Source

Module: astra.models.source

The Source model represents a single astronomical object. Every spectrum and pipeline result in Astra is linked back to a Source. Each source has a unique primary key (pk) and carries identifiers, astrometry, photometry, targeting information, and reddening estimates.

Key Fields

Identifiers

Field	Type	Description
pk	AutoField	Primary key
sdss_id	BigIntegerField	Unique SDSS-V identifier
sdss4_apogee_id	TextField	APOGEE identifier from SDSS-IV (e.g., 2M00000+000000)
gaia_dr2_source_id	BigIntegerField	Gaia DR2 source identifier
gaia_dr3_source_id	BigIntegerField	Gaia DR3 source identifier
tic_v8_id	BigIntegerField	TESS Input Catalog (v8) identifier
healpix	IntegerField	HEALPix index for spatial indexing
catalogid	BigIntegerField	SDSS-V catalog identifier
catalogid21	BigIntegerField	SDSS-V catalog identifier (v21 cross-match)
catalogid25	BigIntegerField	SDSS-V catalog identifier (v25 cross-match)
catalogid31	BigIntegerField	SDSS-V catalog identifier (v31 cross-match)

Astrometry

Field	Type	Description
ra	FloatField	Right ascension (degrees, J2000)
dec	FloatField	Declination (degrees, J2000)
l	FloatField	Galactic longitude (degrees)
b	FloatField	Galactic latitude (degrees)
plx	FloatField	Parallax (mas), from Gaia
e_plx	FloatField	Parallax uncertainty (mas)
pmra	FloatField	Proper motion in RA (mas/yr)
e_pmra	FloatField	Proper motion in RA uncertainty (mas/yr)
pmde	FloatField	Proper motion in Dec (mas/yr)
e_pmde	FloatField	Proper motion in Dec uncertainty (mas/yr)
gaia_v_rad	FloatField	Radial velocity from Gaia (km/s)
gaia_e_v_rad	FloatField	Gaia radial velocity uncertainty (km/s)

Photometry

The Source model stores photometry from several surveys:

Field	Type	Description
g_mag, bp_mag, rp_mag	FloatField	Gaia G, BP, RP magnitudes
j_mag, h_mag, k_mag	FloatField	2MASS J, H, K magnitudes
e_j_mag, e_h_mag, e_k_mag	FloatField	2MASS magnitude uncertainties
w1_mag, w2_mag	FloatField	unWISE W1, W2 magnitudes
e_w1_mag, e_w2_mag	FloatField	unWISE magnitude uncertainties
w1_flux, w2_flux	FloatField	unWISE raw fluxes
mag4_5	FloatField	GLIMPSE (Spitzer 4.5 micron) magnitude

Synthetic photometry from Gaia XP spectra:

Field	Type	Description
u_jkc_mag, b_jkc_mag, v_jkc_mag, r_jkc_mag, i_jkc_mag	FloatField	Johnson-Kron-Cousins magnitudes
u_sdss_mag, g_sdss_mag, r_sdss_mag, i_sdss_mag, z_sdss_mag	FloatField	SDSS magnitudes
y_ps1_mag	FloatField	Pan-STARRS y-band magnitude

Reddening

Field	Type	Description
ebv	FloatField	Adopted E(B-V) reddening
e_ebv	FloatField	Uncertainty on adopted E(B-V)
ebv_flags	BitField	Provenance of adopted E(B-V)
ebv_zhang_2023	FloatField	E(B-V) from Zhang (2023)
ebv_sfd	FloatField	E(B-V) from SFD
ebv_bayestar_2019	FloatField	E(B-V) from Bayestar (2019)
ebv_edenhofer_2023	FloatField	E(B-V) from Edenhofer (2023)
ebv_rjce_glimpse	FloatField	E(B-V) from RJCE (GLIMPSE)
ebv_rjce_allwise	FloatField	E(B-V) from RJCE (AllWISE)

The ebv_flags bit field indicates the provenance of the adopted E(B-V): Zhang (2023), Edenhofer (2023), SFD, RJCE (GLIMPSE or AllWISE), or Bayestar (2019).

External Stellar Parameter Estimates

Field	Type	Description
zgr_teff	FloatField	Effective temperature from Zhang, Green & Rix (2023)
zgr_logg	FloatField	Surface gravity from ZGR (2023)
zgr_fe_h	FloatField	Metallicity from ZGR (2023)
r_med_geo	FloatField	Geometric distance from Bailer-Jones (EDR3, 2021)
r_med_photogeo	FloatField	Photogeometric distance from Bailer-Jones (EDR3, 2021)

Observations Summary

Field	Type	Description
n_boss_visits	IntegerField	Number of BOSS visits
n_apogee_visits	IntegerField	Number of APOGEE visits
boss_min_mjd, boss_max_mjd	IntegerField	MJD range of BOSS observations
apogee_min_mjd, apogee_max_mjd	IntegerField	MJD range of APOGEE observations

Targeting Flags

The Source model carries extensive targeting flags from both SDSS-IV (sdss4_apogee_target1_flags, sdss4_apogee2_target1_flags, etc.) and SDSS-V (sdss5_target_flags). These can be queried with the helper methods described below.

Methods and Properties

assigned_to_program(program)

Check whether this source is assigned to any carton in the given program. Can be used in queries.

# Find all sources in the "mwm_yso" program
sources = Source.select().where(Source.assigned_to_program("mwm_yso"))

assigned_to_carton_label(label)

Check whether this source is assigned to the given carton by label.

sources = Source.select().where(Source.assigned_to_carton_label("mwm_yso_disk_apogee"))

assigned_to_mapper(mapper)

Check whether this source is assigned to any carton in the given mapper.

sources = Source.select().where(Source.assigned_to_mapper("MWM"))

assigned_to_carton_pk(pk)

Check whether this source is assigned to the carton with the given primary key.

assigned_to_carton_with_name(name)

Check whether this source is assigned to any carton with the given name.

assigned_to_carton_with_alt_program(alt_program)

Check whether this source is assigned to any carton with the given alternate program.

assigned_to_carton_with_alt_name(alt_name)

Check whether this source is assigned to any carton with the given alternate name.

sdss5_cartons (property)

Returns the cartons that this source is assigned to, based on the sdss5_target_flags bit field.

sdss5_target_bits (property)

Returns a tuple of bit positions of targeting flags that are set for this source.

is_sdss5_target_bit_set(bit)

Check whether a specific carton bit position is set.

is_any_sdss5_target_bit_set(*bits)

Check whether any of the given carton bit positions are set.

spectra (property)

A generator that yields all spectra (across all spectrum types) associated with this source.

source = Source.get(Source.sdss_id == 12345)
for spectrum in source.spectra:
    print(type(spectrum), spectrum.snr)