# SiO maser observations of a wide dust-temperature range sample

## TL;DR

This study investigates SiO maser emissions across a wide dust-temperature range, revealing correlations between infrared colors and specific SiO maser line intensity ratios, enhancing understanding of maser excitation conditions.

## Contribution

It provides new observational data on SiO maser lines across multiple vibrational states and identifies novel correlations with infrared colors, advancing maser physics knowledge.

## Key findings

- Confirmed correlation between SiO J=1-0 v=2 to v=1 line ratios and infrared colors.
- Discovered possible correlation between SiO J=1-0 v=3 to v=1&2 line ratios and infrared colors.
- Expanded understanding of maser excitation mechanisms across different dust temperatures.

## Abstract

We present the results of SiO line observations of a sample of known SiO maser sources covering a wide dust-temperature range. The aim of the present research is to investigate the causes of the correlation between infrared colors and SiO maser intensity ratios among different transition lines. We observed in total 75 SiO maser sources with the Nobeyama 45m telescope quasi-simultaneously in the SiO J=1-0 v=0, 1, 2, 3, 4 and J=2-1 v=1, 2 lines. We also observed the sample in the 29SiO J=1-0 v=0 and J=2-1 v=0, and 30SiO J=1-0 v=0 lines, and the H2O 6(1,6)-5(2,3) line. As reported in previous papers, we confirmed that the intensity ratios of the SiO J=1-0 v=2 to v=1 lines clearly correlate with infrared colors. In addition, we found possible correlation between infrared colors and the intensity ratios of the SiO J=1-0 v=3 to v=1&2 lines.