The Rotation Curve and Spiral Structure of Milky Way from the Hydrogen 21-cm Line Detection with Campus Radio Telescope

TL;DR

This study uses a DIY radio telescope to measure the Milky Way's rotation curve via hydrogen 21-cm line observations, providing insights into its spiral structure and comparing results with previous research.

Contribution

It demonstrates a cost-effective method for measuring the Milky Way's rotation curve and spiral arms using small radio telescope data and the tangent method.

Findings

Rotation curve of the inner disk was successfully obtained.

Distribution of spiral arms was mapped using the new data.

Results are consistent with previous measurements and models.

Abstract

The rotation curve is significant to research on dark matter and the structure of the Milky Way. But it is a great challenge to measure rotation curve accurately, and different ways obtain distinct results. In this work, we use a DIY small radio telescope to carry out hydrogen 21-cm line observations on campus, and calculate the rotation curve of inner disk by tangent method based on the model of Przemek et al. (the rotation speed of the Sun $v(R_0)=233.6\pm2.8$ km/s, and distance to the Galactic center $R_0=8.122\pm0.031$ kpc). Furthermore, we obtain the distribution of spiral arms in the Milky Way with our data by adopting different rotation curve models. We also compare our rotation curve result with previous works, analyse the possible measurement error in the tangent method, and discuss the consistence of our result with others.