A Classification Scheme for X-ray Bright Type Ia Supernova Remnants Based on Their Circumstellar Interaction

TL;DR

We investigate how Type Ia supernova progenitor mass loss shapes the circumstellar medium (CSM) and influences the resulting supernova remnants (SNRs) by constructing a comprehensive grid of isotropic outflow models and evolving SNRs with coupled hydrodynamics and non-equilibrium ionization (HD+NEI) calculations. The grid varies three outflow parameters—mass-loss rate $\dot{M}$, wind speed $v_{wind}$, and outflow duration $t_{wind}$—and differentiates between momentum-driven and energy-driven CSM structures, using a single near-$M_{Ch}$ CO WD explosion model with $E_K=1.43\times10^{51}$ erg. The analysis classifies observed Ia SNRs into three groups: roughly 55% compatible with a uniform ambient medium (AM), about 30% exhibiting dense CSM interactions, and around 15% consistent with cavity explosions carved by fast winds. The work highlights that many Ia SNRs do not require substantial CSM on pc scales, while a substantial minority show clear CSM signatures, suggesting multiple progenitor channels; limitations include 1D symmetry and the neglect of cosmic-ray feedback, pointing to future multi-D HD+NEI studies and higher-resolution spectroscopy with upcoming facilities.

Abstract

The parameter space for mass loss in Type Ia supernova progenitors is large, with different progenitor scenarios favoring different mass loss regimes. Here we focus on the impact that uniform and isotropic outflows have on the circumstellar environment of Type Ia supernova progenitors. We vary mass loss rate, wind velocity, and outflow duration, and evolve supernova remnant (SNR) models in this grid of circumstellar structures in order to compare the bulk properties of these models (ages, radii, and \feka\ centroids and luminosities) to observations. We find that roughly 55\% (7/13) of young X-ray bright Type Ia SNRs in the Milky Way and the Large Magellanic Cloud had progenitors that did not substantially modify their surroundings on $\sim$pc scales. This group includes SN Ia with a range of luminosities, and at least one likely product of a double detonation explosion in a sub-Chandrasekhar white dwarf. The other half of our sample can be divided in two distinct classes. A small subset of SNRs ($\sim$15\%, 2/13) have large radii and low \feka\ centroids and are likely expanding into large cavities that might have been excavated by fast ($\sim$1000 km/s), sustained progenitor outflows. The majority of the SNRs that are expanding into a modified medium ($\sim30\%$, 4/13) show evidence for dense material, likely associated with slow ($\sim$10 km/s) progenitor outflows, possibly a byproduct of accretion processes in near-Chandrasekhar white dwarfs spawned by younger stellar populations.

Figures (10)

• Figure 1: CSM structures sculpted by constant isotropic outflows, shown as density profiles as a function of radius, color coded by $t_{\mathrm{wind}}$. Each simulation spans $10^6$ years. The CSM is simulated to the size of the largest Type Ia SNRs, $\sim 15$ parsecs - the dynamic range of observed SNR sizes is indicated by the gray shaded region. The vertical dashed line corresponds to the outer layer of our ddt24 explosion model after $10^7$ s of homologous expansion (see text for details). The top, middle, and bottom rows correspond to a mass loss rate of $\dot{M}$ = $10^{-6},\ 10^{-7},\ 10^{-8}$$M_{\odot}$/yr, respectively. The left, middle, and right columns correspond to $v_{\mathrm{wind}}$ = 10, 100, 1000 km/s, respectively. The density profiles used for the remnant simulations are overlayed in black at $t_{\mathrm{wind}}$ values of 100,000 years and 1,000,000 years.
• Figure 2: Critical velocity for our isotropic outflow models (white circles). The solid colored lines indicate different mass loss rates, while the dashed black line shows the $v_{\mathrm{crit}}=v_{\mathrm{wind}}$ boundary that divides, slow, momentum driven outflows from fast, energy-driven outflows koo_dynamics_1992.
• Figure 3: Comparison between SNR models interacting with a uniform AM and SNR observations. Bulk properties are shown as a function of $\mathrm{Fe\:K\alpha}$ centroid energy: $\mathrm{Fe\:K\alpha}$ luminosity (top), forward shock radius (middle), and remnant age (bottom). The shaded region highlights the area of parameter space covered by the uniform ambient medium models with the line style representing the density. The purple overlaid line corresponds to a more energetic explosion model (ddt40 - see text for details). Observed values for Type Ia SNRs are shown with red symbols, while Core Collapse SNRs are shown with blue symbols. The shape of these symbols (circles vs. squares) distinguishes Milky Way from LMC SNRs.
• Figure 4: Comparison between SNR models interacting with slow outflows ($v_{\mathrm{wind}}=10$ km/s) and SNR observations. Bulk properties are shown as a function of $\mathrm{Fe\:K\alpha}$ centroid energy: $\mathrm{Fe\:K\alpha}$ luminosity (top), forward shock radius (middle), and remnant age (bottom). The dashed-dotted green line corresponds to $\mathrm{\dot{M}=10^{-8}\ M_{\odot}/yr}$, the dashed orange line corresponds to $\mathrm{\dot{M}=10^{-7}\ M_{\odot}/yr}$, and the solid blue line corresponds to $\mathrm{\dot{M}=10^{-6}\ M_{\odot}/yr}$, with empty symbols indicating specific SNR ages. Observed values for Type Ia SNRs are shown with filled red symbols, while Core Collapse SNRs are shown with filled blue symbols. The shape of these symbols (circles and squares) distinguishes Milky Way from LMC SNRs. A shaded region corresponding to the parameter space spanned by the uniform $\mathrm{\rho_{\mathrm{AM}}}$ models is included for comparison.
• Figure 5: Comparison between SNR models interacting with fast outflows and SNR observations: $v_{\mathrm{wind}}$$=100$ km/s (left column) and $v_{\mathrm{wind}}$$=1000$ km/s (right column). Bulk properties are shown as a function of $\mathrm{Fe\:K\alpha}$ centroid energy: $\mathrm{Fe\:K\alpha}$ luminosity (top row), forward shock radius (middle row), and remnant age (bottom row). The dashed-dotted green line corresponds to $\mathrm{\dot{M}=10^{-8}\ M_{\odot}/yr}$, the dashed orange line corresponds to $\mathrm{\dot{M}=10^{-7}\ M_{\odot}/yr}$, and the solid blue line corresponds to $\mathrm{\dot{M}=10^{-6}\ M_{\odot}/yr}$, with empty symbols indicating specific SNR ages. Observed values for Type Ia SNRs are shown with filled red symbols, while Core Collapse SNRs are shown with filled blue symbols. The shape of these symbols (circles and squares) distinguishes Milky Way from LMC SNRs. A shaded region corresponding to the parameter space spanned by the uniform $\mathrm{\rho_{\mathrm{AM}}}$ models is included for comparison.