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.

Diffuse X-ray emission around an ultraluminous X-ray pulsar

Abstract

Ultraluminous X-ray sources (ULXs) are extragalactic X-ray emitters located off-centre of their host galaxy and with a luminosity in excess of a few 1039 erg s−1, if emitted isotropically1,2. The discovery of periodic modulation revealed that in some ULXs the accreting compact object is a neutron star3,4,5,6,7, indicating luminosities substantially above their Eddington limit. The most extreme object in this respect is NGC 5907 ULX-1 (ULX1), with a peak luminosity that is 500 times its Eddington limit. During a Chandra observation to probe a low state of ULX1, we detected diffuse X-ray emission at the position of ULX1. Its diameter is 2.7 ± 1.0 arcsec and contains 25 photons, none below 0.8 keV. We interpret this extended structure as an expanding nebula powered by the wind of ULX1. Its diameter of about 200 pc, characteristic energy of ~1.9 keV and luminosity of ~2 × 1038 erg s−1 imply a mechanical power of 1.3 × 1041 erg s−1 and an age of ~7 × 104 yr. This interpretation suggests that a genuinely super-Eddington regime can be sustained for timescales much longer than the spin-up time of the neutron star powering the system. As the mechanical power from a single ULX nebula can rival the injection rate of cosmic rays of an entire galaxy8, ULX nebulae could be important cosmic ray accelerators9.

This is a preview of subscription content, access via your institution

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Fig. 1: Multi-instrument soft X-ray light curve of NGC 5907 ULX-1 since April 2017, when the Swift monitoring resumed.
Fig. 2: X-ray sky map between 0.3 and 7.0 keV of the region around the direction of NGC 5907 ULX-1 as observed by Chandra in November 2017.

Data availability

The datasets analysed in this work (XMM-Newton OBSIDs: 0804090301, 0804090401, 0804090501, 0804090601, 0804090701; Chandra OBSIDs: 12987, 20830, 20994, 20995) are available for download from the HEASARC archive at https://heasarc.gsfc.nasa.gov. The data that support the plots within this paper and other findings of this study are available from the corresponding author on reasonable request.

Code availability

The code used in this work is available from the corresponding author on reasonable request.

References

  1. Feng, H. & Soria, R. Ultraluminous X-ray sources in the Chandra and XMM-Newton era. New Astron. Rev. 55, 166–183 (2011).

    Article  ADS  Google Scholar 

  2. Kaaret, P., Feng, H. & Roberts, T. P. Ultraluminous X-ray sources. Annu. Rev. Astron. Astrophys. 55, 303–341 (2017).

    Article  ADS  Google Scholar 

  3. Bachetti, M. et al. An ultraluminous X-ray source powered by an accreting neutron star. Nature 514, 202–204 (2014).

    Article  ADS  Google Scholar 

  4. Fürst, F. et al. Discovery of coherent pulsations from the ultraluminous X-ray source NGC 7793 P13. Astrophys. J. Lett. 831, L14 (2016).

    Article  ADS  Google Scholar 

  5. Israel, G. L. et al. An accreting pulsar with extreme properties drives an ultraluminous X-ray source in NGC 5907. Science 355, 817–819 (2017).

    Article  ADS  Google Scholar 

  6. Israel, G. L. et al. Discovery of a 0.42-s pulsar in the ultraluminous X-ray source NGC7793 P13. Mon. Not. R. Astron. Soc. 466, L48–L52 (2017).

    Article  ADS  Google Scholar 

  7. Carpano, S., Haberl, F., Maitra, C. & Vasilopoulos, G. Discovery of pulsations from NGC 300 ULX1 and its fast period evolution. Mon. Not. R. Astron. Soc. 476, L45–L49 (2018).

    Article  ADS  Google Scholar 

  8. Drury, L. O. Origin of cosmic rays. Astropart. Phys. 39, 52–60 (2012).

    Article  ADS  Google Scholar 

  9. Abeysekara, A. U. et al. Very-high-energy particle acceleration powered by the jets of the microquasar SS 433. Nature 562, 82–85 (2018).

    Article  ADS  Google Scholar 

  10. Xilouris, E. M., Byun, Y. I., Kylafis, N. D., Paleologou, E. V. & Papamastorakis, J. Are spiral galaxies optically thin or thick? Astron. Astrophys. 344, 868–878 (1999).

    ADS  Google Scholar 

  11. Tully, R. B. et al. Cosmicflows-2: the data. Astron. J. 146, 86 (2013).

    Article  ADS  Google Scholar 

  12. Just, A., Möllenhoff, C. & Borch, A. An evolutionary disc model of the edge-on galaxy NGC 5907. Astron. Astrophys. 459, 703–716 (2006).

    Article  ADS  Google Scholar 

  13. Blondin, J. M., Wright, E. B., Borkowski, K. J. & Reynolds, S. P. Transition to the radiative phase in supernova remnants. Astrophys. J. 500, 342–354 (1998).

    Article  ADS  Google Scholar 

  14. Fryer, C. L. et al. Compact remnant mass function: dependence on the explosion mechanism and metallicity. Astrophys. J. 749, 91 (2012).

    Article  ADS  Google Scholar 

  15. Barkov, M. V. & Komissarov, S. S. Recycling of neutron stars in common envelopes and hypernova explosions. Mon. Not. R. Astron. Soc. 415, 944–958 (2011).

    Article  ADS  Google Scholar 

  16. Pakull, M. W. & Mirioni, L. Optical counterparts of ultraluminous X-ray sources. Preprint at https://arxiv.org/abs/astro-ph/0202488 (2002).

  17. Pakull, M. W. & Mirioni, L. Bubble nebulae around ultraluminous X-ray sources. Rev. Mex. Astron. Astrofis. 15, 197–199 (2003).

    Google Scholar 

  18. Pakull, M. W. & Grisé, F. in A Population Explosion: The Nature and Evolution of X-ray Binaries in Diverse Environments (eds Bandyopadhyay, R. M. et al.) 303–307 (AIP, 2008).

  19. Lang, C. C., Kaaret, P., Corbel, S. & Mercer, A. A radio nebula surrounding the ultraluminous X-ray source in NGC 5408. Astrophys. J. 666, 79–85 (2007).

    Article  ADS  Google Scholar 

  20. Kaaret, P., Corbel, S., Prestwich, A. H. & Zezas, A. Radio emission from an ultraluminous X-ray source. Science 299, 365–368 (2003).

    Article  ADS  Google Scholar 

  21. Castor, J., McCray, R. & Weaver, R. Interstellar bubbles. Astrophys. J. 200, L107–L110 (1975).

    Article  ADS  Google Scholar 

  22. Weaver, R., McCray, R., Castor, J., Shapiro, P. & Moore, R. Interstellar bubbles. II – Structure and evolution. Astrophys. J. 218, 377–395 (1977).

    Article  ADS  Google Scholar 

  23. Pakull, M. W., Soria, R. & Motch, C. A 300-parsec-long jet-inflated bubble around a powerful microquasar in the galaxy NGC 7793. Nature 466, 209–212 (2010).

    Article  ADS  Google Scholar 

  24. Dopita, M. A., Payne, J. L., Filipović, M. D. & Pannuti, T. G. The physical parameters of the microquasar S26 in the sculptor group galaxy NGC 7793. Mon. Not. R. Astron. Soc. 427, 956–967 (2012).

    Article  ADS  Google Scholar 

  25. Pinto, C., Middleton, M. J. & Fabian, A. C. Resolved atomic lines reveal outflows in two ultraluminous X-ray sources. Nature 533, 64–67 (2016).

    Article  ADS  Google Scholar 

  26. Kosec, P. et al. Evidence for a variable ultrafast outflow in the newly discovered ultraluminous pulsar NGC 300 ULX-1. Mon. Not. R. Astron. Soc. 479, 3978–3986 (2018).

    Article  ADS  Google Scholar 

  27. Walton, D. J. et al. An iron K component to the ultrafast outflow in NGC 1313 X-1. Astrophys. J. 826, L26 (2016).

    Article  ADS  Google Scholar 

  28. Rand, R. J. Diffuse ionized gas in nine edge-on galaxies. Astrophys. J. 462, 712 (1996).

    Article  ADS  Google Scholar 

  29. Mezcua, M., Roberts, T. P., Sutton, A. D. & Lobanov, A. P. Radio observations of extreme ULXs: revealing the most powerful ULX radio nebula ever or the jet of an intermediate-mass black hole? Mon. Not. R. Astron. Soc. 436, 3128–3134 (2013).

    Article  ADS  Google Scholar 

  30. Dopita, M. A. & Sutherland, R. S. Spectral signatures of fast shocks. I. Low-density model grid. Astrophys. J. Suppl. Ser. 102, 161–188 (1996).

    Article  Google Scholar 

  31. Caplan, J. & Deharveng, L. Extinction and reddening of H II regions in the large magellanic cloud. Astron. Astrophys. 155, 297–313 (1986).

    ADS  Google Scholar 

  32. Begelman, M. C., King, A. R. & Pringle, J. E. The nature of SS433 and the ultraluminous X-ray sources. Mon. Not. R. Astron. Soc. 370, 399–404 (2006).

    Article  ADS  Google Scholar 

  33. Garmire, G. P., Bautz, M. W., Ford, P. G., Nousek, J. A. & Ricker, G. R. Jr. Advanced CCD imaging spectrometer (ACIS) instrument on the Chandra X-ray observatory. Proc. SPIE 4851, 28–44 (2003).

    Article  ADS  Google Scholar 

  34. Fruscione, A. et al. CIAO: Chandra’s data analysis system. Proc. SPIE https://doi.org/10.1117/12.671760 (2006).

  35. CalDB 4.8.4 (Chandra X-ray Center, 2019); https://go.nature.com/2naVcgC

  36. Strüder, L. et al. The European photon imaging camera on XMM-Newton: the pn-CCD camera. Astron. Astrophys. 365, L18–L26 (2001).

    Article  ADS  Google Scholar 

  37. Turner, M. J. L. et al. The European photon imaging camera on XMM-Newton: the MOS cameras. Astron. Astrophys. 365, L27–L35 (2001).

    Article  ADS  Google Scholar 

  38. Gabriel, C. et al. The XMM-Newton SAS - distributed development and maintenance of a large science analysis system: a critical analysis. In Astronomical Data Analysis Software and Systems (ADASS) XIII (eds Ochsenbein, F. et al.) 759–763 (ASP, 2004).

  39. Pintore, F. et al. A new ultraluminous X-ray source in the galaxy NGC 5907. Mon. Not. R. Astron. Soc. 477, L90–L95 (2018).

    Article  ADS  Google Scholar 

  40. Arnaud, K. A. XSPEC: the first ten years. In Astronomical Data Analysis Software and Systems V (eds Jacoby, G. H. & Barnes, J.) 17–20 (ASP, 1996).

  41. Wilms, J., Allen, A. & McCray, R. On the absorption of X-rays in the interstellar medium. Astrophys. J. 542, 914–924 (2000).

    Article  ADS  Google Scholar 

  42. Burrows, D. N. et al. The swift X-ray telescope. Space Sci. Rev. 120, 165–195 (2005).

    Article  ADS  Google Scholar 

  43. Blackburn, J. K. FTOOLS: a fits data processing and analysis software package. In Astronomical Data Analysis Software and Systems IV (eds Shaw, R. A. et al.) 367–370 (ASP, 1995).

  44. Davis, J. E. et al. Raytracing with MARX: X-ray observatory design, calibration, and support. Proc. SPIE https://doi.org/10.1117/12.926937 (2012).

  45. Draine, B. T. Scattering by interstellar dust grains. II. X-rays. Astrophys. J. 598, 1026–1037 (2003).

    Article  ADS  Google Scholar 

  46. Cash, W. Parameter estimation in astronomy through application of the likelihood ratio. Astrophys. J. 228, 939–947 (1979).

    Article  ADS  Google Scholar 

  47. Siwek, M., Sadowski, A., Narayan, R., Roberts, T. P. & Soria, R. Optical and X-ray luminosities of expanding nebulae around ultraluminous X-ray sources. Mon. Not. R. Astron. Soc. 470, 361–371 (2017).

    Article  ADS  Google Scholar 

  48. Walton, D. J. et al. A 78 day X-ray period detected from NGC 5907 ULX1 by swift. Astrophys. J. 827, L13 (2016).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

This research is based on observations made with the Chandra X-ray Observatory and has made use of software provided by the Chandra X-ray Center (CXC) in the application packages CIAO, ChIPS and Sherpa. This research also made use of data obtained with the Neil Gehrels Swift Observatory and XMM-Newton. Swift is a NASA mission with participation of the Italian Space Agency and the UK Space Agency. XMM-Newton is an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. A.B. is grateful to A. Fabian for an interesting discussion and to S. Covino for help in optical data reduction. A.B. and G.N. are supported by EXTraS, a project funded by the European Union’s Seventh Framework Programme under grant agreement no. 607452. We acknowledge funding in the framework of the project ULTraS (ASI-INAF contract no. 2017-14-H.0). M.M. acknowledges funding from ASI-INAF contract no. 2015-023-R.0. D.J.W. acknowledges financial support from an STFC Ernest Rutherford Fellowship.

Author information

Authors and Affiliations

Authors

Contributions

A.B., A.T., F.P., G.N. and P.E. processed and analysed the data. A.B. and D.M. performed the statistical analysis. Theoretical interpretation was mainly provided by A.B. with contributions and inputs by A.D.L., A.T., F.P., P.E., R.S. and other co-authors. A.B. and P.E. composed the text. All authors discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Andrea Belfiore.

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.

Supplementary information

Supplementary Information

Supplementary Figs. 1–4, Table 1 and refs. 1–21

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Belfiore, A., Esposito, P., Pintore, F. et al. Diffuse X-ray emission around an ultraluminous X-ray pulsar. Nat Astron 4, 147–152 (2020). https://doi.org/10.1038/s41550-019-0903-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41550-019-0903-z

This article is cited by

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