# Arecibo Pulsar Survey Using ALFA. IV. Mock Spectrometer Data Analysis, Survey Sensitivity, and the Discovery of 40 Pulsars

Lazarus, P., Brazier, A., Hessels, J. W. T., Karako-Argaman, C., Kaspi, V. M., Lynch, R., Madsen, E., Patel, C., Ransom, S. M., Scholz, P., Swiggum, J., Zhu, W. W., Allen, B., Bogdanov, S., Camilo, F., Cardoso, F., Chatterjee, S., Cordes, J. M., Crawford, F., Deneva, J. S., Ferdman, R., Freire, P. C. C., Jenet, F. A., Knispel, B., Lee, K. J., van Leeuwen, J., Lorimer, D. R., Lyne, A. G., McLaughlin, M. A., Siemens, X., Spitler, L. G., Stairs, I. H., Stovall, K. and Venkataraman, A. (2015) Arecibo Pulsar Survey Using ALFA. IV. Mock Spectrometer Data Analysis, Survey Sensitivity, and the Discovery of 40 Pulsars. Astrophysical Journal, 812 (1). ISSN 0004-637X

 Preview
PDF (Published manuscript) - Published Version
The on-going Arecibo Pulsar-ALFA (PALFA) survey began in 2004 and is searching for radio pulsars in the Galactic plane at 1.4 GHz. Here we present a comprehensive description of one of its main data reduction pipelines that is based on the PRESTO software and includes new interference-excision algorithms and candidate selection heuristics. This pipeline has been used to discover 40 pulsars, bringing the survey's discovery total to 144 pulsars. Of the new discoveries, eight are millisecond pulsars (MSPs; $P\lt 10$ ms) and one is a Fast Radio Burst (FRB). This pipeline has also re-detected 188 previously known pulsars, 60 of them previously discovered by the other PALFA pipelines. We present a novel method for determining the survey sensitivity that accurately takes into account the effects of interference and red noise: we inject synthetic pulsar signals with various parameters into real survey observations and then attempt to recover them with our pipeline. We find that the PALFA survey achieves the sensitivity to MSPs predicted by theoretical models but suffers a degradation for $P\gtrsim 100$ ms that gradually becomes up to ~10 times worse for $P\gt 4\;{\rm{s}}$ at $\mathrm{DM}\lt 150$ pc cm−3. We estimate 33 ± 3% of the slower pulsars are missed, largely due to red noise. A population synthesis analysis using the sensitivity limits we measured suggests the PALFA survey should have found 224 ± 16 un-recycled pulsars in the data set analyzed, in agreement with the 241 actually detected. The reduced sensitivity could have implications on estimates of the number of long-period pulsars in the Galaxy.