# Asymptotic States of Black Holes in KMY Model

## TL;DR

This paper investigates the long-term behavior of black holes in the KMY model, revealing two classes of asymptotic states, including thin shell configurations that differ from idealized zero-thickness shells.

## Contribution

It identifies and characterizes two distinct classes of asymptotic solutions in the KMY model, especially highlighting the properties of low-energy effective thin shell states.

## Key findings

- Existence of two classes of asymptotic solutions.
- Characterization of thin shell states with small thickness.
- Differentiation from ideal zero-thickness shell models.

## Abstract

Following the work of Kawai, Matsuo, and Yokokura, we study the dynamical collapsing process with spherical symmetry in the time-dependent space-time background including the back reaction of Hawking radiation. We show that in this model there are two classes of asymptotic solutions. One of the two classes is known previously. These states have the slope $\partial a/\partial r$ approximately equal to 1. The other class of asymptotic solutions is that of shells with a small thickness. We emphasize that these thin shells should be properly understood as configurations in the low-energy effective theory. They behave characteristically differently from the singular states of ideal thin shells of zero thickness.