5. CCF Test Functions

pcassie.ccf_tests.inject_simulated_signal(sim_wave, sim_flux, R_p, R_star, multiple=1, verbose=False, **kwargs)[source]

Inject a simulated signal into the observed flux array. Both flux and sim_flux must be normalized.

Parameters:

  • sim_wave (array) – Refer to pipeline.pipeline.

  • sim_flux (array) – Refer to pipeline.pipeline.

  • R_p (float) – Radius of the exoplanet. Units must be the same as R_star.

  • R_star (float) – Radius of the host star. Units must be tha same as R_p.

  • multiple (int) – Scalar multiple of the injection. E.g. if you want the injected signal to be 0.5x the scale of the expected planet signal, set multiple=0.5.

  • verbose (boolean) – Refer to utility_functions.debug_print.

  • **kwargs – Refer to pipeline.pipeline.

Returns:

new flux array with injected signal

Return type:

array

pcassie.ccf_tests.sn_map(planet_frame_ccf, planet_frame_vgrid, Kp_range=array([50000., 51000., 52000., 53000., 54000., 55000., 56000., 57000., 58000., 59000., 60000., 61000., 62000., 63000., 64000., 65000., 66000., 67000., 68000., 69000., 70000., 71000., 72000., 73000., 74000., 75000., 76000., 77000., 78000., 79000., 80000., 81000., 82000., 83000., 84000., 85000., 86000., 87000., 88000., 89000., 90000., 91000., 92000., 93000., 94000., 95000., 96000., 97000., 98000., 99000., 100000., 101000., 102000., 103000., 104000., 105000., 106000., 107000., 108000., 109000., 110000., 111000., 112000., 113000., 114000., 115000., 116000., 117000., 118000., 119000., 120000., 121000., 122000., 123000., 124000., 125000., 126000., 127000., 128000., 129000., 130000., 131000., 132000., 133000., 134000., 135000., 136000., 137000., 138000., 139000., 140000., 141000., 142000., 143000., 144000., 145000., 146000., 147000., 148000., 149000., 150000.]), **kwargs)[source]

SNR map computation for the CCF.

Parameters:

  • planet_frame_ccf (array) – 2d CCF array in the planet rest frame. Refer to pipeline.pipeline.

  • planet_frame_vgrid (array) – 1d velocity grid (km/s). Refer to pipeline.pipeline.

  • Kp_range (array) – Range of velocities in m/s to sample radial velocity amplitude Kp. Like v_shift_range and planet_frame_vgrid, ideal to have in steps of 1 km/s.

  • **kwargs – Refer to pipeline.pipeline.

Returns:

  • array – 2d grid of CCF values over the sampled radial velocity amplitude (Kp) vs. velocity shift space.

  • array – 2d S/N grid made by dividing the Kp vs. velocity shift grid by its the standard deviation of the out trail values.

pcassie.ccf_tests.welch_t_test(Kp_range_ccf, zoom_radius=15)[source]

Performs Welch’s T-test to compare values in the CCF grid that may be associated with the planet with those that are not.

Parameters:

  • Kp_range_ccf (array) – 2d Kp grid from ccf_tests.sn_map. Refer to ccf_tests.sn_map.

  • zoom_radius (int, optional) – Pixel space radius to build the in trail box around. Here, 1 pixel = 1 km/s (if you have your units right).

Returns:

  • array – 2d Kp vs. velocity shift CCF grid for in trail values.

  • array – 2d Kp vs. velocity shift CCF grid for out trail values.

  • int – Welch’s T-test statistic comparing in trail and out trail CCF values.

  • int – Welch’s p value comparing in trail and out trail CCF values.

pcassie.ccf_tests.find_max_sn_in_expected_range(sn_array, v_grid, offset=75, zoom_radius=15, **kwargs)[source]

Finds the maximum S/N value in the range of values expected of the planet.

Parameters:

  • sn_array (array) – 2d S/N map from ccf_tests.sn_map.

  • v_grid (array) – 1d velocity range corresponding to sn_array.

  • offset (int, optional) – Valocity offset of the Kp range. E.g. if you were to sample a CCF from 75 km/s < Kp < 175 km/s, set offset=75.

  • zoom_radius (int) – Refer to ccf_test.welch_t_test.

  • **kwargs – Refer to pipeline.pipeline.

Returns:

Maximum S/N value within the zoom_radius of the expected Kp and velocity shift values (expected v shift value in planet frame is 0).

Return type:

int