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.
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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
Feng, H. & Soria, R. Ultraluminous X-ray sources in the Chandra and XMM-Newton era. New Astron. Rev. 55, 166–183 (2011).
Kaaret, P., Feng, H. & Roberts, T. P. Ultraluminous X-ray sources. Annu. Rev. Astron. Astrophys. 55, 303–341 (2017).
Bachetti, M. et al. An ultraluminous X-ray source powered by an accreting neutron star. Nature 514, 202–204 (2014).
Fürst, F. et al. Discovery of coherent pulsations from the ultraluminous X-ray source NGC 7793 P13. Astrophys. J. Lett. 831, L14 (2016).
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).
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).
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).
Drury, L. O. Origin of cosmic rays. Astropart. Phys. 39, 52–60 (2012).
Abeysekara, A. U. et al. Very-high-energy particle acceleration powered by the jets of the microquasar SS 433. Nature 562, 82–85 (2018).
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).
Tully, R. B. et al. Cosmicflows-2: the data. Astron. J. 146, 86 (2013).
Just, A., Möllenhoff, C. & Borch, A. An evolutionary disc model of the edge-on galaxy NGC 5907. Astron. Astrophys. 459, 703–716 (2006).
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).
Fryer, C. L. et al. Compact remnant mass function: dependence on the explosion mechanism and metallicity. Astrophys. J. 749, 91 (2012).
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).
Pakull, M. W. & Mirioni, L. Optical counterparts of ultraluminous X-ray sources. Preprint at https://arxiv.org/abs/astro-ph/0202488 (2002).
Pakull, M. W. & Mirioni, L. Bubble nebulae around ultraluminous X-ray sources. Rev. Mex. Astron. Astrofis. 15, 197–199 (2003).
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).
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).
Kaaret, P., Corbel, S., Prestwich, A. H. & Zezas, A. Radio emission from an ultraluminous X-ray source. Science 299, 365–368 (2003).
Castor, J., McCray, R. & Weaver, R. Interstellar bubbles. Astrophys. J. 200, L107–L110 (1975).
Weaver, R., McCray, R., Castor, J., Shapiro, P. & Moore, R. Interstellar bubbles. II – Structure and evolution. Astrophys. J. 218, 377–395 (1977).
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).
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).
Pinto, C., Middleton, M. J. & Fabian, A. C. Resolved atomic lines reveal outflows in two ultraluminous X-ray sources. Nature 533, 64–67 (2016).
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).
Walton, D. J. et al. An iron K component to the ultrafast outflow in NGC 1313 X-1. Astrophys. J. 826, L26 (2016).
Rand, R. J. Diffuse ionized gas in nine edge-on galaxies. Astrophys. J. 462, 712 (1996).
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).
Dopita, M. A. & Sutherland, R. S. Spectral signatures of fast shocks. I. Low-density model grid. Astrophys. J. Suppl. Ser. 102, 161–188 (1996).
Caplan, J. & Deharveng, L. Extinction and reddening of H II regions in the large magellanic cloud. Astron. Astrophys. 155, 297–313 (1986).
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).
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).
Fruscione, A. et al. CIAO: Chandra’s data analysis system. Proc. SPIE https://doi.org/10.1117/12.671760 (2006).
CalDB 4.8.4 (Chandra X-ray Center, 2019); https://go.nature.com/2naVcgC
Strüder, L. et al. The European photon imaging camera on XMM-Newton: the pn-CCD camera. Astron. Astrophys. 365, L18–L26 (2001).
Turner, M. J. L. et al. The European photon imaging camera on XMM-Newton: the MOS cameras. Astron. Astrophys. 365, L27–L35 (2001).
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).
Pintore, F. et al. A new ultraluminous X-ray source in the galaxy NGC 5907. Mon. Not. R. Astron. Soc. 477, L90–L95 (2018).
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).
Wilms, J., Allen, A. & McCray, R. On the absorption of X-rays in the interstellar medium. Astrophys. J. 542, 914–924 (2000).
Burrows, D. N. et al. The swift X-ray telescope. Space Sci. Rev. 120, 165–195 (2005).
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).
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).
Draine, B. T. Scattering by interstellar dust grains. II. X-rays. Astrophys. J. 598, 1026–1037 (2003).
Cash, W. Parameter estimation in astronomy through application of the likelihood ratio. Astrophys. J. 228, 939–947 (1979).
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).
Walton, D. J. et al. A 78 day X-ray period detected from NGC 5907 ULX1 by swift. Astrophys. J. 827, L13 (2016).
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.
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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.
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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
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DOI: https://doi.org/10.1038/s41550-019-0903-z
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