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import os
import numpy as np
import astropy.constants as cons
from astropy.table import Table
from scipy import interpolate
from ObservationSim.MockObject import CatalogBase, Star, Galaxy, Quasar
class Catalog_example(CatalogBase):
"""An user customizable class for reading in catalog(s) of objects and SEDs.
NOTE: must inherit the "CatalogBase" abstract class
...
Attributes
----------
cat_dir : str
a directory that contains the catalog file(s)
star_path : str
path to the star catalog file
star_SED_path : str
path to the star SED data
objs : list
a list of ObservationSim.MockObject (Star, Galaxy, or Quasar)
NOTE: must have "obj" list when implement your own Catalog
Methods
----------
load_sed(obj, **kwargs):
load the corresponding SED data for one object
load_norm_filt(obj):
load the filter throughput for the input catalog's photometric system.
"""
def __init__(self, config, **kwargs):
"""Constructor method.
Parameters
----------
config : dict
configuration dictionary which is parsed from the input YAML file
**kwargs : dict
other needed input parameters (in key-value pairs), please modify corresponding
initialization call in "ObservationSim.py" as you need.
Returns
----------
None
"""
super().__init__()
self.cat_dir = os.path.join(config["data_dir"], config["input_path"]["cat_dir"])
if "star_cat" in config["input_path"] and config["input_path"]["star_cat"]:
star_file = config["input_path"]["star_cat"]
star_SED_file = config["SED_templates_path"]["star_SED"]
self.star_path = os.path.join(self.cat_dir, star_file)
self.star_SED_path = os.path.join(config["data_dir"], star_SED_file)
# NOTE: must call _load() method here to read in all objects
self.objs = []
self._load()
def _load(self, **kwargs):
"""Read in all objects in from the catalog file(s).
This is a must implemented method which is used to read in all objects, and
then convert them to ObservationSim.MockObject (Star, Galaxy, or Quasar).
Currently,
the model of ObservationSim.MockObject.Star class requires:
param["star"] : int
specify the object type: 0: galaxy, 1: star, 2: quasar
param["id"] : int
ID number of the object
param["ra"] : float
Right ascension (in degrees)
param["dec"] : float
Declination (in degrees)
param["mag_use_normal"]: float
the absolute magnitude in a particular filter
NOTE: if that filter is not the corresponding CSST filter, the
load_norm_filt(obj) function must be implemented to load the filter
throughput of that particular photometric system
the model of ObservationSim.MockObject.Galaxy class requires:
param["star"] : int
specify the object type: 0: galaxy, 1: star, 2: quasar
param["id"] : int
ID number of the object
param["ra"] : float
Right ascension (in degrees)
param["dec"] : float
Declination (in degrees)
param["mag_use_normal"]: float
the absolute magnitude in a particular filter
NOTE: if that filter is not the corresponding CSST filter, the
load_norm_filt(obj) function must be implemented to load the filter
throughput of that particular photometric system
param["theta"] : float
the position angle (in degrees)
param["bfrac"] : float
the bulge fraction
param["hlr_bulge] : float
the half-light-radius of the bulge
param["hlr_disk] : float
the half-light-radius of the disk
param["ell_bulge] : float
the ellipticity of the bulge
param["ell_disk] : float
the ellipticity of the disk
param["ell_tot] : float
the total ellipticity
the model of ObservationSim.MockObject.Galaxy class requires:
Currently a Quasar is modeled as a point source, just like a Star.
NOTE: To construct an object, according to its type, just call:
Star(param), Galaxy(param), or Quasar(param)
NOTE: All constructed objects should be appened to "self.objs".
Parameters
----------
**kwargs : dict
other needed input parameters (in key-value pairs), please modify corresponding
initialization call in "ObservationSim.py" as you need.
Returns
----------
None
"""
stars = Table.read(self.star_path)
nstars = stars['sourceID'].size
for istars in range(nstars):
param = self.initialize_param()
param['id'] = istars + 1
param['ra'] = stars['RA'][istars]
param['dec'] = stars['Dec'][istars]
param['sed_type'] = stars['sourceID'][istars]
param['model_tag'] = stars['model_tag'][istars]
param['z'] = 0.0
param['star'] = 1 # Star
param['mag_use_normal'] = stars['app_sdss_g'][istars]
obj = Star(param)
self.objs.append(obj)
def load_sed(self, obj, **kwargs):
"""Load the corresponding SED data for a particular obj.
Parameters
----------
obj : ObservationSim.MockObject
the object to get SED data for
**kwargs : dict
other needed input parameters (in key-value pairs), please modify corresponding
initialization call in "ObservationSim.py" as you need.
Returns
----------
sed : Astropy.Table
the SED Table with two columns (namely, "WAVELENGTH", "FLUX"):
sed["WAVELENGTH"] : wavelength in Angstroms
sed["FLUX"] : fluxes in photons/s/m^2/A
NOTE: the range of wavelengthes must at least cover [2450 - 11000] Angstorms
"""
if obj.type == 'star':
wave = Table.read(self.star_SED_path, path=f"/SED/wave_{obj.model_tag}")
flux = Table.read(self.star_SED_path, path=f"/SED/{obj.sed_type}")
wave, flux = wave['col0'].data, flux['col0'].data
else:
raise ValueError("Object type not known")
speci = interpolate.interp1d(wave, flux)
lamb = np.arange(2400, 11001 + 0.5, 0.5)
y = speci(lamb)
# erg/s/cm^2/A --> photons/s/m^2/A
all_sed = y * lamb / (cons.h.value * cons.c.value) * 1e-13
sed = Table(np.array([lamb, all_sed]).T, names=('WAVELENGTH', 'FLUX'))
return sed
def load_norm_filt(self, obj):
"""Load the corresponding thourghput for the input magnitude "param["mag_use_normal"]".
NOTE: if the input magnitude is already in CSST magnitude, simply return None
Parameters
----------
obj : ObservationSim.MockObject
the object to get thourghput data for
Returns
----------
norm_filt : Astropy.Table
the throughput Table with two columns (namely, "WAVELENGTH", "SENSITIVITY"):
norm_filt["WAVELENGTH"] : wavelengthes in Angstroms
norm_filt["SENSITIVITY"] : efficiencies
"""
return None