The First Data Release of LAMOST Low Resolution Single Epoch Spectra

Abstract

LAMOST Data Release 5, covering $\sim$17,000 $de{g}^2$ from $-10^{\circ }$ to $80^{\circ }$ in declination, contains 9 millions co-added low resolution spectra of celestial objects, each spectrum combined from repeat exposure of two to tens of times during Oct 2011 to Jun 2017. In this paper, We present the spectra of individual exposures for all the objects in LAMOST Data Release 5. For each spectrum, equivalent width of 60 lines from 11 different elements are calculated with a new method combining the actual line core and fitted line wings. For stars earlier than F type, the Balmer lines are fitted with both emission and absorption profiles once two components are detected. Radial velocity of each individual exposure is measured by minimizing ${\chi }^2$ between the spectrum and its best template. Database for equivalent widths of spectral lines and radial velocities of individual spectra are available online. Radial velocity uncertainties with different stellar type and signal-to-noise ratio are quantified by comparing different exposure of the same objects. We notice that the radial velocity uncertainty depends on the time lag between observations. For stars observed in the same day and with signal-to-noise ratio higher than 20, the radial velocity uncertainty is below 5km/s, and increase to 10km/s for stars observed in different nights.

arXiv comment21 pages, 15 figures

References in corpus (14)

• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• Kepler Mission Design, Realized Photometric Performance, and Early Science
• A Grid of NLTE Line-Blanketed Model Atmospheres of Early B-type Stars
• The SEGUE Stellar Parameter Pipeline. I. Description and Initial Validation Tests
• The Catalina Surveys Periodic Variable Star Catalog
• Automatic Determination of Stellar Atmospheric Parameters and Construction of Stellar Spectral Templates of the Guoshoujing Telescope (LAMOST)
• A wide star-black-hole binary system from radial-velocity measurements
• Close Binary Companions to APOGEE DR16 Stars: 20,000 Binary-star Systems Across the Color-Magnitude Diagram
• An empirical template library of stellar spectra for a wide range of spectral classes, luminosity classes, and metallicities using SDSS BOSS spectra
• The binarity of Galactic dwarf stars along with effective temperature and metallicity
• A Method to Search for Black Hole Candidates with Giant Companions by LAMOST
• Single-lined Spectroscopic Binary Star Candidates in the RAVE Survey
• Sky Subtraction for LAMOST
• Cosmic Ray Removal in Fiber Spectroscopic Image

Cited by in corpus (1)

• ELM of ELM-WD: An extremely low mass hot star discovered in LAMOST survey