FERIA: Flat Envelope Model with Rotation and Infall under Angular Momentum Conservation

TL;DR

FERIA is a versatile simulation tool that models the physical structure of protostellar environments, including infalling envelopes and disks, aiding interpretation of high-resolution ALMA observations.

Contribution

It introduces a general-purpose code that generates synthetic observational data based on infalling-rotating envelope and Keplerian disk models, facilitating analysis of protostellar regions.

Findings

FERIA produces FITS cube data compatible with observations.

The tool helps in understanding protostellar structure and kinematics.

It can generate data for machine learning applications.

Abstract

Radio observations of low-mass star formation in molecular spectral lines have rapidly progressed since the advent of Atacama Large Millimeter/submillimeter Array (ALMA). A gas distribution and its kinematics within a few 100s au scale around a Class 0-I protostar are spatially resolved, and the region where a protostellar disk is being formed is now revealed in detail. In such studies, it is essential to characterize the complex physical structure around a protostar consisting of an infalling envelope, a rotationally-supported disk, and an outflow. For this purpose, we have developed a general-purpose computer code `{\tt FERIA}' (Flat Envelope model with Rotation and Infall under Angular momentum conservation) generating the image cube data based on the infalling-rotating envelope model and the Keplerian disk model, both of which are often used in observational studies. In this paper, we present the description and the usage manual of {\tt FERIA} and summarize caveats in actual applications. This program outputs cube {\tt FITS} files, which can be used for direct comparison with observations. It can also be used to generate mock data for the machine/deep learnings. Examples of these applications are described and discussed to demonstrate how the model analyses work with actual observational data.