Transforms
DistanceToSNRWeightedDistanceTransform
¤
Bases: ConditionalBijectiveTransform
Transform luminosity distance to the network SNR-weighted distance.
The SNR-weighted distance d_hat absorbs the network sensitivity and chirp-mass
dependence into the distance parameter, making it closer to uniform in the
posterior:
$$
d_{\hat} = \frac{d_L}{\mathcal{M}c^{5/6}\, R{\mathrm{net}}}
$$
Conditioning parameters are (M_c, ra, dec, psi, iota).
Warning
This transform is derived under the assumption that the waveform consists only of the dominant quadrupolar mode (\(\ell = 2, |m| = 2\)), following the parameterisation in arXiv:2207.03508. It is not valid for waveforms that include higher harmonics or orbital precession. Use at your own discretion when such waveform approximants are employed.
Attributes:
| Name | Type | Description |
|---|---|---|
gmst |
Float
|
Greenwich Mean Sidereal Time at the trigger time in radians. |
ifos |
Sequence[GroundBased2G]
|
List of detectors forming the network. |
Methods:
| Name | Description |
|---|---|
__init__ |
Args: |
__init__(trigger_time: float, ifos: Sequence[GroundBased2G]) -> None
¤
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
trigger_time
|
Float
|
GPS trigger time in seconds. |
required |
ifos
|
Sequence[GroundBased2G]
|
Detectors that form the network;
used to compute the network antenna response |
required |
GeocentricArrivalPhaseToDetectorArrivalPhaseTransform
¤
Bases: ConditionalBijectiveTransform
Transform geocentric coalescence phase to detector arrival phase.
In the geocentric convention the orbital phase at coalescence is
phase_c (so the GW phase is phase_c / 2). In the detector
convention the arrival phase is
$$
\phi_{\mathrm{det}} = \frac{\phi_c}{2} + \arg R_{\mathrm{det}}
$$
where \(R_{\mathrm{det}}\) is the complex detector response.
Conditioning parameters are (ra, dec, psi, iota).
Warning
This transform is derived under the assumption that the waveform consists only of the dominant quadrupolar mode (\(\ell = 2, |m| = 2\)), following the parameterisation in arXiv:2207.03508. It is not valid for waveforms that include higher harmonics or orbital precession. Use at your own discretion when such waveform approximants are employed.
Attributes:
| Name | Type | Description |
|---|---|---|
gmst |
Float
|
Greenwich Mean Sidereal Time at the trigger time in radians. |
ifo |
GroundBased2G
|
The target detector. |
Methods:
| Name | Description |
|---|---|
__init__ |
Args: |
__init__(trigger_time: float, ifo: GroundBased2G) -> None
¤
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
trigger_time
|
Float
|
GPS trigger time in seconds. |
required |
ifo
|
GroundBased2G
|
The target detector used to compute the complex antenna response. |
required |
GeocentricArrivalTimeToDetectorArrivalTimeTransform
¤
Bases: ConditionalBijectiveTransform
Transform geocentric coalescence time offset to detector arrival time offset.
In the geocentric convention the signal arrives at Earth's centre at
trigger_time + t_c. In the detector convention it arrives at the
detector at trigger_time + time_delay_from_geocenter + t_det.
Maps t_c → t_det (forward) and t_det → t_c (inverse).
Conditioning parameters are (ra, dec).
Attributes:
| Name | Type | Description |
|---|---|---|
gmst |
Float
|
Greenwich Mean Sidereal Time at the trigger time in radians. |
ifo |
GroundBased2G
|
The target detector. |
Methods:
| Name | Description |
|---|---|
__init__ |
Args: |
__init__(trigger_time: float, ifo: GroundBased2G) -> None
¤
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
trigger_time
|
Float
|
GPS trigger time in seconds. |
required |
ifo
|
GroundBased2G
|
The target detector for which to compute the time delay from the geocentre. |
required |
SkyFrameToDetectorFrameSkyPositionTransform
¤
Bases: BijectiveTransform
Transform sky position from equatorial (RA/Dec) to detector-frame (zenith/azimuth).
Converts (ra, dec) to (zenith, azimuth) relative to the baseline between
two detectors at the given trigger time. The rotation matrix is computed from the
baseline vector between the first two detectors in ifos.
Attributes:
| Name | Type | Description |
|---|---|---|
gmst |
Float
|
Greenwich Mean Sidereal Time at the trigger time in radians. |
rotation |
Float[Array, '3 3']
|
Rotation matrix from equatorial to detector frame. |
rotation_inv |
Float[Array, '3 3']
|
Inverse rotation matrix. |
Methods:
| Name | Description |
|---|---|
__init__ |
Args: |
__init__(trigger_time: float, ifos: Sequence[GroundBased2G]) -> None
¤
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
trigger_time
|
Float
|
GPS trigger time in seconds. |
required |
ifos
|
Sequence[GroundBased2G]
|
At least two detectors; the rotation is
computed from the baseline vector between |
required |
SphereSpinToCartesianSpinTransform
¤
Bases: BijectiveTransform
Transform spin magnitude and angles to Cartesian spin components.
Converts ({label}_mag, {label}_theta, {label}_phi) to
({label}_x, {label}_y, {label}_z) using the standard spherical-to-Cartesian
conversion.
Methods:
| Name | Description |
|---|---|
__init__ |
Args: |
__init__(label: str) -> None
¤
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
label
|
str
|
Parameter label prefix (e.g. |
required |
SpinAnglesToCartesianSpinTransform
¤
Bases: ConditionalBijectiveTransform
Transform spin angles (J-frame convention) to Cartesian spin components.
Converts (theta_jn, phi_jl, tilt_1, tilt_2, phi_12, a_1, a_2) to
(iota, s1_x, s1_y, s1_z, s2_x, s2_y, s2_z) using the LALSimulation
convention. The conditioning parameters are (M_c, q) and optionally
phase_c.
Attributes:
| Name | Type | Description |
|---|---|---|
freq_ref |
Float
|
Reference frequency used in the spin conversion. |
Methods:
| Name | Description |
|---|---|
__init__ |
Args: |
__init__(freq_ref: float, fixed_phase: bool = False) -> None
¤
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
freq_ref
|
Float
|
Reference frequency in Hz for the spin-angle conversion. |
required |
fixed_phase
|
bool
|
If True, the coalescence phase |
False
|