First tied array beam on a pulsar with UTMOST


UTMOST has measured the pulses from the Vela pulsar for the first time using the “tied array beam”, in which 5 of the telescope’s 352 modules were tied together to sum the signal from the pulsar coherently — in other words, to act as an interferometer.

The individual signal to noise ratios from each of the five modules used were 83, 81, 42, 58 and 39. When added “incoherently” the best SNR is ~141 sigma, but if added coherently we get 291 sigma which is over 95% of the theoretical SNR maximum for these modules. In brief, the telescope and the correlator software are achieving near perfect performance acting as an array.

These measurements validate many aspects of the system, from the clock distribution to the RX boxes  and the delay engine in the correlator and the pulsar processor.

Well done to Andrew Jameson and Matthew Bailes for this significant achievement.