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.

A giant protogalactic disk linked to the cosmic web

Abstract

The specifics of how galaxies form from, and are fuelled by, gas from the intergalactic medium remain uncertain. Hydrodynamic simulations suggest that ‘cold accretion flows’—relatively cool (temperatures of the order of 104 kelvin), unshocked gas streaming along filaments of the cosmic web into dark-matter halos1,2,3—are important. These flows are thought to deposit gas and angular momentum into the circumgalactic medium, creating disk- or ring-like structures that eventually coalesce into galaxies that form at filamentary intersections4,5. Recently, a large and luminous filament, consistent with such a cold accretion flow, was discovered near the quasi-stellar object QSO UM287 at redshift 2.279 using narrow-band imaging6. Unfortunately, imaging is not sufficient to constrain the physical characteristics of the filament, to determine its kinematics, to explain how it is linked to nearby sources, or to account for its unusual brightness, more than a factor of ten above what is expected for a filament. Here we report a two-dimensional spectroscopic investigation of the emitting structure. We find that the brightest emission region is an extended rotating hydrogen disk with a velocity profile that is characteristic of gas in a dark-matter halo with a mass of 1013 solar masses. This giant protogalactic disk appears to be connected to a quiescent filament that may extend beyond the virial radius of the halo. The geometry is strongly suggestive of a cold accretion flow.

Your institute does not have access to this article

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Spectral image and pseudo-slit spectrum of the QSO UM287 field.
Figure 2: Spectral image and narrow-band image created from a sheared-velocity window.
Figure 3: Physical properties of the extended disk.
Figure 4: Sketch of the geometry of the QSO–disk system.

References

  1. Birnboim, Y. & Dekel, A. Virial shocks in galactic haloes? Mon. Not. R. Astron. Soc. 345, 349–364 (2003)

    ADS  Article  Google Scholar 

  2. Dekel, A. & Birnboim, Y. Galaxy bimodality due to cold flows and shock heating. Mon. Not. R. Astron. Soc. 368, 2–20 (2006)

    CAS  ADS  Article  Google Scholar 

  3. Kereš, D., Katz, N., Weinberg, D. H. & Davé, R. How do galaxies get their gas? Mon. Not. R. Astron. Soc. 363, 2–28 (2005)

    ADS  Article  Google Scholar 

  4. Stewart, K. et al. Orbiting circumgalactic gas as a signature of cosmological accretion. Astrophys. J. 738, 39 (2011)

    ADS  Article  Google Scholar 

  5. Stewart, K. R. et al. Angular momentum acquisition in galaxy halos. Astrophys. J. 769, 74 (2013)

    ADS  Article  Google Scholar 

  6. Cantalupo, S., Arrigoni-Battaia, F., Prochaska, J. X., Hennawi, J. F. & Madau, P. A cosmic web filament revealed in Lyman-α emission around a luminous high-redshift quasar. Nature 506, 63–66 (2014)

    CAS  ADS  Article  Google Scholar 

  7. Matuszewski, M. et al. The Cosmic Web Imager: an integral field spectrograph for the Hale telescope at Palomar Observatory: instrument design and first results. In Proc. SPIE, Ground-based and Airborne Instrumentation for Astronomy III (eds McLean, I. S. et al.) 77350P (SPIE, 2010)

  8. Martin, D. C. et al. Intergalactic medium emission observations with the Cosmic Web Imager. I. The circum-QSO medium of QSO 1549+19, and evidence for a filamentary gas inflow. Astrophys. J. 786, 106 (2014)

    ADS  Article  Google Scholar 

  9. Martin, D. C. et al. Intergalactic medium emission observations with the Cosmic Web Imager. II. Discovery of extended, kinematically linked emission around SSA22 Lyα blob 2. Astrophys. J. 786, 107 (2014)

    ADS  Article  Google Scholar 

  10. Prescott, M. K. M. et al. Resolving the galaxies within a giant Lyα nebula: witnessing the formation of a galaxy group? Astrophys. J. 752, 86 (2012)

    ADS  Article  Google Scholar 

  11. Prescott, M. K. M., Martin, C. L. & Dey, A. Spatially resolved gas kinematics within a Lyα nebula: evidence for large-scale rotation. Astrophys. J. 799, 62 (2015)

    ADS  Article  Google Scholar 

  12. Ferland, G. J. et al. The 2013 release of Cloudy. Rev. Mex. Astron. Astrofis. 49, 137–163 (2013)

    CAS  ADS  Google Scholar 

  13. Bertoldi, F. The photoevaporation of interstellar clouds. I. Radiation-driven implosion. Astrophys. J. 346, 735–755 (1989)

    CAS  ADS  Article  Google Scholar 

  14. Hennawi, J. F. & Prochaska, J. X. Quasars probing quasars. IV. Joint constraints on the circumgalactic medium from absorption and emission. Astrophys. J. 766, 58 (2013)

    ADS  Article  Google Scholar 

  15. Neufeld, D. A. The transfer of resonance-line radiation in static astrophysical media. Astrophys. J. 350, 216–241 (1990)

    CAS  ADS  Article  Google Scholar 

  16. McGaugh, S. S., Schombert, J. M., de Blok, W. J. G. & Zagursky, M. J. The baryon content of cosmic structures. Astrophys. J. 708, L14–L17 (2010)

    ADS  Article  Google Scholar 

  17. Bullock, J. S. et al. A universal angular momentum profile for galactic halos. Astrophys. J. 555, 240–257 (2001)

    CAS  ADS  Article  Google Scholar 

  18. Krumholz, M. R., McKee, C. F. & Tumlinson, J. The star formation law in atomic and molecular gas. Astrophys. J. 699, 850–856 (2009)

    CAS  ADS  Article  Google Scholar 

  19. Prochaska, J. X. et al. Quasars probing quasars. VI. Excess H I absorption within one proper Mpc of z 2 quasars. Astrophys. J. 776, 136 (2013)

    ADS  Article  Google Scholar 

  20. Sembach, K. R. & Tonry, J. L. Accurate sky subtraction of long-slit spectra: velocity dispersions at Σ V = 24.0 mag/arcsec2 . Astron. J. 112, 797–805 (1996)

    ADS  Article  Google Scholar 

  21. Glazebrook, K. & Bland-Hawthorn, J. Microslit nod-shuffle spectroscopy: a technique for achieving very high densities of spectra. Publ. Astron. Soc. Pacif. 113, 197–214 (2001)

    ADS  Article  Google Scholar 

  22. Cuillandre, J. C. et al. “Va-et-Vient” spectroscopy: a new mode for faint object CCD spectroscopy with very large telescopes. Astron. Astrophys. 281, 603–612 (1994)

    CAS  ADS  Google Scholar 

  23. 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 

  24. Cantalupo, S., Porciani, C., Lilly, S. J. & Miniati, F. Fluorescent Lyα emission from the high-redshift intergalactic medium. Astrophys. J. 628, 61–75 (2005)

    CAS  ADS  Article  Google Scholar 

  25. Cantalupo, S., Porciani, C. & Lilly, S. J. Mapping neutral hydrogen during reionization with the Lyα emission from quasar ionization fronts. Astrophys. J. 672, 48–58 (2008)

    CAS  ADS  Article  Google Scholar 

  26. Barnes, J. E. Encounters of disk/halo galaxies. Astrophys. J. 331, 699–717 (1988)

    ADS  Article  Google Scholar 

  27. Springel, V. & White, S. D. M. Tidal tailspin cold dark matter cosmologies. Mon. Not. R. Astron. Soc. 307, 162–178 (1999)

    CAS  ADS  Article  Google Scholar 

  28. Toomre, A. & Toomre, J. Galactic bridges and tails. Astrophys. J. 178, 623–666 (1972)

    ADS  Article  Google Scholar 

  29. Hopkins, P. F., Hernquist, L., Cox, T. J. & Kereš, D. A cosmological framework for the co‐evolution of quasars, supermassive black holes, and elliptical galaxies. I. Galaxy mergers and quasar activity. Astrophys. J. 175 (Suppl.). 356–389 (2008)

    ADS  Article  Google Scholar 

  30. Guyon, O., Sanders, D. B. & Stockton, A. Near‐infrared adaptive optics imaging of QSO host galaxies. Astrophys. J. 166 (Suppl.). 89–127 (2006)

    CAS  ADS  Article  Google Scholar 

  31. Hutchings, J. B. Host galaxies of z 4.7 quasars. Astron. J. 125, 1053–1059 (2003)

    CAS  ADS  Article  Google Scholar 

  32. Hutchings, J. B., Cherniawsky, A., Cutri, R. M. & Nelson, B. O. Host galaxies of two micron all sky survey-selected QSOs at redshift over 0.3. Astron. J. 131, 680–685 (2006)

    ADS  Article  Google Scholar 

  33. Kawakatu, N., Anabuki, N., Nagao, T., Umemura, M. & Nakagawa, T. Type I ultraluminous infrared galaxies: transition stage from ULIRGs to QSOs. Astrophys. J. 637, 104–113 (2006)

    CAS  ADS  Article  Google Scholar 

  34. Urrutia, T., Lacy, M. & Becker, R. H. Evidence for quasar activity triggered by galaxy mergers in HST observations of dust‐reddened quasars. Astrophys. J. 674, 80–96 (2008)

    CAS  ADS  Article  Google Scholar 

  35. Hibbard, J. E., van der Hulst, J. M., Barnes, J. E. & Rich, R. M. High-resolution H i mapping of NGC 4038/39 (“The Antennae”) and its tidal dwarf galaxy candidates. Astron. J. 122, 2969–2992 (2001)

    ADS  Article  Google Scholar 

Download references

Acknowledgements

We thank T. Tombrello and S. Kulkarni for their support of PCWI. This work was supported by the National Science Foundation and the California Institute of Technology.

Author information

Authors and Affiliations

Authors

Contributions

D.C.M. is the principal investigator of PCWI, led the observations and analysis of UM287, and was principal author on the paper. M.M., D.C., and P.M. designed, constructed, and operated PCWI. A.M. was the project and technical manager (2006–2010). J.D.N., M.M., and D.C.M. developed the PCWI/KCWI data pipeline and produced the final data cubes. M.M., P.M., S.C., and J.X.P. contributed Keck data and helped edit the paper.

Corresponding author

Correspondence to D. Christopher Martin.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Illustration of raw and conventionally smoothed data.

a, Raw-data spectral image of pseudo-slit obtained in the slit shown in b. 1σ error is about 3 kLU or approximately one colour scale step. b, Raw-data narrow-band image obtained in the 3,970–4,000 Å band. 1σ error is 50 kLU or about 0.5 colour scale steps. c, Raw spectral image shown in a, conventionally boxcar smoothed by 10 pixels. d, Raw narrow-band image shown in b, conventionally boxcar smoothed by 10 pixels. e, Spectral image obtained by 3D adaptive smoothing as discussed in the Methods. f, Narrow-band image (3,970–4,000 Å) obtained by summing over the 3D adaptively smoothed data cube, as discussed in the Methods.

Extended Data Figure 2 Channel maps of the UM287 data cube.

al, Panels show individual velocity channels that are 150 km s−1 wide, corresponding to a 2 Å width. Sources A–D near QSO UM287 are plotted. Velocities are with respect to the UM287 systemic velocity. QSO A has been subtracted by calculating an average PSF for the QSO over the 3,970–4,000 Å band, and then subtracting this slice by slice, within an elliptical radius of 6 arcsec in the x direction and 7.2 arcsec in the y direction. The residual flux in certain channels is due to three effects. (1) At the centre of QSO A, the residual flux is due to emission lines in the QSO around Lyα. (2) At the elliptical boundary surrounding the QSO, a small subtraction residual can be seen outside the ellipse within which the subtraction is performed. This is typically 3–5 kLU, and can be seen clearly without additional sources in c and d. (3) Emission sources are present near the QSO in certain channels. Source C shows line emission primarily in j and k (430 km s−1 < v < 731 km s−1), and its continuum emission is subtracted along with the QSO. Any emission near the subtraction boundary above 5 kLU is not a subtraction residual due to the QSO. The disk emission appears bright in b southeast of QSO A, and moves north, approaching the QSO as the velocity moves redward. In the two central velocity channels, the emission appears almost ring-like and continues to move north, roughly centred on source D. The emission continues to move north in hj. The emission is 15–25 kLU and therefore cannot be QSO subtraction residuals. The emission is also not partially subtracted emission from source C. The emission in i and j are several arcseconds east of source C. Further evidence for this point is given in Extended Data Figs 4 and 5. To indicate the approximate disk location, we show an elliptical contour with a major axis radius of 8.5 arcsec, position angle of 15.5°, and an ellipticity corresponding to an inclination of 70°.

Extended Data Figure 3 Comparison of PCWI data and Keck narrow-band and continuum images.

a, PCWI narrow-band image created by summing 3,970–4,000 Å data-cube slices from the adaptively smoothed data cube. Sources A, B, C, and D are shown. PCWI image is not continuum subtracted. b, Keck continuum-subtracted narrow-band image on the same intensity scale as the PCWI image in a. c, Keck V-band image. Sources A, C, and D are shown; continuum magnitudes in the V band are approximately (±2 mag) 16.6 AB, 22.2 AB, and 23.8 AB respectively. d, Keck continuum-subtracted narrow-band image on an expanded intensity scale.

Extended Data Figure 4 Channel maps of the UM287 data cube.

Panels show individual velocity channels that are 150 km s−1 wide, corresponding to a 2 Å width, as in Extended Data Fig. 2. In this case, no source subtraction has been performed. Sources near the QSO are plotted. Ellipses are drawn as in Extended Data Fig. 2. Velocities are with respect to the UM287 systemic velocity.

Extended Data Figure 5 Channel maps of the UM287 data cube.

al, Individual velocity channels that are 150 km s−1 wide, corresponding to a 2 Å width, as in Extended Data Fig. 2. In this case, the wavelength-averaged cube has been subtracted from the cube over the full field of view. Sources near the QSO are plotted. Ellipses are drawn as in Extended Data Fig. 2. Velocities are with respect to the UM287 systemic velocity. This subtraction removes the average continuum from all sources, including source C. The emission centred on source C is present in j and k from line emission (presumably Lyα). The progression of the disk emission can be seen as in Extended Data Fig. 2 from v = −700 km s−1 to v = +600 km s−1.

Extended Data Figure 6 Spectral image and rectangular pseudo-slit slices of the UM287 data cube.

ac, The spectral image shown at left is in the same format as Fig. 1, and the narrow-band image that is obtained using a −600 km s−1 < v < 600 km s−1 velocity cut is shown on the right with the corresponding slit location from which the spectral image is obtained. The vertical slits are 2.5 arcsec wide, and are positioned at 0 arcsec, 3.75 arcsec, and 5.0 arcsec in the positive x direction (northeast) with respect to the 0 reference position. The average QSO A spectrum has been subtracted in the bright regions. In each spectral image, strong emission appears with a large, quasi-linear velocity shear centred on the QSO velocity. Also, the narrow-band image in this velocity range illustrates that, as the emission approaches the QSO, there is an offset to the northeast that is not consistent with a direct entry into the QSO. df, The same plots with the minimum intensity range set to a negative value to show negative residuals from the QSO subtraction.

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Martin, D., Matuszewski, M., Morrissey, P. et al. A giant protogalactic disk linked to the cosmic web. Nature 524, 192–195 (2015). https://doi.org/10.1038/nature14616

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature14616

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

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing