The fully developed remnant of a neutrino-driven supernova: Evolution of ejecta structure and asymmetries in SNR Cassiopeia A

Abstract

Context. The remnants of core-collapse supernovae (SNe) are probes of the physical processes associated with their parent SNe. Aims. Here we aim at exploring to which extent the remnant keeps memory of the asymmetries that develop stochastically in the neutrino-heating layer due to hydrodynamic instabilities (e.g., convective overturn and the standing accretion shock instability; SASI) during the first second after core bounce. Methods. We coupled a 3D hydrodynamic model of a neutrino-driven SN explosion which has the potential to reproduce the observed morphology of the Cassiopeia A (Cas A) remnant, with 3D (magneto)-hydrodynamic simulations of the remnant formation. The simulations cover ≈ 2000 years of expansion and include all physical processes relevant to describe the complexities in the SN evolution and the subsequent interaction of the stellar debris with the wind of the progenitor star.Results. The interaction of large-scale asymmetries left from the earliest phases of the explosion with the reverse shock produces, at the age of ≈ 350 years, an ejecta structure and a remnant morphology which are remarkably similar to those observed in Cas A. Small-scale structures in the large-scale Fe-rich plumes created during the initial stages of the SN, combined with hydrodynamic instabilities that develop after the passage of the reverse shock, naturally produce a pattern of ring-and crown-like structures of shocked ejecta. The consequence is a spatial inversion of the ejecta layers with Si-rich ejecta being physically interior to Fe-rich ejecta. The full-fledged remnant shows voids and cavities in the innermost unshocked ejecta (in most cases physically connected with ring-like features of shocked ejecta in the main shell) resulting from the expansion of Fe-rich plumes and their inflation due to the decay of radioactive species. The asymmetric distributions of 44 Ti and 56 Fe (mostly concentrated in the northern hemisphere, pointing opposite to the kick velocity of the neutron star) and their abundance ratio are both compatible with those inferred from high-energy observations of Chandra and NuSTAR. Finally, the simulations show that the fingerprints of the SN can still be evident ≈ 2000 years after the explosion. Conclusions. The main asymmetries and features observed in the ejecta distribution of Cas A can be explained by the interaction of the reverse shock with the initial large-scale asymmetries that developed from stochastic processes (convective overturn and SASI activity) that originate during the first seconds of the SN blast.

3D mapping of the Crab Nebula with SITELLE. I. Deconvolution and kinematic reconstruction

“…These lines will be measured and modeled to determine temperature, density and abundances at very fine scales, and combined with an updated proper motion investigation of filaments (Martin et al, in preparation) to improve the accuracy of our reconstruction at fine scales. Our work contributes to a larger suite of detailed supernova remnant reconstructions being developed that will provide unique constraints for increasingly sophisticated three-dimensional core-collapse simulations (Couch et al 2015;Wongwathanarat et al 2017;Burrows et al 2019;Stockinger et al 2020), that are being evolved to middle-aged supernova remnants (Orlando et al 2015(Orlando et al , 2016(Orlando et al , 2020, attempting to model the complete multi-messenger signals of supernovae (Andresen et al 2017;Kuroda et al 2017;Westernacher-Schneider et al 2019;Mezzacappa et al 2020).…”

“…Asymmetries in chemical or ionization structure, expansion E-mail: thomas.martin.1@ulaval.ca velocity or density can then be probed with much greater precision than what is possible for unresolved extragalactic objects (Milisavljevic & Fesen 2017). Such reconstructions, made for SNRs including Cassiopeia A (Cas A) (DeLaney et al 2010;Milisavljevic & Fesen 2013;Alarie et al 2014;Milisavljevic & Fesen 2015;Grefenstette et al 2017), 1E 0102.2-7219 (Vogt & Dopita 2010;Vogt et al 2018), and N132D (Law et al 2020), are critical for establishing strong empirical links between SNe and SNRs that can be compared to state-of-the-art simulations evolving from core collapse to remnant (Orlando et al 2015(Orlando et al , 2016(Orlando et al , 2020Ono et al 2020).…”

Modeling particle acceleration and non-thermal emission in supernova remnants

“…These models describe the evolution from the SN to the development of its full-fledged remnant (e.g. Orlando et al 2015Orlando et al , 2016Wongwathanarat et al 2017;Ferrand et al 2019;Ono et al 2020;Orlando et al 2020a;Tutone et al 2020;Orlando et al 2020b). The strategy is based on the coupling between SN models and SNR models.…”

“…The SNR models include: the effects of an ambient magnetic field, the radiative cooling, the deviations from equilibrium of ionization and from electron-proton temperature equilibration, the heating due to radioactive decay of unstable elements, and the back-reaction of accelerated CRs (e.g. Orlando et al 2016Orlando et al , 2020b. The SNR models also describe the geome-try and density structure of the ambient medium through which the remnant expands on the base of constraints from multi-λ observations.…”

Fermi-LAT Detection of GeV Gamma-Ray Emission from The Highly Asymmetric Shell Supernova Remnant: SNR G317.3-0.2

“…The 843 MHz flux density map with a higher spatial resolution of 43 of SNR G317.3-0.2 presents a clear and asymmetric structure, which enabled us to better study the spatial distribution of its GeV γ-ray radiation by using the Fermi-LAT analysis method provided by the Fermi Science Support Center 1 . In addition, the highly asymmetric structure of SNR G317.3-0.2 at 843 MHz, which makes it be an excellent source for studying the asymmetric evolution of SNR and the unknown origin of cosmic rays in the Milky Way in the future (Aharonian et al 2004;Helder et al 2012;Ackermann et al 2013;Bao et al 2018;Ferrand et al 2019;Orlando et al 2020).…”