Abstract
The formation of relativistic jets by an accreting compact object is one of the fundamental mysteries of astrophysics. Although the theory is poorly understood, observations of relativistic jets from systems known as microquasars (compact binary stars)1,2 have led to a well established phenomenology3,4. Relativistic jets are not expected to be produced by sources with soft or supersoft X-ray spectra, although two such systems are known to produce relatively low-velocity bipolar outflows5,6. Here we report the optical spectra of an ultraluminous supersoft X-ray source (ULS7,8) in the nearby galaxy M81 (M81 ULS-1; refs 9, 10). Unexpectedly, the spectra show blueshifted, broad Hα emission lines, characteristic of baryonic jets with relativistic speeds. These time-variable emission lines have projected velocities of about 17 per cent of the speed of light, and seem to be similar to those from the prototype microquasar SS 433 (refs 11, 12). Such relativistic jets are not expected to be launched from white dwarfs13, and an origin from a black hole or a neutron star is hard to reconcile with the persistence of M81 ULS-1’s soft X-rays10. Thus the unexpected presence of relativistic jets in a ULS challenges canonical theories of jet formation3,4, but might be explained by a long-speculated, supercritically accreting black hole with optically thick outflows14,15,16,17,18,19,20.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Mirabel, I. F. & Rodriguez, L. F. Microquasars in our Galaxy. Nature 392, 673–676 (1998)
Paredes, J. M. & Marti, J. Microquasars in the Galaxy. Contrib. Sci. 2, 303–314 (2003)
Fender, R. P., Belloni, T. M. & Gallo, E. Towards a unified model for black hole X-ray binary jets. Mon. Not. R. Astron. Soc. 355, 1105–1118 (2004)
Migliari, A. & Fender, R. P. Jets in neutron star X-ray binaries: a comparison with black holes. Mon. Not. R. Astron. Soc. 366, 79–91 (2006)
Southwell, K. A., Livio, M., Charles, P. A., O’Donoghue, D. & Sutherland, W. J. The nature of the supersoft X-ray source RX J0513–69. Astrophys. J. 470, 1065–1074 (1996)
Becker, C. M., Remillard, R. A., Rappaport, S. A. & McClintock, J. E. Bipolar jets and orbital dynamics of the supersoft X-ray source RX J0019.8+2156. Astrophys. J. 506, 880–891 (1998)
Di Stefano, R. & Kong, A. K. H. Luminous supersoft X-ray sources in external galaxies. Astrophys. J. 592, 884–899 (2003)
Swartz, D. A., Ghosh, K. K., Suleimanov, V., Tennant, A. F. & Wu, K. Chandra discovery of luminous supersoft X-ray sources in M81. Astrophys. J. 574, 382–397 (2002)
Liu, J.-F. & Di Stefano, R. An ultraluminous supersoft X-ray source in M81: an intermediate-mass black hole? Astrophys. J. 674, L73–L76 (2008)
Liu, J.-F. No periodicity revealed for an “eclipsing” ultraluminous supersoft X-ray source in M81. Astrophys. J. (Suppl.) 177, 181–188 (2008)
Margon, B. Observations of SS 433. Annu. Rev. Astron. Astrophys. 22, 507–536 1984)
Blundell, K. M., Bowler, M. G. & Schmidtobreick, L. Fluctuations and symmetry in the speed and direction of the jets of SS 433 on different timescales. Astron. Astrophys. 474, 903–910 (2007)
Livio, M. Astrophysical jets. In Proc. Astron. Soc. Pacific Conf. on Probing the Physics of Active Galactic Nuclei (eds Peterson, B. M., Pogge, R. W. & Polidan, R. S. ) 224, 225–248 (Astron. Soc. Pacific, 2001)
Paczýnski, B. & Wiita, P. J. Thick accretion disks and supercritical luminosities. Astron. Astrophys. 88, 23–31 (1980)
Abramowicz, M. A., Czerny, B., Lasota, J. P. & Szuszkiewicz, E. Slim accretion disks. Astrophys. J. 332, 646–658 (1988)
Jiang, Y.-F., Stone, J. M. & Davis, S. W. A global three-dimensional radiation magneto-hydrodynamic simulation of super-Eddington accretion disks. Astrophys. J. 796, 106 (2014)
Sadowski, A. & Narayan, R. Powerful radiative jets in super-critical accretion disks around non-spinning black holes. Preprint at http://arxiv.org/abs/1503.00654 (2015)
Ohsuga, K., Mori, M., Nakamoto, T. & Mineshige, S. Supercritical accretion flows around black holes: two-dimensional, radiation pressure-dominated disks with photon trapping. Astrophys. J. 628, 368–381 (2005)
King, A. & Pounds, K. Black hole winds. Mon. Not. R. Astron. Soc. 345, 657–659 (2003)
Shen, R.-F., Duran, R. B., Nakar, E. & Piran, T. The nature of ULX source M101 ULX-1: optically thick outflow from a stellar mass black hole. Mon. Not. R. Astron. Soc. 447, L60–L64 (2015)
Bai, Y., Liu, J. & Wang, S. Spectroscopic studies of an ultraluminous supersoft X-ray source in M81. Astrophys. J. 802, L27 (2015)
Schilizzi, R. T. et al. Preliminary specifications for the Square Kilometre Array. https://www.skatelescope.org/uploaded/5110_100_Memo_Schilizzi.pdf (2007)
Kahabka, P. & van den Heuvel, E. P. J. Luminous supersoft X-ray sources. Annu. Rev. Astron. Astrophys. 35, 69–100 (1997)
Iben, I. Jr Hot accreting white dwarfs in the quasi-static approximation. Astrophys. J. 259, 244–266 (1982)
Nomoto, K. Accreting white dwarf models for type I supernovae. I. Presupernova evolution and triggering mechanisms. Astrophys. J. 253, 798–810 (1982)
Di Stefano, R. & Kong, A. The discovery of quasi-soft and supersoft sources in external galaxies. Astrophys. J. 609, 710–727 (2004)
Di Stefano, R., Primini, F. A., Liu, J.-F., Kong, A. & Patel, B. Populations of supersoft X-ray sources: novae, tidal disruption, type Ia supernovae, accretion-induced collapse, ionization, and intermediate-mass black holes? Astron. Nachr. 331, 205–211 (2010)
Remillard, R. A. & McClintock, J. E. X-ray properties of black-hole binaries. Annu. Rev. Astron. Astrophys. 44, 49–92 (2006)
Hasinger, G. & van der Klis, M. Two patterns of correlated X-ray timing and spectral behaviour in low-mass X-ray binaries. Astron. Astrophys. 225, 79–96 (1989)
Gu, W.-M. Mechanism of outflows in accretion system: advective cooling cannot balance viscous heating? Astrophys. J. 799, 71 (2015)
Vittone, A., Rusconi, L., Sedmak, G., Mammano, A. & Ciatti, F. Correlations and periodicities of equivalent widths in SS 433. Astron. Astrophys. (Suppl.) 53, 109–117 (1983)
Freedman, W. L. et al. The Hubble Space Telescope extragalactic distance scale key project. 1. The discovery of Cepheids and a new distance to M81. Astrophys. J. 427, 628–655 (1994)
Acknowledgements
We thank K. Blundell, R. Narayan, Z. Li, T. Wang, F. Yuan, X. Fang, J. Irwin, T. Maccarone and D. Swartz for helpful discussions. We acknowledge support from the Chinese Academy of Sciences (grant XDB09000000), from the 973 Program (grant 2014CB845705), and from the National Science Foundation of China (grants NSFC-11333004/11425313). This work is based partly on observations made with the Gran Telescopio Canarias, installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, on the island of La Palma. Some of the data were obtained at the W. M. Keck Observatory, which is operated through a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. This Observatory was made possible through the financial support of the W. M. Keck Foundation.
Author information
Authors and Affiliations
Contributions
J.-F.L. proposed the observations. J.-F.L., Y.B., S.W. and J.-C. G. reduced the optical and X-ray data and carried out the analysis. J.-F.L., S.J., Y.-J.L. and R.D.S. discussed the results and drafted the manuscript. A. C.-L., P.A., Y.C and S.K. helped with the observations. All authors commented on and helped in improving the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Extended data figures and tables
Extended Data Figure 1 The power of Hα− emission versus that of Hα emission for M81 ULS-1, in units of 10−16erg s−1 cm−2.
The error bars denote 68.3% uncertainty. Observations are given as year followed by month followed by day.
Extended Data Figure 2 Variation in the power of emission lines from M81 ULS-1, in units of 10−16 erg s−1 cm−2.
The error bars denote 68.3% uncertainty. The x-axis gives the observation date as a Heliocentric Julian Date (HJD).
Extended Data Figure 3 The centre of Hα− emission as a function of the relative observational date.
The dates of observations are marked in the figure; the ‘relative observational date’ refers to the date relative to the first observation of 2010 or 2015. The error bars denote 68.3% uncertainty.
Extended Data Figure 4 The M81 ULS-1 spectra and model fitting.
The spectra from Chandra observation ID 735, the combined high-state observations, and the combined low-state observations are shown with red, blue, and black crosses respectively. The corresponding blackbody models in the energy range 0.3–8.0 keV are shown with red, blue, and black dotted lines. The yellow dashed line indicates photon energy of 0.3 keV. The error bars denote 68.3% uncertainty.
PowerPoint slides
Rights and permissions
About this article
Cite this article
Liu, JF., Bai, Y., Wang, S. et al. Relativistic baryonic jets from an ultraluminous supersoft X-ray source. Nature 528, 108–110 (2015). https://doi.org/10.1038/nature15751
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nature15751
This article is cited by
-
MeV astrophysical spectroscopic surveyor (MASS): a compton telescope mission concept
Experimental Astronomy (2024)
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.
