pint.models.binary_dd.BinaryDDGR

class pint.models.binary_dd.BinaryDDGR[source]

Bases: BinaryDD

Damour and Deruelle model assuming GR to be correct

It supports all the parameters defined in pint.models.pulsar_binary.PulsarBinary and pint.models.binary_dd.BinaryDD plus:

MTOT

Total mass

XPBDOT

Excess PBDOT beyond what GR predicts

XOMDOT

Excess OMDOT beyond what GR predicts

It also reads but converts:

SINI PBDOT OMDOT GAMMA DR DTH

into read-only parameters

The actual calculations for this are done in pint.models.stand_alone_psr_binaries.DDGR_model.DDGRmodel.

Parameters supported:

Name / Aliases

Description

Kind

PB

Orbital period

d

A1

Projected semi-major axis of pulsar orbit, ap*sin(i)

ls

A1DOT / XDOT

Derivative of projected semi-major axis, d[ap*sin(i)]/dt

ls / s

ECC / E

Eccentricity

number

EDOT

Eccentricity derivative respect to time

1 / s

T0

Epoch of periastron passage

d

OM

Longitude of periastron

deg

M2

Companion mass

solMass

FB{number}

0th time derivative of frequency of orbit

1 / s

A0

DD model aberration parameter A0

s

B0

DD model aberration parameter B0

s

MTOT

Total system mass in units of Solar mass

solMass

XOMDOT

Excess longitude of periastron advance compared to GR

deg / yr

XPBDOT

Excess Orbital period derivative respect to time compared to GR

number

MP

Pulsar mass

solMass

OMDOT

Rate of advance of periastron

deg / yr

SINI

Sine of inclination angle

number

PBDOT

Orbital period derivative respect to time

number

GAMMA

Time dilation & gravitational redshift

s

DR

Relativistic deformation of the orbit

number

DTH / DTHETA

Relativistic deformation of the orbit

number

References

  • Taylor and Weisberg (1989), ApJ, 345, 434 [tw89]

Methods

FBX_description(n)

FBX_unit(n)

add_param(param[, deriv_func, setup])

Add a parameter to the Component.

apply_units()

Apply units to parameter value.

binarymodel_delay(toas[, acc_delay])

Return the binary model independent delay call.

change_binary_epoch(new_epoch)

Change the epoch for this binary model.

check_required_params(required_params)

d_binary_delay_d_xxxx(toas, param, acc_delay)

Return the binary model delay derivatives.

get_params_of_type(param_type)

Get all the parameters in timing model for one specific type.

get_prefix_mapping_component(prefix)

Get the index mapping for the prefix parameters.

is_in_parfile(para_dict)

Check if this subclass included in parfile.

match_param_aliases(alias)

Return the parameter corresponding to this alias.

param_help()

Print help lines for all available parameters in model.

pb([t])

Return binary period and uncertainty (optionally evaluated at different times) regardless of binary model

print_par([format])

param format:

Parfile output format. PINT outputs the 'tempo', 'tempo2' and 'pint'

register_deriv_funcs(func, param)

Register the derivative function in to the deriv_func dictionaries.

remove_param(param)

Remove a parameter from the Component.

set_special_params(spcl_params)

setup()

Parameter setup.

update_binary_object(toas[, acc_delay])

Update stand alone binary's parameters and toas from PINT-facing object.

validate()

Validate parameters.

validate_toas(toas)

Check that this model component has TOAs where needed.

Attributes

aliases_map

Return all the aliases and map to the PINT parameter name.

category

component_types

free_params_component

Return the free parameters in the component.

param_prefixs

register

setup()[source]

Parameter setup.

validate()[source]

Validate parameters.

update_binary_object(toas, acc_delay=None)[source]

Update stand alone binary’s parameters and toas from PINT-facing object.

This function passes the PINT-facing object’s parameter values and TOAs to the stand-alone binary object. If the TOAs are not provided, it only updates the parameters not the TOAs.

Parameters:

  • toas (pint.toa.TOAs) – The TOAs that need to pass to the stand alone model.Default value is None. If toas is None, this function only updates the parameter value. If ‘acc_delay’ is not provided, the stand alone binary receives the standard barycentered TOAs.

  • acc_delay (numpy.ndarray) – If provided, TOAs will be corrected by provided acc_delay instead of the standard barycentering. The stand alone binary receives the input TOAs - acc_delay.

Notes

The values for obs_pos (the observatory position wrt the Solar System Barycenter) and psr_pos (the pulsar position wrt the Solar System Barycenter) are both computed in the same reference frame, ICRS or ECL depending on the model.

Warns:

  • If passing ‘None’ to ‘toa’ argument, the stand alone binary model will use

  • the TOAs were passed to it from last iteration (i.e. last barycentered

  • TOAs) or no TOAs for stand alone binary model at all. This behavior will

  • cause incorrect answers. Allowing the passing None to ‘toa’ argument is

  • for some lower level functions and tests. We do not recommend PINT

  • user to use it.

add_param(param, deriv_func=None, setup=False)

Add a parameter to the Component.

The parameter is stored in an attribute on the Component object. Its name is also recorded in a list, self.params.

Parameters:

  • param (pint.models.Parameter) – The parameter to be added.

  • deriv_func (function) – Derivative function for parameter.

property aliases_map

Return all the aliases and map to the PINT parameter name.

This property returns a dictionary from the current in timing model parameters’ aliase to the pint defined parameter names. For the aliases of a prefixed parameter, the aliase with an existing prefix index maps to the PINT defined parameter name with the same index. Behind the scenes, the indexed parameter adds the indexed aliase to its aliase list.

apply_units()

Apply units to parameter value.

binarymodel_delay(toas, acc_delay=None)

Return the binary model independent delay call.

change_binary_epoch(new_epoch)

Change the epoch for this binary model.

T0 will be changed to the periapsis time closest to the supplied epoch, and the argument of periapsis (OM), eccentricity (ECC), and projected semi-major axis (A1 or X) will be updated according to the specified OMDOT, EDOT, and A1DOT or XDOT, if present.

Note that derivatives of binary orbital frequency higher than the first (FB2, FB3, etc.) are ignored in computing the new T0, even if present in the model. If high-precision results are necessary, especially for models containing higher derivatives of orbital frequency, consider re-fitting the model to a set of TOAs. The use of pint.simulation.make_fake_toas() and the pint.fitter.Fitter option track_mode="use_pulse_number" can make this extremely simple.

Parameters:

new_epoch (float MJD (in TDB) or astropy.Time object) – The new epoch value.

d_binary_delay_d_xxxx(toas, param, acc_delay)

Return the binary model delay derivatives.

property free_params_component

Return the free parameters in the component.

This function collects the non-frozen parameters.

Return type:

A list of free parameters.

get_params_of_type(param_type)

Get all the parameters in timing model for one specific type.

get_prefix_mapping_component(prefix)

Get the index mapping for the prefix parameters.

Parameters:

prefix (str) – Name of prefix.

Returns:

A dictionary with prefix parameter real index as key and parameter name as value.

Return type:

dict

is_in_parfile(para_dict)

Check if this subclass included in parfile.

Parameters:

para_dict (dictionary) – A dictionary contain all the parameters with values in string from one parfile

Returns:

Whether the subclass is included in the parfile.

Return type:

bool

match_param_aliases(alias)

Return the parameter corresponding to this alias.

Parameters:

alias (str) – Alias name.

Note

This function only searches the parameter aliases within the current component. If one wants to search the aliases in the scope of TimingModel, please use TimingModel.match_param_aliase().

param_help()

Print help lines for all available parameters in model.

pb(t=None)

Return binary period and uncertainty (optionally evaluated at different times) regardless of binary model

Parameters:

t (astropy.time.Time, astropy.units.Quantity, numpy.ndarray, float, int, str, optional) – Time(s) to evaluate period

Returns:

  • astropy.units.Quantity – Binary period

  • astropy.units.Quantity – Binary period uncertainty

print_par(format='pint')
Parameters:

format (str, optional) – Parfile output format. PINT outputs the ‘tempo’, ‘tempo2’ and ‘pint’ format. The defaul format is pint. Actual formatting done elsewhere.

Returns:

str

Return type:

formatted line for par file

register_deriv_funcs(func, param)

Register the derivative function in to the deriv_func dictionaries.

Parameters:

  • func (callable) – Calculates the derivative

  • param (str) – Name of parameter the derivative is with respect to

remove_param(param)

Remove a parameter from the Component.

Parameters:

param (str or pint.models.Parameter) – The parameter to remove.

validate_toas(toas)

Check that this model component has TOAs where needed.