kshitijd/mmu-norm-vipers

VIPERS PDR2 spectra — repaired L1 (release v1)

This L1 repository contains 91,507 optical spectra from the VIMOS Public Extragalactic Redshift Survey PDR2. Two data corrections were validated against 500 original ESO spectra:

1. The upstream ivar field stored 1/(NOISE·1e34). This repository uses ivar = ivar_upstream² × 1e34, with a residual of 6e-8 against the reference data.
2. zflg is the VIPERS redshift quality flag joined from CDS J/A+A/609/A84.

Schema (one row per spectrum)

Column	Meaning
object_id	VIPERS ID (e.g. 104176271)
lambda_angstrom	observer-frame wavelength, air convention, Å
flux_1e-17_erg_s_cm2_A	flux density ×10⁻¹⁷ erg s⁻¹ cm⁻² Å⁻¹
ivar	inverse variance of the flux column (repaired)
native_mask	VIPERS mask codes 0–3, unmodified
valid	mask==0 AND ivar>0 AND finite(flux) — default usable-sample policy
redshift, zflg	spectroscopic redshift and true quality flag
exptime, norm, mag	native metadata

Caveats

• Flux calibration is tied to CFHTLS photometry and carries about 10% systematic uncertainty.
• Resolving power ≈ 220; 5500–9600 Å.
• This repository includes the full 91,507-spectrum PDR2 sample, including sources without a match in the wider release.

Split assignments are in mmu-norm-index → splits/v1/payload_splits/vipers_w1.parquet and vipers_w4.parquet.

Credit: VIPERS (ESO LP 182.A-0886), Scodeggio et al. 2018, A&A 609, A84. Sourced via Multimodal Universe; provenance.json describes the data corrections.