LAMOST Medium-Resolution Spectral Survey of Galactic Nebulae (LAMOST MRS-N): An overview of scientific goals and survey plan

Wu, Chao-Jian; Wu, Hong; Zhang, Wei; Ren, Juanjuan; Chen, Jianjun; Hsia, Chih-Hao; Wu, Yu-Dong; Zhu, Hui; Li, Bin; Hou, Yonghui; Wang, Junlin; Yu, Shuoran

doi:10.1088/1674-4527/21/4/96

Cited by 13 publications

(15 citation statements)

References 64 publications

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“…Its scientific goals mainly include stellar multiplicity, stellar pulsation, host stars of exoplanets, star formation, emission nebulae, galactic archaeology, and open clusters. According to the scientific goals, LAMOST-MRS is divided into MRS-B (TD), MRS-K (TD), [38,39] MRS-T (TD), MRS-S (TD or NT), MRS-N (NT), [40] MRS-G (NT) fields and MRS-O (NT). [35] Each field has a PI who is responsible for the target selection.…”

Section: Lamost-mrsmentioning

confidence: 99%

LAMOST medium-resolution spectroscopic survey of binarity and exotic star (LAMOST-MRS-B): Observation strategy and target selection

Li¹,

Jiang-Dan²,

Guo³

et al. 2023

Chinese Phys. B

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LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution ($R\sim7500$) spectroscopic survey. It aims at studying the statistical properties (e.g. binary fraction, orbital period distribution, mass ratio distribution) of binary stars and exotic stars. We intend to observe about 30,000 stars ($10\leq G < 14.5$ mag) with at least 10 visits in five years. We first planned to observe 25 plates around the Galactic plane in 2018. Then the plates were reduced to 12 in 2019 because of the limitation of observation. At the same time, two new plates located at the high Galactic Latitude were added to explore binary properties influenced by the different environments. In this survey project, we set the identified exotic and low-metallicity stars with the highest observation priorities. For the rest of the selected stars, we gave the higher priority to the relatively brighter stars in order to obtain high quality spectra as many as possible. Spectra of 49,129 stars have been obtained in LAMOST-MRS-B field and released in DR8, of which 28,828 and 3,375 stars have been visited more than twice and ten times with $\rm SNR \geq 10$, respectively. Most of the sources are B-, A-, and F-type stars with $\rm -0.6 < [Fe/H] < 0.4 $ dex. We also obtain 347 identified variable and exotic stars and about 250 stars with $\rm [Fe/H] <-1$ dex. We measure radial velocities (RVs) by using 892,233 spectra of the stars. The uncertainties of RV achieve about 1 and 10 kms-1 for 95% of late- and early-type stars, respectively. The datasets presented in this paper is available in Science Data Bank.

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Section: Lamost-mrsmentioning

confidence: 99%

LAMOST medium-resolution spectroscopic survey of binarity and exotic star (LAMOST-MRS-B): Observation strategy and target selection

Li¹,

Jiang-Dan²,

Guo³

et al. 2023

Chinese Phys. B

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“…The spectra of the contaminants are displayed in Figure C1. More than half of the stellar contaminants show Hα emission lines, which might be raised from emission-line stars or diffuse Hα-emitting gas (e.g., H II regions, supernova remnants; see Drew et al 2005;Wu et al 2021). These stellar and galaxy contaminants have IR excesses and their mid-IR (AllWISE) colors are similar to those of quasars.…”

Section: Validation On the Gpq Candidate Catalogmentioning

confidence: 99%

Finding Quasars behind the Galactic Plane. II. Spectroscopic Identifications of 204 Quasars at ∣b∣ < 20°

Fu¹,

Wu²,

Jiang³

et al. 2022

ApJS

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Quasars behind the Galactic plane (GPQs) are important astrometric references and valuable probes of Galactic gas, yet the search for GPQs is difficult due to severe extinction and source crowding in the Galactic plane. In this paper, we present a sample of 204 spectroscopically confirmed GPQs at ∣b∣ < 20°, 191 of which are new discoveries. This GPQ sample covers a wide redshift range from 0.069 to 4.487. For the subset of 230 observed GPQ candidates, the lower limit of the purity of quasars is 85.2%, and the lower limit of the fraction of stellar contaminants is 6.1%. Using a multicomponent spectral fitting, we measure the emission line and continuum flux of the GPQs, and estimate their single-epoch virial black hole masses. Due to selection effects raised from Galactic extinction and target magnitude, these GPQs have higher black hole masses and continuum luminosities in comparison to the SDSS DR7 quasar sample. The spectral-fitting results and black hole mass estimates are compiled into a main spectral catalog, and an extended spectral catalog of GPQs. The successful identifications prove the reliability of both our GPQ selection methods and the GPQ candidate catalog, shedding light on the astrometric and astrophysical programs that make use of a large sample of GPQs in the future.

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“…The LAMOST-II Medium-Resolution Spectroscopic Survey (LAMOST-II MRS) is the advanced project of the LAMOST-I low-resolution spectroscopic survey (Luo et al 2015). LAMOST MRS is expected to advance stellar physical science research, such as detailed observations of various variable stars (Zong et al 2020;Wang et al 2021), planet host stars (Chen et al 2021a(Chen et al , 2021b, emission nebulae (Zhang et al 2021;Ren et al 2021;Wu et al 2021), open star clusters, young pre-mainsequence stars, etc. (see Liu et al 2020 for more details).…”

Section: Introductionmentioning

confidence: 99%

Stellar Parameters and Chemical Abundances Estimated from LAMOST-II DR8 MRS Based on Cycle-StarNet

Wang

Luo

Zhang

et al. 2023

ApJS

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Deriving stellar atmospheric parameters and chemical abundances from stellar spectra is crucial for understanding the evolution of the Milky Way. By performing a fitting with MARCS model atmospheric theoretical synthetic spectra combined with a domain-adaptation method, we estimate the fundamental stellar parameters (T eff, log g, [Fe/H], v mic, and v mac) and 11 chemical abundances for 1.38 million FGKM-type stars of the Medium-Resolution Spectroscopic Survey (MRS) from LAMOST-II DR8. The domain-adaptation method, cycle-starnet, is employed to reduce the gap between observed and synthetic spectra, and the L-BFGS algorithm is used to search the best-fit synthetic spectra. By combining the Two Micron All Sky Survey photometric survey data, Gaia EDR3 parallax, and MIST isochrones, the surface gravities of the stars are constrained after estimating their bolometric luminosities. The accuracy of T eff, log g, and [Fe/H] can reach 150 K, 0.11 dex, and 0.15 dex, evaluated by the PASTEL catalog, asteroseismic samples, and other spectroscopic surveys. The precision of these parameters and elemental abundances ([C/Fe], [Na/Fe], [Mg/Fe], [Si/Fe], [Ca/Fe], [Ti/Fe], [Cr/Fe], [Mn/Fe], [Co/Fe], [Ni/Fe], and [Cu/Fe]) is assessed by repeated observations and validated by cluster members. For spectra with signal-to-noise ratios (S/Ns) greater than 10, the precision of the three stellar parameters and elemental abundances can achieve 76 K, 0.014 dex, 0.096 dex, and 0.04–0.15 dex. For spectra with S/Ns higher than 100, the precision stabilizes at 22 K, 0.006 dex, 0.043 dex, and 0.01–0.06 dex. The full LAMOST MRS stellar properties catalog is available at doi: 10.12149/101242.

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LAMOST Medium-Resolution Spectral Survey of Galactic Nebulae (LAMOST MRS-N): An overview of scientific goals and survey plan

Cited by 13 publications

References 64 publications

LAMOST medium-resolution spectroscopic survey of binarity and exotic star (LAMOST-MRS-B): Observation strategy and target selection

LAMOST medium-resolution spectroscopic survey of binarity and exotic star (LAMOST-MRS-B): Observation strategy and target selection

Finding Quasars behind the Galactic Plane. II. Spectroscopic Identifications of 204 Quasars at ∣b∣ < 20°

Stellar Parameters and Chemical Abundances Estimated from LAMOST-II DR8 MRS Based on Cycle-StarNet

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