Investigating the Changes in Flux Density of Methanol Masers in the Orion Nebula

The VLA Orion-A Large Survey (VOLS) collaboration used the Karl G. Jansky Very Large Array (VLA) telescope to observe a methanol maser in the Orion Nebula 20 times from April 3rd, 2022 to July 1st, 2022, corresponding to 20 different epochs of data. This study aimed to characterize this methanol maser in terms of flux density consistency, fast variability, and light wave polarization on both a short-term and long-term scale using these data, forming three objectives. The flux density was consistent for 17 epochs and inconsistent for 3 epochs based on the measurement errors, insinuating consistent calibration between pointings for most epochs. Within an epoch, the scans generally slightly differed in flux density over a 60-80 minute period, with mild evidence of fast variability in certain epochs. We saw no linear or circular polarization in any of the epochs. However, we saw many discrepancies in specific epochs such as offset pointing averages in epoch 2, an offset scan in epoch 3, negative sidelobes in a few epochs, and a software error in epoch 11. Through this study of many 2022 epochs, the maser’s behavior on a short time scale was analyzed more accurately than previous studies looking at epoch averages.