Towards the development of the Infrared Guide Star Catalogue for the adaptive optics observations by the Thirty Meter Telescope

Abstract

At first light, the NIR instruments of TMT will be assisted by a multi-conjugate adaptive optics instrument, known as the Narrow Field Infrared Adaptive Optics System (NFIRAOS). NFIRAOS will use laser guide stars for distortion correction in a field of view of 2 arcmin diameter, but natural guide stars will be required for tip/tilt correction. A catalogue of guide stars with NIR magnitudes as faint as 22 mags in J band (Vega system), covering the TMT-observable sky will be a critical resource for the efficient operation of NFIRAOS and no catalogue currently exists with objects so faint and cover the entire TMT observable sky. Hence it is essential to develop such a catalogue by computing the expected NIR magnitudes of stellar sources, identified in deep optical sky surveys, by using their optical magnitudes. In this paper, we will discuss a road map created for the generation of the Infrared Guide Star Catalogue (IRGSC) for the TMT using the optical data of stellar sources from the Pan-STARRS observations and computing their NIR magnitudes by using stellar atmospheric models and Spectral Energy Distribution (SED) fits. We have validated the computed NIR magnitudes of the sources in some fields by using the available NIR data for those fields. We find our method to be satisfactory, thereby creating a path for the final production of the IRGSC using the Pan-STARRS and put forward the challenges that need to be overcome in the future development of IRGSC.