Abstract

Gamma-ray bursts (GRBs) are the strongest explosions in the Universe since the Big Bang. They are believed to be produced either in the formation of black holes at the end of massive star evolution1,2,3 or the merging of compact objects4. Spectral and timing properties of GRBs suggest that the observed bright gamma-rays are produced in the most relativistic jets in the Universe4; however, the physical properties (especially the structure and magnetic topologies) of the jets are still not well known, despite several decades of studies. It is widely believed that precise measurements of the polarization properties of GRBs should provide crucial information on the highly relativistic jets5. As a result, there have been many reports of GRB polarization measurements with diverse results (see ref. 6); however, many such measurements suffer from substantial uncertainties, most of which are systematic (ref. 7 and the references therein). After the first successful measurements by the Gamma-Ray Burst Polarimeter (GAP) and Compton Spectrometer and Imager (COSI) instruments8,9,10, here we report a statistically meaningful sample of precise polarization measurements, obtained with the dedicated GRB polarimeter POLAR onboard China’s Tiangong-2 space laboratory. Our results suggest that the gamma-ray emission is at most polarized at a level lower than some popular models have predicted, although our results also show intrapulse evolution of the polarization angle. This indicates that the low polarization degrees could be due to an evolving polarization angle during a GRB.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Data availability

All data that support the plots within this paper and other findings of this study are available from the POLAR Collaboration (merlin.kole@unige.ch) upon reasonable request.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

  1. 1.

    Woosley, S. E. Gamma-ray bursts from stellar mass accretion disks around black holes. Astrophys. J. 405, 273–277 (1993).

  2. 2.

    Iwamoto, K. et al. A hypernova model for the supernova associated with the γ-ray burst of 25 April 1998. Nature 395, 672–674 (1998).

  3. 3.

    MacFadyen, A. I. & Woosley, S. E. Collapsars: gamma-ray bursts and explosions in ‘failed supernovae’. Astrophys. J. 524, 262–289 (1999).

  4. 4.

    Gehrels, N. & Razzaque, S. Gamma-ray bursts in the Swift–Fermi era. Front. Phys. 8, 661–678 (2013).

  5. 5.

    Toma, K. et al. Statistical properties of gamma-ray burst polarization. Astrophys. J. 698, 1042–1054 (2009).

  6. 6.

    Covino, S. & Götz, D. Polarization of prompt and afterglow emission of gamma-ray bursts. Astron. Astrophys. Trans. 29, 205–239 (2016).

  7. 7.

    McConnel, M. High energy polarimetry of prompt GRB emission. New Astr. Rev. 76, 1–21 (2017).

  8. 8.

    Lowell, A. W. et al. Polarimetric analysis of the long duration gamma-ray burst GRB 160530A with the balloon borne Compton Spectrometer and Imager. Astrophys. J. Lett. 848, 119–129 (2017).

  9. 9.

    Yonetoku, D. et al. Magnetic structures in gamma-ray burst jets probed by gamma-ray polarization. Astrophys. J. Lett. 758, L1 (2012).

  10. 10.

    Yonetoku, D. et al. Detection of gamma-ray polarization in prompt emission of GRB 100826A. Astrophys. J. Lett. 743, L30 (2011).

  11. 11.

    Produit, N. et al. Design and construction of the POLAR detector. Nucl. Instrum. Methods Phys. Res. A 877, 259–268 (2018).

  12. 12.

    Li, Z. H. et al. In-orbit instrument performance study and calibration for POLAR polarization measurements. Nucl. Instrum. Methods Phys. Res. A 900, 8–24 (2018).

  13. 13.

    Kole, M. et al. Instrument performance and simulation verification of the POLAR detector. Nucl. Instrum. Methods Phys. Res. A 872, 28–40 (2017).

  14. 14.

    Koshut, T. M. et al. T 90 as a measurement of the duration of GRBs. 186th AAS Meeting of the Bulletin of the American Astronomical Society 886 (Conference Series Volume 27, American Astronomical Society, 1995).

  15. 15.

    Maier, D., Tenzer, C. & Santangelo, A. Point and interval estimation on the degree and the angle of polarization: a Bayesian approach. Publ. Astron. Soc. Pac. 126, 459–468 (2014).

  16. 16.

    Westfold, K. C. The polarization of synchrotron radiation. Astrophys. J. 130, 241–258 (1959).

  17. 17.

    McMaster, W. H. Matrix representation of polarization. Rev. Mod. Phys. 33, 8–28 (1961).

  18. 18.

    Lazzati, D., Rossi, E., Ghisellini, G. & Rees, M. J. Compton drag as a mechanism for very high linear polarization in gamma-ray bursts. Mon. Not. R. Astron. Soc. 347, L1–L5 (2004).

  19. 19.

    Granot, J. The most probable cause for the high gamma-ray polarization in GRB 021206. Astrophys. J. Lett. 596, L17–L21 (2003).

  20. 20.

    Lan, M. X., Wu, X. F. & Dai, Z. G. Gamma-ray burst optical afterglows with two-component jets: polarization evolution revisited. Astrophys. J. 860, 44–51 (2018).

  21. 21.

    Rossi, E. M., Lazzati, D., Salmonson, J. D. & Ghisellini, G. The polarization of afterglow emission reveals gamma-ray bursts jet structure. Mon. Not. R. Astron. Soc. 354, 86–100 (2004).

  22. 22.

    Gill, R. & Granot, J. Afterglow imaging and polarization of misaligned structured GRB jets and cocoons: breaking the degeneracy in GRB 170817A. Mon. Not. R. Astron. Soc. 478, 4128–4141 (2018).

  23. 23.

    Rees, M. J. & Meszaros, P. Unsteady outflow models for cosmological gamma-ray bursts. Astrophys. J. Lett. 430, L93–L96 (1994).

  24. 24.

    Paczynski, B. & Xu, G. Neutrino bursts from gamma-ray bursts. Astrophys. J. 427, 708–713 (1994).

  25. 25.

    Mészáros, P. & Rees, M. J. Steep slopes and preferred breaks in gamma-ray burst spectra: the role of photospheres and comptonization. Astrophys. J. 530, 292–298 (2000).

  26. 26.

    Rees, M. J. & Mészáros, P. Dissipative photosphere models of gamma-ray bursts and X-ray flashes. Astrophys. J. 628, 847–852 (2005).

  27. 27.

    Zhang, B. & Yan, H. The internal-collision-induced magnetic reconnection and turbulence (ICMART) model of gamma-ray bursts. Astrophys. J. 726, 90–113 (2011).

  28. 28.

    Lundman, C., Vurm, I. & Beloborodov, A. M. Polarization of gamma-ray bursts in the dissipative photosphere model. Astrophys. J. 856, 145 (2018).

  29. 29.

    Deng, W., Zhang, H., Zhang, B. & Li, H. Collision-induced magnetic reconnection and a unified interpretation of polarization properties of GRBs and blazars. Astrophys. J. Lett. 821, L12–L19 (2016).

  30. 30.

    Xiong, S. L. et al. Overview of the GRB observation by POLAR. In 35th International Cosmic Ray Conference 640 (Proceedings of Science, 2017).

  31. 31.

    Band, D. et al. BATSE observations of gamma-ray burst spectra. I—spectral diversity. Astrophys. J. 413, 281–292 (1993).

  32. 32.

    Avni, Y. Energy spectra of X-ray clusters of galaxies. Astrophys. J. 210, 642–646 (1976).

  33. 33.

    GCN Circular: GRB 170114A: Fermi GBM Detection (2015); https://gcn.gsfc.nasa.gov/other/170114A.gcn3

Download references

Acknowledgements

We gratefully acknowledge financial support from the National Basic Research Program (973 Program) of China (grant number 2014CB845800); Joint Research Fund in Astronomy, under cooperative agreement between the National Natural Science Foundation of China and Chinese Academy of Sciences (grant number U1631242); National Natural Science Foundation of China (grant numbers 11503028 and 11403028); Strategic Priority Research Program of the Chinese Academy of Sciences (grant number XDB23040400); Swiss Space Office of the State Secretariat for Education, Research and Innovation (ESA PRODEX Programme); National Science Center of Poland (grant number 2015/17/N/ST9/03556); and Youth Innovation Promotion Association of the Chinese Academy of Sciences (grant number 2014009). We also thank J. M. Burgess of MPE, Garching, Germany, for providing the energy spectra for GRB 170114A.

Author information

Author notes

  1. These authors contributed equally: Shuang-Nan Zhang, Merlin Kole.

Affiliations

  1. Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China

    • Shuang-Nan Zhang
    • , Tian-Wei Bao
    • , Jun-Ying Chai
    • , Yong-Wei Dong
    • , Han-Cheng Li
    • , Lu Li
    • , Zheng-Heng Li
    • , Jiang-Tao Liu
    • , Xin Liu
    • , Hao-Li Shi
    • , Li-Ming Song
    • , Jian-Chao Sun
    • , Rui-Jie Wang
    • , Yuan-Hao Wang
    • , Xing Wen
    • , Bo-Bing Wu
    • , Hua-Lin Xiao
    • , Shao-Lin Xiong
    • , Lai-Yu Zhang
    • , Li Zhang
    • , Xiao-Feng Zhang
    •  & Yong-Jie Zhang
  2. University of Chinese Academy of Sciences, Beijing, China

    • Shuang-Nan Zhang
    • , Jun-Ying Chai
    • , Han-Cheng Li
    • , Zheng-Heng Li
    • , Xin Liu
    • , Li-Ming Song
    • , Yuan-Hao Wang
    •  & Xing Wen
  3. Department of Nuclear and Particle Physics, University of Geneva, Geneva, Switzerland

    • Merlin Kole
    • , Franck Cadoux
    • , Silvio Orsi
    • , Martin Pohl
    •  & Xin Wu
  4. National Centre for Nuclear Research, Otwock, Poland

    • Tadeusz Batsch
    • , Dominik Rybka
    • , Jacek Szabelski
    • , Teresa Tymieniecka
    •  & Anna Zwolinska
  5. ISDC/Geneva Observatory, University of Geneva, Versoix, Switzerland

    • Tancredi Bernasconi
    • , Neal Gauvin
    •  & Nicolas Produit
  6. School of Astronomy and Space Science, Nanjing University, Nanjing, China

    • Zi-Gao Dai
    •  & Mi-Xiang Lan
  7. Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing, China

    • Zi-Gao Dai
  8. Paul Scherrer Institut, Villigen, Switzerland

    • Wojtek Hajdas
    • , Radoslaw Marcinkowski
    •  & Hua-Lin Xiao
  9. Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, China

    • Mi-Xiang Lan
    •  & Xue-Feng Wu

Authors

  1. Search for Shuang-Nan Zhang in:

  2. Search for Merlin Kole in:

  3. Search for Tian-Wei Bao in:

  4. Search for Tadeusz Batsch in:

  5. Search for Tancredi Bernasconi in:

  6. Search for Franck Cadoux in:

  7. Search for Jun-Ying Chai in:

  8. Search for Zi-Gao Dai in:

  9. Search for Yong-Wei Dong in:

  10. Search for Neal Gauvin in:

  11. Search for Wojtek Hajdas in:

  12. Search for Mi-Xiang Lan in:

  13. Search for Han-Cheng Li in:

  14. Search for Lu Li in:

  15. Search for Zheng-Heng Li in:

  16. Search for Jiang-Tao Liu in:

  17. Search for Xin Liu in:

  18. Search for Radoslaw Marcinkowski in:

  19. Search for Nicolas Produit in:

  20. Search for Silvio Orsi in:

  21. Search for Martin Pohl in:

  22. Search for Dominik Rybka in:

  23. Search for Hao-Li Shi in:

  24. Search for Li-Ming Song in:

  25. Search for Jian-Chao Sun in:

  26. Search for Jacek Szabelski in:

  27. Search for Teresa Tymieniecka in:

  28. Search for Rui-Jie Wang in:

  29. Search for Yuan-Hao Wang in:

  30. Search for Xing Wen in:

  31. Search for Bo-Bing Wu in:

  32. Search for Xin Wu in:

  33. Search for Xue-Feng Wu in:

  34. Search for Hua-Lin Xiao in:

  35. Search for Shao-Lin Xiong in:

  36. Search for Lai-Yu Zhang in:

  37. Search for Li Zhang in:

  38. Search for Xiao-Feng Zhang in:

  39. Search for Yong-Jie Zhang in:

  40. Search for Anna Zwolinska in:

Contributions

T.-W.B., T.Batsch, T.Bernasconi, F.C., J.-Y.C., Y.-W.D., N.G., W.H., M.K., H.-C.L., L.L., Z.-H.L., J.-T.L., X.L., R.M., S.O., M.P., N.P., D.R., H.-L.S., L.-M.S., J.-C.S., J.S., T.T., R.-J.W., X.Wen, B.-B.W., X.Wu, H.-L.X., S.-L.X., L.-Y.Z., L.Z., S.-N.Z., X.-F.Z., Y.-J.Z. and A.Z. contributed to the development of the mission concept and/or construction and testing of POLAR. M.K., Z.-H.L., N.P., J.-C.S., Y.-H.W., S.-L.X. and S.-N.Z. were involved in the presented analysis. Z.-G.D., M.-X.L. and X.-F.W. contributed to the theoretical discussions. The manuscript was produced by M.K., Z.-H.L., J.-C.S., Y.-H.W. and S.-N.Z. The principal investigators of the POLAR collaboration are S.-N.Z., M.P. and X.Wu.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to Shuang-Nan Zhang or Merlin Kole.

Supplementary information

  1. Supplementary Information

    Supplementary Figures 1–12, Supplementary Tables 1–7, Supplementary References 1–20

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/s41550-018-0664-0

Further reading