Selected Publications

Chandrasekhar-mass white dwarfs accreting mass from non-degenerate stellar companions through the single-degenerate channel have reigned for decades as the leading explanation of Type Ia supernovae. Yet, a comprehensive theoretical explanation has not yet emerged to explain the expected properties of the canonical near-Chandrasekhar-mass white dwarf model. A simmering phase within the convective core of the white dwarf leads to the ignition of one or more flame bubbles scattered across the core. Consequently, near-Chandrasekhar-mass single-degenerate SNe Ia are inherently stochastic, and are expected to lead to a range of outcomes, from subluminous SN 2002cx-like events, to overluminous SN 1991T-like events. However, all prior simulations of the single-degenerate channel carried through the detonation phase have set the ignition points as free parameters. In this work, for the first time, we place a single ignition point as predicted by {\it ab initio} models of the convective phase leading up to ignition, and follow through the detonation phase in fully three-dimensional simulations. Single-degenerates in this framework are characteristically overluminous. Using a statistical approach, we determine the $^{56}$Ni mass distribution arising from stochastic ignition. While there is a total spread of $\gtrsim$ 0.2 $M_{\odot}$. for detonating models, the distribution is strongly left-skewed, and with a narrow standard deviation of $\simeq 0.03 M_{\odot}$. Conversely, if single-degenerates are not overluminous but primarily yield normal or failed events, then our models require fine-tuning of the ignition parameters, or otherwise require revised physics or WD models. We discuss implications of our findings for the modeling of single-degenerate SNe Ia.
The Intrinsic Stochasticity of the $^{56}$Ni Distribution of Single-Degenerate Near-Chandrasekhar Mass Type Ia Supernovae, 2019

Lyman-$\alpha$ emitters (LAEs) are a promising probe of the large-scale structure at high redshift, $z\gtrsim 2$. In particular, the Hobby-Eberly Telescope Dark Energy Experiment aims at observing LAEs at 1.9 $<z<$ 3.5 to measure the Baryon Acoustic Oscillation (BAO) scale and the Redshift-Space Distortion (RSD). However, (Zheng et al. 2011) pointed out that the complicated radiative transfer (RT) of the resonant Lyman-$\alpha$ emission line generates an anisotropic selection bias in the LAE clustering on large scales, $s\gtrsim 10\,{\rm Mpc}$. This effect could potentially induce a systematic error in the BAO and RSD measurements. Also, (Croft et al. 2016) claims an observational evidence of the effect in the Lyman-$\alpha$ intensity map, albeit statistically insignificant. We aim at quantifying the impact of the Lyman-$\alpha$ RT on the large-scale galaxy clustering in detail. For this purpose, we study the correlations between the large-scale environment and the ratio of an apparent Lyman-$\alpha$ luminosity to an intrinsic one, which we call the “observed fraction”, at $2<z<6$. We apply our Lyman-$\alpha$ RT code by post-processing the full Illustris simulations. We simply assume that the intrinsic luminosity of the Lyman-$\alpha$ emission is proportional to the star formation rate of galaxies in Illustris, yielding a sufficiently large sample of LAEs to measure the anisotropic selection bias. We find little correlations between large-scale environment and the observed fraction induced by the RT, and hence a smaller anisotropic selection bias than what was claimed by (Zheng et al. 2011). We argue that the anisotropy was overestimated in the previous work due to the insufficient spatial resolution: it is important to keep the resolution such that it resolves the high density region down to the scale of the interstellar medium, $\sim1$ physical kpc. We also find that the correlation can be further enhanced by assumptions in modeling intrinsic Lyman-$\alpha$ emission.
The impact of Lyman-α radiative transfer on large-scale clustering in the Illustris simulation, 2017

Recent Publications

. The Intrinsic Stochasticity of the $^{56}$Ni Distribution of Single-Degenerate Near-Chandrasekhar Mass Type Ia Supernovae. The Intrinsic Stochasticity of the $^{56}$Ni Distribution of Single-Degenerate Near-Chandrasekhar Mass Type Ia Supernovae, 2019.

Preprint Project

. Lya RT Real Space Clustering. The impact of Lyman-α radiative transfer on large-scale clustering in the Illustris simulation, 2017.

Preprint Project

. Viscosity, pressure, and support of the gas in simulations of merging cool-core clusters. Viscosity, pressure, and support of the gas in simulations of merging cool-core clusters, 2017.

Preprint

. Constraining The Single-Degenerate Channel of Type Ia Supernovae With Stable Iron-Group Elements in SNR 3C 397. Constraining The Single-Degenerate Channel of Type Ia Supernovae With Stable Iron-Group Elements in SNR 3C 397, 2017.

Preprint

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