Relative flux calibration for the LAMOST Spectroscopic Survey of the Galactic anticentre

Xiang, Maosheng; Liu, X. W.; Yuan, Haibo; Huo, Zhi-Ying; Huang, Yang; Zheng, Yong; Zhang, Huangwei; Chen, Bingqiu; Sun, Ning-Chen; Wang, C.; Zhao, Yi; Shi, Jianrong; Luo, A-Li; Li, G. P.; Bai, Zhong-Rui; Zhang, Yating; Hou, Yonghui; Yuan, Hailong

doi:10.1093/mnras/stu2434

Cited by 26 publications

(11 citation statements)

References 29 publications

(31 reference statements)

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“…DR1 contains a total of 2,204,696 spectra, 1,944,392 of which are catalogued as main-sequence stars by the LAMOST pipeline (Luo et al 2015). Of these, 794,371 are flagged as F, G or K mainsequence stars and all of them have effective temperature, surface gravity and metallicity values derived via the LAM-OST stellar parameter pipeline (Wu et al 2014;Xiang et al 2015). We selected only those objects having spectra with a signal-to-noise ratio of greater than 10, to ensure that the stellar parameters are robust.…”

Section: The Northern Hemisphere Samplementioning

confidence: 99%

The white dwarf binary pathways survey – I. A sample of FGK stars with white dwarf companions

Parsons

Rebassa‐Mansergas

Schreiber

et al. 2016

Mon. Not. R. Astron. Soc.

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The number of spatially unresolved white dwarf plus main-sequence star binaries has increased rapidly in the last decade, jumping from only ∼30 in 2003 to over 3000. However, in the majority of known systems the companion to the white dwarf is a low-mass M dwarf, since these are relatively easy to identify from optical colours and spectra. White dwarfs with more massive FGK type companions have remained elusive due to the large difference in optical brightness between the two stars. In this paper, we identify 934 main-sequence FGK stars from the Radial Velocity Experiment survey in the Southern hemisphere and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey in the Northern hemisphere, that show excess flux at ultraviolet wavelengths which we interpret as the likely presence of a white dwarf companion. We obtained Hubble Space Telescope ultraviolet spectra for nine systems which confirmed that the excess is indeed caused, in all cases, by a hot compact companion, eight being white dwarfs and one a hot subdwarf or pre-helium white dwarf, demonstrating that this sample is very clean. We also address the potential of this sample to test binary evolution models and Type Ia supernovae formation channels.

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Section: The Northern Hemisphere Samplementioning

confidence: 99%

The white dwarf binary pathways survey – I. A sample of FGK stars with white dwarf companions

Parsons

Rebassa‐Mansergas

Schreiber

et al. 2016

Mon. Not. R. Astron. Soc.

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“…The raw 2-dimension data are processed with the LAMOST 2D pipeline for spectral extraction, wavelength calibration, flat fielding, background subtraction and flux calibration to produce 1D spectra . Given that the Anti-center survey (LSS-GAC) targets fields of low Galactic latitudes that suffer from high dust extinction, a specific flux calibration pipeline has been developed at Peking University for accurate spectral flux calibration (Xiang et al 2015c).…”

Section: The Lamost Galactic Surveysmentioning

confidence: 99%

“…The LAMOST-Kepler project targets stars in the Kepler fields with the LAMOST, and more than 100 000 spectra have been collected by September, 2014(De Cat et al 2015. We have processed the raw LAMOST-Kepler data collected since the beginning of the LAMOST pilot survey initiated in October, 2011 until June 2014, using the LAMOST 2D pipeline and the flux calibration pipeline developed for the LSS-GAC survey (Xiang et al 2015c). The data set includes about 53 000 spectra of SNR higher than 10 per pixel at 4650 Å.…”

Section: The Lamost-kepler Starsmentioning

confidence: 99%

“…Lower panel: The dg values as a function of the spectral signal-to-noise ratio. Only results of 10 000 stars randomly selected from the whole sample are shown in the plots.tra used in this work are processed at Peking University with the LAMOST 2D pipeline (v2.6;Luo et al 2015) and the flux calibration pipeline developed specifically for the LSS-GAC(Xiang et al 2015c).…”

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confidence: 99%

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Estimating stellar atmospheric parameters, absolute magnitudes and elemental abundances from the LAMOST spectra with Kernel-based principal component analysis

Xiang

Liu

Shi

et al. 2016

Mon. Not. R. Astron. Soc.

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Accurate determination of stellar atmospheric parameters and elemental abundances is crucial for Galactic archeology via large-scale spectroscopic surveys. In this paper, we estimate stellar atmospheric parameters -effective temperature T eff , surface gravity log g and metallicity [Fe/H], absolute magnitudes M V and M Ks , α-element to metal (and iron) abundance ratio [α/M] (and [α/Fe]), as well as carbon and nitrogen abundances [C/H] and [N/H] from the LAMOST spectra with a multivariate regression method based on kernel-based principal component analysis, using stars in common with other surveys (Hipparcos, Kepler, APOGEE) as training data sets. Both internal and external examinations indicate that given a spectral signal-to-noise ratio (SNR) better than 50, our method is capable of delivering stellar parameters with a precision of ∼100 K for T eff , ∼0.1 dex for log g, 0. abundances from a vast data set of LAMOST, and, to our knowledge, the first reported implementation of absolute magnitude estimation directly based on the observed spectra. The derived stellar parameters for millions of stars from the LAMOST surveys will be publicly available in the form of value-added catalogues.

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“…The blue-and red-arm spectra are processed independently in the 2D pipeline and joined together after flux calibration. Flux calibration for the LSS-GAC observations is performed using an iterative algorithm developed at Peking University by Xiang et al (2015), achieving an accuracy of about 10 per cent for the whole wavelength ranges of blue-and red-arm spectra. A detailed description of the target selection algorithm, survey design, observations, data reduction, and value-added catalogs of the first LSS-GAC data release is presented in Yuan et al (2015).…”

Section: The Lamost Spectroscopic Survey Of the Galactic Anti-centermentioning

confidence: 99%

DA white dwarfs from the LSS-GAC survey DR1: the preliminary luminosity and mass functions and formation rate

Rebassa‐Mansergas¹,

Liu²,

Cojocaru³

et al. 2015

Monthly Notices of the Royal Astronomical Society

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Modern large-scale surveys have allowed the identification of large numbers of white dwarfs. However, these surveys are subject to complicated target selection algorithms, which make it almost impossible to quantify to what extent the observational biases affect the observed populations. The LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) Spectroscopic Survey of the Galactic anti-center (LSS-GAC) follows a well-defined set of criteria for selecting targets for observations. This advantage over previous surveys has been fully exploited here to identify a small yet wellcharacterised magnitude-limited sample of hydrogen-rich (DA) white dwarfs. We derive preliminary LSS-GAC DA white dwarf luminosity and mass functions. The space density and average formation rate of DA white dwarfs we derive are 0.83±0.16×10 −3 pc −3 and 5.42 ± 0.08 × 10 −13 pc −3 yr −1 , respectively. Additionally, using an existing Monte Carlo population synthesis code we simulate the population of single DA white dwarfs in the Galactic anti-center, under various assumptions. The synthetic populations are passed through the LSS-GAC selection criteria, taking into account all possible observational biases. This allows us to perform a meaningful comparison of the observed and simulated distributions. We find that the LSS-GAC set of criteria is highly efficient in selecting white dwarfs for spectroscopic observations (80-85 per cent) and that, overall, our simulations reproduce well the observed luminosity function. However, they fail at reproducing an excess of massive white dwarfs present in the observed mass function. A plausible explanation for this is that a sizable fraction of massive white dwarfs in the Galaxy are the product of white dwarf-white dwarf mergers.

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Relative flux calibration for the LAMOST Spectroscopic Survey of the Galactic anticentre

Cited by 26 publications

References 29 publications

The white dwarf binary pathways survey – I. A sample of FGK stars with white dwarf companions

The white dwarf binary pathways survey – I. A sample of FGK stars with white dwarf companions

Estimating stellar atmospheric parameters, absolute magnitudes and elemental abundances from the LAMOST spectra with Kernel-based principal component analysis

DA white dwarfs from the LSS-GAC survey DR1: the preliminary luminosity and mass functions and formation rate

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