Development of cross-correlation spectrometry and the coherent structures of maser sources

TL;DR

This paper introduces cross-correlation spectrometry (XCS), a new data processing method for radio telescope data that measures temporal coherence of maser sources, revealing potential coherent astrophysical masers.

Contribution

The paper presents XCS, a novel autocorrelation technique that extends time lags over integration time to measure temporal coherence in single-dish radio observations.

Findings

Measured coherence lengths of masers in W3 (H2O), W49N, and W75N.

Demonstrated XCS enhances detection of temporal coherence.

Indicated possible existence of coherent astrophysical masers.

Abstract

We have developed a new method of data processing for radio telescope observation data to measure time-dependent temporal coherence, and we named it cross-correlation spectrometry (XCS). XCS is an autocorrelation procedure that expands time lags over the integration time and is applied to data obtained from a single-dish observation. The temporal coherence property of received signals is enhanced by XCS. We tested the XCS technique using the data of strong H2O masers in W3 (H2O), W49N and W75N. We obtained the temporal coherent lengths of the maser emission to be 17.95 $\pm$ 0.33 {\mu}s, 26.89 $\pm$ 0.49 {\mu}s and 15.95 $\pm$ 0.46 {\mu}s for W3 (H2O), W49N and W75N, respectively. These results may indicate the existence of a coherent astrophysical maser.