Studies reveal characteristics of galaxy star populations in LAMOST spectral surveys

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Based on LAMOST data, Tokushu University PhD candidate Wang Lili and her collaborators have derived the age and metal content of approximately 43,000 galaxy star populations in DR7 of the LAMOST spectral survey. rice field.

The derived results are included in the LAMOST value-added catalog, enriching the LAMOST galaxy data. LAMOST, a large airspace multi-object fiber spectroscopic telescope, is operated by the National Astronomical Observatory of the Chinese Academy of Sciences (NAOC).

The study was published in Astrophysical Journal Supplement Series..

A galaxy is a system of stars, gas, and dust. A galaxy spectrum of light wavelengths, composed primarily of the accumulated light of hundreds of billions of stars, encodes the distribution of star age and metal content. From the population analysis of the stars in the galaxy spectrum Star formation And the history of chemical evolution Galaxy Expected to be decoded.

A common method of population analysis for stars is template fitting based on the full spectrum. However, uncertainty is always present as a result of flux calibration inaccuracies and galaxy high dust densities.

In this study, researchers proposed a template fitting method based on small features to estimate the average age and metal content of the LAMOST galaxy.

This new method separates small features from the large components of the galaxy spectrum, namely absorption features, and fits only the small features observed in the model that are unaffected by the overall shape of the continuum. ..

The results of several tests and comparisons have proved that the properties obtained by this method are reliable. “One of the advantages of this method is that it is suitable for galaxy star population analysis with uncertain flux calibration or spatially non-uniform dust attenuation, which was difficult with conventional methods.” WANG said.

This study provides the first estimates of galaxy age and metal content in LAMOST spectroscopy. It plays an important role in the study of the physical properties of low redshift galaxies and galaxies.

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For more information:
Li-Li Wang et al, Galactic Star Population in LAMOST Spectral Survey, Astrophysical Journal Supplement Series (2021). DOI: 10.3847 / 1538-4365 / ac3241

Quote: The study was a LAMOST spectral survey obtained on February 18, 2022 from https: // (February 18, 2022). ) To characterize the galactic star population

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Studies reveal characteristics of galaxy star populations in LAMOST spectral surveys

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