The recent upgrade to MWAX necessitates verification that the system is capable of observing high time resolution phenomena, such as pulsars. To this end, we put in a successful proposal for an MWA observing campaign to being in the end of 2021 and into the beginning of 2022. The requested observations fall into two categories:

1. commissioning observations, and

2. the remaining SMART observations.

This page details the progress made in taking the observations and performing the tests to complete the commissioning phase. Progress with the SMART survey is detailed elsewhere.

The stated goals of the commissioning observations are:

1. To develop and test the tied-array beamformer for the new VCS data format

2. Verification of frequency labelling

3. Data recording and timing stability

4. Polarimetric verification and leakage assessment

5. Full coherent beam sensitivity and timing accuracy

6. The voltage dump and trigger mode (in response to external triggers)

7. Correlation and imaging of data recorded in the new VCS format

A partial list of requested observations to satisfy the above goals are:

The following link performs a query on the MWA observation database, showing the details of the observations made so far:

https://ws.mwatelescope.org/metadata/find/?search=search&html=1&pagesize=100&projectid=G0057&mintime_utc=2021-12-13T01%3A00&maxtime_utc=2021-12-29T01%3A00

The following table is a summary of the same observations, and which of the goals (see the table above) that they are intended to satisfy:

*VCSBeam version is the earliest version that was successfully used for the processing. For calibration observations, this means using mwa_plot_calibration, and for the VCS observations, make_mwa_tied_array_beam.

Create Hyperdrive batch script:

Run the Hyperdrive script (on Garrawarla):

Create VCSBeam plotting script:

Run plotting script:

Plot the calibration solutions (on your local computer, after downloading a copy of plot_calibration.py and plot_data.txt:

It looks like the solutions are probably fine for most, if not all the antennas (except possibly HexE23, since there's a lot of power in the off-diagonal terms, Dpq and Dqp), but the curviness of the phases makes it hard to tell. Therefore, I will choose a reference antenna to plot all the phases relative to that. Since there's a bunch of tiles whose phases are strongly sloped (near the middle of the plot), I'll choose a reference tile with a negative slope as well, but whose gradient is not as steep... HexE25 will do. To do this, I need to re-run the plotting script with the following change:

If I want to keep the old plots, I just make sure I rename the various output files to something different. Remaking the plots gives:

These solutions look fine (the on-diagonal terms, Dpp and Dqq, look straight). At the moment, I'm not trying to do polarimetry, so I don't need to worry about either the reference antenna or the PQ phase. By default, I should probably get rid of the cross terms (taking guidance from the imaging team). Therefore, I should be able to simply apply this solution with the following options to make_mwa_tied_array_beam:

Make sure you have a calibration solution ready. this example uses the solution derived from observation 1323690320.

Create a VCSBeam beamforming script:

Prepare a pointings file (PSR B0031-07):

Run the VCSBeam beamforming script:

Generate an ephemeris:

Use PRESTO's prepfold utility to fold on the pulsar's period from the FITS files:

Open

Use DSPSR and PSRCHIVE to fold on the pulsar's period from the VDIF files:

Open

Create a VCSBeam beamforming script:

Prepare a pointings file (PSR J0036-1033):

Run the VCSBeam beamforming script:

Get an ephemeris from Nick:

Use PRESTO's prepfold utility to fold on the pulsar's period from the FITS files:

Open

Use DSPSR and PSRCHIVE to fold on the pulsar's period from the VDIF files:

Create a VCSBeam beamforming script:

Prepare a pointings file (PSR J0034-0534):

Run the VCSBeam beamforming script:

Use PRESTO's prepfold utility to fold on the pulsar's period from the FITS files:

Open

FAIL!!

Generate an ephemeris:

Use DSPSR and PSRCHIVE to fold on the pulsar's period from the VDIF files: