lightcurvelynx.models.agn

A model for an AGN.

Adapted from https://github.com/RickKessler/SNANA/blob/master/src/gensed_AGN.py with the authors’ permission.

Classes

AGN

A model for an AGN.

Functions

sample_damped_random_walk(times, tau_v, sf_inf, t0[, rng])

Sample a damped random walk.

Module Contents

sample_damped_random_walk(times, tau_v, sf_inf, t0, rng=None)[source]

Sample a damped random walk.

Parameters:

  • times (np.ndarray) – A length T array with the times at which to sample the damped random walk (in MJD).

  • tau_v (np.ndarray) – A length W array with timescale of the damped random walk (in s).

  • sf_inf (np.ndarray) – A length W array with structure function at infinity time in magnitude.

  • t0 (float) – The initial time moment (in MJD).

  • rng (np.random.Generator, optional) – The random number generator to use. Default: None

Returns:

samples – The sampled value of the damped random walk.

Return type:

float

class AGN(t0, blackhole_mass, edd_ratio, *, inclination_rad=None, node_label=None, seed=None, **kwargs)[source]

Bases: lightcurvelynx.models.physical_model.SEDModel

A model for an AGN.

Parameterized values include:

  • accretion_rate - The accretion rate (ME_dot) at Eddington luminosity in g/s.

  • blackhole_accretion_rate - The accretion rate of the black hole in g/s.

  • blackhole_mass - The black hole mass in solar mass.

  • edd_ratio - The Eddington ratio.

  • dec - The object’s declination in degrees. [from BasePhysicalModel]

  • distance - The object’s luminosity distance in pc. [from BasePhysicalModel]

  • inclination - The inclination of the accretion disk in radians (sampled uniformly between 0 and pi/2).

  • L_bol - The bolometric luminosity in erg/s.

  • mag_i - The i band absolute magnitude.

  • ra - The object’s right ascension in degrees. [from BasePhysicalModel]

  • redshift - The object’s redshift. [from BasePhysicalModel]

  • t0 - The t0 of the zero phase, date. [from BasePhysicalModel]

Parameters:

  • t0 (float) – initial time moment in days.

  • blackhole_mass (float) – The black hole mass in solar masses.

  • edd_ratio (float) – Eddington ratio

  • inclination_rad (float or None) – The inclination of the accretion disk in radians. If None then the value is sampled uniformly between 0 and pi/2. Default = None

  • node_label (str, optional) – The label for the node in the model graph. Default: None

  • seed (int, optional) – The seed to use for the random number generator. Default: None

  • **kwargs (dict) – Additional keyword arguments.

static compute_critical_accretion_rate(blackhole_mass)[source]

Compute the critical accretion rate at Eddington luminosity.

Parameters:

blackhole_mass (float) – The black hole mass in g.

Returns:

accretion_rate – The accretion rate (ME_dot) at Eddington luminosity in g/s.

Return type:

float

static compute_blackhole_accretion_rate(accretion_rate, edd_ratio)[source]

Compute the accretion rate of the blackhole.

Parameters:

  • accretion_rate (float) – The accretion rate (ME_dot) at Eddington luminosity in g/s.

  • edd_ratio (float) – The Eddington ratio.

Returns:

bh_accretion_rate – The accretion rate of the black hole in g/s.

Return type:

float

static compute_bolometric_luminosity(edd_ratio, blackhole_mass)[source]

Compute the bolometric luminosity of an AGN.

Parameters:

  • edd_ratio (float) – The Eddington ratio.

  • blackhole_mass (float) – The black hole mass in g.

Returns:

bolometric_luminosity – The bolometric luminosity in erg/s.

Return type:

float

static compute_sed_standard_disk(*, Mdot, nu, rin_to_rg, i, d, M)[source]

Compute the flux based on a standard disk model.

References

Lipunova, G., Malanchev, K., Shakura, N. (2018) https://doi.org/10.1007/978-3-319-93009-1_1

All inputs are in CGS.

Parameters:

  • Mdot (float or np.ndarray) – The accretion rate at the previous time step.

  • nu (float or np.ndarray) – The frequency.

  • rin_to_rg (float or np.ndarray) – The inner radius of the accretion disk to gravitation radius ratio.

  • i (float or np.ndarray) – The inclination in radians.

  • d (float or np.ndarray) – The distance.

  • M (float or np.ndarray) – The mass of the gravitating center.

Returns:

flux – The flux at the given time step.

Return type:

float

static compute_mag_i(bolometric_luminosity)[source]

Compute the i band magnitude from the bolometric luminosity.

References

Shen et al., 2013 - https://adsabs.harvard.edu/full/2013BASI…41…61S

Parameters:

bolometric_luminosity (float) – The bolometric luminosity in erg/s.

Returns:

mag_i – The i band magnitude.

Return type:

float

static compute_r_0(r_in)[source]

Compute the initial radius of the ring (r_0) in a standard disk model given the inner radius.

References

Lipunova, G., Malanchev, K., Shakura, N. (2018) https://doi.org/10.1007/978-3-319-93009-1_1

Parameters:

r_in (float) – The inner radius of the accretion disk.

Returns:

r_0 – The initial radius of the ring.

Return type:

float

static compute_structure_function_at_inf(sf_inf_4000aa, wavelength)[source]

Adjust the structure function at infinity time for given wavelengths

References

Suberlak et al. 2021 - DOI 10.3847/1538-4357/abc698

Parameters:

  • sf_inf_4000aa (float) – The structure function at infinity time for 4000 angstroms

  • wavelength (np.ndarray) – A length W array with wavelength in cm.

Returns:

result – A length W array with structure function at infinity time in magnitude.

Return type:

np.ndarray

static compute_sf_inf_4000aa(mag_i=-23, blackhole_mass=1000000000.0 * M_SUN_G)[source]

Compute the structure function at infinity time in magnitude, for 4000 A

References

Suberlak et al. 2021 - DOI 10.3847/1538-4357/abc698

Parameters:

  • mag_i (float, optional) – The i band magnitude. Default: -23

  • blackhole_mass (float, optional) – The black hole mass in g. Default: 1e9 * M_SUN_G

Returns:

result – A length W array with structure function at infinity time in magnitude for 4000 angstroms.

Return type:

np.ndarray

static compute_tau_4000aa(mag_i=-23, blackhole_mass=1000000000.0 * M_SUN_G)[source]

Compute the timescale (tau_v) at 4000 angstroms.

References

Suberlak et al. 2021 - DOI 10.3847/1538-4357/abc698

Parameters:

  • mag_i (float, optional) – The i band magnitude. Default: -23

  • blackhole_mass (float, optional) – The black hole mass in g. Default: 1e9 * M_SUN_G

Returns:

tau_v – A length W array with the timescale for 4000 angstroms.

Return type:

np.ndarray

static compute_tau(tau_4000aa, wavelength)[source]

Adjust the timescale (tau_v) for given wavelengths

References

Suberlak et al. 2021 - DOI 10.3847/1538-4357/abc698

Parameters:

  • tau_4000aa (float) – The timescale for 4000 angstroms.

  • wavelength (np.ndarray) – A length W array with wavelength in cm.

static compute_temp_at_r_0(M, Mdot, r_in)[source]

Compute the effective temperature at r0. This is the same as the maximum effective temperature at the disc surface (Tmax).

References

Lipunova, G., Malanchev, K., Shakura, N. (2018) https://doi.org/10.1007/978-3-319-93009-1_1

Parameters:

  • M (float) – The mass of the gravitating centre.

  • Mdot (float) – The accretion rate at the previous time step.

  • r_in (float) – The inner radius of the accretion disk.

Returns:

T_0 – The effective temperature at r0.

Return type:

float

compute_sed(times, wavelengths, graph_state, **kwargs)[source]

Draw effect-free observations for this object.

Parameters:

  • times (numpy.ndarray) – A length T array of rest frame timestamps.

  • wavelengths (numpy.ndarray, optional) – A length N array of wavelengths (in angstroms).

  • graph_state (GraphState) – An object mapping graph parameters to their values.

  • **kwargs (dict, optional) – Any additional keyword arguments.

Returns:

flux_density – A length T x N matrix of SED values (in nJy).

Return type:

numpy.ndarray