frb.surveys.euclid

Methods related to Euclid survey queries via astroquery.esa.euclid

Provides access to Euclid Q1 data release through the ESA Euclid Archive, including photometry (VIS+NIR), morphology, and optional spectroscopy.

class frb.surveys.euclid.Euclid_Survey(coord, radius, **kwargs)[source]

Bases: SurveyCoord

Class to handle queries on the Euclid survey database.

Queries the ESA Euclid Archive for photometry and optional spectroscopy from the Q1 (March 2025) public data release. Primary data source is the mer_catalogue table which contains VIS+NIR photometry and morphology.

Args:

  • coord (SkyCoord) – Coordinate for surveying around

  • radius (Angle) – Search radius around the coordinate

  • verbose (bool, optional) – Verbosity flag

Examples

>>> from astropy.coordinates import SkyCoord
>>> from astropy import units as u
>>> from frb.surveys.euclid import Euclid_Survey
>>> coord = SkyCoord(ra=267.78*u.deg, dec=65.53*u.deg)
>>> radius = 10*u.arcmin
>>> survey = Euclid_Survey(coord, radius)
>>> catalog = survey.get_catalog()
__init__(coord, radius, **kwargs)[source]
get_catalog(query_fields=None, timeout=120, check_spectra=False)[source]

Query Euclid for all objects within a given radius of input coordinates.

Queries the mer_catalogue table for photometry and morphology. Optionally searches for associated spectroscopy if photometry is found.

Args:

  • query_fields (list, optional) – List of column names to retrieve from database. If None, uses default set: object_id, right_ascension, declination, plus all photometric and morphological columns.

  • timeout (float, optional) – Query timeout in seconds. Default: 120 s.

  • print_query (bool, optional) – If True, print the ADQL query. Default: False.

  • check_spectra (bool, optional) – If True, check for associated spectra for photometric sources. Default: False.

Returns:

Catalog of sources with standardized FRB column names. Includes ra, dec, and Euclid_{VIS,J,H,Y} magnitudes. Empty table if no sources found.

Return type:

astropy.table.Table

spectra_exist(euclid_ids: list | ndarray | int)[source]

Check if spectroscopic data exists for photometric sources.

Queries the spectra_source table and attempts to match with photometric catalog. Only adds spectrum if found.

Adds two columns to self.catalog:

  • Euclid_has_spectrum (bool)

  • Euclid_n_datalinks (int)

This method queries Euclid datalinks using the Euclid object IDs in the catalog.

get_spectrum(euclid_id, output_folder=None, timeout=120)[source]

Retrieve the spectrum for a given Euclid object ID.

Args:

  • euclid_id (int) – The Euclid object ID to retrieve the spectrum for.

  • output_folder (str, optional) – Output folder for spectrum FITS. If None, uses temporary location.

  • timeout (float, optional) – Query timeout in seconds. Default: 120 s.

Returns:

(spectrum_data, spectrum_header) if spectrum found, (None, None) otherwise.

Return type:

tuple

get_cutout(imsize=None, output_file=None, verbose=None, timeout=120)[source]

Get a cutout of a Euclid MER background-subtracted mosaic image.

Queries the mosaic_product table to find MER background-subtracted mosaics covering the target region, then retrieves a cutout.

Args:

  • imsize (Angle, optional) – Size of cutout image. Default: 2 arcmin.

  • output_file (str, optional) – Output filename for cutout FITS. If None, uses temporary location.

  • verbose (bool, optional) – Verbosity. If None, uses self.verbose.

Returns:

(data_array, fits_header) if cutout successful, (None, None) otherwise.

Return type:

tuple

Note

MER cutouts are background-subtracted VIS-band mosaic images. Each ~1’x1’ cutout weighs ~5.5 MB and takes <1 second to download.