Program: GS-2023A-Q-201

Study of the properties of the low ionization emission lines (LILs) pertaining to the broad-line region (BLR) in active galaxies is crucial to understand how the super-massive black hole at the very centers of these galaxies works and affects the environment in its proximity. Among these emission lines, the singly-ionized iron (Fe II) emission has multi-faceted usage, including being the primary parameter of the Quasar Main Sequence - an evolutionary sequence for un-obscured (Type-1) AGNs. The complexity in the study of optical Fe II has paved way for the study of effective proxies, Ca II being the foremost among them. Fe II emission in the optical and the corresponding singly-ionized calcium (Ca II) triplet emission in the near-infrared (NIR) show a strong correlation in their emission strengths. The NIR Ca II triplet is a significantly better tracer of the accretion rate of the AGN, that allows to improve our understanding of the central engine of these accreting systems. A special class of AGNs - the Narrow line Seyfert 1 galaxies (NLS1s) are sources with ``narrower'' broad emission lines and, among many properties, show stronger Fe II emission. Thus, they are optimal targets to observe the NIR Ca II triplet. We request to obtain GEMINI/FLAMINGOS2 and GMOS-S spectra of 4 and 7 NLS1s, respectively, selected from the NLS1 catalogue of the Southern hemisphere compiled from the 6dF survey. The new targets will help realize the full potential of Ca II emission and its connection to the black hole and the BLR parameters which can be useful in - (1) the classification of Type-1 AGNs, especially NLS1s, in the context of the main sequence of quasars, (2) the close connection of Ca II to Fe II will allow us to use the ratio of the two species to quantify the chemical evolution in these active galaxies across cosmic time, and (3) to realize a NIR-version of the Quasar Main Sequence using Ca II emission.