MWM Combined Models

Module: astra.models.mwm

The MWM (Milky Way Mapper) spectrum models unify APOGEE and BOSS spectra into a common framework. They resample all spectra onto standardized wavelength grids in the source rest frame, making them ready for scientific analysis.

MWM Mixins

MWMStarMixin

Base mixin for co-added (star-level) MWM spectrum models. Provides a path property that generates the mwmStar file path.

path (property)

# Returns path like:
# $MWM_ASTRA/<v_astra>/spectra/star/<sdss_id_groups>/mwmStar-<v_astra>-<sdss_id>.fits

MWMVisitMixin

Base mixin for visit-level MWM spectrum models. Provides a path property that generates the mwmVisit file path.

path (property)

# Returns path like:
# $MWM_ASTRA/<v_astra>/spectra/visit/<sdss_id_groups>/mwmVisit-<v_astra>-<sdss_id>.fits

MWMSpectrumProductStatus

Tracks whether MWM spectrum products have been created for a given source.

Field	Type	Description
source_pk	ForeignKeyField	Link to the Source
task_pk	AutoField	Primary key
v_astra	IntegerField	Astra version
flags	BitField	Processing status flags

Status flags:

Flag	Description
flag_skipped_because_no_sdss_id	Source has no SDSS ID
flag_skipped_because_not_stellar_like	Source is not stellar-like
flag_attempted_but_exception	Exception occurred during processing
flag_created_mwm_visit	mwmVisit file created successfully
flag_created_mwm_star	mwmStar file created successfully

BossRestFrameVisitSpectrum

A BOSS visit spectrum that has been resampled onto a common log-lambda wavelength grid and shifted to the source rest frame. Stored in mwmVisit files. Inherits from MWMVisitMixin.

Key Fields

Field	Type	Description
spectrum_pk	ForeignKeyField	Unique spectrum identifier
source	ForeignKeyField	Foreign key to Source
drp_spectrum_pk	ForeignKeyField	Link to the original BossVisitSpectrum
sdss_id	BigIntegerField	SDSS-V unique identifier
release	TextField	Data release
run2d	TextField	BOSS reduction pipeline version
mjd	IntegerField	Modified Julian Date
fieldid	IntegerField	Field identifier
catalogid	BigIntegerField	SDSS catalog identifier
telescope	TextField	Telescope used

Spectral data (source rest frame):

Field	Type	Description
wavelength	PixelArray	Log-lambda grid (4648 pixels, crval=3.5523, cdelt=1e-4)
flux	PixelArray	Flux array
ivar	PixelArray	Inverse variance array
pixel_flags	PixelArray	Per-pixel quality flags

Quality and radial velocity:

Field	Type	Description
snr	FloatField	Signal-to-noise ratio
in_stack	BooleanField	Whether this visit was used in the combined spectrum
xcsao_v_rad	FloatField	Radial velocity from XCSAO (km/s)
xcsao_teff	FloatField	Effective temperature from XCSAO
xcsao_logg	FloatField	Surface gravity from XCSAO
xcsao_fe_h	FloatField	Metallicity from XCSAO

NMF continuum model:

Field	Type	Description
continuum	PixelArray	NMF continuum model
nmf_rchi2	FloatField	Reduced chi-squared of NMF fit
nmf_flags	BitField	NMF continuum method flags

Methods and Properties

path (property)

Inherited from MWMVisitMixin. Returns the mwmVisit file path.

e_flux (property)

Returns flux uncertainty as ivar**-0.5.

BossCombinedSpectrum

A co-added BOSS spectrum created by stacking all good rest-frame visit spectra for a source. This fills the gap left by the BOSS DRP, which does not produce stacked spectra. Stored in mwmStar files. Inherits from MWMStarMixin.

Key Fields

Field	Type	Description
spectrum_pk	ForeignKeyField	Unique spectrum identifier
source	ForeignKeyField	Foreign key to Source
sdss_id	BigIntegerField	SDSS-V unique identifier
release	TextField	Data release
run2d	TextField	BOSS reduction pipeline version
telescope	TextField	Telescope used

Observation summary:

Field	Type	Description
n_visits	IntegerField	Number of BOSS visits
n_good_visits	IntegerField	Number of good visits
n_good_rvs	IntegerField	Number of good RV measurements
min_mjd	IntegerField	Minimum MJD of contributing visits
max_mjd	IntegerField	Maximum MJD of contributing visits

Radial velocity:

Field	Type	Description
v_rad	FloatField	Mean radial velocity (km/s)
e_v_rad	FloatField	Uncertainty on mean radial velocity (km/s)
std_v_rad	FloatField	Standard deviation of visit radial velocities (km/s)
median_e_v_rad	FloatField	Median per-visit RV uncertainty (km/s)
xcsao_teff	FloatField	Effective temperature from XCSAO
xcsao_logg	FloatField	Surface gravity from XCSAO
xcsao_fe_h	FloatField	Metallicity from XCSAO

Spectral data:

Field	Type	Description
wavelength	PixelArray	Log-lambda grid (4648 pixels, crval=3.5523, cdelt=1e-4)
flux	PixelArray	Co-added flux
ivar	PixelArray	Co-added inverse variance
pixel_flags	PixelArray	Per-pixel quality flags
snr	FloatField	Signal-to-noise ratio of co-added spectrum

NMF continuum model:

Field	Type	Description
continuum	PixelArray	NMF continuum model
nmf_rectified_model_flux	PixelArray	NMF rectified model flux
nmf_rchi2	FloatField	Reduced chi-squared of NMF fit
nmf_flags	BitField	NMF continuum method flags

Methods and Properties

path (property)

Inherited from MWMStarMixin. Returns the mwmStar file path.

ApogeeCombinedSpectrum

A co-added APOGEE spectrum in the MWM framework. Similar in structure to BossCombinedSpectrum but for APOGEE data, using the APOGEE log-lambda grid (8575 pixels, crval=4.179, cdelt=6e-6). Stored in mwmStar files. Inherits from MWMStarMixin.

Key Fields

Field	Type	Description
spectrum_pk	ForeignKeyField	Unique spectrum identifier
source	ForeignKeyField	Foreign key to Source
sdss_id	BigIntegerField	SDSS-V unique identifier
release	TextField	Data release
apred	TextField	APOGEE reduction pipeline version
obj	TextField	Object name
telescope	TextField	Telescope used

Observation summary:

Field	Type	Description
n_entries	IntegerField	Number of apStar entries for this object
n_visits	IntegerField	Number of APOGEE visits
n_good_visits	IntegerField	Number of good visits
n_good_rvs	IntegerField	Number of good RV measurements
min_mjd	IntegerField	Minimum MJD of contributing visits
max_mjd	IntegerField	Maximum MJD of contributing visits

Summary statistics and radial velocity:

Field	Type	Description
snr	FloatField	Signal-to-noise ratio
mean_fiber	FloatField	S/N-weighted mean visit fiber number
std_fiber	FloatField	Standard deviation of visit fiber numbers
v_rad	FloatField	Mean radial velocity (km/s)
e_v_rad	FloatField	Uncertainty on mean radial velocity (km/s)
std_v_rad	FloatField	Standard deviation of visit radial velocities (km/s)
doppler_teff	FloatField	Effective temperature from Doppler
doppler_logg	FloatField	Surface gravity from Doppler
doppler_fe_h	FloatField	Metallicity from Doppler

Spectral data:

Field	Type	Description
wavelength	PixelArray	Log-lambda grid (8575 pixels, crval=4.179, cdelt=6e-6)
flux	PixelArray	Co-added flux
ivar	PixelArray	Co-added inverse variance
pixel_flags	PixelArray	Per-pixel quality flags

NMF continuum model:

Field	Type	Description
continuum	PixelArray	NMF continuum model
nmf_rectified_model_flux	PixelArray	NMF rectified model flux
nmf_rchi2	FloatField	Reduced chi-squared of NMF fit
nmf_flags	BitField	NMF continuum method flags

Methods and Properties

path (property)

Inherited from MWMStarMixin. Returns the mwmStar file path.

ApogeeRestFrameVisitSpectrum

An APOGEE visit spectrum resampled onto the common APOGEE log-lambda grid and shifted to the source rest frame. The APOGEE analogue of BossRestFrameVisitSpectrum. Stored in mwmVisit files. Inherits from MWMVisitMixin.

Key Fields

Field	Type	Description
spectrum_pk	ForeignKeyField	Unique spectrum identifier
source	ForeignKeyField	Foreign key to Source
sdss_id	BigIntegerField	SDSS-V unique identifier
release	TextField	Data release
apred	TextField	APOGEE reduction pipeline version
telescope	TextField	Telescope used
plate	TextField	Plate identifier
fiber	IntegerField	Fiber number
mjd	IntegerField	Modified Julian Date
field	TextField	Field identifier
obj	TextField	Object name

Quality and radial velocity:

Field	Type	Description
snr	FloatField	Signal-to-noise ratio
in_stack	BooleanField	Whether this visit was used in the combined spectrum
spectrum_flags	BitField	Quality flags (same bit definitions as ApogeeVisitSpectrum)
v_rad	FloatField	Absolute radial velocity (km/s)
v_rel	FloatField	Relative radial velocity (km/s)
e_v_rel	FloatField	Uncertainty on relative RV (km/s)
doppler_teff	FloatField	Effective temperature from Doppler
doppler_logg	FloatField	Surface gravity from Doppler
doppler_fe_h	FloatField	Metallicity from Doppler

Spectral data (source rest frame):

Field	Type	Description
wavelength	PixelArray	Log-lambda grid (8575 pixels, crval=4.179, cdelt=6e-6)
flux	PixelArray	Flux array
ivar	PixelArray	Inverse variance array
pixel_flags	PixelArray	Per-pixel quality flags
continuum	PixelArray	NMF continuum model
nmf_rchi2	FloatField	Reduced chi-squared of NMF fit

Methods and Properties

path (property)

Inherited from MWMVisitMixin. Returns the mwmVisit file path.

flag_bad (hybrid property)

Returns True if any critical quality flags are set. Can be used in database queries.

flag_warn (hybrid property)

Returns True if any spectrum flag is set. Can be used in database queries.