The host galaxy of a fast radio burst


In recent years, millisecond-duration radio signals originating in distant galaxies appear to have been discovered in the so-called fast radio bursts1,2,3,4,5,6,7,8,9. These signals are dispersed according to a precise physical law and this dispersion is a key observable quantity, which, in tandem with a redshift measurement, can be used for fundamental physical investigations10,11. Every fast radio burst has a dispersion measurement, but none before now have had a redshift measurement, because of the difficulty in pinpointing their celestial coordinates. Here we report the discovery of a fast radio burst and the identification of a fading radio transient lasting ~6 days after the event, which we use to identify the host galaxy; we measure the galaxy’s redshift to be z = 0.492 ± 0.008. The dispersion measure and redshift, in combination, provide a direct measurement of the cosmic density of ionized baryons in the intergalactic medium of ΩIGM = 4.9 ± 1.3 per cent, in agreement with the expectation from the Wilkinson Microwave Anisotropy Probe12, and including all of the so-called ‘missing baryons’. The ~6-day radio transient is largely consistent with the radio afterglow of a short γ-ray burst13, and its existence and timescale do not support progenitor models such as giant pulses from pulsars, and supernovae. This contrasts with the interpretation8 of another recently discovered fast radio burst, suggesting that there are at least two classes of bursts.

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Figure 1: The FRB 150418 radio signal.
Figure 2: The FRB host galaxy radio light curve.
Figure 3: Optical analysis of the FRB host galaxy.


  1. 1

    Lorimer, D. R., Bailes, M., McLaughlin, M. A., Narkevic, D. J. & Crawford, F. A bright millisecond radio burst of extragalactic origin. Science 318, 777–780 (2007)

    ADS  CAS  Article  Google Scholar 

  2. 2

    Keane, E. F., Stappers, B. W., Kramer, M. & Lyne, A. G. On the origin of a highly dispersed coherent radio burst. Mon. Not. R. Astron. Soc. 425, L71–L75 (2012)

    ADS  Article  Google Scholar 

  3. 3

    Thornton, D. et al. A population of fast radio bursts at cosmological distances. Science 341, 53–56 (2013)

    ADS  CAS  Article  Google Scholar 

  4. 4

    Spitler, L. G. et al. Fast radio burst discovered in the Arecibo pulsar ALFA survey. Astrophys. J. 790, 101–110 (2014)

    ADS  Article  Google Scholar 

  5. 5

    Burke-Spolaor, S. & Bannister, K. W. The galactic position dependence of fast radio bursts and the discovery of FRB 011025. Astrophys. J. 792, 19–26 (2014)

    ADS  Article  Google Scholar 

  6. 6

    Ravi, V., Shannon, R. M. & Jameson, A. A fast radio burst in the direction of the Carina dwarf spheroidal galaxy. Astrophys. J. 799, L5–L10 (2015)

    ADS  Article  Google Scholar 

  7. 7

    Petroff, E. et al. A real-time fast radio burst: polarization detection and multiwavelength follow-up. Mon. Not. R. Astron. Soc. 447, 246–255 (2015)

    ADS  CAS  Article  Google Scholar 

  8. 8

    Masui, K. et al. Dense magnetized plasma associated with a fast radio burst. Nature 528, 523–525 (2015)

    ADS  CAS  Article  Google Scholar 

  9. 9

    Champion, D. et al. Five new fast radio bursts from the HTRU high latitude survey: RST evidence for two-component bursts. Mon. Not. R. Astron. Soc . (submitted); preprint at (2015)

  10. 10

    McQuinn, M. Locating the “missing” baryons with extragalactic dispersion measure estimates. Astrophys. J. 780, L33 (2014)

    ADS  Article  Google Scholar 

  11. 11

    Zhou, B., Li, X., Wang, T., Fan, Y.-Z. & Wei, D.-M. Fast radio bursts as a cosmic probe? Phys. Rev. D 89, 107303 (2014)

    ADS  Article  Google Scholar 

  12. 12

    Hinshaw, G. et al. Nine-year Wilkinson Microwave Anisotropy Probe (WMAP) observations: cosmological parameter results. Astrophys. J . 208 (Suppl.), 19 (2013)

    Google Scholar 

  13. 13

    Chandra, P. & Frail, D. A. A. Radio-selected sample of gamma-ray burst afterglows. Astrophys. J. 746, 156 (2012)

    ADS  Article  Google Scholar 

  14. 14

    Cordes, J. M. & Lazio, T. J. W. NE2001.I. A new model for the Galactic distribution of free electrons and its fluctuations. Preprint at (2002)

  15. 15

    Bhat, N. D. R., Cordes, J. M., Camilo, F., Nice, D. J. & Lorimer, D. R. Multifrequency observations of radio pulse broadening and constraints on interstellar electron density microstructure. Astrophys. J. 605, 759–783 (2004)

    ADS  Article  Google Scholar 

  16. 16

    Bell, M. E. et al. A search for variable and transient radio sources in the extended Chandra Deep Field South at 5.5 GHz. Mon. Not. R. Astron. Soc. 450, 4221–4232 (2015)

    ADS  Article  Google Scholar 

  17. 17

    Brown, M. J. I., Jannuzi, B. T., Floyd, D. J. E. & Mould, J. R. The ubiquitous radio continuum emission from the most massive early-type galaxies. Astrophys. J. 731, L41 (2011)

    ADS  Article  Google Scholar 

  18. 18

    Mooley, K. P. et al. The Caltech-NRAO Stripe 82 Survey (CNSS) paper I: the pilot radio transient survey in 50 deg2. Astrophys. J. (in the press); (2016)

  19. 19

    Ioka, K. The cosmic dispersion measure from gamma-ray burst afterglows: probing the reionization history and the burst environment. Astrophys. J. 598, L79–L82 (2003)

    ADS  CAS  Article  Google Scholar 

  20. 20

    Inoue, S. Probing the cosmic reionization history and local environment of gamma-ray bursts through radio dispersion. Mon. Not. R. Astron. Soc. 348, 999–1008 (2004)

    ADS  CAS  Article  Google Scholar 

  21. 21

    Dolag, K., Gaensler, B. M., Beck, A. M. & Beck, M. C. Constraints on the distribution and energetics of fast radio bursts using cosmological hydrodynamic simulations. Mon. Not. R. Astron. Soc. 451, 4277–4289 (2015)

    ADS  CAS  Article  Google Scholar 

  22. 22

    Xu, J. & Han, J. L. Extragalactic dispersion measures of fast radio bursts. Res. Astron. Astrophys. 15, 1629 (2015)

    ADS  CAS  Article  Google Scholar 

  23. 23

    Fukugita, M. & Peebles, P. J. E. The cosmic energy inventory. Astrophys. J. 616, 643–668 (2004)

    ADS  CAS  Article  Google Scholar 

  24. 24

    Bregman, J. N. The search for the missing baryons at low redshift. Annu. Rev. Astron. Astrophys. 45, 221–259 (2007)

    ADS  CAS  Article  Google Scholar 

  25. 25

    Staveley-Smith, L. et al. The Parkes 21 cm multibeam receiver. Publ. Astron. Soc. Aust . 13, 243–248 (1996)

    ADS  Article  Google Scholar 

  26. 26

    Pietka, M., Fender, R. P. & Keane, E. F. The variability time-scales and brightness temperatures of radio flares from stars to supermassive black holes. Mon. Not. R. Astron. Soc. 446, 3687–3696 (2015)

    ADS  CAS  Article  Google Scholar 

  27. 27

    Fong, W., Berger, E., Margutti, R. & Ashley, B. A. A decade of short-duration gamma-ray burst broad-band afterglows: energetics, circumburst densities, and jet opening angles. Astrophys. J. 815, 102 (2015)

    ADS  Article  Google Scholar 

  28. 28

    Berger, E. Short-duration gamma-ray bursts. Annu. Rev. Astron. Astrophys. 52, 43–105 (2014)

    ADS  Article  Google Scholar 

  29. 29

    Frail, D. A., Kulkarni, S. R., Nicastro, L., Feroci, M. & Taylor, G. B. The radio afterglow from the γ-ray burst of 8 May 1997. Nature 389, 261–263 (1997)

    ADS  CAS  Article  Google Scholar 

  30. 30

    Kulkarni, S. R., Ofek, E. O. & Neill, J. D. The Arecibo fast radio burst: dense circum-burst medium. Preprint at (2015)

  31. 31

    Zheng, Z., Ofek, E. O., Kulkarni, S. R., Neill, J. D. & Juric, M. Probing the intergalactic medium with fast radio bursts. Astrophys. J. 797, 71 (2014)

    ADS  Article  Google Scholar 

  32. 32

    Dennison, B. Fast radio bursts: constraints on the dispersing medium. Mon. Not. R. Astron. Soc. 443, L11–L14 (2014)

    ADS  Article  Google Scholar 

  33. 33

    Hotan, A. W., van Straten, W. & Manchester, R. N. PSRCHIVE and PSRFITS: an open approach to radio pulsar data storage and analysis. Publ. Astron. Soc. Aust . 21, 302–309 (2004)

    ADS  Article  Google Scholar 

  34. 34

    Tingay, S. J. et al. The Murchison Widefield Array: The Square Kilometre Array precursor at low radio frequencies. Publ. Astron. Soc. Aust . 30, e007 (2013)

    ADS  Article  Google Scholar 

  35. 35

    Abbott, B. P. et al. LIGO: the Laser Interferometer Gravitational-Wave Observatory. Rep. Prog. Phys. 72, 076901 (2009)

    ADS  Article  Google Scholar 

  36. 36

    Becker, R. H., Helfand, D. J., White, R. L. & Proctor, D. D. Variable radio sources in the Galactic Plane. Astron. J. 140, 157–166 (2010)

    ADS  CAS  Article  Google Scholar 

  37. 37

    Ofek, E. O. et al. A very large array search for 5 GHz radio transients and variables at low galactic latitudes. Astrophys. J. 740, 65 (2011)

    ADS  Article  Google Scholar 

  38. 38

    Frail, D. A., Kulkarni, S. R., Ofek, E. O., Bower, G. C. & Nakar, E. A revised view of the transient radio sky. Astrophys. J. 747, 70 (2012)

    ADS  Article  Google Scholar 

  39. 39

    Croft, S., Bower, G. C. & Whysong, D. The Allen Telescope Array Pi GHz Sky Survey. III. The ELAIS-N1, Coma, and Lockman hole fields. Astrophys. J. 762, 93 (2013)

    ADS  Article  Google Scholar 

  40. 40

    Gal-Yam, A. et al. Radio and optical follow-up observations of a uniform radio transient search: implications for gamma-ray bursts and supernovae. Astrophys. J. 639, 331–339 (2006)

    ADS  CAS  Article  Google Scholar 

  41. 41

    Miyazaki, S. et al. Subaru Prime Focus Camera—Suprime-Cam. Publ. Astron. Soc. Jpn 54, 833–853 (2002)

    ADS  Article  Google Scholar 

  42. 42

    Davenport, J. R. A. et al. The SDSS-2MASS-WISE 10-dimensional stellar colour locus. Mon. Not. R. Astron. Soc. 440, 3430–3438 (2014)

    ADS  Article  Google Scholar 

  43. 43

    Cohen, M., Wheaton, W. A. & Megeath, S. T. Spectral irradiance calibration in the infrared. XIV. The absolute calibration of 2MASS. Astron. J. 126, 1090–1096 (2003)

    ADS  Article  Google Scholar 

  44. 44

    Jarrett, T. H. et al. The Spitzer-WISE survey of the ecliptic poles. Astrophys. J. 735, 112 (2011)

    ADS  Article  Google Scholar 

  45. 45

    Brammer, G. B., van Dokkum, P. G. & Coppi, P. EAZY: a fast, public photometric redshift code. Astrophys. J. 686, 1503–1513 (2008)

    ADS  Article  Google Scholar 

  46. 46

    da Cunha, E., Charlot, S. & Elbaz, D. A simple model to interpret the ultraviolet, optical and infrared emission from galaxies. Mon. Not. R. Astron. Soc. 388, 1595–1617 (2008)

    ADS  CAS  Article  Google Scholar 

  47. 47

    Faber, S. M. & Jackson, R. E. Velocity dispersions and mass-to-light ratios for elliptical galaxies. Astrophys. J. 204, 668–683 (1976)

    ADS  CAS  Article  Google Scholar 

  48. 48

    Bullock, J. S. et al. Profiles of dark haloes: evolution, scatter and environment. Mon. Not. R. Astron. Soc. 321, 559–575 (2001)

    ADS  Article  Google Scholar 

  49. 49

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

    ADS  CAS  Article  Google Scholar 

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The Parkes radio telescope and the Australia Telescope Compact Array are part of the Australia Telescope National Facility, which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. Parts of this research were conducted by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO) and used the gSTAR national facility at Swinburne University of Technology. Parts of this work are based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan, the Murchison Radio-astronomy Observatory operated by CSIRO, the Giant Metrewave Radio Telescope (GMRT), which is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research, the Sardinia Radio Telescope as part of scientific commissioning of the telescope, and the 100-m telescope of the MPIfR at Effelsberg. We acknowledge the Wajarri Yamatji people as the traditional owners of the MWA Observatory site.

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E.F.K. is the principal investigator of the SUPERB project, created SUPERB survey infrastructure at Parkes and Swinburne, led survey planning, formulated and wrote (with input from co-authors) the contents of this manuscript, performed the ΩIGM calculation, calculated the FRB spectral index, produced the FRB waterfall plot and the light curve plot. S.J. and S.B. performed ATCA observations and data analysis. S.J. and B.W.S. worked on radio light curve interpretation. S.B., N.D.R.B. and P.C. performed GMRT observations and data analysis. E.B. created survey infrastructure at Parkes and Swinburne and created the MWA shadowing infrastructure. Additionally, E.F.K., S.J., S.B., E.B., N.D.R.B., M. Burgay, M.C., C.F., M.K., E.P., A.P., W.v.S., M. Bailes., S.B.-S. and R.P.E. all performed observations for the SUPERB survey at Parkes. A.J. created and maintained the Parkes and Swinburne hardware and software infrastructure and performed data management for the SUPERB project. M. Bailes additionally provided Parkes and Swinburne hardware. C.F. and M.K. also worked on the calculation of the cosmic density of ionized baryons in the intergalactic medium. M.K. additionally performed FRB radio profile fitting. Polarization analysis of the FRB signal was performed by M.C., E.P. and W.v.S. W.v.S. also produced the polarization profile plot. E.P. additionally performed the Swift analysis. Non-imaging radio follow-up was performed by M. Burgay, A.P. and D.P. with the Sardinia Radio Telescope, by R.P.E. and M. Berezina with the Effelsberg Radio Telescope, and by B.W.S., M.M. and C.B. at the Lovell Telescope at Jodrell Bank. T. Totani, M.H., H.F., T.H., T.M., Y.N., H.S., T. Terai, N.T, S.Y. and N.Y. performed the Subaru observations. T. Totani, T.H., N.T. and S.Y. additionally performed Subaru data analysis, determined the spectral redshift and created the optical profile plot. C.F., T. Totani, S.Y. and R.A. performed the optical profile fitting. J.C. performed data analysis on the Keck and Subaru data, also obtained the spectral redshift and produced the optical spectrum plot. J.J. performed the Palomar observations. M.M.K. performed the Keck observation. MWA observations were performed by N.D.R.B., D.L.K., S.J.T., A.W. and R.W. with data analysis by D.L.K. and S.J.T. D.L.K. additionally measured the photometric redshift and produced the RGB (red–green–blue) image and photo-z plots (Extended Data Fig. 1).

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Correspondence to E. F. Keane.

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Extended data figures and tables

Extended Data Figure 1 The photometric redshift of the FRB host galaxy.

A χ2 fit of the redshift of the galaxy based on the spectral energy (Lv) distribution is shown. The photometric redshift determined from this is 0.48 < z < 0.56 (68% confidence, denoted by the shaded regions). Two spectral fits are shown, and these are denoted by the red and blue shading respectively. The spectral redshift is denoted by the dashed vertical line. The inset shows the spectral energy distribution fit, with the seven photometric estimates overplotted with 1σ error bars.

Extended Data Figure 2 The optical surface brightness profile of the FRB host galaxy.

The surface brightness profile of the galaxy in the Subaru i′ band image was fitted to an ellipsoidal Sersic function. Best-fit values for the half-light radius (Re), Sersic index (n), axis ratio (b/a) and position angle (PA) are given in the inset. The model profiles and data are shown as the flux along an ellipse as a function of semi-major axis. The image point spread function (PSF) profile is also shown as a function of radius. Error bars give the root-mean-square scatter of the pixel counts along the axis.

Extended Data Table 1 Summary of follow-up observations of FRB 150418

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Keane, E., Johnston, S., Bhandari, S. et al. The host galaxy of a fast radio burst. Nature 530, 453–456 (2016).

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