LAMOST Time-Domain survey, first results

The low-resolution spectroscopic survey acquired 282 exposures (~46.6h) over 25 nights, yielding a total of about 767000 spectra, and the medium-resolution survey took 177 exposures (~49.1h) over 27 nights, collecting about 478000 spectra. More than 70%/50% of low-resolution/medium-resolution spectra have signal-to-noise ratio higher than 10.

We determine stellar parameters (e.g., Teff, logg, [Fe/H]) and radial velocity (RV) with different methods, including LASP, DD-Payne and SLAM. In general, these parameter estimations from different methods show good agreement, and the stellar parameter values are consistent with those of APOGEE. We use the Gaia DR2 RV values to calculate a median RV zero point (RVZP) for each spectrograph exposure by exposure, and the RVZP-corrected RVs agree well with the APOGEE data.