low-mass end of the fundamental relation for gravitationally lensed star-forming galaxies at 1 < z < 6. Mon. Not. Roy. Astron. Soc 427, 1953 (2012).

  47. 47.

    Richard, J., Kneib, J.-P., Limousin, M., Edge, A. & Jullo, E. Abell 370 revisited: refurbished Hubble imaging of the first strong lensing cluster. Mon. Not. Roy. Astron. Soc 402, L44–L48 (2010).

  48. 48.

    Jullo, E. et al. A Bayesian approach to strong lensing modelling of galaxy clusters. New J. Phys. 9, 447 (2007).

Download references


The work of A.C., D.S., M.D.-Z., L.M. and V.T. is supported by the STARFORM Sinergia Project funded by the Swiss National Science Foundation. J.R. acknowledges support from the European Research Council starting grant 336736-CALENDS. P.G.P.-P. acknowledges support from Spanish Government MINECO grants AYA2015-70815-ERC and AYA2015-63650-P. This work has made use of the Rainbow Cosmological Surveys Database, which is operated by the Universidad Complutense de Madrid (UCM), partnered with the University of California Observatories at Santa Cruz (UCO/Lick, UCSC). Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA).

Author information


  1. Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290, Versoix, Switzerland

    • Antonio Cava
    • , Daniel Schaerer
    •  & Miroslava Dessauges-Zavadsky
  2. CNRS, IRAP, 14 Avenue E. Belin, 31400, Toulouse, France

    • Daniel Schaerer
  3. Univ Lyon, Univ Lyon1, Ens de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon, UMR5574, F-69230, Saint-Genis-Laval, France

    • Johan Richard
  4. Departamento de Astrofísica y Ciencias de la Atmósfera, Facultad de CC. Físicas, Universidad Complutense de Madrid, E-28040, Madrid, Spain

    • Pablo G. Pérez-González
  5. Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland

    • Lucio Mayer
    •  & Valentina Tamburello
  6. Physik-Institut, University of Zurich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland

    • Lucio Mayer
    •  & Valentina Tamburello


  1. Search for Antonio Cava in:

  2. Search for Daniel Schaerer in:

  3. Search for Johan Richard in:

  4. Search for Pablo G. Pérez-González in:

  5. Search for Miroslava Dessauges-Zavadsky in:

  6. Search for Lucio Mayer in:

  7. Search for Valentina Tamburello in:


Data analysis and interpretation: A.C., D.S., J.R., P.P.-G., M.D.-Z., L.M. and V.T. SED fitting: D.S. and A.C. Photometry: A.C. and P.P-G. Lens modelling: J.R. and A.C. Drafting text, figures and methods: the bulk of the text was written by A.C. All authors commented on the manuscript at all stages.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Antonio Cava.

Electronic supplementary material

  1. Supplementary Information

    Supplementary Figures 1–10 and Supplementary Tables 1–5

About this article

Publication history