# RadioAstron probes the ultra-fine spatial structure in the H$_2$O maser emission in the star forming region W49N

## TL;DR

RadioAstron observations of W49N's water masers revealed ultra-fine spatial structures on unprecedented baselines, indicating turbulence effects in the maser or interstellar medium, advancing understanding of star-forming regions.

## Contribution

First detection of ultra-fine maser structures on space-ground baselines up to 9.6 Earth diameters using RadioAstron.

## Key findings

- Detected structures on baselines up to 9.6 Earth diameters
- Correlated flux densities are 0.1% to 0.6% of total flux
- Low correlated flux suggests turbulence in maser or interstellar medium

## Abstract

H$_2$O maser emission associated with the massive star formation region W49N were observed with the Space-VLBI mission RadioAstron. The procedure for processing of the maser spectral line data obtained in the RadioAstron observations is described. Ultra-fine spatial structures in the maser emission were detected on space-ground baselines of up to 9.6 Earth diameters. The correlated flux densities of these features range from 0.1% to 0.6% of the total flux density. These low values of correlated flux density are probably due to turbulence either in the maser itself or in the interstellar medium.