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Generation of a Near Infra-Red Guide Star Catalog for Thirty-Meter Telescope Observations


The requirements for the production of a near Infra-Red Guide Star Catalog (IRGSC) for Thirty Meter Telescope (TMT) observations are identified and presented. A methodology to compute the expected J band magnitude of stellar sources from their optical (g, r, i) magnitudes is developed. The computed and observed J magnitudes of sources in three test fields are compared and the methodology developed is found to be satisfactory for the magnitude range, JVega = 16–22 mag. From this analysis, we found that for the production of final TMT IRGSC (with a limiting magnitude of JVega = 22 mag), we need g, r, i bands optical data which go up to i AB ~ 23 mag. Fine tuning of the methodology developed, such as using Spectral Energy Distribution (SED) template fitting for optimal classification of stars in the fainter end, incorporating spectral libraries in the model, to reduce the scatter, and modification of the existing colour–temperature relation to increase the source density are planned for the subsequent phase of this work.

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The authors are grateful to Prof. T. P. Prabhu for a critical reading of the document and for his valuable comments. We also thank Brent Ellerbroek and Matthias Schoeck for their inputs. One of the authors (SS) would also like to thank Ramya and Jessy for interesting discussions.

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Correspondence to Smitha Subramanian.

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Subramanian, S., Subramaniam, A., Simard, L. et al. Generation of a Near Infra-Red Guide Star Catalog for Thirty-Meter Telescope Observations. J Astrophys Astron 34, 175–192 (2013).

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