A galaxy lacking dark matter


Studies of galaxy surveys in the context of the cold dark matter paradigm have shown that the mass of the dark matter halo and the total stellar mass are coupled through a function that varies smoothly with mass. Their average ratio Mhalo/Mstars has a minimum of about 30 for galaxies with stellar masses near that of the Milky Way (approximately 5 × 1010 solar masses) and increases both towards lower masses and towards higher masses1,2. The scatter in this relation is not well known; it is generally thought to be less than a factor of two for massive galaxies but much larger for dwarf galaxies3,4. Here we report the radial velocities of ten luminous globular-cluster-like objects in the ultra-diffuse galaxy5 NGC1052–DF2, which has a stellar mass of approximately 2 × 108 solar masses. We infer that its velocity dispersion is less than 10.5 kilometres per second with 90 per cent confidence, and we determine from this that its total mass within a radius of 7.6 kiloparsecs is less than 3.4 × 108 solar masses. This implies that the ratio Mhalo/Mstars is of order unity (and consistent with zero), a factor of at least 400 lower than expected2. NGC1052–DF2 demonstrates that dark matter is not always coupled with baryonic matter on galactic scales.

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Figure 1: HST/Advanced Camera for Surveys (ACS) image of NGC1052–DF2.
Figure 2: Spectra of the compact objects.
Figure 3: Velocity dispersion.
Figure 4: Constraints on the halo mass.


  1. 1

    Moster, B. P. et al. Constraints on the relationship between stellar mass and halo mass at low and high redshift. Astrophys. J. 710, 903–923 (2010)

    ADS  CAS  Article  Google Scholar 

  2. 2

    Behroozi, P. S., Wechsler, R. H. & Conroy, C. The average star formation histories of galaxies in dark matter halos from z = 0–8. Astrophys. J. 770, 57 (2013)

    ADS  Article  Google Scholar 

  3. 3

    More, S. et al. Satellite kinematics—III. Halo masses of central galaxies in SDSS. Mon. Not. R. Astron. Soc. 410, 210–226 (2011)

    ADS  Article  Google Scholar 

  4. 4

    Oman, K. A. et al. Missing dark matter in dwarf galaxies? Mon. Not. R. Astron. Soc. 460, 3610–3623 (2016)

    ADS  CAS  Article  Google Scholar 

  5. 5

    van Dokkum, P. G. et al. Forty-seven Milky Way-sized, extremely diffuse galaxies in the Coma cluster. Astrophys. J. 798, L45 (2015)

    ADS  Article  Google Scholar 

  6. 6

    Abraham, R. G. & van Dokkum, P. G. Ultra-low surface brightness imaging with the Dragonfly telephoto array. Publ. Astron. Soc. Pac. 126, 55–69 (2014)

    ADS  Article  Google Scholar 

  7. 7

    Karachentsev, I. D., Karachentseva, V. E., Suchkov, A. A. & Grebel, E. K. Dwarf galaxy candidates found on the SERC EJ sky survey. Astron. Astrophys. Suppl. Ser. 145, 415–423 (2000)

    ADS  Article  Google Scholar 

  8. 8

    Danieli, S. et al. The Dragonfly Nearby Galaxies Survey. III. The luminosity function of the M101 group. Astrophys. J. 837, 136 (2017)

    ADS  Article  Google Scholar 

  9. 9

    Tonry, J. L. et al. The SBF survey of galaxy distances. IV. SBF magnitudes, colors, and distances. Astrophys. J. 546, 681–693 (2001)

    ADS  Article  Google Scholar 

  10. 10

    Blakeslee, J. P., Lucey, J. R., Barris, B. J., Hudson, M. J. & Tonry, J. L. A synthesis of data from fundamental plane and surface brightness fluctuation surveys. Mon. Not. R. Astron. Soc. 327, 1004–1020 (2001)

    ADS  CAS  Article  Google Scholar 

  11. 11

    Peng, C. Y., Ho, L. C., Impey, C. D. & Rix, H.-W. Detailed structural decomposition of galaxy images. Astron. J. 124, 266–293 (2002)

    ADS  Article  Google Scholar 

  12. 12

    van Dokkum, P. et al. Extensive globular cluster systems associated with ultra diffuse galaxies in the Coma cluster. Astrophys. J. 844, L11 (2017)

    ADS  Article  Google Scholar 

  13. 13

    McLaughlin, D. E. & van der Marel, R. P. Resolved massive star clusters in the Milky Way and its satellites: brightness profiles and a catalog of fundamental parameters. Astrophys. J. Suppl. Ser. 161, 304–360 (2005)

    ADS  CAS  Article  Google Scholar 

  14. 14

    Beasley, M. A. et al. An overmassive dark halo around an ultra-diffuse galaxy in the Virgo cluster. Astrophys. J. 819, L20 (2016)

    ADS  Article  Google Scholar 

  15. 15

    McConnachie, A. W. The observed properties of dwarf galaxies in and around the Local Group. Astron. J. 144, 4 (2012)

    ADS  Article  Google Scholar 

  16. 16

    Watkins, L. L., Evans, N. W. & An, J. H. The masses of the Milky Way and Andromeda galaxies. Mon. Not. R. Astron. Soc. 406, 264–278 (2010)

    ADS  CAS  Article  Google Scholar 

  17. 17

    Wolf, J. et al. Accurate masses for dispersion-supported galaxies. Mon. Not. R. Astron. Soc. 406, 1220–1237 (2010)

    ADS  Google Scholar 

  18. 18

    Bournaud, F. et al. Missing mass in collisional debris from galaxies. Science 316, 1166 (2007)

    ADS  CAS  Article  Google Scholar 

  19. 19

    Ploeckinger, S. et al. Tidal dwarf galaxies in cosmological simulations. Mon. Not. R. Astron. Soc. 474, 580–596 (2018)

    ADS  CAS  Article  Google Scholar 

  20. 20

    Natarajan, P., Sigurdsson, S. & Silk, J. Quasar outflows and the formation of dwarf galaxies. Mon. Not. R. Astron. Soc. 298, 577–582 (1998)

    ADS  Article  Google Scholar 

  21. 21

    Canning, R. E. A. et al. Filamentary star formation in NGC 1275. Mon. Not. R. Astron. Soc. 444, 336–349 (2014)

    ADS  Article  Google Scholar 

  22. 22

    Mandelker, N., van Dokkum, P. G., Brodie, J. P. & Ceverino, D. Cold filamentary accretion and the formation of metal poor globular clusters. Preprint at https://arxiv.org/abs/1711.09108 (2017)

  23. 23

    van Breugel, W., Filippenko, A. V., Heckman, T. & Miley, G. Minkowski’s object—a starburst triggered by a radio jet. Astrophys. J. 293, 83–93 (1985)

    ADS  CAS  Article  Google Scholar 

  24. 24

    Clowe, D. et al. A direct empirical proof of the existence of dark matter. Astrophys. J. 648, L109–L113 (2006)

    ADS  CAS  Article  Google Scholar 

  25. 25

    Milgrom, M. A modification of the Newtonian dynamics as a possible alternative to the hidden mass hypothesis. Astrophys. J. 270, 365–370 (1983)

    ADS  Article  Google Scholar 

  26. 26

    Verlinde, E. P. Emergent gravity and the dark universe. SciPost Phys. 2, 016 (2017)

    ADS  Article  Google Scholar 

  27. 27

    Kroupa, P. The dark matter crisis: falsification of the current standard model of cosmology. Publ. Astron. Soc. Aust. 29, 395–433 (2012)

    ADS  Article  Google Scholar 

  28. 28

    Angus, G. W. Dwarf spheroidals in MOND. Mon. Not. R. Astron. Soc. 387, 1481–1488 (2008)

    ADS  Article  Google Scholar 

  29. 29

    Navarro, J. F., Frenk, C. S. & White, S. D. M. A universal density profile from hierarchical clustering. Astrophys. J. 490, 493–508 (1997)

    ADS  Article  Google Scholar 

  30. 30

    Rodríguez-Puebla, A., Primack, J. R., Avila-Reese, V. & Faber, S. M. Constraining the galaxy–halo connection over the last 13.3 Gyr: star formation histories, galaxy mergers and structural properties. Mon. Not. R. Astron. Soc. 470, 651–687 (2017)

    ADS  Article  Google Scholar 

  31. 31

    Merritt, A., van Dokkum, P., Abraham, R. & Zhang, J. The Dragonfly Nearby Galaxies Survey. I. Substantial variation in the diffuse stellar halos around spiral galaxies. Astrophys. J. 830, 62 (2016)

    ADS  Article  Google Scholar 

  32. 32

    Abolfathi, B. et al. The Fourteenth Data Release of the Sloan Digital Sky Survey: first spectroscopic data from the extended Baryon Oscillation Sky Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment. Preprint available at http://arxiv.org/abs/1707.09322 (2017)

  33. 33

    Napolitano, N. R. et al. The Planetary Nebula Spectrograph elliptical galaxy survey: the dark matter in NGC 4494. Mon. Not. R. Astron. Soc. 393, 329–353 (2009)

    ADS  CAS  Article  Google Scholar 

  34. 34

    Hook, I. M. et al. The Gemini-North Multi-Object Spectrograph: Performance in imaging, long-slit, and multi-object spectroscopic modes. Publ. Astron. Soc. Pac. 116, 425–440 (2004)

    ADS  Article  Google Scholar 

  35. 35

    Bertin, E. & Arnouts, S. SExtractor: Software for source extraction. Astron. Astrophys. Suppl. 117, 393–404 (1996)

    ADS  Google Scholar 

  36. 36

    Sersic, J. L. Atlas de galaxias australes (Observatorio Astronomico, Cordoba, 1968)

  37. 37

    Faber, S. M . et al. in Instrument Design and Performance for Optical/Infrared Ground-based Telescopes, Proc. SPIE Vol. 4841 (eds Iye, M . & Moorwood, A. F. M. ) 1657–1669 (SPIE, 2003)

  38. 38

    Oke, J. B. et al. The Keck Low-Resolution Imaging Spectrometer. Publ. Astron. Soc. Pac. 107, 375 (1995)

    ADS  Article  Google Scholar 

  39. 39

    van Dokkum, P. et al. A high stellar velocity dispersion and ~100 globular clusters for the ultra-diffuse galaxy Dragonfly 44. Astrophys. J. 828, L6 (2016)

    ADS  Article  Google Scholar 

  40. 40

    Foreman-Mackey, D., Hogg, D. W., Lang, D. & Goodman, J. emcee: The MCMC hammer. Publ. Astron. Soc. Pac. 125, 306–312 (2013)

    ADS  Article  Google Scholar 

  41. 41

    Conroy, C., Gunn, J. E. & White, M. The propagation of uncertainties in stellar population synthesis modeling. I. The relevance of uncertain aspects of stellar evolution and the initial mass function to the derived physical properties of galaxies. Astrophys. J. 699, 486–506 (2009)

    ADS  Article  Google Scholar 

  42. 42

    van Dokkum, P. G., Kriek, M. & Franx, M. A high stellar velocity dispersion for a compact massive galaxy at redshift z = 2.186. Nature 460, 717–719 (2009)

    ADS  CAS  Article  Google Scholar 

  43. 43

    Beers, T. C., Flynn, K. & Gebhardt, K. Measures of location and scale for velocities in clusters of galaxies—a robust approach. Astron. J. 100, 32–46 (1990)

    ADS  Article  Google Scholar 

  44. 44

    Mould, J. R. et al. The Hubble Space Telescope Key Project on the extragalactic distance scale. XXVIII. Combining the constraints on the Hubble constant. Astrophys. J. 529, 786–794 (2000)

    ADS  Article  Google Scholar 

  45. 45

    Rejkuba, M. Globular cluster luminosity function as distance indicator. Astrophys. Space Sci. 341, 195–206 (2012)

    ADS  Article  Google Scholar 

  46. 46

    Mei, S. et al. The Advanced Camera for Surveys Virgo Cluster Survey. V. Surface brightness fluctuation calibration for giant and dwarf early-type galaxies. Astrophys. J. 625, 121–129 (2005)

    ADS  Article  Google Scholar 

  47. 47

    Blakeslee, J. P. et al. Surface brightness fluctuations in the Hubble Space Telescope ACS/WFC F814W bandpass and an update on galaxy distances. Astrophys. J. 724, 657–668 (2010)

    ADS  Article  Google Scholar 

  48. 48

    Bahcall, J. N. & Tremaine, S. Methods for determining the masses of spherical systems. I—Test particles around a point mass. Astrophys. J. 244, 805–819 (1981)

    ADS  Article  Google Scholar 

  49. 49

    Danieli, S., van Dokkum, P. & Conroy, C. Hunting faint dwarf galaxies in the field using integrated light surveys. Preprint at http://arxiv.org/abs/1711.00860 (2017)

  50. 50

    Gu, M. et al. Low metallicities and old ages for three ultra-diffuse galaxies in the Coma cluster. Preprint at http://arxiv.org/abs/1709.07003 (2017)

  51. 51

    Kroupa, P. On the variation of the initial mass function. Mon. Not. R. Astron. Soc. 322, 231–246 (2001)

    ADS  Article  Google Scholar 

  52. 52

    Struble, M. F. Optical discovery of intracluster matter on the Palomar Observatory Sky Survey—the star pile in A545. Astrophys. J. 330, L25–L28 (1988)

    ADS  Article  Google Scholar 

  53. 53

    Salinas, R. et al. Crazy heart: kinematics of the “star pile” in Abell 545. Astron. Astrophys. 528, A61 (2011)

    Article  Google Scholar 

  54. 54

    Merritt, A. et al. The Dragonfly Nearby Galaxies Survey. II. Ultra-diffuse galaxies near the elliptical galaxy NGC 5485. Astrophys. J. 833, 168 (2016)

    ADS  Article  Google Scholar 

  55. 55

    Collins, M. L. M. et al. A kinematic study of the Andromeda dwarf spheroidal system. Astrophys. J. 768, 172 (2013)

    ADS  Article  Google Scholar 

  56. 56

    Tollerud, E. J. et al. The SPLASH Survey: spectroscopy of 15 M31 dwarf spheroidal satellite galaxies. Astrophys. J. 752, 45 (2012)

    ADS  Article  Google Scholar 

  57. 57

    Baumgardt, H., Parmentier, G., Gieles, M. & Vesperini, E. Evidence for two populations of Galactic globular clusters from the ratio of their half-mass to Jacobi radii. Mon. Not. R. Astron. Soc. 401, 1832–1838 (2010)

    ADS  Article  Google Scholar 

  58. 58

    McKay, N. P. F. et al. The discovery of new galaxy members in the NGC 5044 and 1052 groups. Mon. Not. R. Astron. Soc. 352, 1121–1134 (2004)

    ADS  CAS  Article  Google Scholar 

  59. 59

    Caldwell, N. & Romanowsky, A. J. Star clusters in M31. VII. Global kinematics and metallicity subpopulations of the globular clusters. Astrophys. J. 824, 42 (2016)

    ADS  Article  Google Scholar 

  60. 60

    Franx, M. Galactic Bulges, Proc. 153th Symp. International Astronomical Union (ed. Dejonghe, H. & Habing, H. J. ) 243–262 (IAU, 1993)

  61. 61

    Kochanek, C. S. The dynamics of luminous galaxies in isothermal halos. Astrophys. J. 436, 56–66 (1994)

    ADS  Article  Google Scholar 

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A.J.R. was supported by National Science Foundation grant AST-1616710 and as a Research Corporation for Science Advancement Cottrell Scholar. Results are based on observations obtained with the W. M. Keck Observatory on Mauna Kea, Hawaii. We are grateful for the opportunity to conduct observations from this mountain and wish to acknowledge its important cultural role within the indigenous Hawaiian community.

Author information




P.v.D. led the observations, data reduction and analysis, and wrote the manuscript. S.D. visually identified the galaxy in the Dragonfly data and created the model galaxies to determine the distance. Y.C. measured the structural parameters of the object. A.M. used an automated approach to verify the visual detections of low-surface-brightness galaxies in the Dragonfly data. J.Z. and A.M. reduced the Dragonfly data. E.O’S. provided the MMT image. All authors contributed to aspects of the analysis and to the writing of the manuscript.

Corresponding author

Correspondence to Pieter van Dokkum.

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Extended data figures and tables

Extended Data Figure 1 NGC1052–DF2 in the Dragonfly field.

The full Dragonfly field, approximately 11 degree2, centred on NGC 1052. The zoom-in shows the immediate surroundings of NGC 1052, with NGC1052–DF2 highlighted in the inset.

Extended Data Figure 2 Comparison to Local Group galaxies.

Open symbols are galaxies from the Nearby Dwarf Galaxies catalogue15 and the solid symbol with error bars is NGC1052–DF2. The size of each symbol indicates the logarithm of the stellar mass, as shown in the key. There are no galaxies in the Local Group that are similar to NGC1052–DF2. Galaxies with a similar velocity dispersion are a factor of about 10 smaller and have stellar masses that are a factor of about 100 larger. The object labelled And XIX is an Andromeda satellite that is thought to be in the process of tidal disruption55.

Extended Data Figure 3 Analysis of surface brightness fluctuation.

We use the surface brightness fluctuation (SBF) signal in the HST I814 band to constrain the distance to NGC1052–DF2. a, The galaxy after subtracting a smooth model and masking background galaxies and globular clusters. The image spans 33″ × 33″. b, The azimuthally averaged power spectrum. Following previous studies9,46,47, the power spectrum is fitted by a combination of a constant (dotted line) and an expectation power spectrum E(k) (dashed line). From the normalization of E(k) we find that the SBF magnitude m814 = 29.45 ± 0.10. The implied distance is DSBF = 19.0 ± 1.7 Mpc, consistent with the 20 Mpc distance of the luminous elliptical galaxy NGC 1052.

Extended Data Figure 4 Morphological coherence.

a, The sum of g and r images taken with the Dragonfly Telephoto Array. The image was smoothed by a 10″ × 10″ median filter to bring out faint emission. The lowest surface brightness levels visible in the image are about 29 mag arcsec−2. b, Sum of SDSS g, r and i images. In SDSS, the overdensity of compact objects stands out. c, The Gemini-North i-band image of NGC1052–DF2, which provides the best information on the morphology of the galaxy. Black ellipses mark R = Re and R = 2Re. White arrows mark the most obvious reduction artefacts. The galaxy is regular out to at least R ≈ 2Re, with a well-defined centre and a position angle and axis ratio that do not vary strongly with radius.

Extended Data Figure 5 Are the globular clusters in a thin rotating disk?

a, b, Globular cluster velocities as a function of projected position along the major axis (a) and the minor axis (b). There is no evidence for any trends. For reference, a Gaussian with σ = 8.4 km s−1 is shown in b.

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van Dokkum, P., Danieli, S., Cohen, Y. et al. A galaxy lacking dark matter. Nature 555, 629–632 (2018). https://doi.org/10.1038/nature25767

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