orca.utils.beam

Primary beam models for OVRO-LWA observations.

Provides abstract base class and implementations for computing beam response as a function of position. Includes analytic approximations and simulation-derived beam models (Woody beam).

Attributes

BEAM_FILE_PATH

Classes

`BaseBeam`	Abstract base class for beam models.
`AnalyticBeam`	Simple analytic beam model using sin(el)^1.6 approximation.
`WoodyBeam`	Simulation-derived LWA dipole beam model.
`jones`	For loading and returning LWA dipole beam values (derived from DW beam simulations) on the ASTM.

Module Contents

orca.utils.beam.BEAM_FILE_PATH = b'.'[source]

class orca.utils.beam.BaseBeam(msfile: str)[source]

Bases: abc.ABC

Abstract base class for beam models.

Defines the interface for computing beam response at arbitrary sky positions.

abstractmethod srcIQUV(az: float, el: float) → Tuple[float, float, float, float][source]

Get beam response in Stokes I, Q, U, V at given position.

Parameters:

az – Azimuth in degrees.
el – Elevation in degrees.

Returns:

Tuple of (I, Q, U, V) beam response values.

class orca.utils.beam.AnalyticBeam(msfile: str)[source]

Bases: BaseBeam

Simple analytic beam model using sin(el)^1.6 approximation.

srcIQUV(az: float, el: float) → Tuple[float, float, float, float][source]

Compute analytic beam response.

Parameters:

az – Azimuth in degrees (unused).
el – Elevation in degrees.

Returns:

Tuple of (I, 0, 0, 0) with I = sin(el)^1.6.

class orca.utils.beam.WoodyBeam(msfile: str)[source]

Bases: BaseBeam

Simulation-derived LWA dipole beam model.

Uses pre-computed beam grids from DW beam simulations interpolated to the observation frequency. Supports full Stokes (I, Q, U, V).

CRFREQ[source]

path[source]

azelgrid[source]

gridsize[source]

beamIQUVfile[source]

beamIQUV[source]

Ibeam[source]

Qbeam[source]

Ubeam[source]

Vbeam[source]

srcIQUV(az, el)[source]

Compute beam scaling factor :param az: azimuth in degrees :param el: elevation in degrees

Returns: [I,Q,U,V] flux factors, where for an unpolarized source [I,Q,U,V] = [1,0,0,0]

plotbeam()[source]: Show the IQUV beams at MS center frequency, and azimuth,elevation grids.

class orca.utils.beam.jones(msfile)[source]

For loading and returning LWA dipole beam values (derived from DW beam simulations) on the ASTM. Last edit: 11 September 2020

CRFREQ[source]

path[source]

beamjonesfile[source]

srcjones(l, m)[source]

Compute beam scaling factor :param (l: :param m) coordinates:

Returns: Jones matrix at coordinates (l,m)