Lyman alpha Year 1 correlations Catalog
Overview
This folder contains the measured correlations, distortion matrices and covariances used for the Lyman alpha (Lya) Y1 BAO analysis. The analysis uses over 420,000 Lya forest spectra and their correlation with the spatial distribution of more than 700,000 quasars above redshift z>1.77. We consider two different Lya catalogues corresponding to Lya absorption in two different regions of the quasar spectra. Region “A” is defined as the rest-frame wavelength range from 1040 to 1205 angstrom, while region “B” covers the range from 920 to 1020 angstrom. These cuts in observed and rest-frame wavelength limit the redshift range of the background quasars from z = 2.1 to z = 4.4 for the region “A” and z = 2.6 to z = 5.1 for “B”, respectively. Data and results are presented in DESI 2024 IV: Baryon Acoustic Oscillations from the Lyman Alpha Forest.
Data Access
Data URL: https://data.desi.lbl.gov/public/dr1/vac/dr1/lya-correlations
NERSC access:
/global/cfs/cdirs/desi/public/dr1/vac/dr1/lya-correlations
Documentation
Files
This directory contains the following data. The Lya Y1 BAO analysis includes auto- and cross-correlations of both Lya forest regions, denoted by lya for region “A” and lyb for region “B”, and quasars, denoted by qso. In total, we compute for correlations: lyaxlya, lyaxlyb, qsoxlya, qsoxlyb. For each correlation we provide a fits file containing the correlation function (cf), the distortion matrix (dmat) to model the effect of the continuum fitting, and one smoothed covariance matrix (covmat). All files have checksums to ensure data integrity.
- Smoothed Covariance
correlation-covmat-0-0-0/full-covariance-smoothed.fits
- smoothed covariance for lyaxlya, lyaxlyb, lyaxqso, lybxqso
- Lya x Lya
correlation-lyalya-0-0-0/cf_lya_x_lya_exp.fits
- measured correlation function lyaxlyacorrelation-lyalya-0-0-0/dmat_lya_x_lya.fits
- measured distortion matrix lyaxlya
- Lya x Lyb
correlation-lyalyb-0-0-0/cf_lya_x_lyb_exp.fits
- measured correlation function lyaxlybcorrelation-lyalyb-0-0-0/dmat_lya_x_lyb.fits
- measured distortion matrix lyaxlyb
- QSO x Lya
correlation-qsolya-0-0-0/cf_qso_x_lya_exp.fits
- measured correlation function qsoxlyacorrelation-qsolya-0-0-0/dmat_qso_x_lya.fits
- measured distortion matrix qsoxlya
- QSO x Lyb
-
correlation-qsolyb-0-0-0/cf_qso_x_lyb_exp.fits
- measured correlation function qsoxlyb
- correlation-qsolyb-0-0-0/dmat_qso_x_lyb.fits
- measured distortion matrix qsoxlyb
Data Model
- entries are 8-byte float64
- EXTENSION are given below as EXT
- shared information stored in the header is:
| Name |
Type |
Units |
Description |
| NAXIS2 |
float64 |
- |
Number of rows in table (size NP x NT) |
| RPMIN |
float64 |
h^-1 Mpc |
Minimum r-parallel |
| RPMAX |
float64 |
h^-1 Mpc |
Maximum r-parallel |
| RTMAX |
float64 |
h^-1 Mpc |
Maximum r-transverse |
| NP |
int64 |
- |
Number of bins in r-parallel |
| NT |
int64 |
- |
Number of bins in r-transverse |
| COEFMOD |
float64 |
- |
Coefficient for model binning |
| ZCUTMIN |
float64 |
- |
Minimum redshift of pairs |
| ZCUTMAX |
float64 |
- |
Maximum redshift of pairs |
| REJ |
float64 |
- |
Rejection factor to compute distortion matrix |
| OMEGAM |
float64 |
- |
Omega_matter(z=0) of fiducial LambdaCDM cosmology |
| OMEGAR |
float64 |
- |
Omega_radiation(z=0) of fiducial LambdaCDM cosmology |
| OMEGAK |
float64 |
- |
Omega_k(z=0) of fiducial LambdaCDM cosmology |
| WL |
float64 |
- |
Equation of state of dark energy of fiducial LambdaCDM cosmology |
| BLINDING |
str |
- |
String specifying the blinding strategy (desi-y1) |
Smoothed Covariance File
| Name |
Type |
Units |
Description |
| COV |
float64 |
- |
Covariance matrix of size NP x NT |
Correlation Files
- HDU
COR containing the correlation and auxiliary files. The columns are:
| Name |
Type |
Units |
Description |
| DA |
float64 |
- |
Correlation function in RP, RT bins |
| RP |
float64 |
h^-1 Mpc |
r_parallel bin centre |
| RT |
float64 |
h^-1 Mpc |
r_transverse bin centre |
| Z |
float64 |
- |
Redshift of bin |
| CO |
float64 |
- |
Covariance of correlation function per bin |
| DM |
float64 |
- |
Distortion matrix in RP, RT bins |
| NB |
int64 |
- |
Number of pairs per bin |
- HDU
DMATTRI containing the modelled distortion matrix corresponding to the correlation function. The columns are:
| Name |
Type |
Units |
Description |
| DMRP |
float64 |
h^-1 Mpc |
R-parallel model |
| DMRT |
float64 |
h^-1 Mpc |
R-transverse model |
| DMZ |
float64 |
- |
Redshift model |
Distortion Matrix Files
- HDU
DMAT containing the measured distortion matrix. The columns are:
| Name |
Type |
Units |
Description |
| WDM |
float64 |
- |
Weights distortion matrix |
| DM_BLIND |
float64 |
- |
Distortion matrix |
- HDU
ATTRI containing attributes required for correlation function measurement and theory modeling. The columns are:
| Name |
Type |
Units |
Description |
| RP |
float64 |
h^-1 Mpc |
r_parallel bin center |
| RT |
float64 |
h^-1 Mpc |
r_transverse bin center |
| Z |
float64 |
- |
Measured redshift per bin |
Contact Roger de Belsunce for questions about this catalog.