roman_shear_sims.catalog

Attributes

`LAYOUT_KINDS`
`GAL_TYPES`

Classes

`SimpleGalaxyCatalog`	A simple galaxy catalog with a single galaxy type.
`GalaxyCatalog`	Galaxy simulation from Sheldon et al. 2019
`DiffSkyCatalog`	Build catalog based on the DiffSky simulation.
`SimpleDiffSkyCatalog`	A simple DiffSky catalog with galaxies arranged in a grid or random

Functions

`get_simple_pos`(simu_type, img_size, rng[, ...])	Those functions are taken from the descwl-shear-sims package,
`get_g_BA`(rng[, sigma, size])	Generate a set of galaxy intrinsic ellipticities using the

Module Contents

LAYOUT_KINDS = ['grid', 'random'][source]

GAL_TYPES = ['gauss', 'exp', 'dev'][source]

class SimpleGalaxyCatalog(img_size, seed, simu_type='sca', gal_type='exp', hlr=DEFAULT_HLR, mag=DEFAULT_MAG, layout_kind='grid', buffer=0, spacing=5.0, n_gal=None, exp_time=roman.exptime, chromatic=False, gal_sed_path=None)[source]

A simple galaxy catalog with a single galaxy type.

Parameters:

img_size (int) – Image size in pixels.
seed (int) – Random seed for the catalog.
simu_type (str, optional) – The type of simulation to run. Options are ‘sca’ for SCA simulation and ‘imcom’ for IMCOM simulation. Default: ‘sca’.
gal_type (str) – Galaxy type, one of [‘gauss’, ‘exp’, ‘dev’]. Default: ‘exp’.
hlr (float) – Half-light radius of the galaxy. Default: DEFAULT_HLR.
mag (float) – Magnitude of the galaxy. Default: DEFAULT_MAG.
layout_kind (str) – Layout kind, one of [‘grid’, ‘random’]. Default: ‘grid’.
buffer (int) – Buffer size in pixels. Default: 0.
spacing (float) – Spacing between galaxies in pixels. Default: 5.0.
n_gal (int or None) – Number of galaxies to draw. If None, will use as many as possible. Default: None.
exp_time (float) – Exposure time in seconds.
chromatic (bool) – Whether to use chromatic SEDs. Default: False.
gal_sed_path (str or None) – Path to the galaxy SED file. If None, will use a default SED. Default: None.

_simu_type = 'sca'[source]

img_size[source]

rng[source]

gal_type = 'exp'[source]

_hlr = 0.5[source]

_mag = 25[source]

_exp_time = 139.8[source]

layout_kind = 'grid'[source]

buffer = 0[source]

spacing = 5.0[source]

n_gal = None[source]

_chromatic = False[source]

getNObjects()[source]

Get the number of objects in the catalog.

Returns:: The number of objects in the catalog.
Return type:: int

getObjList(bandpass)[source]

Get the object list to draw for a given bandpass.

Parameters:: bandpass (galsim.Bandpass) – The bandpass to use for the objects.
Returns:: A dictionary containing the object list.
Return type:: dict

_init_catalog(chromatic=False, gal_sed_path=None)[source]

_get_gsobject(index)[source]

get_gsobject_delta()[source]

Get a galsim DeltaFunction gsobject with the appropriate SED.

Returns:: The galsim DeltaFunction gsobject.
Return type:: galsim.DeltaFunction

get_flux(index, zp)[source]

Get the flux of the object at a given index in the catalog.

Parameters:

index (int) – The index of the object.
zp (float) – The zero point to use for the flux calculation.

Returns:

The flux of the object.

Return type:

float

_set_gsobject(gal_sed=1)[source]

_set_gsobject_delta(gal_sed=None)[source]

_get_zeropoint(bp)[source]

get_flux_scaling(band, target_zp=COMMON_ZERO_POINT)[source]

Get the flux scaling factor to convert from the current zeropoint to the target zeropoint.

Parameters:

band (str) – The band to use for the flux scaling.
target_zp (float) – The target zero point.

Returns:

The flux scaling factor.

Return type:

float

_get_sed(gal_sed_path)[source]

class GalaxyCatalog(img_size, seed, simu_type='sca', flux_range=None, layout_kind='grid', buffer=0, spacing=5.0, n_gal=None, exp_time=roman.exptime, chromatic=False, gal_sed_path=None, ref_band='Y106')[source]

Bases: SimpleGalaxyCatalog

Galaxy simulation from Sheldon et al. 2019 ref: https://arxiv.org/abs/1911.02505 Section 3.2

Parameters:

img_size (int) – Image size in pixels.
seed (int) – Random seed for the catalog.
simu_type (str, optional) – The type of simulation to run. Options are ‘sca’ for SCA simulation and ‘imcom’ for IMCOM simulation. Default: ‘sca’.
flux_range (list or None) – Range of flux values for the galaxies. Default: None, which means no limit.
layout_kind (str) – Layout kind, one of [‘grid’, ‘random’]. Default: ‘grid’.
buffer (int) – Buffer size in pixels. Default: 0.
spacing (float) – Spacing between galaxies in pixels. Default: 5.0.
n_gal (int or None) – Number of galaxies to draw. If None, will use as many as possible. Default: None.
exp_time (float) – Exposure time in seconds.
chromatic (bool) – Whether to use chromatic SEDs. Default: False.
gal_sed_path (str or None) – Path to the galaxy SED file. If None, will use a default SED. Default: None.
ref_band (str) – Reference band for flux range selection. Default: “Y106”.

_flux_range = None[source]

getObjList(bandpass)[source]

Get the object list to draw for a given bandpass.

Parameters:: bandpass (galsim.Bandpass) – The bandpass to use for the objects.
Returns:: A dictionary containing the object list.
Return type:: dict

_get_gsobject(index)[source]

set_bandpass_ref(ref_band)[source]

Set the reference bandpass for the flux range selection.

Parameters:: ref_band (str) – The reference bandpass name.

_set_gsobject(gal_sed=1)[source]

class DiffSkyCatalog(img_size, seed, skycatalog_config_path, simu_type='sca', object_types=None, do_knots=True, flux_range=None, cell_world_center=WORLD_ORIGIN, buffer=0, exp_time=roman.exptime, chromatic=False, gal_sed_path=None, ref_band='Y106')[source]

Bases: GalaxyCatalog

Build catalog based on the DiffSky simulation.

Parameters:

img_size (int) – Image size in pixels.
seed (int) – Random seed for the catalog.
skycatalog_config_path (str) – Path to the SkyCatalogs configuration file.
simu_type (str, optional) – The type of simulation to run. Options are ‘sca’ for SCA simulation and ‘imcom’ for IMCOM simulation. Default: ‘sca’.
object_types (list) – List of object types to include in the catalog. Default: [‘diffsky_galaxy’].
do_knots (bool) – Whether to include knots in the galaxy model. Default: True.
flux_range (list or None) – Range of flux values for the galaxies. Default: None, which means no limit.
cell_world_center (galsim.celestial.CelestialCoord) – Center of the cell in world coordinates (RA, Dec). Default: WORLD_ORIGIN.
buffer (int) – Buffer size around the image in pixels. Default: 0.
exp_time (float) – Exposure time in seconds. Default: roman.exptime.
chromatic (bool) – Whether to include chromatic effects in the galaxy model. Default: False.
gal_sed_path (str or None) – If provided, will use this SED for all galaxies. Path to the galaxy SED file. Default: None.
ref_band (str) – Reference band for flux range selection. Default: “Y106”.

img_size[source]

_simu_type = 'sca'[source]

_do_knots = True[source]

_coadd_center[source]

_chromatic = False[source]

_exp_time = 139.8[source]

_gal_sed_path = None[source]

rng[source]

galsim_rng[source]

_init_catalog(coadd_center, img_size, skycatalog_config_path, simu_type='sca', buffer=0, chromatic=True, gal_sed_path=None)[source]

_init_pos()[source]

_get_gsobject(index, bandpass=None)[source]

getObjList(bandpass)[source]

Get the object list to draw for a given bandpass.

Parameters:: bandpass (galsim.Bandpass) – The bandpass to use for the objects.
Returns:: A dictionary containing the object list.
Return type:: dict

_set_gsobject(gal_sed=None, gsparams=None, rng=None)[source]

_get_diffsky_gsobject(row, sed_row, gal_sed=None, gsparams=None, rng=None)[source]

abstractmethod _get_star_gsobject(row, sed_row, gsparams=None)[source]

_get_pos(i, ra, dec)[source]

_get_flux_components(sed_dict, bandpass, cache=True)[source]

_set_flux(flux_range)[source]

class SimpleDiffSkyCatalog(img_size, seed, skycatalog_config_path, simu_type='sca', object_types=None, do_knots=True, flux_range=None, cell_world_center=WORLD_ORIGIN, layout_kind='grid', buffer=0, spacing=5.0, n_gal=None, exp_time=roman.exptime, chromatic=False, gal_sed_path=None, ref_band='Y106')[source]

Bases: DiffSkyCatalog

A simple DiffSky catalog with galaxies arranged in a grid or random layout.

Parameters:

img_size (int) – Image size in pixels.
seed (int) – Random seed for the catalog.
skycatalog_config_path (str) – Path to the SkyCatalogs configuration file.
simu_type (str, optional) – The type of simulation to run. Options are ‘sca’ for SCA simulation and ‘imcom’ for IMCOM simulation. Default: ‘sca’.
object_types (list) – List of object types to include in the catalog. Default: [‘diffsky_galaxy’].
do_knots (bool) – Whether to include knots in the galaxy model. Default: True.
flux_range (list or None) – Range of flux values for the galaxies. Default: None, which means no limit.
cell_world_center (galsim.celestial.CelestialCoord) – Center of the cell in world coordinates (RA, Dec). Default: WORLD_ORIGIN.
layout_kind (str) – Layout kind, one of [‘grid’, ‘random’].
buffer (int) – Buffer size around the image in pixels. Default: 0.
spacing (float) – Spacing between galaxies in arcsec. Default: 5.0.
n_gal (int or None) – Number of galaxies to draw. If None, will use as many as possible. Default: None.
exp_time (float) – Exposure time in seconds. Default: roman.exptime.
chromatic (bool) – Whether to include chromatic effects in the galaxy model. Default: False.
gal_sed_path (str or None) – If provided, will use this SED for all galaxies. Path to the galaxy SED file. Default: None.
ref_band (str) – Reference band for flux range selection. Default: “Y106”.

layout_kind = 'grid'[source]

buffer = 0[source]

spacing = 5.0[source]

n_gal = None[source]

getObjList(bandpass)[source]

Get the object list to draw for a given bandpass.

Parameters:: bandpass (galsim.Bandpass) – The bandpass to use for the objects.
Returns:: A dictionary containing the object list.
Return type:: dict

_init_pos()[source]

_get_pos(i, ra, dec)[source]

get_simple_pos(simu_type, img_size, rng, layout_kind='grid', buffer=0, spacing=5.0, n_gal=None)[source]

Those functions are taken from the descwl-shear-sims package, refs: https://github.com/LSSTDESC/descwl-shear-sims/blob/master/descwl_shear_sims/layout/shifts.py

Parameters:

simu_type (str, optional) – The type of simulation to run. Options are ‘sca’ for SCA simulation and ‘imcom’ for IMCOM simulation. Default: ‘sca’.
img_size (int) – Image size in pixels.
rng (np.random.RandomState) – Random number generator.
layout_kind (str) – Layout kind, one of [‘grid’, ‘random’]. Default: ‘grid’.
buffer (int) – Buffer size in pixels. Default: 0.
spacing (float) – Spacing between galaxies in pixels. Default: 5.0.
n_gal (int or None) – Number of galaxies to draw. If None, will use as many as possible. Default: None.

Returns:

xx (np.ndarray) – x-coordinates of the galaxies in arcsec.
yy (np.ndarray) – y-coordinates of the galaxies in arcsec.

get_g_BA(rng, sigma=0.3, size=1)[source]

Generate a set of galaxy intrinsic ellipticities using the Bernstein & Armstrong (2014) equation 24.

\[p(e) = (1 - e^2)^2 e^{-e^2 / (2 \sigma^2)} 2 \pi e\]

Parameters:

rng (np.random.RandomState) – Random number generator.
sigma (float) – Sigma parameter of the function. Default: 0.3.
size (int) – Number of samples to generate. Default: 1.

Returns:

Array of galaxy intrinsic ellipticities.

Return type:

np.ndarray