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تسجيل مستخدم جديدCorrection of near-infrared high-resolution spectra for telluric absorption at 0.90-1.35 microns
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We report a method of correcting a near-infrared (0.90-1.35 $mu$m) high-resolution ($lambda/Deltalambdasim28,000$) 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 $sim$20% if telluric standard stars are observed under the following conditions: (1) the difference in airmass between the target and the standard is $lesssim 0.05$; and (2) that in time is less than 1 h. 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.
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