CLOVER: Convnet Line-fitting Of Velocities in Emission-line Regions.

When multiple star-forming gas structures overlap along the line of sight and emit optically thin emission at significantly different radial velocities, the emission can become non-Gaussian and often exhibits two distinct peaks. Traditional line-fitting techniques can fail to account adequately for these double-peaked profiles, providing inaccurate measurements of cloud kinematics. We present a new method, called Convnet Line-fitting Of Velocities in Emission-line Regions (CLOVER), for distinguishing between one-component, two-component, and noise-only emission lines using 1D convolutional neural networks trained with synthetic spectral cubes. CLOVER utilizes spatial information in spectral cubes by predicting on 3 × 3 pixel subcubes, using both the central pixel’s spectrum and the average spectrum over the 3 × 3 grid as input. On an unseen set of 10,000 synthetic spectral cubes in each predicted class, CLOVER has classification accuracies of ∼99% for the one-component class and ∼97% for the two-component class. For the noise-only class, which is analogous to a signal-to-noise cutoff of four for traditional line-fitting methods, CLOVER has classification accuracy of 100%. CLOVER also has exceptional performance on real observations, correctly distinguishing between the three classes across a variety of star-forming regions. In addition, CLOVER quickly and accurately extracts kinematics directly from spectra identified as two-component class members. Moreover, we show that CLOVER is easily scalable to emission lines with hyperfine splitting, making it an attractive tool in the new era of large-scale NH3 and N2H+ mapping surveys. [ABSTRACT FROM AUTHOR]