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Direct evidence for shock-powered optical emission in a nova

Abstract

Classical novae are thermonuclear explosions that occur on the surfaces of white dwarf stars in interacting binary systems1. It has long been thought that the luminosity of classical novae is powered by continued nuclear burning on the surface of the white dwarf after the initial runaway2. However, recent observations of gigaelectronvolt γ-rays from classical novae have hinted that shocks internal to the nova ejecta may dominate the nova emission. Shocks have also been suggested to power the luminosity of events as diverse as stellar mergers3, supernovae4 and tidal disruption events5, but observational confirmation has been lacking. Here we report simultaneous space-based optical and γ-ray observations of the 2018 nova V906 Carinae (ASASSN-18fv), revealing a remarkable series of distinct correlated flares in both bands. The optical and γ-ray flares occur simultaneously, implying a common origin in shocks. During the flares, the nova luminosity doubles, implying that the bulk of the luminosity is shock powered. Furthermore, we detect concurrent but weak X-ray emission from deeply embedded shocks, confirming that the shock power does not appear in the X-ray band and supporting its emergence at longer wavelengths. Our data, spanning the spectrum from radio to γ-ray, provide direct evidence that shocks can power substantial luminosity in classical novae and other optical transients.

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Fig. 1: Nova V906 Car was discovered in a complex region of the Galaxy near the Carina nebula and the red giant star HD 92063, which was being monitored by the BRITE satellite constellation.
Fig. 2: The optical and GeV γ-ray light curves of nova V906 Car are correlated, showing simultaneous flares in both bands.

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Data availability

The data that support the plots within this paper and other findings of this study are available from http://scan.sai.msu.ru/~kirx/v906car/ or from the corresponding authors upon reasonable request.

References

  1. Bode, M. F. & Evans, A. Classical Novae 2nd edn (Cambridge Astrophysics Series No. 43, Cambridge Univ. Press, 2008).

  2. Gallagher, J. S. & Starrfield, S. Theory and observations of classical novae. Annu. Rev. Astron. Astrophys. 16, 171–214 (1978).

    Article  ADS  Google Scholar 

  3. Metzger, B. D. & Pejcha, O. Shock-powered light curves of luminous red novae as signatures of pre-dynamical mass-loss in stellar mergers. Mon. Not. R. Astron. Soc. 471, 3200–3211 (2017).

    Article  ADS  Google Scholar 

  4. Moriya, T. J., Sorokina, E. I. & Chevalier, R. A. Superluminous supernovae. Space Sci. Rev. 214, 59 (2018).

    Article  ADS  Google Scholar 

  5. Roth, N., Kasen, D., Guillochon, J. & Ramirez-Ruiz, E. The X-ray through optical fluxes and line strengths of tidal disruption events. Astrophys. J. 827, 3 (2016).

    Article  ADS  Google Scholar 

  6. Warner, B. Cataclysmic Variable Stars 2nd edn (Cambridge Astrophysics Series No. 28, Cambridge Univ. Press, 1995).

  7. Wolf, W. M., Bildsten, L., Brooks, J. & Paxton, B. Hydrogen burning on accreting white dwarfs: stability, recurrent novae, and the post-nova supersoft phase. Astrophys. J. 777, 136 (2013).

    Article  ADS  Google Scholar 

  8. Strope, R. J., Schaefer, B. E. & Henden, A. A. Catalog of 93 nova light curves: classification and properties. Astron. J. 140, 34–62 (2010).

    Article  ADS  Google Scholar 

  9. Cassatella, A., Lamers, H. J. G. L. M., Rossi, C., Altamore, A. & González-Riestra, R. A study of the expanding envelope of nova V1974 Cyg 1992 based on IUE high resolution spectroscopy. Astron. Astrophys. 420, 571–588 (2004).

    Article  ADS  Google Scholar 

  10. Hillman, Y., Prialnik, D., Kovetz, A., Shara, M. M. & Neill, J. D. Nova multiwavelength light curves: predicting UV precursor flashes and pre-maximum halts. Mon. Not. R. Astron. Soc. 437, 1962–1975 (2014).

    Article  ADS  Google Scholar 

  11. Goranskij, V. P. et al. Photometric and spectroscopic study of nova Cassiopeiae 1995 (V723 Cas). Astrophys. Bull. 62, 125–146 (2007).

    Article  ADS  Google Scholar 

  12. Chochol, D. & Pribulla, T. Photometric variability of the slow nova V723 Cas. Contrib. Astron. Obs. Skaln. Pleso 28, 121 (1998).

    ADS  Google Scholar 

  13. Shappee, B. J. et al. The man behind the curtain: X-rays drive the UV through NIR variability in the 2013 active galactic nucleus outburst in NGC 2617. Astrophys. J. 788, 48 (2014).

    Article  ADS  Google Scholar 

  14. ASAS-SN Discovery of a possible, very bright galactic nova ASASSN-18fv. The Astronomer’s Telegram 11454 (2018).

  15. Luckas, P. Spectroscopic observations of ASASSN-18fv as a classical nova in the iron curtain phase. The Astronomer’s Telegram 11460 (2018).

  16. Pablo, H. et al. The BRITE constellation nanosatellite mission: testing, commissioning, and operations. Publ. Astron. Soc. Pac. 128, 125001 (2016).

    Article  ADS  Google Scholar 

  17. Jean, P., Cheung, C. C., Ojha, R., van Zyl, P. & Angioni, R. Fermi-LAT bright gamma-ray detection of nova ASASSN-18fv. The Astronomer’s Telegram 11546 (2018).

  18. Franckowiak, A., Jean, P., Wood, M., Cheung, C. C. & Buson, S. Search for gamma-ray emission from galactic novae with the Fermi-LAT. Astron. Astrophys. 609, A120 (2018).

    Article  ADS  Google Scholar 

  19. Li, K.-L. et al. A nova outburst powered by shocks. Nat. Astron. 1, 697–702 (2017).

    Article  ADS  Google Scholar 

  20. Chomiuk, L. et al. Binary orbits as the driver of γ-ray emission and mass ejection in classical novae. Nature 514, 339–342 (2014).

    Article  ADS  Google Scholar 

  21. Metzger, B. D. et al. Gamma-ray novae as probes of relativistic particle acceleration at non-relativistic shocks. Mon. Not. R. Astron. Soc. 450, 2739–2748 (2015).

    Article  ADS  Google Scholar 

  22. Tatischeff, V. & Hernanz, M. Evidence for nonlinear diffusive shock acceleration of cosmic rays in the 2006 outburst of the recurrent nova RS Ophiuchi. Astrophys. J. Lett. 663, 101–104 (2007).

    Article  ADS  Google Scholar 

  23. Martin, P., Dubus, G., Jean, P., Tatischeff, V. & Dosne, C. Gamma-ray emission from internal shocks in novae. Mon. Not. R. Astron. Soc. 612, A38 (2018).

    Google Scholar 

  24. Chugai, N. N. et al. The type IIn supernova 1994w: evidence for the explosive ejection of a circumstellar envelope. Mon. Not. R. Astron. Soc. 352, 1213–1231 (2004).

    Article  ADS  Google Scholar 

  25. Slane, P., Bykov, A., Ellison, D. C., Dubner, G. & Castro, D. Supernova remnants interacting with molecular clouds: X-ray and gamma-ray signatures. Space Sci. Rev. 188, 187–210 (2015).

    Article  ADS  Google Scholar 

  26. Steinberg, E. & Metzger, B. D. The multidimensional structure of radiative shocks: suppressed thermal X-rays and relativistic ion acceleration. Mon. Not. R. Astron. Soc. 479, 687–702 (2018).

    ADS  Google Scholar 

  27. Caprioli, D. & Spitkovsky, A. Simulations of ion acceleration at non-relativistic shocks. I. Acceleration efficiency. Astrophys. J. 783, 91 (2014).

    Article  ADS  Google Scholar 

  28. Nelson, T. et al. NuSTAR detection of X-rays concurrent with gamma-rays in the nova V5855 Sgr. Astrophys. J. 872, 86 (2019).

    Article  ADS  Google Scholar 

  29. Pejcha, O., Metzger, B. D. & Tomida, K. Cool and luminous transients from mass-losing binary stars. Mon. Not. R. Astron. Soc. 455, 4351–4372 (2016).

    Article  ADS  Google Scholar 

  30. Smith, N. & McCray, R. Shell-shocked diffusion model for the light curve of SN 2006gy. Astrophys. J. Lett. 671, L17–L20 (2007).

    Article  ADS  Google Scholar 

  31. Silverman, J. M. et al. Type Ia supernovae strongly interacting with their circumstellar medium. Astrophys. J. Suppl. Ser. 207, 3 (2013).

    Article  ADS  Google Scholar 

  32. Dong, S. et al. ASASSN-15lh: a highly super-luminous supernova. Science 351, 257–260 (2016).

    Article  ADS  Google Scholar 

  33. Chatzopoulos, E. et al. Extreme supernova models for the super-luminous transient ASASSN-15lh. Astrophys. J. 828, 94 (2016).

    Article  ADS  Google Scholar 

  34. Murase, K., Thompson, T. A. & Ofek, E. O. Probing cosmic ray ion acceleration with radio-submm and gamma-ray emission from interaction-powered supernovae. Mon. Not. R. Astron. Soc. 440, 2528–2543 (2014).

    Article  ADS  Google Scholar 

  35. Murase, K., Franckowiak, A., Maeda, K., Margutti, R. & Beacom, J. F. High-energy emission from interacting supernovae: new constraints on cosmic-ray acceleration in dense circumstellar environments. Astrophys. J. 874, 80 (2019).

    Article  ADS  Google Scholar 

  36. Kochanek, C. S. et al. The All-sky Automated Survey for Supernovae (ASAS-SN) light curve server v1.0. Publ. Astron. Soc. Pac. 129, 104502 (2017).

    Article  ADS  Google Scholar 

  37. Corbett, H. et al. Pre-discovery detection of ASASSN-18fv by Evryscope. The Astronomer’s Telegram 11467 (2018).

  38. Weiss, W. W. et al. BRITE-constellation: nanosatellites for precision photometry of bright stars. Publ. Astron. Soc. Pac. 126, 573 (2014).

    Article  ADS  Google Scholar 

  39. Popowicz, A. et al. BRITE constellation: data processing and photometry. Astron. Astrophys. 605, A26 (2017).

    Article  Google Scholar 

  40. Pigulski, A. BRITE cookbook 2.0. In 3rd BRITE Science Conference Vol. 8 (eds Wade, G. A. et al.) 175–192 (Polish Astronomical Society, 2018).

  41. Abdollahi, S. et al. Fermi Large Area Telescope fourth source catalog. Astrophys. J. Suppl. Ser. 247, 33 (2020).

    Article  ADS  Google Scholar 

  42. Harrison, F. A. et al. The Nuclear Spectroscopic Telescope Array (NuSTAR) high-energy X-ray mission. Astrophys. J. 770, 103 (2013).

    Article  ADS  Google Scholar 

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Acknowledgements

E.A., L.C. and K.V.S. acknowledge NSF award AST-1751874, NASA award 11-Fermi 80NSSC18K1746 and a Cottrell fellowship of the Research Corporation. K.L.L. was supported by the Ministry of Science and Technology of Taiwan through grant 108-2112-M-007-025-MY3. J.S. was supported by the Packard Foundation. O.P. was supported by Horizon 2020 ERC Starting Grant ‘Cat-In-hAT’ (grant agreement number 803158) and INTER-EXCELLENCE grant LTAUSA18093 from the Czech Ministry of Education, Youth, and Sports. Support for K.J.S. was provided by NASA through the Astrophysics Theory Program (NNX17AG28G). G.A.W. acknowledges Discovery Grant support from the Natural Sciences and Engineering Research Council (NSERC) of Canada. A.F.J.M. is grateful for financial assistance from NSERC (Canada) and FQRNT (Quebec). A.Pigulski acknowledges support provided by the Polish National Science Center (NCN) grant No.number 2016/21/B/ST9/01126. A.Popowicz was supported by statutory activities grant SUT 02/010/BKM19 t.20. D.A.H.B. gratefully acknowledge the receipt of research grants from the National Research Foundation (NRF) of South Africa. A.Kniazev acknowledges the National Research Foundation of South Africa and the Russian Science Foundation (project no.14-50-00043). R.K., W.W. and K.Z. acknowledge support from the Austrian Space Application Programme (ASAP) of the Austrian Research Promotion Agency (FFG). I.V. acknowledges the support by the Estonian Research Council grants IUT26-2 and IUT40-2, and by the European Regional Development Fund (TK133). This research has been partly founded by the National Science Centre, Poland, through grant OPUS 2017/27/B/ST9/01940 to J.M. This work is based on data collected by the BRITE Constellation satellite mission, designed, built, launched, operated and supported by the Austrian Research Promotion Agency (FFG), the University of Vienna, the Technical University of Graz, the University of Innsbruck, the Canadian Space Agency (CSA), the University of Toronto Institute for Aerospace Studies (UTIAS), the Foundation for Polish Science and Technology (FNiTP MNiSW) and National Science Centre (NCN). G.H. is indebeted to the Polish National Science Center for funding by grant number 2015/18/A/ST9/00578. C.S.K. is supported by NSF grants AST-1908952 and AST-1814440. We acknowledge the use of public data from the Swift data archive. UK funding for the Neil Gehrels Swift Observatory is provided by the UK Space Agency. This research has made use of data and/or software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC and the High Energy Astrophysics Division of the Smithsonian Astrophysical Observatory. A part of this work is based on observations made with the Southern African Large Telescope (SALT), under the Large science Programme on transient 2018-2-LSP-001. Polish participation in SALT is funded by grant number MNiSW DIR/WK/2016/07. The Australia Telescope Compact Array is part of the Australia Telescope National Facility, which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge ARAS observers T. Bohlsen, B. Heathcote and P. Luckas for their optical spectroscopic observations which complement our database. Nova research at Stony Brook is supported in part by NSF grant AST 1614113, and by research support from Stony Brook University. We thank E. R. Colmenero for initiating the collaboration that has led to this paper.

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E.A. wrote the text. A.Pigulski, A.Popowicz, R.K., K.V.S., L.C., S.R., M.F., R.A., P.Manojlović, R.L.d.O., J.S., K.L.L., A.Kniazev, L.I., F.M.W. and K.R.P. obtained and reduced the data. All authors contributed to the interpretation of the data and commented on the final manuscript.

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Correspondence to Elias Aydi, Kirill V . Sokolovsky or Laura Chomiuk.

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Aydi, E., Sokolovsky, K.V., Chomiuk, L. et al. Direct evidence for shock-powered optical emission in a nova. Nat Astron 4, 776–780 (2020). https://doi.org/10.1038/s41550-020-1070-y

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