Near infrared background with 1.2-m telescope at Mount Abu

Abstract

We present an estimation and analysis of Near Infrared (NIR) background for the astronomical site at Mount Abu. Mount Abu Observatory is situated at Gurushikhar, Rajasthan, India, operated by the Physical Research Laboratory. Data obtained from the NIR observations of various sources using the Near Infrared Camera/Spectrograph (NICS) on the 1.2-m telescope are used to derive the NIR background estimates. We notice seasonal variations in these values, with the summer months showing brighter background compared to the winter. We also present a comparison of synthetic atmospheric transmission at Mount Abu with other Indian observatories at various altitudes. We identify the plausible contributors to the NIR background in our observations and discuss the potential ones that can contribute to the noticed seasonal variations. Overall, we found that the NIR background does not show any systematic variation over the period of observations from 2010 to 2019. The results reported here are specific to the NICS instrument on the 1.2-m telescope.