The catalogue can be downloaded from the link on main page in HDF5 or FITS format. Below is the detail of the catalogue.
Filenames:
- SDSS_DR16_QSO_based_MgII_Absorber_Catalog.hdf5
- SDSS_DR16_QSO_based_MgII_Absorber_Catalog.fits
Description of the Keywords:
====== MgII absorbers details, N ~ 160,000 systems =======
- Z_ABS: [float], redshifts of the MgII absorbers
- Z_ABS_ERR: [float], error in redshifts of the MgII absorbers
- Z_QSO: [float], redshift of the Quasars in which the absorber is detected
- PLATE: [int], plate number of SDSS quasar spectra
- MJD: [int], Modified Julian Date of SDSS quasar spectra observation
- FIBER_ID: [int], Fiber ID of SDSS quasar spectra (Note: combination of PLATE-MJD-FIBER_ID makes one unique observation in SDSS)
- RA_QSO: [float], Right Ascension of Quasars (in degrees)
- DEC_QSO: [float], Declination of Quasars (in degrees)
- PARENT_QSO_ID: [int], ID of Quasars associated with absorbers (NOTE: just to be used to find the number of unique quasars. These are just the serial numbers that I gave to the quasars that I searched for absorbers. To see the quasar spectra associated with a given absorber, please use the corresponding PLATE-MJD-FIBER combination. Thanks to Ying Zu (SJTU) for pointing me to clarify.)
- REST_EW_MGII_2796: [float], rest frame equivalent width of MgII 2796 line in [Angstrom]
- REST_EW_MGII_2803: [float], rest frame equivalent width of MgII 2803 line in [Angstrom]
- ERR_REST_EW_MGII_2796: [float], error in rest frame equivalent width of MgII 2796 line in [Angstrom]
- ERR_REST_EW_MGII_2803: [float], error in rest frame equivalent width of MgII 2803 line in [Angstrom]
- DELTA_V_MGII_2796: [float], Velocity shift from line centre (2796) based on Gaussian fitting [km/s] (NOTE: I calculate this using difference between gaussian fit line-centre and true vacuum MgII wavelength.)
- DELTA_V_MGII_2803: [float], Velocity shift from line centre (2803) based on Gaussian fitting [km/s]
- ERR_DELTA_V_MGII_2796: [float], Error in Velocity shift from line centre (2796) based on Gaussian fitting [km/s]
- ERR_DELTA_V_MGII_2803: [float], Error in Velocity shift from line centre (2803) based on Gaussian fitting [km/s]
- FWHM_VDISP_MGII_2796: [float], FWHM Velocity dispersion of MgII 2796 line in [km/s] , this is corrected for SDSS instrumental velocity dispersion
- FWHM_VDISP_MGII_2803: [float], FWHM Velocity dispersion of MgII 2803 line in [km/s] , this is corrected for SDSS instrumental velocity dispersion
- ERR_FWHM_VDISP_MGII_2796: [float], Error in FWHM Velocity dispersion of MgII 2796 line in [km/s]
- ERR_FWHM_VDISP_MGII_2803: [float], Error in FWHM Velocity dispersion of MgII 2803 line in [km/s]
- SNR_2796: [float], Signal-to-Noise (SNR) of MgII 2796 line
- SNR_2803: [float], Signal-to-Noise (SNR) of MgII 2803 line
- SNR_QSO_MEDIAN: [float], Median Signal-to-Noise (SNR) of Quasar spectra
- EIGENSPEC_INDEX: [int], Eigenspec set number, used to fit the quasar continuum
NOTE: Use only absorbers that have completeness corrected values > 0. As for very weak absorbers completeness corrected number can not be trusted because of low statistics, therefore I put them as -1. Only <~0.05 % of the absorbers have this issue.
In my opinion, A good selection will be absorbers having EW2796 >=0.3 A, or select based on your best judgement :)
- CORRECTED_NABS_WITH_ALL_QSO: [float], this is the corrected number of absorbers to account for the completeness of our detection algorithm. To estimate this correction I used all DR16 quasars. You can apply this corrected number to all absorbers.
- CORRECTED_NABS_WITH_QSO_SN_GR_1: [float], this is the corrected number of absorbers to account for the completeness of our detection algorithm. To estimate this correction I used only quasars with S/N >1. You can apply this corrected number to all absorbers that are associated with QSOs having SNR_QSO_MEDIAN>1.
- CORRECTED_NABS_WITH_QSO_SN_GR_2: [float], this is the corrected number of absorbers to account for the completeness of our detection algorithm. To estimate this correction I used only quasars having S/N >2. You can apply this corrected number to all absorbers that are associated with QSOs having SNR_QSO_MEDIAN>2.
======================================== END OF THE CATALOGUE ======================================