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The diffuse γ-ray background is dominated by star-forming galaxies

Nature volume 597, pages 341–344 (2021)Cite this article

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Abstract

The Fermi Gamma-ray Space Telescope has revealed a diffuse γ-ray background at energies from 0.1 gigaelectronvolt to 1 teraelectronvolt, which can be separated into emission from our Galaxy and an isotropic, extragalactic component1. Previous efforts to understand the latter have been hampered by the lack of physical models capable of predicting the γ-ray emission produced by the many candidate sources, primarily active galactic nuclei2,3,4,5 and star-forming galaxies6,7,8,9,10, leaving their contributions poorly constrained. Here we present a calculation of the contribution of star-forming galaxies to the γ-ray background that does not rely on empirical scalings and is instead based on a physical model for the γ-ray emission produced when cosmic rays accelerated in supernova remnants interact with the interstellar medium11. After validating the model against local observations, we apply it to the observed cosmological star-forming galaxy population and recover an excellent match to both the total intensity and the spectral slope of the γ-ray background, demonstrating that star-forming galaxies alone can explain the full diffuse, isotropic γ-ray background.

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Fig. 1: The γ-ray spectra of nearby SFGs.
Fig. 2: The FIR–γ correlation.
Fig. 3: The γ-ray source count distribution.
Fig. 4: The diffuse isotropic γ-ray background.

Data availability

The data that were used to produce the figures and that support the findings of this study are available in Zenodo with the identifier https://doi.org/10.5281/zenodo.4764111. Source data are provided with this paper.

Code availability

The code used to derive the key findings of this study is available in Zenodo with the identifier https://doi.org/10.5281/zenodo.4609628.

References

  1. Ackermann, M. et al. The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV. Astrophys. J. 799, 86 (2015).

    Article  ADS  Google Scholar 

  2. Cuoco, A., Komatsu, E. & Siegal-Gaskins, J. M. Joint anisotropy and source count constraints on the contribution of blazars to the diffuse gamma-ray background. Phys. Rev. D 86, 063004 (2012).

    Article  ADS  Google Scholar 

  3. Di Mauro, M., Calore, F., Donato, F., Ajello, M. & Latronico, L. Diffuse γ-ray emission from misaligned active galactic nuclei. Astrophys. J. 780, 161 (2014).

    Article  ADS  Google Scholar 

  4. Fornasa, M. & Sánchez-Conde, M. A. The nature of the diffuse gamma-ray background. Phys. Rep. 598, 1–58 (2015).

    Article  ADS  MathSciNet  CAS  Google Scholar 

  5. Qu, Y., Zeng, H. & Yan, D. Gamma-ray luminosity function of BL Lac objects and contribution to the extragalactic gamma-ray background. Mon. Not. R. Astron. Soc. 490, 758–765 (2019).

    Article  ADS  CAS  Google Scholar 

  6. Fields, B. D., Pavlidou, V. & Prodanović, T. Cosmic gamma-ray background from star-forming galaxies. Astrophys. J. 722, L199–L203 (2010).

    Article  ADS  Google Scholar 

  7. Ackermann, M. et al. GeV observations of star-forming galaxies with the Fermi Large Area Telescope. Astrophys. J. 755, 164 (2012).

    Article  ADS  Google Scholar 

  8. Xia, J.-Q., Cuoco, A., Branchini, E. & Viel, M. Tomography of the Fermi-LAT γ-ray diffuse extragalactic signal via cross correlations with galaxy catalogs. Astrophys. J. Suppl. 217, 15 (2015).

    Article  ADS  Google Scholar 

  9. Linden, T. Star-forming galaxies significantly contribute to the isotropic gamma-ray background. Phys. Rev. D 96, 083001 (2017).

    Article  ADS  Google Scholar 

  10. Ajello, M., Di Mauro, M., Paliya, V. S. & Garrappa, S. The γ-ray emission of star-forming galaxies. Astrophys. J. 894, 88 (2020).

    Article  ADS  CAS  Google Scholar 

  11. Krumholz, M. R. et al. Cosmic ray transport in starburst galaxies. Mon. Not. R. Astron. Soc. 493, 2817–2833 (2020).

    Article  ADS  CAS  Google Scholar 

  12. Ajello, M. et al. The origin of the extragalactic gamma-ray background and implications for dark matter annihilation. Astrophys. J. 800, L27 (2015).

    Article  ADS  Google Scholar 

  13. Bell, A. R. Cosmic ray acceleration. Astropart. Phys. 43, 56–70 (2013).

    Article  ADS  Google Scholar 

  14. Woosley, S. E. & Weaver, T. A. The evolution and explosion of massive Stars II: explosive hydrodynamics and nucleosynthesis. Astrophys. J. Suppl. 101, 181–235 (1995).

    Article  ADS  CAS  Google Scholar 

  15. Dermer, C. D. & Powale, G. Gamma rays from cosmic rays in supernova remnants. Astron. Astrophys. 553, A34 (2013).

    Article  ADS  Google Scholar 

  16. Lacki, B. C., Thompson, T. A. & Quataert, E. The physics of the far-infrared-radio correlation. I. Calorimetry, conspiracy,and implications. Astrophys. J. 717, 1–28 (2010).

    Article  ADS  CAS  Google Scholar 

  17. Bell, A. R. The acceleration of cosmic rays in shock fronts—I. Mon. Not. R. Astron. Soc. 182, 147–156 (1978).

    Article  ADS  CAS  Google Scholar 

  18. Blandford, R. & Eichler, D. Particle acceleration at astrophysical shocks: a theory of cosmic ray origin. Phys. Rep. 154, 1–75 (1987).

    Article  ADS  CAS  Google Scholar 

  19. Caprioli, D. Understanding hadronic gamma-ray emission from supernova remnants. J. Cosmol. Astropart. Phys. 2011, 026 (2011).

    Article  Google Scholar 

  20. Caprioli, D. Cosmic-ray acceleration in supernova remnants: non-linear theory revised. J. Cosmol. Astropart. Phys. 2012, 038 (2012).

    Article  Google Scholar 

  21. Grogin, N. A. et al. CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. Astrophys. J. Suppl. 197, 35 (2011).

    Article  ADS  Google Scholar 

  22. van der Wel, A. et al. Structural parameters of galaxies in CANDELS. Astrophys. J. Suppl. 203, 24 (2012).

    Article  ADS  Google Scholar 

  23. Ballet, J., Burnett, T. H., Digel, S. W. & Lott, B. Fermi Large Area Telescope Fourth Source Catalog Data Release 2. Preprint at https://arxiv.org/abs/2005.11208 (2020).

  24. Peng, F.-K., Wang, X.-Y., Liu, R.-Y., Tang, Q.-W. & Wang, J.-F. First detection of GeV emission from an ultraluminous infrared galaxy: Arp 220 as seen with the Fermi Large Area Telescope. Astrophys. J. 821, L20 (2016).

    Article  ADS  Google Scholar 

  25. Kornecki, P. et al. The γ-ray/infrared luminosity correlation of star-forming galaxies. Astron. Astrophys. 641, A147 (2020).

    Article  CAS  Google Scholar 

  26. Ando, S., Fornasa, M., Fornengo, N., Regis, M. & Zechlin, H.-S. Astrophysical interpretation of the anisotropies in the unresolved gamma-ray background. Phys. Rev. D 95, 123006 (2017).

    Article  ADS  Google Scholar 

  27. Manconi, S. et al. Testing gamma-ray models of blazars in the extragalactic sky. Phys. Rev. D 101, 103026 (2020).

    Article  ADS  CAS  Google Scholar 

  28. Komis, I., Pavlidou, V. & Zezas, A. Extragalactic gamma-ray background from star-forming galaxies: will empirical scalings suffice? Mon. Not. R. Astron. Soc. 483, 4020–4030 (2019).

    Article  ADS  CAS  Google Scholar 

  29. Cherenkov Telescope Array Consortium et al. Science with the Cherenkov Telescope Array (World Scientific, 2019).

  30. Di Sciascio, G. & Lhaaso Collaboration. The LHAASO experiment: from gamma-ray astronomy to cosmic rays. Nucl. Part. Phys. Proc. 279–281, 166–173 (2016).

    Article  Google Scholar 

  31. Kafexhiu, E., Aharonian, F., Taylor, A. M. & Vila, G. S. Parametrization of gamma-ray production cross sections for pp interactions in a broad proton energy range from the kinematic threshold to PeV energies. Phys. Rev. D 90, 123014 (2014).

    Article  ADS  Google Scholar 

  32. Chabrier, G. Galactic stellar and substellar initial mass function. Publ. Astron. Soc. Pacif. 115, 763–795 (2003).

    Article  ADS  Google Scholar 

  33. Heger, A., Fryer, C. L., Woosley, S. E., Langer, N. & Hartmann, D. H. How massive single stars end their life. Astrophys. J. 591, 288–300 (2003).

    Article  ADS  Google Scholar 

  34. Crocker, R. M., Krumholz, M. R. & Thompson, T. A. Cosmic rays across the star-forming galaxy sequence—I. Cosmic ray pressures and calorimetry. Mon. Not. R. Astron. Soc. 502, 1312–1333 (2021).

    Article  ADS  Google Scholar 

  35. Peretti, E., Blasi, P., Aharonian, F. & Morlino, G. Cosmic ray transport and radiative processes in nuclei of starburst galaxies. Mon. Not. R. Astron. Soc. 487, 168–180 (2019).

    Article  ADS  CAS  Google Scholar 

  36. Kelner, S. R., Aharonian, F. A. & Bugayov, V. V. Energy spectra of gamma rays, electrons, and neutrinos produced at proton–proton interactions in the very high energy regime. Phys. Rev. D 74, 034018 (2006).

    Article  ADS  Google Scholar 

  37. Kelner, S. R., Aharonian, F. A. & Bugayov, V. V. Erratum: Energy spectra of gamma rays, electrons, and neutrinos produced at proton–proton interactions in the very high energy regime. Phys. Rev. D 79, 039901 (2009).

    Article  ADS  Google Scholar 

  38. Magnelli, B. et al. The evolution of the dust temperatures of galaxies in the SFR−M* plane up to z ~ 2. Astron. Astrophys. 561, A86 (2014).

    Article  Google Scholar 

  39. Persic, M., Rephaeli, Y. & Arieli, Y. Very-high-energy emission from M 82. Astron. Astrophys. 486, 143–149 (2008).

    Article  ADS  CAS  Google Scholar 

  40. Thompson, T. A. Gravitational instability in radiation pressure-dominated backgrounds. Astrophys. J. 684, 212–225 (2008).

    Article  ADS  Google Scholar 

  41. Schlickeiser, R. Cosmic Ray Astrophysics (Springer, 2002).

  42. Ghisellini, G. Radiative Processes in High Energy Astrophysics (Springer, 2013).

  43. Fang, K., Bi, X.-J., Lin, S.-J. & Yuan, Q. Klein–Nishina effect and the cosmic ray electron spectrum. Preprint at https://arxiv.org/abs/2007.15601 (2020).

  44. Bethe, H. & Heitler, W. On the stopping of fast particles and on the creation of positive electrons. Proc. R. Soc. Lond. A 146, 83–112 (1934).

    Article  ADS  CAS  MATH  Google Scholar 

  45. Gould, R. J. High-energy bremsstrahlung in collisions of electrons with one- and two-electron atoms. Phys. Rev. 185, 72–79 (1969).

    Article  ADS  CAS  Google Scholar 

  46. Blumenthal, G. R. & Gould, R. J. Bremsstrahlung, synchrotron radiation, and Compton scattering of high-energy electrons traversing dilute gases. Rev. Mod. Phys. 42, 237–270 (1970).

    Article  ADS  CAS  Google Scholar 

  47. Razzaque, S., Mészáros, P. & Zhang, B. GeV and higher energy photon interactions in gamma-ray burst fireballs and surroundings. Astrophys. J. 613, 1072–1078 (2004).

    Article  ADS  CAS  Google Scholar 

  48. Franceschini, A. & Rodighiero, G. The extragalactic background light revisited and the cosmic photon–photon opacity. Astron. Astrophys. 603, A34 (2017).

    Article  ADS  Google Scholar 

  49. Berezinsky, V. & Kalashev, O. High-energy electromagnetic cascades in extragalactic space: physics and features. Phys. Rev. D 94, 023007 (2016).

    Article  ADS  Google Scholar 

  50. van der Wel, A. et al. 3D-HST+CANDELS: The evolution of the galaxy size-mass distribution since z = 3. Astrophys. J. 788, 28 (2014).

    Article  ADS  Google Scholar 

  51. Shi, Y. et al. Extended Schmidt law: role of existing stars in current star formation. Astrophys. J. 733, 87 (2011).

    Article  ADS  Google Scholar 

  52. Yu, X. et al. What drives the velocity dispersion of ionized gas in star-forming galaxies? Mon. Not. R. Astron. Soc. 486, 4463–4472 (2019).

    Article  ADS  Google Scholar 

  53. Forbes, J., Krumholz, M. & Burkert, A. Evolving gravitationally unstable disks over cosmic time: implications for thick disk formation. Astrophys. J. 754, 48 (2012).

    Article  ADS  Google Scholar 

  54. Madau, P. & Dickinson, M. Cosmic star-formation history. Annu. Rev. Astron. Astrophys. 52, 415–486 (2014).

    Article  ADS  Google Scholar 

  55. Kennicutt, R. C. Jr The global Schmidt law in star-forming galaxies. Astrophys. J. 498, 541–552 (1998).

    Article  ADS  CAS  Google Scholar 

  56. Crain, R. A., McCarthy, I. G., Frenk, C. S., Theuns, T. & Schaye, J. X-ray coronae in simulations of disc galaxy formation. Mon. Not. R. Astron. Soc. 407, 1403–1422 (2010).

    Article  ADS  CAS  Google Scholar 

  57. Bothwell, M. S. et al. The star formation rate distribution function of the local Universe. Mon. Not. R. Astron. Soc. 415, 1815–1826 (2011).

    Article  ADS  CAS  Google Scholar 

  58. Bothwell, M. S. et al. Erratum: The star formation rate distribution function of the local Universe. Mon. Not. R. Astron. Soc. 438, 3608 (2014).

    Article  ADS  Google Scholar 

  59. Rodríguez Zaurín, J., Tadhunter, C. N. & González Delgado, R. M. Optical spectroscopy of Arp220: the star formation history of the closest ULIRG. Mon. Not. R. Astron. Soc. 384, 875–885 (2008). 

    Article  ADS  Google Scholar 

  60. Wright, G. S., James, P. A., Joseph, R. D., McLean, I. S. & Doyon, R. Infrared images of merging galaxies. In NASA Conference Publication (eds Sulentic, J. W. et al.) 3098, 321–326 (1990).

  61. Parkash, V., Brown, M. J. I., Jarrett, T. H. & Bonne, N. J. Relationships between HI gas mass, stellar mass, and the star formation rate of HICAT+WISE (H I-WISE) galaxies. Astrophys. J. 864, 40 (2018). 

  62. IRSA. NASA/IPAC Infrared Science Archive, https://irsa.ipac.caltech.edu.

  63. Sakamoto, K. et al. Molecular superbubbles in the Starburst Galaxy NGC 253. Astrophys. J. 636, 685–697 (2006).

    Article  ADS  CAS  Google Scholar 

  64. Bendo, G. J. et al. ALMA observations of 99 GHz free-free and H40α line emission from star formation in the centre of NGC 253. Mon. Not. R. Astron. Soc. 450, L80–L84 (2015).

  65. Rahmani, S., Lianou, S. & Barmby, P. Star formation laws in the Andromeda galaxy: gas, stars, metals and the surface density of star formation. Mon. Not. R. Astron. Soc. 456, 4128–4144 (2016).

  66. Iijima, T., Ito, K., Matsumoto, T. & Uyama, K. Near-infrared profile of M31. Pub. Astron. Soc. Japan 28, 27–34 (1976).

  67. Braun, R. & Walterbos, R. A. M. Physical properties of neutral gas in M31 and the galaxy. Astrophys. J. 386, 120 (1992).

  68. Caldú-Primo, A. & Schruba, A. Molecular gas velocity dispersions in the Andromeda galaxy. Astron. J. 151, 34 (2016).

  69. Davis, B. L., Graham, A. W. & Cameron, E. Black hole mass scaling relations for spiral galaxies. II. MBH−M★,tot and MBH−M★,disk. Astrophys. J. 869, 113 (2018).

  70. de Vaucouleurs, G. Southern galaxies. V. Isophotometry of the large barred spiral NGC 4945. Astrophys. J. 139, 899 (1964).

  71. Bendo, G. J. et al. Free-free and H42α emission from the dusty starburst within NGC 4945 as observed by ALMA. Mon. Not. R. Astron. Soc. 463, 252–269 (2016).

  72. Ott, M., Whiteoak, J. B., Henkel, C. & Wielebinski, R. Atomic and molecular gas in the starburst galaxy NGC 4945. Astron. Astrophys. 372, 463–476 (2001).

  73. Stettner, J. Measurement of the diffuse astrophysical muon-neutrino spectrum with ten years of IceCube data. In 36th International Cosmic Ray Conference (ICRC2019) 36, 1017 (2019).

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Acknowledgements

This research has made use of the NASA/IPAC Infrared Science Archive, which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. Funding for this work was provided by the Australian Government through the Australian Research Council, awards FT180100375 (M.R.K.) and DP190101258 (R.M.C. and M.R.K.), and the Australian National University through a research scholarship (M.A.R.). R.M.C. thanks O. Macias and S. Ando for conversations while a Kavli IPMU-funded guest of the GRAPPA Institute at the University of Amsterdam.

Author information

Authors and Affiliations

  1. Research School of Astronomy and Astrophysics, The Australian National University, Canberra, Australian Capital Territory, Australia

    Matt A. Roth, Mark R. Krumholz & Roland M. Crocker

  2. ARC Centre of Excellence for All-Sky Astrophysics in Three Dimensions (ASTRO-3D), Canberra, Australian Capital Territory, Australia

    Mark R. Krumholz

  3. Dipartimento di Fisica dell’Università La Sapienza and INFN, Rome, Italy

    Silvia Celli

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Contributions

All authors were involved in the design of the study and the interpretation of the results. M.A.R. performed the modelling and data analysis with input from M.R.K., R.M.C. and S.C. The manuscript was written by M.A.R., M.R.K. and R.M.C., and reviewed by all authors.

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Correspondence to Matt A. Roth.

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Extended data figures and tables

Extended Data Fig. 1 The effect of varying model parameters.

The plots presented here show the result of our calculations when varying the model parameters as discussed in the Supplementary Information. Our fiducial choice is plotted as a solid blue line, with the dashed and dash-dotted lines showing the spectrum for the upper and lower limits respectively of the varied parameter. The black points correspond to the Fermi data as in Fig. 4. Plot a shows MA plotted for reasonable values of 1.6 and 2.3, and extremal values of 1.1 and 3.0; b the ionization fraction χ for values of 10−2 and 10−6; c the injection index q for values 2.1 and 2.3; and finally d the conversion fraction of supernova energy to CR electrons for values of 1% and 3%, which is equivalent to 10% and 30% of the total energy injected in all cosmic ray species. Note that varying the total CR energy budget results in a trivial scaling of the result by the same fraction, and thus is not shown

Source data.

Extended Data Fig. 2 The contribution of SFGs in the \(\dot{{{\boldsymbol{M}}}_{\ast }}\) - z plane.

The contribution of SFGs to the total γ-ray spectrum at selected energies in the star-formation rate \((\dot{{M}_{\ast }})\), redshift (z) plane. Coloured pixels show the fractional contribution (as indicated in the colourbar) from galaxies in each bin of \(\dot{{M}_{\ast }}\) and z to the diffuse isotropic γ-ray background at the indicated energy; a fractional contribution of unity corresponds to that pixel producing all of the background, with no contribution from galaxies outside the pixel. Grey points show individual CANDELS galaxies in regions of \(\dot{{M}_{\ast }}\) and z that contribute <10−3 of the total. Flanking histograms show the fractional contribution binned in one dimension – \(\dot{{M}_{\ast }}\) (right) and z (top). We see that the background at lower energies is dominated by emission from galaxies on the high side of the star forming main sequence at z ~ 1−2, while at high energies it is dominated by the brightest systems at low redshift.

Extended Data Fig. 3 The diffuse isotropic γ-ray and neutrino backgrounds.

The blue line and black points show the model-predicted and observed γ-ray background, and are identical to those shown in Fig. 4. The red lines show our model prediction for the neutrino background (single flavour) with Ecut = 100 PeV (solid line) and Ecut = 1 PeV (dashed line), computed as described in the Supplementary Information. We assume a neutrino flavour ratio at the detector of (νe:νμ:ντ) = (1:1:1). The red filled band shows a power-law fit73 to the single flavour astrophysical neutrino background with the 90% likelihood limit, as measured by IceCube, which is also shown as grey points, where the horizontal bars show the energy bin and the vertical bars the 1 σ uncertainty limit

Source data.

Extended Data Fig. 4 Cosmic ray calorimetry in the E - Σg plane.

Mean calorimetry fraction fcal(E) in the surface gas density Σg, cosmic ray energy E plane, binned in redshift intervals. This figure is constructed by deriving the gas surface density and energy dependent calorimetry fraction for each galaxy in the CANDELS sample using our model. The colour of each pixel gives the mean calorimetry fraction of all the galaxies within that particular range of Σg, E, and redshift. The horizontal white stripes correspond to ranges of Σg into which no CANDELS galaxies fall for the corresponding redshift range. Several physical processes contribute to the behaviour visible in the plot. At low Σg, galaxies have low fcal at all energies E because there are few targets for hadronic collisions with CRs. As Σg increases, the increased ISM density results in efficient calorimetry and conversion of CR energy into γ-rays for low CR energies; however, at higher energies the CR number density is low, yielding a high CR streaming velocity and rapid escape, resulting in low fcal. As Σg increases further, the increasing density results in the streaming instability being suppressed efficiently by ion-neutral damping towards lower energies, reducing the calorimetry fraction further. Finally, at the highest Σg, the streaming instability is suppressed completely by ion-neutral damping, but streaming is still limited to the speed of light. Consequently, increasing Σg further only results in increased collisions, and thus a higher calorimetry fraction.

Extended Data Fig. 5 Cosmic ray calorimetry in the z - Σg plane.

Mean calorimetry fraction in the surface gas density (Σg), redshift (z) plane at CR energies E = 1 GeV, 10 GeV, 1 TeV and 10 TeV. To construct this figure, for each CANDELS sample galaxy, we apply our model to compute Σg and fcal(E) at the indicated energies. The colour indicates the average fcal(E) value computed over bins of (z, Σg), while contours indicate the density of the CANDELS sample in this plane. Note that the non-monotonic behaviour of fcal(E) with Σg that is most prominently visible in the 1 TeV panel is expected, for the reasons explained in the caption of Extended Data Fig. 4.

Extended Data Fig. 6 Contributions to the diffuse isotropic γ-ray background.

The blue line and black points show the model-predicted and observed γ-ray background, and are identical to those shown in Fig. 4. The green line shows the contribution from π0 decay, the olive lines the contribution from bremsstrahlung emission, and the cyan lines the contribution from the inverse Compton emission. In both cases, dashed lines show the spectrum produced by primary CR electrons and the dash-dotted lines the spectrum from secondary electrons and positrons. The red line shows the contributions from the EBL cascade

Source data.

Extended Data Table 1 Local galaxy data
Full size table

Supplementary information

Supplementary Information

This file contains the following supplementary sections: Confidence intervals for source count distributions; Sensitivity of the result to model parameters; Comparison to earlier work; Neutrinos. Supplementary equations 1 – 10 are included within these sections.

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Roth, M.A., Krumholz, M.R., Crocker, R.M. et al. The diffuse γ-ray background is dominated by star-forming galaxies. Nature 597, 341–344 (2021). https://doi.org/10.1038/s41586-021-03802-x

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