qsospec

qsospec fits UV, optical, and near-infrared quasar spectra. It provides coverage-aware emission-line recipes, continuum decomposition, optional pPXF host subtraction, QA figures, and resumable Parquet run bundles.

Installation

python -m pip install qsospec

For host-galaxy decomposition:

python -m pip install "qsospec[host]"

Minimal example

import qsospec

spectrum = qsospec.Spectrum.from_arrays(
    wavelength,
    flux,
    err=uncertainty,
    z=redshift,
    wave_frame="observed",
    flux_unit="cgs",
    ra=ra,
    dec=dec,
)

result = qsospec.fit_object_to_store(
    spectrum,
    "runs/my-quasar",
    object_id="my-quasar",
    global_config=qsospec.GlobalContinuumConfig(
        power_law=qsospec.PowerLawConfig(mode="auto"),
    ),
    write_qa=True,
)

result.show_qa()

Uncorrected spectra are dereddened by default with Planck GNILC and the Fitzpatrick (1999) law. This requires locally configured dustmaps data; already-corrected spectra can be declared with galactic_extinction_corrected=True.

Features

• Single or automatically selected broken power-law continua, Fe II, and a continuous Balmer pseudo-continuum.
• Lyα/N V, C IV, C III], Mg II, Balmer, optical, and NIR line complexes.
• Optional pPXF host decomposition for quasars at z < 1.2.
• Notebook-friendly and saved QA figures.
• Shared single-object and parallel batch run format.

See the documentation for setup, workflows, model definitions, examples, and API reference.

qsospec is distributed under the GPLv3 license.