Radiative Transfer Modeling of An SN 1987A Light Echo$-$AT2019xis

TL;DR

This study uses Monte Carlo radiative transfer modeling to simulate and analyze the light echo from SN 1987A, comparing theoretical results with observations to estimate dust cloud properties and understand early UV radiation effects.

Contribution

It introduces a detailed Monte Carlo radiative transfer model to simulate light echoes from SN 1987A and compares these with observations to derive dust cloud characteristics.

Findings

Estimated dust cloud mass of approximately 8-9 solar masses.

Identified morphological differences in light echoes across wavelengths.

Provided insights into early UV radiation of SN 1987A.

Abstract

We use a Monte Carlo radiative transfer model (MCRTM) to simulate the UBVRI light curves, images and linear polarization of a light echo from supernova SN$~$1987A in the Large Magellanic Cloud (LMC) using various dust cloud shapes, sizes, and optical properties. We compare the theoretical simulations to the observations of AT2019xis, a light echo detected at a large angular distance (4.05$^{'}$) from SN$~$1987A. We estimate the size and optical thickness of the dust cloud based on the simulation results and the observations of Optical Gravitational Lensing Experiment (OGLE-IV) Transient Detection System (OTDS) I-band light curve. The mass of the dust cloud is calculated using the estimated size, optical thickness and extinction coefficient. If the dust cloud is assumed to correspond to a gas-to-dust ratio of 300, the total mass of the dust cloud is approximately 7.8-9.3 $M_{\odot}$. Based on these theoretical models, we show that the morphological shapes of the light echoes in the wavelength range in or shorter than the U-band to be very different from those in the longer wavelength bands, and the difference carries important information on the early UV radiation of SN$~$1987A.