LAMOST DR11 catalogs

Spectra. - There are 11,931,197 flux (relatively) - and wavelength-calibrated, sky-subtracted spectra, including 11,570,626 stellar spectra, 277,566 galaxy spectra, and 83,005 quasar spectra, and they cover the wavelength range of 3700{AA}-9000{AA} with a resolution of 1800 at the 5500{AA}. 2. Spectroscopic Parameter Catalogs. - In this data release, 11 spectroscopic parameter catalogs are also published, and they are the LAMOST LRS General Catalog, the LAMOST LRS Stellar Parameter Catalog of A, F, G and K Stars, the LAMOST LRS Line-Index Catalog of A Type Stars, the LAMOST LRS Catalog of gM, dM, and sdM Stars, the LAMOST LRS Multiple Epoch Catalog, the LAMOST LRS Observed Plate Information Catalog, the LAMOST LRS Input Catalog, the LAMOST LRS Catalog of Cataclysmic Variable Stars, the LAMOST LRS Catalog of White Dwarf Stars, the LAMOST LRS Catalog of Stellar Population Synthesis of Galaxies, and LAMOST LRS Catalog of Emission Line Features of QSOs, respectively.

More than a hundred parameters are included in these catalogs, such as right ascension, declination, signal to noise ratio (S/N), Gaia source identifier and magnitudes, atmospheric parameters (effective temperature, surface gravity, and metallicity), radial velocity, element abundance, spectral line indices, line widths, the metallicity sensitive parameter, and the magnetic activity flag. Data Release Eleven of LAMOST Medium-Resolution Spectroscopic Survey (MRS).

Since October 2018, LAMOST started the second stage survey program (LAMOST II), which contains both low- and medium-resolution spectroscopic surveys. LAMOST II takes about 50% nights (dark/gray nights) to continue the previous low-resolution spectroscopic survey, and another 50% nights (bright/gray nights) to conduct the medium-resolution survey (MRS). For LAMOST MRS, it includes two surveys, i.e., the time-domain and the non time-domain surveys.

The main purpose of the time-domain survey is to investigate variable targets, which were repeatedly observed in several observation nights, but targets of the non time-domain survey were observed only in one night in general. This time, 36,955,439 single exposure spectra and 9,997,571 coadded spectra were obtained, which were written into 5,140,907 FITS files. For objects close to the moon, spectra may be affected by the moon, thus targets with the angular distances to the moon less than 10 degrees were not observed.

For the non time-domain survey, there are totally 2,737,394 coadded spectra published, and for the time-domain survey, 10,418,656 single exposure spectra were released. The data products of this data release can be available from the website lamost.org/dr11/v2.0/, and they include: 1. Spectra. - For a target of MRS, we can get two spectra within an exposure, including a blue (B) and a red (R) band spectrum, with their wavelength ranges [4950{AA},5350{AA}] and [6300{AA},6800{AA}], respectively, and these spectra have been sky-subtracted and wavelength-calibrated.

Generally, each object was observed several times, and we would obtain the coadded B and R band spectra by combing the single exposure spectra. Few targets, however, lack of the spectral data of either band for some reason like the wavelength calibration, only one even no coadded spectra exists in their FITS file. For single exposure and coadd spectra, they both have a resolution of 7500 respectively at 5163{AA} (blue) and 6593{AA} (red). 2.

Spectroscopic Parameter Catalogs. - In this data release, five spectroscopic parameter catalogs are published, and they are the LAMOST MRS General Catalog, the LAMOST MRS Parameter Catalog, the LAMOST MRS Multiple Epoch Catalog, the LAMOST MRS Observed Plate Information Catalog, and the LAMOST MRS Input Catalog, respectively. More than a hundred parameters are included in these catalogs, such as right ascension, declination, signal to noise ratio (S/N), Gaia source identifier and magnitudes, atmospheric parameters (effective temperature, surface gravity, and metallicity), radial velocity, element abundance, and dome seeing.