A search for optical bursts from the rotating radio transient J1819-1458 with ULTRACAM

Abstract

We report on the search for optical bursts from J1819-1458, a member of the recently discovered Rotating Radio Transients (RRATs). J1819-1458 exhibits 3 millisecond bursts with a peak flux at 1.4 GHz of 3.6 Jy every ~3.4 minutes, implying that it is visible for only ~1 second per day at radio wavelengths. Assuming that the optical light behaves in a similar manner, the most sensitive way of detecting RRATs is hence not to take long exposures of the field, but instead to capture individual bursts using a high-speed camera mounted on a large aperture telescope. Using ULTRACAM on the 4.2-m William Herschel Telescope (WHT) we obtained 97100 images of the field of J1819-1458, each of 18.1 milliseconds exposure time and with essentially no dead-time between the frames. We find no evidence for bursts in u', g' and i' at magnitudes brighter than 15.1, 17.4 and 16.6 (5 sigma), corresponding to fluxes of less than 3.3, 0.4 and 0.8 mJy at 3560A, 4820A and 7610A, respectively.