2015A&A...576A..78K


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.10CEST09:16:05

2015A&A...576A..78K - Astronomy and Astrophysics, volume 576A, 78-78 (2015/4-1)

Molecfit: A general tool for telluric absorption correction. II. Quantitative evaluation on ESO-VLT/X-Shooter spectra.

KAUSCH W., NOLL S., SMETTE A., KIMESWENGER S., BARDEN M., SZYSZKA C., JONES A.M., SANA H., HORST H. and KERBER F.

Abstract (from CDS):

Absorption by molecules in the Earth's atmosphere strongly affects ground-based astronomical observations. The resulting absorption line strength and shape depend on the highly variable physical state of the atmosphere, i.e. pressure, temperature, and mixing ratio of the different molecules involved. Usually, supplementary observations of so-called telluric standard stars (TSS) are needed to correct for this effect, which is expensive in terms of telescope time. We have developed the software package molecfit to provide synthetic transmission spectra based on parameters obtained by fitting narrow ranges of the observed spectra of scientific objects. These spectra are calculated by means of the radiative transfer code LBLRTM and an atmospheric model. In this way, the telluric absorption correction for suitable objects can be performed without any additional calibration observations of TSS. We evaluate the quality of the telluric absorption correction using molecfit with a set of archival ESO-VLT/X-Shooter visible and near-infrared spectra. Thanks to the wavelength coverage from the U to the K band, X-Shooter is well suited to investigate the quality of the telluric absorption correction with respect to the observing conditions, the instrumental set-up, input parameters of the code, the signal-to-noise of the input spectrum, and the atmospheric profiles. These investigations are based on two figures of merit, Ioff and Ires, that describe the systematic offsets and the remaining small-scale residuals of the corrections. We also compare the quality of the telluric absorption correction achieved with mf to the classical method based on a telluric standard star. The evaluation of the telluric correction with mf shows a convincing removal of atmospheric absorption features. The comparison with the classical method reveals that mf performs better because it is not prone to the bad continuum reconstruction, noise, and intrinsic spectral features introduced by the telluric standard star. Fitted synthetic transmission spectra are an excellent alternative to the correction based on telluric standard stars. Moreover, mf offers wide flexibility for adaption to various instruments and observing sites.

Abstract Copyright:

Journal keyword(s): radiative transfer - atmospheric effects - instrumentation: spectrographs - methods: data analysis - methods: numerical - techniques: spectroscopic

Simbad objects: 11

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Number of rows : 11

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HD 67140 * 08 05 58.8260473679 -19 53 33.047287426   6.98 6.96     B9V 7 0
2 HE 1331-0247 Pe* 13 34 31.9615273835 -03 02 29.052645616   14.32 13.00     C-H 5 0
3 HD 132101 * 14 59 19.2954290789 -51 34 34.078612672   6.73 6.78     B5V 17 0
4 NGC 5812 GiP 15 00 55.708 -07 27 26.33   12   11.19   ~ 151 0
5 GRB 130606A gB 16 37 35.12 +29 47 46.4           ~ 114 0
6 CD-42 11721 Be* 16 59 06.7622892572 -42 42 08.404916931 12.16 12.28 11.00     B0IVe 155 1
7 V* V1012 Sco bL* 17 15 22.3248282198 -38 12 46.692073735 5.87 8.66 8.61 7.83   O9.7III(n) 56 0
8 HD 157546 * 17 24 37.0396045402 -18 26 44.764809726   6.372 6.334     B8V 45 0
9 HD 158859 * 17 33 06.0167321387 -33 03 28.041340631 6.84 8.77 8.58 8.23   B2II 25 0
10 PN Tc 1 PN 17 45 35.2877697798 -46 05 23.713203258   11.30 11.49     PCyg 240 0
11 ICRF J193925.0-634245 Sy2 19 39 25.02671 -63 42 45.6255   18.87 18.37 17.64   ~ 954 1

    Equat.    Gal    SGal    Ecl

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2020.07.10-09:16:05

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