| We have used the 305 m radio telescope of the Arecibo Observatory to search for millisecond pulsars in the disk of the Galaxy. Our survey was sensitive to long period pulsars with flux densities greater than 0.7 mJy, and to pulsars with spin periods P {dollar}sbsp{lcub}sim{rcub}{lcub}>{rcub}{dollar} 0.5 ms, albeit at reduced sensitivity.; We successfully analyzed data collected on about 1350 deg{dollar}sp2{dollar} of sky, or 1/30 of the celestial sphere, and discovered 22 pulsars. Four of the new objects have P {dollar}<{dollar} 60 ms and three are in binary systems, with companions of mass 0.2-0.9 M{dollar}sbodot{dollar}.; Follow-up studies of the discovered pulsars revealed that PSR J2229+2643, a 2.98 ms pulsar in a 93.0 day orbit, has the largest spindown timescale of any known pulsar, with a measured characteristic age of 25 {dollar}times{dollar} 10{dollar}sp9{dollar} yr; PSR J2317+1439, a 3.45 ms pulsar in a 2.46 day orbit, has the smallest orbital eccentricity of any known object in the Universe, {dollar}e < 1.2 times 10sp{lcub}-6{rcub}{dollar}; PSR J1022+10, a 16.45 ms pulsar in a 7.81 day orbit with a {dollar}sim{dollar}0.9M{dollar}sbodot{dollar} companion, displays a kind of average pulse shape variability previously unobserved. One of the pulsars, PSR J2235+1506, is an isolated object with P = 59.8 ms and inferred surface magnetic dipole field strength of {dollar}3times 10sp9{dollar} G.; Timing studies of another millisecond pulsar, PSR J1713+0747, resulted in only the second measurement of distance to a pulsar via timing parallax (d = 1.1{dollar}sbsp{lcub}-0.3{rcub}{lcub}+0.5{rcub}{dollar}kpc), and in the constraining of the pulsar and companion masses ({dollar}msb1>1.2rm Msbodot{dollar}; {dollar}msb2 > 0.27rm Msbodot{dollar}) via the measurement of the general relativistic "Shapiro delay." This pulsar, with a post-fit root-mean-square timing residual of about 0.4 {dollar}mu{dollar}s, may one day prove to be the best of all known pulsars for high-precision timing studies.; Our measurements of proper motions for PSRs J1713+0747, J2235+1506, and J2317+1439, together with recent similar measurements for other millisecond pulsars, suggest that the typical transverse velocity of these old objects is low, {dollar}sbsp{lcub}sim{rcub}{lcub}<{rcub}{dollar}100 km s{dollar}sp{lcub}-1{rcub}{dollar}.; Our studies of a sample of 29 slow pulsars suggest that there may be a substantial population of "sub-luminous" pulsars, with radio luminosities below 1mJykpc{dollar}sp2{dollar}. |
