Update configuration file for localisation

Updating the localisation file for localisation is mostly the same as for the Repeater localisation tutorial. The main difference is that FRB 190709 was found in a drift scan, so we need to specify the HA and Dec, instead of RA and Dec.

Note

The filterbank header always lists the pointing as RA and Dec. The RA field really contains the HA in case of a drift scan. The Dec is then the local Dec.

The scripts automatically convert HA and Dec into J2000 RA and Dec. Both the localisation grid and CB/telescope pointing coordinates can be given in the HADEC frame. For CB/telescope pointing this works out of the box: the burst arrival time is used to convert HADEC to RADEC. In the case of the localisation grid, however, this is not the case. There might be several bursts with different arrival times, so the code does not know which time to use. Therefore, the user has to manually put in the timestamp to use for converting the localisation grid HADEC to RADEC. In this case, we of course want this timestamp to coincide with the burst arrival time.

Note

To calculate the burst arrival time from the observation start time and arrival time of the burst within the observation, use something like this:

>>> from astropy.time import Time, TimeDelta
>>> (Time('2019-07-09T05:02:24.064') + TimeDelta(657.977, format='sec')).isot
'2019-07-09T05:13:22.041'

The final configuration file looks like this:

global:
    fmin_data: 1219.70092773
    bandwidth: 300
    snrmin: 5

snr:
    window_load: 2.0
    window_zoom: 0.5
    dm: 663.1
    width_max: 100

localisation:
    ha: -12.52167
    dec: 31.95253
    time: '2019-07-09T05:13:22.041'

    size: 35
    resolution: 10
    cb_model: gauss

burst00:
    fmin: 1300
    filterbank: 'data/CB{cb}_10.0sec_dm0_t0657_sb-1_tab{tab}.fil'
    cbs: [10]
    neighbours: False
    main_cb: 10
    main_sb: 36

    tstart: '2019-07-09T05:02:24.064'
    toa: 657.977
    reference_cb: CB10

    CB10:
        ha: -12.52167
        dec: 31.95253
        snr_array: 'snr/FRB190709_burst00_CB10_SNR.txt'