LAMOST medium-resolution spectral survey of Galactic nebulae (LAMOST-MRS-N): subtraction of geocoronal Hα emission

Zhang, Wei; Wu, Hong; Wu, Chao-Jian; Ren, Juanjuan; Chen, Jian-Hun; Hsia, Chih-Hao; Wu, Yu-Dong; Zhu, Hui; Shi, Jianrong; Bai, Zhong-Rui; Qi, Zhaoxiang; Zhao, Yi; Hou, Yonghui

doi:10.1088/1674-4527/21/11/280

Cited by 5 publications

(7 citation statements)

References 25 publications

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“…So we developed the MRS-N Pipeline. The MRS-N Pipeline includes removing cosmic rays, merging single exposure, fitting skylight emission lines (Ren et al 2021), subtracting skylight (Zhang et al 2021), wavelength recalibration, parameters measurement of nebular emission lines, creating catalogs and packing spectra. Figure 2 illustrates a flowchart of MRS-N Pipeline.…”

Section: Methodsmentioning

confidence: 99%

“…The traditional method (Soto et al 2016) of removing sky light is not suitable for MRS-N data. Zhang et al (2021) introduced Then the constructed I(Hα sky ) is subtracted from the MRS-N spectra. By using this method, 90% of the sky light mixed in nebular Hα emission lines can be reduced, which significantly improves the accuracy of nebulae classification and the measurements of nebular physical parameters.…”

Section: Subtracting Sky Lightmentioning

confidence: 99%

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The Data Processing of the LAMOST Medium-resolution Spectral Survey of Galactic Nebulae (LAMOST MRS-N Pipeline)

Wu¹,

Wu²,

Zhang³

et al. 2022

Res. Astron. Astrophys.

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The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) medium-resolution spectral survey of Galactic Nebulae (MRS-N) has conducted for more than three years since Sep. 2018 and observed more than 190 thousands nebular spectra and 20 thousands stellar spectra. However, there is not yet a data processing pipeline for nebu- lar spectra. To significantly improve the accuracy of nebulae classification and their physical parameters, we developed the MRS-N Pipeline. This article presented in detail each data processing step of the MRS-N Pipeline, such as removing cosmic rays, merging single ex- posure, fitting sky light emission lines, wavelength recalibration, subtracting skylight, mea- suring nebular parameters, creating catalogs and packing spectra. Finally, a description of the data products, including nebular spectra files and parameter catalogs, is provided.

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Section: Methodsmentioning

confidence: 99%

Section: Subtracting Sky Lightmentioning

confidence: 99%

The Data Processing of the LAMOST Medium-resolution Spectral Survey of Galactic Nebulae (LAMOST MRS-N Pipeline)

Wu¹,

Wu²,

Zhang³

et al. 2022

Res. Astron. Astrophys.

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“…For spectral observations, the standard arc lines and skylines are commonly used to estimate the instrumental broadening. Zhang et al (2021) have compared one by one the line dispersion of the arc lines with the λ6554 skyline of LAMOST MRS-N spectra, and found that the line dispersion of λ6554 is identical with that of the arc line. Because the values of line dispersion are different for different fibers, in this work, the instrumental broadening of each spectrum has been removed with its own λ6554 skyline.…”

Section: Calibration Of Fwhmmentioning

confidence: 99%

LAMOST MRS-N Observations of the W80 Region

Li,

Wu,

Yao

et al. 2022

Preprint

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The spectral observations and analysis for the W80 Region are presented by using the data of Medium-Resolution Spectroscopic Survey of Nebulae (MRS-N) with the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST). A total of 2982 high-quality nebular spectra have been obtained in the 20 square degree field of view (FoV) which covers the W80 complex, and the largest sample of spectral data have been established for the first time. The relative intensities, radial velocities (RVs), and Full Widths at Half Maximum (FWHMs) are measured with the high spectral resolution of LAMOST MRS, for Hα λ 6563 Å, [N II] λλ 6548 Å, 6584 Å , and [S II] λλ 6716 Å, 6731 Å emission lines. In the field of view of whole W80 Region, the strongest line emissions are found to be consistent with the bright nebulae, NGC 7000, IC 5070, and LBN 391, and weak line emissions also truly exist in the Middle Region, where no bright nebulae are detected by the wide-band optical observations. The large-scale spectral observations to the W80 Region reveal the systematic spatial variations of RVs and FWHMs, and several unique structural features. A 'curved feature' to the east of the NGC 7000, and a 'jet feature' to the west of the LBN 391 are detected to be showing with larger radial velocities. A 'wider FWHM region' is identified in the eastern part of the NGC 7000. The variations of [S II] / Hα ratios display a gradient from southwest to northeast in the NGC 7000 region, and manifest a ring shape around the 'W80 bubble' ionized by an O-type star in the L935. Further spectral and multi-band observations are guaranteed to investigate in detail the structural features.

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“…Some bright stars and a large number of Galactic nebulae are set to be observed. For detailed information about the MRS-N, refer to Wu et al (2021), Ren et al (2021), Zhang et al (2021), andWu et al (2021b). Wu et al (2021) presented the survey plan of LAMOST MRS-N and the detailed scientific goals.…”

Section: Data Selectionmentioning

confidence: 99%

LAMOST MRS-N Observation of the W80 Region

Li¹,

Wu²,

Yao³

et al. 2022

Res. Astron. Astrophys.

Self Cite

View full text Add to dashboard Cite

The spectral observations and analysis for the W80 region are presented by using the data of Medium-Resolution Spectroscopic Survey of Nebulae (MRS-N) with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). A total of 2982 high-quality nebular spectra have been obtained in the 20 square degree field of view which covers the W80 complex, and the largest sample of spectral data has been established for the first time. The relative intensities, radial velocities (RVs), and full widths at half maximum (FWHMs) are measured with the high spectral resolution of LAMOST MRS-N, for Hα λ6563 Å, [N ii] λλ6548 Å, 6584 Å, and [S ii] λλ6716 Å, 6731 Å emission lines. In the field of view of the whole W80 region, the strongest line emissions are found to be consistent with the bright nebulae NGC 7000, IC 5070, and LBN 391, and weak line emissions also exist in the Middle Region, where no bright nebulae are detected by the wide-band optical observations. The large-scale spectral observations of the W80 region reveal the systematic spatial variations of RVs and FWHMs, and several unique structural features. A “curved feature” to the east of NGC 7000, and a “jet feature” to the west of LBN 391 are detected to be showing larger RVs. A “wider FWHM region” is identified in the eastern part of NGC 7000. The variations of [S ii]/Hα ratios display a gradient from southwest to northeast in the NGC 7000 region, and manifest a ring shape around the “W80 bubble” ionized by an O-type star in L935. Further spectral and multi-band observations are guaranteed to investigate in detail the structural features.

show abstract

LAMOST medium-resolution spectral survey of Galactic nebulae (LAMOST-MRS-N): subtraction of geocoronal Hα emission

Cited by 5 publications

References 25 publications

The Data Processing of the LAMOST Medium-resolution Spectral Survey of Galactic Nebulae (LAMOST MRS-N Pipeline)

The Data Processing of the LAMOST Medium-resolution Spectral Survey of Galactic Nebulae (LAMOST MRS-N Pipeline)

LAMOST MRS-N Observations of the W80 Region

LAMOST MRS-N Observation of the W80 Region

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