gaiaspec

Turn Gaia XP spectra into standard-star spectra for atmospheric calibration of AuxTel (and other instruments), in the same CALSPEC dictionary format as the reference standards.

📖 Full documentation (API reference + user guide): https://corentinravoux.github.io/gaiaspec/

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What it does

star name / Gaia id ─▶ getGaia            resolve id + load XP coefficients
                    ─▶ gaiaxpy calibrate  flux vs wavelength
                    ─▶ spectrum_correction empirical flux correction
                    ─▶ CALSPEC-format spectrum (WAVELENGTH/FLUX/STATERROR/SYSERROR)

Gaia archive ─▶ standard  build the bundled source / spectra parquet tables

Install

pip install .              # deps: pandas, numpy, scipy, matplotlib, astropy,
                           #       gaiaxpy, pyarrow, fastparquet
pip install -e ".[dev]"    # + pytest, to run the test suite

The archive/resolution features additionally use getCalspec and astroquery. The bundled tables under gaiaspec/data/ let most of the package work offline.

Quick start

from gaiaspec import getGaia

star = getGaia.Gaia("HD111980")                 # resolve via Simbad -> Gaia DR3
spec = star.get_spectrum_numpy(flux_correction="m3")
wavelength = spec["WAVELENGTH"]                 # astropy Quantity (nm)
flux       = spec["FLUX"]                        # W m^-2 nm^-1

Apply a flux correction to your own Gaia flux:

import numpy as np
from gaiaspec import spectrum_correction

correction = spectrum_correction.return_gaia_spectra_correction(
    wavelength, flux, corr_threshold=0.8, choose_corr="m3",
)
corrected_flux = flux * correction

Package map

Module	Role
getGaia	Resolve a star, load/download its Gaia XP spectrum, calibrate it and format it as a CALSPEC dict; the Gaia standard-star class
spectrum_correction	Correlate a spectrum against bundled Gaia/CALSPEC pairs and return the empirical flux correction
standard	Query the Gaia archive around sky fields, select by quality flag / spectral type, download spectra and write the reference tables
utils	Small internal helpers

gaiaspec/data/ holds the bundled Gaia source / spectra tables, the CALSPEC matching table and the flux-correction table. scripts/ holds the DDF-catalog builder.

Conventions

• Wavelengths in nm, fluxes in W m⁻² nm⁻¹ (astropy Quantity).
• A spectrum is a dict with keys WAVELENGTH, FLUX, STATERROR, SYSERROR (CALSPEC convention), so gaiaspec spectra are drop-in standards.

Documentation

📖 Online: https://corentinravoux.github.io/gaiaspec/

Built from the in-code docstrings with MkDocs Material + mkdocstrings and deployed to GitHub Pages on every push to main. Build locally with:

pip install -r requirements-docs.txt
mkdocs serve

Tests

pip install -e ".[dev]"
pytest -q

See test/README.md for the layout of the suite.