pint.models.astrometry.AstrometryEcliptic

class pint.models.astrometry.AstrometryEcliptic[source]

Bases: Astrometry

Astrometry in ecliptic coordinates.

Parameters supported:

Name / Aliases	Description	Kind
POSEPOCH	Reference epoch for position	d
PX	Parallax	mas
ELONG / LAMBDA	Ecliptic longitude	deg
ELAT / BETA	Ecliptic latitude	deg
PMELONG / PMLAMBDA	Proper motion in ecliptic longitude	mas / yr
PMELAT / PMBETA	Proper motion in ecliptic latitude	mas / yr
ECL	Obliquity of the ecliptic (reference)	string

Methods

`add_param`(param[, deriv_func, setup])	Add a parameter to the Component.
`as_ECL`([epoch, ecl])	Return pint.models.astrometry.Astrometry object in PulsarEcliptic frame.
`as_ICRS`([epoch])	Return pint.models.astrometry.Astrometry object in ICRS frame.
`barycentric_radio_freq`(toas)	Return radio frequencies (MHz) of the toas corrected for Earth motion
`change_posepoch`(new_epoch)	Change POSEPOCH to a new value and update the position accordingly.
`coords_as_ECL`([epoch, ecl])	Return the pulsar's ecliptic coordinates as an astropy coordinate object.
`coords_as_GAL`([epoch])	Return the pulsar's galactic coordinates as an astropy coordinate object.
`coords_as_ICRS`([epoch])	Return the pulsar's ICRS coordinates as an astropy coordinate object.
`d_delay_astrometry_d_ELAT`(toas[, param, ...])	Calculate the derivative wrt DECJ
`d_delay_astrometry_d_ELONG`(toas[, param, ...])	Calculate the derivative wrt RAJ.
`d_delay_astrometry_d_PMELAT`(toas[, param, ...])	Calculate the derivative wrt PMDEC
`d_delay_astrometry_d_PMELONG`(toas[, param, ...])	Calculate the derivative wrt PMRA
`d_delay_astrometry_d_POSEPOCH`(toas[, param, ...])	Calculate the derivative wrt POSEPOCH
`d_delay_astrometry_d_PX`(toas[, param, acc_delay])	Calculate the derivative wrt PX
`get_d_delay_quantities`(toas)	Calculate values needed for many d_delay_d_param functions
`get_d_delay_quantities_ecliptical`(toas)	Calculate values needed for many d_delay_d_param functions.
`get_params_as_ICRS`()
`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.
`get_psr_coords`([epoch])	Returns pulsar sky coordinates as an astropy ecliptic coordinate instance.
`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.
`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`()	Finalize construction loaded values.
`solar_system_geometric_delay`(toas[, acc_delay])	Returns geometric delay (in sec) due to position of site in solar system.
`ssb_to_psb_xyz_ECL`([epoch, ecl])	Returns unit vector(s) from SSB to pulsar system barycenter under ECL.
`ssb_to_psb_xyz_ICRS`([epoch])	Returns unit vector(s) from SSB to pulsar system barycenter under ICRS.
`sun_angle`(toas[, heliocenter, also_distance])	Compute the pulsar-observatory-Sun angle.
`validate`()	Validate Ecliptic coordinate parameter inputs.
`validate_toas`(toas)	Check that this model component has TOAs where needed.
`xyz_from_latlong`(lon, lat)

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`

validate()[source]: Validate Ecliptic coordinate parameter inputs.

barycentric_radio_freq(toas: TOAs) → Quantity[source]: Return radio frequencies (MHz) of the toas corrected for Earth motion

get_psr_coords(epoch: float | Quantity | Time = None) → SkyCoord[source]

Returns pulsar sky coordinates as an astropy ecliptic coordinate instance.

Parameters:

epoch (astropy.time.Time or float or astropy.units.Quantity, optional) – new epoch for position. If float or Quantity, MJD(TDB) is assumed

Returns:

position – PulsarEcliptic SkyCoord object optionally with proper motion applied
If epoch (MJD) is specified, proper motion is included to return
the position at the given epoch.

coords_as_ICRS(epoch: float | Quantity | Time = None) → SkyCoord[source]

Return the pulsar’s ICRS coordinates as an astropy coordinate object.

Parameters:: epoch (float or astropy.time.Time or astropy.units.Quantity, optional) – If float or Quantity, MJD(TDB) is assumed.
Return type:: astropy.coordinates.SkyCoord

coords_as_GAL(epoch: float | Quantity | Time = None) → SkyCoord[source]

Return the pulsar’s galactic coordinates as an astropy coordinate object.

Parameters:: epoch (float or astropy.time.Time or astropy.units.Quantity, optional) – If float or Quantity, MJD(TDB) is assumed
Return type:: astropy.coordinates.SkyCoord

coords_as_ECL(epoch: float | Quantity | Time = None, ecl: str = None) → SkyCoord[source]

Return the pulsar’s ecliptic coordinates as an astropy coordinate object.

The value used for the obliquity of the ecliptic can be controlled with the ecl keyword, which should be one of the codes listed in ecliptic.dat. If ecl is left unspecified, the model’s ECL parameter will be used.

Parameters:

epoch (float or astropy.time.Time or astropy.units.Quantity, optional) – If float or Quantity, MJD(TDB) is assumed
ecl (str) –

Return type:

astropy.coordinates.SkyCoord

ssb_to_psb_xyz_ECL(epoch: float | Quantity | Time = None, ecl: str = None) → Quantity[source]

Returns unit vector(s) from SSB to pulsar system barycenter under ECL.

If epochs (MJD) are given, proper motion is included in the calculation.

Parameters:

epoch (float or astropy.time.Time or astropy.units.Quantity, optional) – If float or Quantity, MJD(TDB) is assumed
ecl (str, optional) – Obliquity (IERS2010 by default)

Returns:

(len(epoch), 3) array of unit vectors

Return type:

np.ndarray

get_d_delay_quantities_ecliptical(toas: TOAs) → Quantity[source]: Calculate values needed for many d_delay_d_param functions.

d_delay_astrometry_d_ELONG(toas: TOAs, param='', acc_delay=None) → Quantity[source]

Calculate the derivative wrt RAJ.

For the RAJ and DEC derivatives, use the following approximate model for the pulse delay. (Inner-product between two Cartesian vectors)

de = Earth declination (wrt SSB) ae = Earth right ascension dp = pulsar declination aa = pulsar right ascension r = distance from SSB to Earth c = speed of light

delay = r*[cos(de)*cos(dp)*cos(ae-aa)+sin(de)*sin(dp)]/c

elate = Earth elat (wrt SSB) elonge = Earth elong elatp = pulsar elat elongp = pulsar elong r = distance from SSB to Earth c = speed of light

delay = r*[cos(elate)*cos(elatp)*cos(elonge-elongp)+sin(elate)*sin(elatp)]/c

d_delay_astrometry_d_ELAT(toas: TOAs, param='', acc_delay=None) → Quantity[source]

Calculate the derivative wrt DECJ

Definitions as in d_delay_d_RAJ

d_delay_astrometry_d_PMELONG(toas: TOAs, param='', acc_delay=None) → Quantity[source]

Calculate the derivative wrt PMRA

Definitions as in d_delay_d_RAJ. Now we have a derivative in mas/yr for the pulsar RA

d_delay_astrometry_d_PMELAT(toas: TOAs, param='', acc_delay=None) → Quantity[source]

Calculate the derivative wrt PMDEC

Definitions as in d_delay_d_RAJ. Now we have a derivative in mas/yr for the pulsar DEC

print_par(format: str = 'pint') → str[source]

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

change_posepoch(new_epoch: float | Quantity | Time)[source]

Change POSEPOCH to a new value and update the position accordingly.

Parameters:: new_epoch (float or astropy.Time or astropy.units.Quantity object) – The new POSEPOCH value.

as_ECL(epoch: float | Quantity | Time = None, ecl: str = 'IERS2010') → AstrometryEcliptic[source]

Return pint.models.astrometry.Astrometry object in PulsarEcliptic frame.

Parameters:

epoch (float or astropy.time.Time or astropy.units.Quantity, optional) – If float or Quantity, MJD(TDB) is assumed. New epoch for position.
ecl (str, optional) – Obliquity for PulsarEcliptic frame

Return type:

pint.models.astrometry.AstrometryEcliptic

as_ICRS(epoch: float | Quantity | Time = None) → AstrometryEquatorial[source]

Return pint.models.astrometry.Astrometry object in ICRS frame.

Parameters:: epoch (float or astropy.time.Time or astropy.units.Quantity, optional) – If float or Quantity, MJD(TDB) is assumed. New epoch for position.
Return type:: pint.models.astrometry.AstrometryEquatorial

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.

d_delay_astrometry_d_POSEPOCH(toas, param='', acc_delay=None): Calculate the derivative wrt POSEPOCH

d_delay_astrometry_d_PX(toas: TOAs, param='', acc_delay=None) → Quantity

Calculate the derivative wrt PX

Roughly following Smart, 1977, chapter 9.

px_r: Extra distance to Earth, wrt SSB, from pulsar r_e: Position of earth (vector) wrt SSB u_p: Unit vector from SSB pointing to pulsar t_d: Parallax delay c: Speed of light delta: Parallax

The parallax delay is due to a distance orthogonal to the line of sight to the pulsar from the SSB:

px_r = sqrt( r_e**2 - (r_e.u_p)**2 ),

with delay

t_d = 0.5 * px_r * delta’/ c, and delta = delta’ * px_r / (1 AU)

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_d_delay_quantities(toas: TOAs) → dict: Calculate values needed for many d_delay_d_param functions

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.

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.

setup(): Finalize construction loaded values.

solar_system_geometric_delay(toas: TOAs, acc_delay=None) → Quantity

Returns geometric delay (in sec) due to position of site in solar system. This includes Roemer delay and parallax.

NOTE: currently assumes XYZ location of TOA relative to SSB is available as 3-vector toa.xyz, in units of light-seconds.

ssb_to_psb_xyz_ICRS(epoch: float | Quantity | Time = None) → Quantity

Returns unit vector(s) from SSB to pulsar system barycenter under ICRS.

If epochs (MJD) are given, proper motion is included in the calculation.

Parameters:: epoch (float or astropy.time.Time or astropy.units.Quantity, optional) – If float or Quantity, MJD(TDB) is assumed
Returns:: (len(epoch), 3) array of unit vectors
Return type:: np.ndarray

sun_angle(toas: TOAs, heliocenter: bool = True, also_distance: bool = False) → ndarray

Compute the pulsar-observatory-Sun angle.

This is the angle between the center of the Sun and the direction to the pulsar, as seen from the observatory (for each TOA).

This angle takes into account the motion of the Sun around the solar system barycenter.

Parameters:

toas (pint.toa.TOAs) – The pulse arrival times at which to evaluate the sun angle.
heliocenter (bool) – Whether to use the Sun’s actual position (the heliocenter) or the solar system barycenter. The latter may be useful for comparison with other software.
also_distance (bool) – If True, also return the observatory-Sun distance as a Quantity

Returns:

The angle in radians

Return type:

array

validate_toas(toas): Check that this model component has TOAs where needed.