Lya Working Group Quasar Redshift Catalog (zlya)¶
Overview¶
This catalog contains the redshifts used for the Lya Forest BAO analysis in Y1. The catalog was constructed using DESI DR1 z>1.6 MAIN survey DARK program quasars. Only quasars with a Redrock ZWARN flag of [0,4] are included. Redshifts were determined using a modified version of the DR1 Redrock rrtemplate-qso-HIZ templates with a 3000 km/s tophat prior about the DR1 LSS redshifts. Broad absorption line info is also provided per quasar. See Filbert et al. (2024) for a description of the BAL attributes provided and Martini et al. (2024) for an overview of BAL quasars in DESI Y1.
The modified rrtemplate-qso-HIZ templates can be found in redrock-templates/0.8.1.
Section 6 of Bault et al. (2024) provides a description of these templates and their redshift performance.
Data Access¶
Data URL: https://data.desi.lbl.gov/public/dr1/vac/dr1/zlya
NERSC access:
/global/cfs/cdirs/desi/public/dr1/vac/dr1/zlya
Documentation¶
Files¶
qso_cat_dr1_main_dark_healpix_zlya-v0.fits: Redshift catalogplot-RR-fit.ipynb: Notebook illustrating how to reconstruct Redrock best fitplot-RR-fit.html: HTML export of notebook illustrating how to reconstruct Redrock best fit
Data Model¶
| Name | Type | Units | Description |
|---|---|---|---|
| TARGETID | int64 | - | Unique DESI target ID |
| Z | float64 | - | Updated redshift |
| ZERR | float64 | - | Estimated error on updated redshift |
| ZWARN | int64 | - | Redshift warning bitmask for updated redshift (see: https://github.com/desihub/redrock/blob/main/py/redrock/zwarning.py ) |
| CHI2 | float64 | - | Chi-squared of template fit at best-fit redshift |
| COEFF | float64[4] | - | Coefficients of updated QSO-HIZ for best fit |
| NPIXELS | int64 | - | Number of input pixels (wavelengths) included in fit |
| TARGET_RA | float64 | deg | Right Ascension in decimal degrees (J2000) |
| TARGET_DEC | float64 | deg | Declination in decimal degrees (J2000) |
| DESI_TARGET | int64 | - | DESI target selection bitmask |
| HPXPIXEL | int64 | - | HEALPixel containing target at HPXNSIDE |
| SURVEY | string | - | main |
| PROGRAM | string | - | dark |
| BI_CIV | float64 | km/s | Equivalent width of CIV absorption by Balnicity index definition |
| ERR_BI_CIV | float64 | km/s | Uncertainty in BI_CV, infinity values indicate a potentially problematic fit |
| NCIV_2000 | int64 | - | Number of absorption troughs from CIV extending > 2000 km/s |
| VMIN_CIV_2000 | float64[5] | km/s | Minimum velocity of BI absorption troughs blueward of CIV |
| VMAX_CIV_2000 | float64[5] | km/s | Maximum velocity of BI absorption troughs blueward of CIV |
| AI_CIV | float64 | km/s | Equivalent width of the CIV absorption by absorption index definition |
| ERR_AI_CIV | float64 | km/s | Uncertainty in AI_CIV, infinity values indicate a potentially problematic fit |
| NCIV_450 | int64 | - | Number of absorption troughs from CIV extending > 450 km/s |
| VMIN_CIV_450 | float64[17] | km/s | Minimum velocity of AI absoprtion troughs blueward of CIV |
| VMAX_CIV_450 | float64[17] | km/s | Maximum velocity of AI absorption troughs blueward of CIV |
| ZMASK | float64 | - | Redshift after masking AI_CIV>0 BAL features |
Contact¶
Contact Allyson Brodzeller for questions about this catalog