Astronomy Spectra

Overview

astro.spectra links the focused catalogue record to supported survey spectra. Separate panels cover DESI, SDSS/BOSS, and Euclid so that each survey’s archive, identifiers, and retrieval rules remain clear.

Euclid Spectra

The Euclid Spectra panel retrieves and displays Euclid Red Grism spectra, showing both the raw data and a box-filter-smoothed version.

Spectra can be retrieved in two ways:

Identifier Query

Retrieves a single spectrum using an identifier column from the main table.

Cone Search

Retrieves all spectra within a user-defined radius around the source coordinates and displays them in order of increasing distance from the source.

The cone-search radius can also be linked to the Euclid cutout size, allowing all spectra within the cutout region to be retrieved. The positions of the selected spectra can then be overlaid on the Euclid image.

Common emission-line positions can be displayed on the spectrum when a redshift is available. The redshift can be:

  • queried from the Euclid pipeline using catalogue.spectro_zcatalog_spe_classification, with the most reliable redshift solution returned;

  • read from a mapped column in the main table;

  • entered manually.

DESI and SDSS Spectra

The DESI Spectra and SDSS Spectra panels provide similar functionality to the Euclid Spectra panel, but retrieve spectra from the DESI and SDSS/eBOSS surveys. Data are accessed using the SPARCL package (Juneau et al. 2024).

For these panels, the source redshift is retrieved together with the spectrum and can be used directly to display common emission-line positions.

What You Do

  1. Map the record ID and sky-coordinate columns.

  2. Optionally map a survey-specific target ID for direct lookup.

  3. Open the panel for the required survey.

  4. Focus a source in another panel.

  5. Use automatic reload or manually load a spectrum by coordinates or target ID.

  6. Adjust the matching radius, smoothing, and plot options where required.

  7. Open produced astro.spectra artifacts with the Spectrum Viewer.

Requirements

The plugin uses:

  • numpy

  • pandas

  • panel

  • holoviews

  • matplotlib

  • astropy

  • astroquery

  • sparcl

  • mocpy

  • requests

Individual panels also declare the smaller subset of packages required by their survey backend.

Required Mappings

All survey panels require:

  • record_id

  • coords.ra

  • coords.dec

Optional survey identifiers allow direct target-ID retrieval:

  • spectra.desi_target_id

  • spectra.sdss_target_id

  • spectra.euclid_source_id

Panels

DESI Spectra

Retrieves DESI DR1 spectra through SPARCL. The panel can use a mapped target ID or perform a coordinate search within the selected matching radius.

SDSS Spectra

Retrieves BOSS DR17 and SDSS DR17 spectra through SPARCL. As with DESI, lookup can use either the mapped survey identifier or the focused sky coordinates.

Euclid Spectra

Retrieves Euclid Q1 spectra through the shared Euclid client. The panel supports source-ID or coordinate lookup and can query Euclid redshift information for the focused result.

All three panels support automatic reload on focus changes, configurable smoothing, and plot-refresh controls. DESI and SDSS can also show spectral models and line markers where available.

Jobs and Focus Changes

Archive retrieval runs through the platform JobManager. Rapid focus changes are debounced, previous requests are cancelled where possible, and generation checks prevent a late result for an old source from replacing the current display.

The panels listen to selection focus, active-dataset, and mapping changes. With automatic reload disabled, focus changes update the target information without starting a new archive request.

Artifacts

Successful retrievals produce astro.spectra artifacts and, where coordinates are available, astro.coords artifacts.

The plugin also publishes spectrum-running, spectrum-updated, and coordinate-updated events for other platform components.

The Spectrum Viewer is the default viewer for astro.spectra artifacts and displays a retrieved result independently of the live survey panel.

Note

Survey footprint, target matching, archive availability, and access rules differ between DESI, SDSS/BOSS, and Euclid. A source with no returned spectrum is not necessarily an application error.