Pulsar ALFA Galactic Plane Survey Arecibo Project P2030 Progress Report

This report summarizes activity for the PALFA projects P2030 (survey), P2177 (general timing) and P2180 (timing of the relativistic pulsar J1906+0746) from 2006 to mid-2007. We discuss progress made toward the goals of our original 2004 survey proposal. We describe the end to end survey data-analysis pipeline and follow-up timing analyses of discovered pulsars. We also describe data products and databases and web-based tools for accessing them. Notable results include: 1. We have discovered pulsars in important subclasses that are the target of our survey: a millisecond pulsar, a relativistic binary pulsar, an object with a likely high-energy counterpart, and several intermittent objects found with our single-pulse analysis. 2. Data have been processed at full resolution with two end-to-end pipelines and we expect to process all PALFA data with both pipelines. The “Cornell” pipeline is faster because it does not do an acceleration search, which the “PRESTO” pipeline does. Currently it takes about 3 hr to process all seven beams of each 5 min pointing compared to about 20 hr for the two respective pipelines (if one CPU is used per beam). 3. The signal diversity —canonical pulsar emission with relatively steady pulse amplitudes as well as highly intermittent objects — warrants our use of two processing algorithms, one that targets periodic signals and one that is sensitive to single, dispersed pulses. Of the known pulsars that we have blindly detected, all are seen in the periodicity search while 62% are found in the single pulse analysis. 4. We expect to develop algorithms for detecting additional signal types that go beyond the single-pulse analysis with standard dedispersion. 5. RFI is highly episodic. It was low level in 2004 and became severe in 2005 and early 2006. Later in 2006 it became low level again. A high-pass filter was introduced into the signal path in 2006 December. This has reduced the influence of out-of-band radars in Puerto Rico on the measurements. For RFI purposes, only about 10% of the sky positions will need to be reobserved. 6. To consolidate processing results we have developed a system of databases using MySQL and SQL Server software. These have required a great deal of planning and effort, but are now working well. Related web and scripting tools have been developed that allow data products to be accessed over the network from the Cornell Center for Advanced Computing (CCAC). 7. Raw PALFA data have been made available to the PALFA Consortium primarily by shipment of portable disks. We now have a network based mechanism in place for restoring data from the robotic tape system at the CCAC and then by ftp to a remote computer. Implementation of this system still requires addressing network costs. These are nil for sites on the Teragrid or National Lambda Rail, but are potentially substantial for other sites. This will be the mechanism for making raw data publicly available. Introduction: The Pulsar-ALFA (PALFA) Consortium is undertaking a large-scale Galactic plane survey for pulsars and transients. Precursor work with ALFA began in August 2004 under project P1944, leading to our 2004 October proposal to NAIC for a multi-year survey, which became the P2030 project. An affiliated follow-up timing project using Arecibo (P2177) commenced in 2007 March and routinely acquires full-Stokes arrival-times on some PALFA discoveries. A few specific PALFA pulsars have been timed elsewhere, including the Parkes and Jodrell telescopes. Our goal is to complete a deep search of the Galactic plane, defined as latitudes within 5 degrees of the midplane for the two longitude sectors available to Arecibo. This entails usage of the new PALFA spectrometer starting in 1 Astronomy Department, Cornell University, Ithaca, NY 14853, [email protected] 2 Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027 3 See end pages for list