Correction of Near-infrared High-resolution Spectra for Telluric Absorption at 0.90–1.35 μ m

• Published in: Publications of the Astronomical Society of the Pacific 2018-07, Vol.130 (989), p.74502
• Main Authors: Sameshima, Hiroaki, Matsunaga, Noriyuki, Kobayashi, Naoto, Kawakita, Hideyo, Hamano, Satoshi, Ikeda, Yuji, Kondo, Sohei, Fukue, Kei, Taniguchi, Daisuke, Mizumoto, Misaki, Arai, Akira, Otsubo, Shogo, Takenaka, Keiichi, Watase, Ayaka, Asano, Akira, Yasui, Chikako, Izumi, Natsuko, Yoshikawa, Tomohiro
• Format: Article
• Language: English
• Subjects: Absorption; Accuracy; Atmospheric transmittance; Water vapor
• ISSN: 0004-6280; 1538-3873
• DOI: 10.1088/1538-3873/aac1b4

We report a method of correcting a near-infrared (0.90–1.35 μm) high-resolution (λ/Δλ ~ 28,000) spectrum for telluric absorption using the corresponding spectrum of a telluric standard star. The proposed method uses an A0 V star or its analog as a standard star from which on the order of 100 intrinsic stellar lines are carefully removed with the help of a reference synthetic telluric spectrum. We find that this method can also be applied to feature-rich objects having spectra with heavily blended intrinsic stellar and telluric lines and present an application to a G-type giant using this approach. We also develop a new diagnostic method for evaluating the accuracy of telluric correction and use it to demonstrate that our method achieves an accuracy better than 2% for spectral parts for which the atmospheric transmittance is as low as ~20% if telluric standard stars are observed under the following conditions: (1) the difference in airmass between the target and the standard is ≲ 0.05; and (2) that in time is less than 1 hr. In particular, the time variability of water vapor has a large impact on the accuracy of telluric correction and minimizing the difference in time from that of the telluric standard star is important especially in near-infrared high-resolution spectroscopic observation.