Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The Magellanic Corona as the key to the formation of the Magellanic Stream

Abstract

The dominant gaseous structure in the Galactic halo is the Magellanic Stream. This extended network of neutral and ionized filaments surrounds the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC), the two most massive satellite galaxies of the Milky Way1,2,3,4. Recent observations indicate that the LMC and SMC are on their first passage around the Galaxy5, that the Magellanic Stream is made up of gas stripped from both clouds2,6,7 and that the majority of this gas is ionized8,9. Although it has long been suspected that tidal forces10,11 and ram-pressure stripping12,13 contributed to the formation of the Magellanic Stream, models have not been able to provide a full understanding of its origins3. Several recent developments—including the discovery of dwarf galaxies associated with the Magellanic group14,15,16, determination of the high mass of the LMC17, detection of highly ionized gas near stars in the LMC18,19 and predictions of cosmological simulations20,21—support the existence of a halo of warm (roughly 500,000 kelvin) ionized gas around the LMC (the ‘Magellanic Corona’). Here we report that, by including this Magellanic Corona in hydrodynamic simulations of the Magellanic Clouds falling onto the Milky Way, we can reproduce the Magellanic Stream and its leading arm. Our simulations explain the filamentary structure, spatial extent, radial-velocity gradient and total ionized-gas mass of the Magellanic Stream. We predict that the Magellanic Corona will be unambiguously observable via high-ionization absorption lines in the ultraviolet spectra of background quasars lying near the LMC.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: The Magellanic Stream in zenithal equal-area coordinates.
Fig. 2: Gas column density and velocity in Magellanic coordinates.
Fig. 3: Mass budget for the Magellanic Stream.

Data availability

The simulation data that support our findings are available at https://github.com/DOnghiaGroup/lucchini-2020-sim/Source data are provided with this paper.

Code availability

The GIZMO code used in this work is publicly available from https://bitbucket.org/phopkins/gizmo-public/. The PyGad code used in this work is publicly available from https://bitbucket.org/broett/pygad/.

References

  1. 1.

    Mathewson, D. S., Cleary, M. N. & Murray, J. D. The Magellanic stream. Astrophys. J. 190, 291–296 (1974).

    ADS  Google Scholar 

  2. 2.

    Nidever, D. L., Majewski, S. R. & Butler Burton, W. The origin of the Magellanic stream and Its leading arm. Astrophys. J. 679, 432–459 (2008).

    ADS  CAS  Google Scholar 

  3. 3.

    D’Onghia, E. & Fox, A. J. The Magellanic stream: circumnavigating the Galaxy. Annu. Rev. Astron. Astrophys. 54, 363–400 (2016).

    ADS  Google Scholar 

  4. 4.

    Brüns, C. et al. The Parkes H I survey of the Magellanic system. Astron. Astrophys. 432, 45–67 (2005).

    ADS  Google Scholar 

  5. 5.

    Kallivayalil, N., van der Marel, R. P., Besla, G., Anderson, J. & Alcock, C. Third-epoch Magellanic cloud proper motions. I. Hubble Space Telescope/WFC3 data and orbit implications. Astrophys. J. 764, 161 (2013).

    ADS  Google Scholar 

  6. 6.

    Fox, A. J. et al. The COS/UVES absorption survey of the Magellanic stream. I. One-tenth solar abundances along the body of the stream. Astrophys. J. 772, 110 (2013).

    ADS  Google Scholar 

  7. 7.

    Richter, P. et al. The COS/UVES absorption survey of the Magellanic stream. II. Evidence for a complex enrichment history of the stream from the Fairall 9 sightline. Astrophys. J. 772, 111 (2013).

    ADS  Google Scholar 

  8. 8.

    Fox, A. J. et al. The COS/UVES absorption survey of the Magellanic stream. III. Ionization, total mass, and inflow rate onto the Milky Way. Astrophys. J. 787, 147 (2014).

    ADS  Google Scholar 

  9. 9.

    Barger, K. A. et al. Revealing the ionization properties of the Magellanic stream using optical emission. Astrophys. J. 851, 110 (2017).

    ADS  Google Scholar 

  10. 10.

    Besla, G. et al. The role of dwarf galaxy interactions in shaping the Magellanic system and implications for Magellanic irregulars. Mon. Not. R. Astron. Soc. 421, 2109–2138 (2012).

    ADS  CAS  Google Scholar 

  11. 11.

    Pardy, S. A., D’Onghia, E. & Fox, A. J. Models of tidally induced gas filaments in the Magellanic stream. Astrophys. J. 857, 101 (2018).

    ADS  Google Scholar 

  12. 12.

    Hammer, F., Yang, Y. B., Flores, H., Puech, M. & Fouquet, S. The Magellanic stream system. I. Ram-pressure tails and the relics of the collision between the Magellanic clouds. Astrophys. J. 813, 110 (2015).

    ADS  Google Scholar 

  13. 13.

    Wang, J. et al. Towards a complete understanding of the Magellanic stream formation. Mon. Not. R. Astron. Soc. 486, 5907–5916 (2019).

    ADS  CAS  Google Scholar 

  14. 14.

    D’Onghia, E. & Lake, G. Small dwarf galaxies within larger dwarfs: why some are luminous while most go dark. Astrophys. J. 686, L61 (2008).

    ADS  Google Scholar 

  15. 15.

    Bechtol, K. et al. Eight new Milky Way companions discovered in first-year dark energy survey data. Astrophys. J. 807, 50 (2015).

    ADS  Google Scholar 

  16. 16.

    Nichols, M., Colless, J., Colless, M. & Bland-Hawthorn, J. Accretion of the Magellanic system onto the Galaxy. Astrophys. J. 742, 110 (2011).

    ADS  Google Scholar 

  17. 17.

    Peñarrubia, J., Gómez, F. A., Besla, G., Erkal, D. & Ma, Y.-Z. A timing constraint on the (total) mass of the Large Magellanic Cloud. Mon. Not. R. Astron. Soc. 456, L54–L58 (2016).

    ADS  Google Scholar 

  18. 18.

    Wakker, B., Howk, J. C., Chu, Y.-H., Bomans, D. & Points, S. D. Coronal C+3 in the Large Magellanic Cloud: evidence for a hot halo. Astrophys. J. 499, L87–L91 (1998).

    ADS  CAS  Google Scholar 

  19. 19.

    Lehner, N., Staveley-Smith, L. & Howk, J. C. Properties and origin of the high-velocity gas toward the Large Magellanic Cloud. Astrophys. J. 702, 940–954 (2009).

    ADS  CAS  Google Scholar 

  20. 20.

    Pardy, S. A. et al. Satellites of satellites: the case for Carina and Fornax. Mon. Not. R. Astron. Soc. 492, 1543–1549 (2020).

    ADS  Google Scholar 

  21. 21.

    Hafen, Z. et al. The origins of the circumgalactic medium in the FIRE simulations. Mon. Not. R. Astron. Soc. 488, 1248–1272 (2019).

    ADS  Google Scholar 

  22. 22.

    Besla, G. et al. Are the Magellanic clouds on their first passage about the Milky Way? Astrophys. J. 668, 949–967 (2007).

    ADS  Google Scholar 

  23. 23.

    Nidever, D. L., Majewski, S. R., Butler Burton, W. & Nigra, L. The 200° long Magellanic stream system. Astrophys. J. 723, 1618–1631 (2010).

    ADS  CAS  Google Scholar 

  24. 24.

    McClure-Griffiths, N. M. et al. GASS: the Parkes galactic all-sky survey. I. Survey description, goals, and initial data release. Astrophys. J. Suppl. Ser. 181, 398–412 (2009).

    ADS  CAS  Google Scholar 

  25. 25.

    Putman, M. E. et al. Tidal disruption of the Magellanic clouds by the Milky Way. Nature 394, 752–754 (1998).

    ADS  CAS  Google Scholar 

  26. 26.

    Heitsch, F. & Putman, M. E. The fate of high-velocity clouds: warm or cold cosmic rain? Astrophys. J. 698, 1485–1496 (2009).

    ADS  CAS  Google Scholar 

  27. 27.

    Tepper-García, T., Bland-Hawthorn, J., Pawlowski, M. S. & Fritz, T. K. The Magellanic system: the puzzle of the leading gas stream. Mon. Not. R. Astron. Soc. 488, 918–938 (2019).

    ADS  Google Scholar 

  28. 28.

    Nidever, D. L. et al. Spectroscopy of the young stellar association Price-Whelan 1: origin in the Magellanic leading arm and constraints on the Milky Way hot halo. Astrophys. J. 887, 115 (2019).

    ADS  CAS  Google Scholar 

  29. 29.

    Price-Whelan, A. M. et al. Discovery of a disrupting open cluster far into the Milky Way halo: a recent star formation event in the leading arm of the Magellanic stream? Astrophys. J. 887, 19 (2019).

    ADS  Google Scholar 

  30. 30.

    Bregman, J. N. et al. The extended distribution of baryons around galaxies. Astrophys. J. 862, 3 (2018).

    ADS  Google Scholar 

  31. 31.

    Hopkins, P. F. A new class of accurate, mesh-free hydrodynamic simulation methods. Mon. Not. R. Astron. Soc. 450, 53–110 (2015).

    ADS  CAS  Google Scholar 

  32. 32.

    Katz, N., Weinberg, D. H. & Hernquist, L. Cosmological simulations with TreeSPH. Astrophys. J. Suppl. Ser. 105, 19–35 (1996).

    ADS  CAS  Google Scholar 

  33. 33.

    Hopkins, P. F. et al. FIRE-2 simulations: physics versus numerics in galaxy formation. Mon. Not. R. Astron. Soc. 480, 800–863 (2018).

    ADS  Google Scholar 

  34. 34.

    Springel, V. & Hernquist, L. Cosmological smoothed particle hydrodynamics simulations: a hybrid multiphase model for star formation. Mon. Not. R. Astron. Soc. 339, 289–311 (2003).

    ADS  Google Scholar 

  35. 35.

    Springel, V. The cosmological simulation code GADGET-2. Mon. Not. R. Astron. Soc. 364, 1105–1134 (2005).

    ADS  Google Scholar 

  36. 36.

    Hernquist, L. An analytical model for spherical galaxies and bulges. Astrophys. J. 356, 359–364 (1990).

    ADS  Google Scholar 

  37. 37.

    D’Onghia, E. & Aguerri, J. A. L. Trojans in the solar neighborhood. Astrophys. J. 890, 117 (2020).

    ADS  Google Scholar 

  38. 38.

    de Blok, W. J. G. & McGaugh, S. S. The dark and visible matter content of low surface brightness disc galaxies. Mon. Not. R. Astron. Soc. 290, 533–552 (1997).

    ADS  Google Scholar 

  39. 39.

    Erkal, D. et al. Modelling the Tucana III stream - a close passage with the LMC. Mon. Not. R. Astron. Soc. 481, 3148–3159 (2018).

    ADS  CAS  Google Scholar 

  40. 40.

    Erkal, D. et al. The total mass of the Large Magellanic Cloud from its perturbation on the Orphan stream. Mon. Not. R. Astron. Soc. 487, 2685–2700 (2019).

    ADS  CAS  Google Scholar 

  41. 41.

    Kallivayalil, N. et al. The missing satellites of the Magellanic clouds? Gaia proper motions of the recently discovered ultra-faint galaxies. Astrophys. J. 867, 19 (2018).

    ADS  Google Scholar 

  42. 42.

    Jethwa, P., Erkal, D. & Belokurov, V. A Magellanic origin of the DES dwarfs. Mon. Not. R. Astron. Soc. 461, 2212–2233 (2016).

    ADS  CAS  Google Scholar 

  43. 43.

    Shen, S., Madau, P., Conroy, C., Governato, F. & Mayer, L. The baryon cycle of dwarf galaxies: dark, bursty, gas-rich polluters. Astrophys. J. 792, 99 (2014).

    ADS  Google Scholar 

  44. 44.

    Anglés-Alcázar, D. et al. The cosmic baryon cycle and galaxy mass assembly in the FIRE simulations. Mon. Not. R. Astron. Soc. 470, 4698–4719 (2017).

    ADS  Google Scholar 

  45. 45.

    Jahn, E. D. et al. Dark and luminous satellites of LMC-mass galaxies in the FIRE simulations. Mon. Not. R. Astron. Soc. 489, 5348–5364 (2019).

    ADS  Google Scholar 

  46. 46.

    Bordoloi, R. et al. The COS-dwarfs survey: the carbon reservoir around sub-L* galaxies. Astrophys. J. 796, 136 (2014).

    ADS  CAS  Google Scholar 

  47. 47.

    Johnson, S. D., Chen, H.-W., Mulchaey, J. S., Schaye, J. & Straka, L. A. The extent of chemically enriched gas around star-forming dwarf galaxies. Astrophys. J. 850, L10 (2017).

    ADS  Google Scholar 

  48. 48.

    Sokołowska, A., Mayer, L., Babul, A., Madau, P. & Shen, S. Diffuse coronae in cosmological simulations of Milky Way-sized galaxies. Astrophys. J. 819, 21 (2016).

    ADS  Google Scholar 

  49. 49.

    Fukugita, M. & Peebles, P. J. E. Massive coronae of Galaxies. Astrophys. J. 639, 590–599 (2006).

    ADS  CAS  Google Scholar 

  50. 50.

    Lehner, N. & Howk, J. C. Highly ionized plasma in the Large Magellanic Cloud: evidence for outflows and a possible galactic wind. Mon. Not. R. Astron. Soc. 377, 687–704 (2007).

    ADS  CAS  Google Scholar 

  51. 51.

    Grand, R. J. J. et al. The Auriga project: the properties and formation mechanisms of disc galaxies across cosmic time. Mon. Not. R. Astron. Soc. 467, 179–207 (2017).

    ADS  CAS  Google Scholar 

  52. 52.

    Miller, M. J. & Bregman, J. N. The structure of the Milky Way’s hot gas halo. Astrophys. J. 770, 118 (2013).

    ADS  Google Scholar 

  53. 53.

    Salem, M. et al. Ram pressure stripping of the Large Magellanic Cloud’s disk as a probe of the Milky Way’s circumgalactic medium. Astrophys. J. 815, 77 (2015).

    ADS  Google Scholar 

  54. 54.

    Bustard, C., Pardy, S. A., D’Onghia, E., Zweibel, E. G. & Gallagher, J. S. The fate of supernova-heated gas in star-forming regions of the LMC: lessons for galaxy formation? Astrophys. J. 863, 49 (2018).

    ADS  Google Scholar 

  55. 55.

    Bustard, C., Zweibel, E. G., D’Onghia, E., Gallagher, J. S. & Farber, R. Cosmic-ray-driven outflows from the Large Magellanic Cloud: contributions to the LMC filament. Astrophys. J. 893, 29 (2020).

    ADS  Google Scholar 

  56. 56.

    Gronke, M. & Oh, S. P. How cold gas continuously entrains mass and momentum from a hot wind. Mon. Not. R. Astron. Soc. 492, 1970–1990 (2020).

    ADS  Google Scholar 

  57. 57.

    Perret, V. et al. Evolution of the mass, size, and star formation rate in high redshift merging galaxies. MIRAGE - a new sample of simulations with detailed stellar feedback. Astron. Astrophys. 562, A1 (2014).

    ADS  Google Scholar 

  58. 58.

    Bland-Hawthorn, J., Sutherland, R., Agertz, O. & Moore, B. The source of Ionization along the Magellanic stream. Astrophys. J. 670, L109–L112 (2007).

    ADS  CAS  Google Scholar 

  59. 59.

    Tepper-García, T., Bland-Hawthorn, J. & Sutherland, R. S. The Magellanic stream: break-up and accretion onto the hot Galactic corona. Astrophys. J. 813, 94 (2015).

    ADS  Google Scholar 

  60. 60.

    Faerman, Y., Sternberg, A. & McKee, C. F. Massive warm/hot galaxy coronae. II. Isentropic model. Astrophys. J. 893, 82 (2020).

    ADS  Google Scholar 

  61. 61.

    Besla, G. et al. Simulations of the Magellanic stream in a first infall scenario. Astrophys. J. 721, L97–L101 (2010).

    ADS  CAS  Google Scholar 

  62. 62.

    D’Onghia, E., Besla, G., Cox, T. J. & Hernquist, L. Resonant stripping as the origin of dwarf spheroidal galaxies. Nature 460, 605–607 (2009).

    ADS  Google Scholar 

  63. 63.

    D’Onghia, E., Vogelsberger, M., Faucher-Giguere, C.-A. & Hernquist, L. Quasi-resonant theory of tidal interactions. Astrophys. J. 725, 353–368 (2010).

    ADS  Google Scholar 

  64. 64.

    Diaz, J. D. & Bekki, K. The tidal origin of the Magellanic stream and the possibility of a stellar counterpart. Astrophys. J. 750, 36 (2012).

    ADS  Google Scholar 

  65. 65.

    Kallivayalil, N. et al. The proper motion of the Large Magellanic Cloud using HST. Astrophys. J. 638, 772–785 (2006).

    ADS  CAS  Google Scholar 

  66. 66.

    Röttgers, B. pygad: Analyzing Gadget Simulations with Python. Astrophysics Source Code Library 1811.014 (2018).

  67. 67.

    Blitz, L. & Robishaw, T. Gas-rich dwarf spheroidals. Astrophys. J. 541, 675–687 (2000).

    ADS  Google Scholar 

  68. 68.

    Stanimirović, S., Dickey, J. M., Krčo, M. & Brooks, A. M. The small-scale structure of the Magellanic stream. Astrophys. J. 576, 773–789 (2002).

    ADS  Google Scholar 

  69. 69.

    Bregman, J. N. & Lloyd-Davies, E. J. X-Ray absorption from the Milky Way halo and the local group. Astrophys. J. 669, 990–1002 (2007).

    ADS  CAS  Google Scholar 

  70. 70.

    Anderson, M. E. & Bregman, J. N. Do hot halos around galaxies contain the missing baryons? Astrophys. J. 714, 320–331 (2010).

    ADS  CAS  Google Scholar 

  71. 71.

    Murali, C. The Magellanic stream and the density of coronal gas in the Galactic halo. Astrophys. J. 529, L81–L84 (2000).

    ADS  CAS  Google Scholar 

Download references

Acknowledgements

E.D. acknowledges the hospitality of the Center for Computational Astrophysics at the Flatiron Institute during the completion of this work.

Author information

Affiliations

Authors

Contributions

S.L., E.D. and A.J.F. conceived and developed the numerical experiments. J.B.-H., C.B. and E.Z. contributed to discussion of the physical processes. All authors helped edit the manuscript. S.L. created the figures with input from C.B.

Corresponding author

Correspondence to E. D’Onghia.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Extended data figures and tables

Extended Data Fig. 1 Radial gas density profile of the Magellanic Corona and Milky Way hot corona.

The number density n of gas in the models of the Magellanic Corona (dashed red line) and the Milky Way’s (MW) hot corona (solid red line) is shown as a function of radius r (from the centre of the LMC and Milky Way, respectively). Estimates of the Milky Way’s hot coronal density from observations are shown in black. The dotted and dot-dashed lines are fits to data30,52,53. The data points are labelled with the corresponding references28,67,68,69,70,71, and are the same as those included in previous studies27. Downward (upward) pointing triangles indicate upper (lower) limits. Horizontal lines show uncertainty in radii measurements.

Source data

Extended Data Fig. 2 Orbital histories of the LMC and SMC.

a, Time evolution of the distance between the centre of mass of the LMC and the centre of mass of the SMC. The clouds interact gravitationally for a period of 5.7 Gyr (three close encounters) before falling into the Milky Way potential. be, Gas column density Σgas at various times during the mutual interactions between the clouds, with the orbital path of the SMC around the LMC shown as a white line (b, at the initial time; c, after 1.4 Gyr; d, after 4.3 Gyr; e, after 5.7 Gyr; marked in a with dotted vertical lines). The gas tidally removed from the LMC and SMC is displayed in addition to the Magellanic coronal gas.

Source data

Extended Data Fig. 3 The effect of the Magellanic Corona on stripped gas temperature.

The gas removed from the Magellanic Clouds after about 5.7 Gyr of mutual interactions (before infall into the Milky Way potential) is shown in Cartesian coordinates projected along the z axis onto the xy plane. The LMC and SMC are at the centre of each panel. a, b, The gas mass surface density of the gas originating in the disks of the clouds. c, d, The gas temperature averaged along the projection axis. Results are shown for models run with (b, d) and without (a, c) the Magellanic Corona included.

Source data

Extended Data Fig. 4 The effect of the warm and hot gas on the formation of the leading arm.

The column density (brightness) and line-of-sight velocity (vLOS; colour scale) for four different models for the formation of the Magellanic Stream are shown in zenithal equal-area coordinates. The white lines mark the location of the Galactic disk in the projection. These four models are the same as those shown in Fig. 3. In all four panels, only the gas originating in the gaseous disks of the Magellanic Clouds is displayed. a, Fiducial model, without the Milky Way’s corona or Magellanic Corona (tidal forces only). b, A Milky Way coronal mass of 5 × 109M is included, but the Magellanic Corona is not present. The leading arm does not survive, in agreement with previous studies27. c, Same as in b, with the total mass of the Milky Way’s hot corona reduced to 2 × 109M (see Extended Data Fig. 1), allowing the leading arm to survive. d, Same as in c, but with the addition of the Magellanic Corona. This model provides the best match to observations.

Source data

Supplementary information

Video 1: The infall of the Clouds in zenthial equal-area coordinates.

Observed H i data (a) and results of the model (b) of the Magellanic Stream, with line-of-sight velocity displayed by the colour bar (from −350 km s−1 to 400 km s−1) and brightness indicating the relative gas column density. Gas originating in both the LMC and SMC disks from the model including the Milky Way's hot corona and the Magellanic Corona. The video begins 550 million years ago and continues until the present day. The Milky Way disk and background are extracted from real H i images. See Fig. 2 for more information.

Video 2: The infall of the Clouds in Magellanic coordinates.

Video showing the past 1.34 billion years of the Clouds’ dynamics shown in Magellanic coordinates. a, The gas column density of the simulated Stream composed of the Magellanic Corona gas and cold disk gas stripped from the Clouds. b, Column density only of the simulated cold gas Stream as compared to H i data, with black, gray, white contours corresponding to the observed column density of 1019, 1020, and 1021 cm−2, respectively.

Video 3: The tidal interactions between the LMC and SMC.

a, Time evolution of the distance between the center of mass of the LMC and the center of mass of the SMC. The clouds interact gravitationally for a period of 5.7 Gyr (three close encounters) before falling into the Milky Way potential. b, Video of gas column density during the Clouds' mutual interactions. Displayed is the gas tidally removed from the LMC and SMC in addition to the Magellanic Coronal gas.

Source data

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Lucchini, S., D’Onghia, E., Fox, A.J. et al. The Magellanic Corona as the key to the formation of the Magellanic Stream. Nature 585, 203–206 (2020). https://doi.org/10.1038/s41586-020-2663-4

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links