SSP

class artpop.stars.SSP(isochrone, num_stars=None, total_mass=None, distance=<Quantity 10. pc>, a_lam=0.0, mag_limit=None, mag_limit_band=None, imf='kroupa', imf_kw=None, mass_tolerance=0.01, add_remnants=True, random_state=None)

Bases: StellarPopulation

Generic Simple Stellar Population (SSP).

Note

You must give total_mass or num_stars.

Parameters

isochroneIsochrone

Isochrone object.

num_starsint or None

Number of stars in source. If None, then must give total_mass.

total_massfloat or Quantity or None

Stellar mass of the source. If None, then must give num_stars. This mass accounts for stellar remnants when add_remnants = True, which means the actual sampled mass will be less than the given value. If float is given, the units are assumed to be solar masses.

distancefloat or Quantity, optional

Distance to source. If float is given, the units are assumed to be Mpc. Default distance is 10 pc.

a_lamfloat or dict, optional

Magnitude(s) of extinction. If float, the same extinction will be applied to all bands. If dict, the keys must be the same as the observational filters.

mag_limitfloat, optional

Only sample individual stars that are brighter than this magnitude. All fainter stars will be combined into an integrated component. Otherwise, all stars in the population will be sampled. You must also give the mag_limit_band if you use this parameter.

mag_limit_bandstr, optional

Bandpass of the limiting magnitude. You must give this parameter if you use the mag_limit parameter.

imfstr or dict

Which IMF to use, if str then must be one of pre-defined: ‘kroupa’, ‘scalo’ or ‘salpeter’. Can also specify custom (broken) power law as dict, which must contain either ‘a’ as a Float (describing the slope of a single power law) or ‘a’ (a list with 3 elements describing the slopes of a broken power law) and ‘b’ (a list with 2 elements describing the locations of the breaks).

imf_kwdict, optional

Optional keyword arguments for sampling the stellar mass function.

mass_tolerancefloat, optional

Tolerance in the fractional difference between the input mass and the final mass of the population. The parameter is only used when total_mass is given.

add_remnantsbool, optional

If True (default), apply scaling factor to total mass to account for stellar remnants in the form of white dwarfs, neutron stars, and black holes.

random_stateNone, int, list of ints, or RandomState

If None, return the RandomState singleton used by numpy.random. If int, return a new RandomState instance seeded with the int. If RandomState, return it. Otherwise raise ValueError.

Attributes Summary

a_lam	Return extinction dictionary.
abs_mag_table	Absolute magnitudes in a Table object.
dist_mod	The distance modulus.
mag_table	Apparent magnitudes in a Table object.
num_pops	The number of simple stellar populations that composes this pop.
num_stars	Number stars in population.
total_initial_live_mass	Total initial stellar mass in solar units.

Methods Summary

build_pop([num_stars, total_mass, ...])	Build the stellar population.
copy()
from_pickle(file_name)	Load pickle of stellar population object.
integrated_color(blue, red[, select])	Calculate the population's integrated color.
mag_integrated_component(bandpass)	Get the magnitude of the integrated component of the population if it exists.
mean_mag(bandpass[, select])	Calculate the population's mean magnitude.
sample_fraction(mag_limit, mag_limit_band)	Calculate the fraction of stars by mass and number that will be sampled with the give limiting magnitude.
sbf_mag(bandpass)	Calculate the apparent SBF magnitude of the stellar population.
set_distance(distance)	Change the distance to the stellar population.
star_mags(bandpass[, select])	Get the stellar apparent magnitudes.
to_pickle(file_name)	Pickle stellar population object.
total_mag(bandpass[, select])	Calculate the population's total magnitude.

Attributes Documentation

a_lam

Return extinction dictionary.

abs_mag_table

Absolute magnitudes in a Table object.

dist_mod

The distance modulus.

mag_table

Apparent magnitudes in a Table object.

num_pops

The number of simple stellar populations that composes this pop.

num_stars

Number stars in population.

total_initial_live_mass

Total initial stellar mass in solar units.

Methods Documentation

build_pop(num_stars=None, total_mass=None, mass_tolerance=0.01, add_remnants=True)

Build the stellar population. You must give total_mass or num_stars as an argument.

Parameters

num_starsint or None

Number of stars in source. If None, then must give total_mass.

total_massfloat or Quantity or None

Stellar mass of the source. If None, then must give num_stars. This mass accounts for stellar remnants when add_remnants = True which means the actual sampled mass will be less than the given value. If float is given, the units are assumed to be solar masses.

mass_tolerancefloat, optional

Tolerance in the fractional difference between the input mass and the final mass of the population. The parameter is only used when total_mass is given.

add_remnantsbool, optional

If True (default), apply scaling factor to total mass to account for stellar remnants in the form of white dwarfs, neutron stars, and black holes.

copy()

static from_pickle(file_name)

Load pickle of stellar population object.

integrated_color(blue, red, select=None)

Calculate the population’s integrated color.

Parameters

bluestr

The blue bandpass. Must be a filter in the given photometric system(s).

redstr

The red bandpass. Must be a filter in the given photometric system(s).

selectndarray, optional

Boolean mask for selecting stars (True for stars to include).

Returns

colorfloat

The integrated color.

mag_integrated_component(bandpass)

Get the magnitude of the integrated component of the population if it exists.

Parameters

bandpassstr

Filter of observation. Must be a filter in the given photometric system(s).

Returns

magfloat

The integrated magnitude if it exists. Otherwise None is returned.

mean_mag(bandpass, select=None)

Calculate the population’s mean magnitude.

Parameters

bandpassstr

Filter of observation. Must be a filter in the given photometric system(s).

selectndarray, optional

Boolean mask for selecting stars (True for stars to include).

Returns

magfloat

The mean magnitude in the given bandpass.

sample_fraction(mag_limit, mag_limit_band)

Calculate the fraction of stars by mass and number that will be sampled with the give limiting magnitude.

Parameters

mag_limitfloat, optional

Only sample individual stars that are brighter than this magnitude.

mag_limit_bandstr, optional

Bandpass of the limiting magnitude.

Returns

m_limfloat

Initial stellar mass associated with mag_limit.

f_num_sampledfloat

Fraction of stars that will be sampled by number.

f_mass_sampledfloat

Fraction of stars that will be sampled by mass.

sbf_mag(bandpass)

Calculate the apparent SBF magnitude of the stellar population.

Parameters

bandpassstr

Filter of observation. Must be a filter in the given photometric system(s).

Returns

mbarfloat

The apparent SBF magnitude of the stellar population in the given bandpass.

set_distance(distance)

Change the distance to the stellar population.

Parameters

distancefloat or Quantity

Distance to source. If float is given, the units are assumed to be Mpc.

star_mags(bandpass, select=None)

Get the stellar apparent magnitudes.

Parameters

bandpassstr

Filter of observation. Must be a filter in the given photometric system(s).

selectndarray, optional

Boolean mask for selecting stars (True for stars to include).

Returns

magsndarray

The stellar apparent magnitudes in the given bandpass.

to_pickle(file_name)

Pickle stellar population object.

total_mag(bandpass, select=None)

Calculate the population’s total magnitude.

Parameters

bandpassstr

Filter of observation. Must be a filter in the given photometric system(s).

selectndarray, optional

Boolean mask for selecting stars (True for stars to include).

Returns

magfloat

The total magnitude in the given bandpass.