Radial Velocity Mask Line

class modules.radial_velocity.src.alg_rv_mask_line.RadialVelocityMaskLine

Mask line calculation for radial velocity analysis.

This module defines class ‘RadialVelocityMaskLine’ and methods to produce mask line data for radial velocity analysis.

mask_line

Instance to store mask information for a series of masks defined by mask file. This is used for cross correlation computation in radial velocity analysis, like:

{
    'start' : numpy.ndarray            # start points of masks
    'end' : numpy.ndarray              # end points of masks
    'center': numpy.ndarray            # center of masks
    'weight': numpy.ndarray            # weight of masks
    'bc_corr_start': numpy.ndarray     # adjusted start points of masks
    'bc_corr_end': numpy.ndarray       # adjusted end points of masks
}

Type:

dict

static air_to_vac(wave_air)

Convert mask wavelength from air to vacuum environment.

Parameters:

wave_air (Union[numpy.ndarray, float]) – Wavelength(s) in air environment.

Returns:

Wavelength(s) in vacuum environment.

Return type:

Union[numpy.ndarray, float]

static compute_mask_line(mask_path, v_steps, zb_min, zb_max, mask_width=0.25, air_to_vacuum=False)

Calculate mask coverage based on the mask center, mask width, and redshift range over a period of time.

The calculation includes the following steps,

• collect the mask centers and weights from the mask file.

• convert mask wavelength from air to vacuum environment if needed.

• compute the start and end points around each center.

• compute adjust start and end points around each center per velocity range and maximum and minimum redshift from barycentric velocity correction over a period of time.

Parameters:

• mask_path (str) – Mask file path.

• v_steps (numpy.ndarray) – Velocity steps at even interval.

• zb_min (float) – Minimum redshift.

• zb_max (float) – Maximum redshift.

• mask_width (float, optional) – Mask width. Defaults to 0.25 (Angstrom)

• air_to_vacuum (bool, optional) – A flag indicating if converting mask from air to vacuum environment. Defaults to False.

Returns:

Information of mask. Please refer to mask_line in Attributes of this class.

Return type:

dict

get_mask_line(mask_path, v_steps, zb_range, mask_width=0.25, air_to_vacuum=False)

Get mask information.

Parameters:

• mask_path (str) – Mask file path.

• v_steps (numpy.ndarray) – Velocity steps at even interval.

• zb_range (numpy.ndarray) – Array containing Barycentric velocity correction minimum and maximum.

• mask_width (float, optional) – Mask width (km/s). Defaults to 0.25.

• air_to_vacuum (bool, optional) – A flag indicating if converting mask from air to vacuum environment. Defaults to False.

Returns:

Information of mask. Please refer to mask_line in Attributes of this class.

Return type:

dict