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Transient emission associated with the birth of neutron stars

This workshop explores the EOS of dense neutron-rich matter and its connection to transient emission associated with the birth of neutron stars. Topics include SLSNe, magnetars, GRB afterglows, and the collapse of white dwarfs.

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Transient emission associated with the birth of neutron stars

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  1. Xiamen-CUSTIPEN Workshop on the EOS of Dense Neutron-Rich Matter in the Era of Gravitational Wave Astronomy 7 Jan 2018 Transient emission associated with the birth of neutron stars Yun-Wei Yu / 俞云伟 Central China Normal University / 华中师范大学

  2. Neutron stars and supernovae Superluminous Supernovae Gal-Yam 2012 Smith et al. 2007

  3. Possible energy sources of SLSNe Pair Instability Supernovae Magnetar engines: Hydrogen-poor SLSNe (Herger & Woosley 2002) Gal-Yam 2009 Shock interaction: Hydrogen-rich SLSNe Smith & McCray 2007 Smith et al. 2007 Nicholl et al. 2013

  4. SLSN magnetars YY, Zhu, Li et al. 2017, ApJ, 840, 12

  5. SLSN magnetars The rotational energy of SLSN magnetars seems correlated with the masses of SLSN ejecta. Why? The rapid and slow classification of SLSN light curves in observation is a natural result of the distribution of the NS magnetic fields. The magnetic fields of SLSN magnetars are just higher than the Landau critical field strength of electrons. Does this mean something? YY, Zhu, Li et al. 2017, ApJ, 840, 12

  6. Spinning-down magnetars and GRB afterglows Zhang et al. 2006 YY & Dai 2007 GRB afterglow emission should be substantially affected by post-GRB engine activity.

  7. Spinning-down magnetars and GRB afterglows Ultra-high magnetic fields could play a crucial role in driving a relativistic jet to produce GRB emission. Gravitational wave radiation could sometimes play an important role in spinning down GRB magnetars. YY, Zhu, Li et al. 2017 YY, Cheng, Cao 2010

  8. The remnant of a NS-NS merger could be long-lived massive NS Short GRBs Shallow-decay afterglows Extended gamma-ray emission GRB 051221A Fan & Xu 2006 GRB 050724 Barthelmy et al. 2005 X-ray afterglow flares

  9. NS-powered mergernovae Fan, YY, Xu et al. (2013) The thermal emission of a merger ejecta could be primarily powered by NS spin-down, rather than by radioactive decays of r-process elements. YY, Zhang, Gao (2013) GRB 130603B: A spin-down power can naturally explain the multi-wavelength afterglow emissions and the associated kilonova emission.

  10. GW 170817 and a post-merger NS The existence of a post-merger massive NS is beneficial for (1) reducing the high requirement on the ejecta masses and (2) reconciling the opacity values. Kilonova AT2017gfo could be powered by radioactivity at early phase and by NS spin-down at late phase YY, Liu, Dai, 2018 In the future, (1) we need more samples, in particular, the more luminous or more faint samples. (2) It is useful to detect the increasing phase of the kilonova emission. (3) On-axis observation is also helpful. Kilonova AT2017gfo could be powered NS spin-down all the time. Li, Liu, YY, Zhang 2018

  11. The suppression of the EMW emission The open field lines could be buried by fallback material and also expelled to be within the light cylinder. AT2017gfo’s luminosity indicates the MDR of the remnant NS is suppressed seriously, if the NS is a magnetar intrinsically. The serious suppression of the MDR may be indicated by the steep decay after an afterglow plateau. GW radiation Magnetic dipole radiation Torres-Forné et al. 2016 YY, Liu, Dai, 2018 Troja et al, 2007

  12. Fast evolving luminous transients YY, Li, Dai (2015) Very different from typical supernovae These FELTs can be explained by a magnetar engine and a low-mass ejecta. Drout et al. 2014

  13. Collapse of white dwarfs Massive WDM remnants could evolve as an AGB star (Schwab et al. 2016). YY, Chen, Wang 2019 The collapse of a super-Chand remnant could happen in a dusty wind environment.

  14. Fast evolving luminous transients Margutti et al. 2018 AT2018cow AT2017gfo Perntice et al. 2018

  15. Summary • NSs in the universe could have very different origins. Different masses? different EOSs? • SLSNe and some long GRBs could have a uniform origin model, whose differences are caused by the different magnetic fields of the magnetar engines. • A long-lived massive NS could exist in some short GRBs/NSMs (e.g. GW170817). • The collapses of super-Chand WDs into a NS will be a very interesting target of transient surveys. • Current and future transient surveys open a new era for researches on newborn NSs.

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