Radio variability in the young stellar cluster Ophiuchus A

Abstract

Utilizing VLA X-band (∼ 10 GHz) observations of the Ophiuchus A young stellar cluster, we study the flux variability of the sources in that region for 17 different epochs spanning approximately one month. In the first part of this work we perform an iterative self-calibration procedure of the visibilities to correct phase and amplitude artifacts, generating 2-field mosaics for each epoch. In the second part, we extract de fluxes of the 22 objects detected across all epochs and establish a variability classification scheme based on comparing each source’s maximum flux difference to a threshold that takes into account both rms and calibration uncertainties. Our results reveal variability in 15 out of the 22 detected sources, with particularly notable cases such as pronounced emission peaks in GGS29 and GGS30-IRS2, as well as a variable flux from the VLA1623A binary system. Furthermore, the sample studied seems to be consistent with the idea that Young Stellar Objects’ (YSOs) variability increases with their evolutionary stage