roman_shear_sims.skycatlog_parser

Attributes

HEALPIX_TEMPLATE
COMPONENTS

Classes

SkyCatalogParser	Parse the OpenUniverse2024 SkyCatalog.
MilkyWayExtinction	Applies extinction to a SED

Functions

get_knot_size(z)	Return the angular knot size. Knots are modelled as the same physical size.
get_knot_n(um_source_galaxy_obs_sm[, gal_id, rng])	Return random value for number of knots based on galaxy sm.
get_redshift_ind(wave_list, redshift, blue_limit, ...)	This is used to only load the part of the SED that is relevant for the

Module Contents

HEALPIX_TEMPLATE = '(?P<healpix>\\d+)'

COMPONENTS = ['bulge', 'disk', 'knots']

class SkyCatalogParser(skycatalog_config_path, img_world_center, img_size, simu_type='sca', buffer=0, object_types=None, read_sed=True)

Parse the OpenUniverse2024 SkyCatalog.

Parameters:

• skycatalog_config_path (str) – The path to the SyCatalog .yaml configuration file.

• img_world_center (galsim.CelestialCoord) – The celestial coordinates of the image center.

• img_size (int) – The size of the image in pixels.

• simu_type (str, optional) – The type of simulation to run. Options are ‘sca’ for SCA simulation and ‘imcom’ for IMCOM simulation. Default: ‘sca’.

• buffer (int, optional) – The buffer size in pixels to extend the image region for catalog queries.

• object_types (list of str, optional) – The list of object types to parse from the catalog. Default is [‘diffsky_galaxy’].

• read_sed (bool, optional) – Whether to read the SEDs from the catalog. Default is True.

img_world_center

img_size

_simu_type = 'sca'

buffer = 0

_read_sed = True

_init_catalog()

_parse_skycatalog(skycatalog_config_path)

Parse the SkyCatalog configuration file.

_get_region(img_world_center, img_size, buffer=0)

Get the region to query the catalog based on the image center and size. This reguion is used for the initial query of the catalog using: min_ra < ra < max_ra and min_dec < dec < max_dec The region is extended by a buffer to ensure that the entire image is covered by the catalog query.

_get_in_img_footprint(ra, dec)

Check if the given RA and Dec are within the image footprint. Compared to the _get_region method, this method uses the image WCS to check each object is within the image footprint + buffer.

_get_hp_pix_list()

Get the HEALPix pixel list that overlaps with the image region.

_get_cat_paths(object_type, get_sed=False)

Get the catalog file paths for a given object type.

_get_cosmology()

Get the cosmology used to create the OpenUniverse2024.

set_catalog(object_type)

Set the catalog for a given object type. This method queries the catalog files for the given object type and filters the objects based on the image region.

NOTE: Probably only works for the diffsky_galaxy object type at the moment.

Parameters:

object_type (str) – The type of object to set the catalog for.

set_sed_catalog(object_type)

Set the SED catalog for a given object type. This method reads the SEDs from the catalog files for the given object type and stores them in the sed_catalog attribute.

NOTE: Probably only works for the diffsky_galaxy object type at the moment.

Parameters:

object_type (str) – The type of object to set the catalog for.

get_knot_size(z)

Return the angular knot size. Knots are modelled as the same physical size.

Parameters:

z (float) – The redshift of the galaxy.

Returns:

The angular size of the knots in arcseconds, or None if the redshift is above 0.6 (where knots are treated as point sources).

Return type:

float or None

get_knot_n(um_source_galaxy_obs_sm, gal_id=None, rng=None)

Return random value for number of knots based on galaxy sm.

Parameters:

• um_source_galaxy_obs_sm (float) – The observed stellar mass of the galaxy.

• gal_id (int, optional) – The galaxy ID to use for the random number generator.

• rng (galsim.BaseDeviate, optional) – The random number generator to use. If None, a new one is created using the gal_id.

Returns:

The number of knots for the galaxy.

Return type:

int

get_redshift_ind(wave_list, redshift, blue_limit, red_limit)

This is used to only load the part of the SED that is relevant for the given redshift and wavelength range covered by the bandpasses.

Parameters:

• wave_list (np.ndarray) – The original wavelength list of the SED.

• redshift (float) – The redshift of the galaxy.

• blue_limit (float) – The blue limit of the wavelength range.

• red_limit (float) – The red limit of the wavelength range.

Returns:

startint

The starting index of the wavelength range.

endint

The ending index of the wavelength range.

z_wave_listnp.ndarray

The wavelength list after applying the redshift.

Return type:

tuple

class MilkyWayExtinction(mwRv=3.1)

Applies extinction to a SED

extinction

get_sed_ext(wls, mwAv)

Returns a SED of the Milky Way extinction

Parameters:

• wls (np.ndarray) – The wavelength list in nanometers.

• mwAv (float) – The Milky Way extinction in magnitudes (Av).

Returns:

mw_ext – The SED of the Milky Way extinction

Return type:

galsim.SED