Parkes observations for project P898 semester 2015OCTS_BPSR_02

Strader et al. (2015) have identified within the error box of the\r\ngamma-ray source 3FGL J1417.5-4402 an extremely interesting optical\r\nand X-ray system in a 5.4-day orbit that they interpret as a massive\r\nneutron star (NS) with a giant companion currently undergoing\r\naccretion. We have discovered at Parkes a radio millisecond pulsar\r\nthat is clearly the NS in this binary. This indicates that the\r\nsystem is not currently accreting, although there are very likely\r\noutflows from the companion. Our early radio results, together with\r\npublished optical data, suggest a mass ratio of about 6; for a\r\nplausible companion mass, this would imply a massive NS, ~2.0 Msun.\r\nHere we propose 1.4 GHz timing observations of PSR J1417-4402 in\r\norder to precisely measure several characteristics of this system\r\nthat appears to be unique in the Galactic disk, including constraining\r\nits NS mass.