TIMING OF FIVE MILLISECOND PULSARS DISCOVERED IN THE PALFA SURVEY

Abstract

We present the discovery of five millisecond pulsars (MSPs) from the PALFA\nGalactic plane survey using Arecibo. Four of these (PSRs J0557+1551,\nJ1850+0244, J1902+0300, and J1943+2210) are binary pulsars whose companions are\nlikely white dwarfs, and one (PSR J1905+0453) is isolated. Phase-coherent\ntiming solutions, ranging from $\\sim$1 to $\\sim$3 years in length, and based on\nobservations from the Jodrell Bank and Arecibo telescopes, provide precise\ndeterminations of spin, orbital, and astrometric parameters. All five pulsars\nhave large dispersion measures ($>100$ pc cm$^{-3}$, within the top 20% of all\nknown Galactic field MSPs) and are faint (1.4 GHz flux density < 0.1 mJy,\nwithin the faintest 5% of all known Galactic field MSPs), illustrating PALFA's\nability to find increasingly faint, distant MSPs in the Galactic plane. In\nparticular, PSR J1850+0244 has a dispersion measure of 540 pc cm$^{-3}$, the\nhighest of all known MSPs. Such distant, faint MSPs are important input for\naccurately modeling the total Galactic MSP population.\n