A Brief History, and my Research Interests and Publications

Refereed publications
Ph.D Thesis: Observations of Binary and Millisecond Pulsars with a Baseband Recording System
I. H. Stairs, Ph. D. Thesis, Princeton University, 1998.
Non-refereed publications
Press releases and some coverage

Current and ongoing projects and a few things in the pipeline (slightly out of date):

• Pulsar searches with ALFA -- the Arecibo L-band Feed Array. A "precursor" survey has recently gotten underway, and our group will be building a beowulf cluster (together with Mona Berciu's group) to process these data and those that will be taken once the full pulsar spectrometer is built in 2005. Our group (Stairs, van Leeuwen, Kasian) will be involved in all aspects of the survey: data acquisition, search processing and follow-up. We expect to find nearly 1000 pulsars in these surveys! It may be possible for another UBC graduate student to work on this project as well.
• ASP/GASP (Arecibo Signal Processor/Green Bank Astronomical Signal Processor): wide-bandwidth coherent dedispersion instruments for the 300-m telescope at Arecibo Observatory in Puerto Rico and the 100-m Green Bank Telescope (GBT) in West Virginia. These instruments will greatly improve the pulse profile quality and therefore the attainable timing precision for ongoing observing projects. This is a collaboration with Don Backer and Ramachandran at UC Berkeley and David Nice at Princeton. Locally, Rob Ferdman is working on analysis software and interference excision for this instrument and using it to obtain better measurements of binary pulsar parameters and limits on the gravitational wave background.
• Globular cluster searches at Arecibo and the GBT in West Virginia. This is work being done in collaboration with Vicky Kaspi, Scott Ransom and Jason Hessels at McGill University. So far we have over 30 new millisecond pulsars, including a number of eclipsing binaries, and a few more good candidates. Long-term monitoring will teach us about the binary parameters, stellar masses, and possibly even yield tests of General Relativity. Steve Begin is working on the GBT search data for his M.Sc. thesis.
• A low-frequency drift-scan survey of the sky visible from the GBT . This survey is more sensitive to pulsars than any previous search in the northern sky. Laura Kasian is reducing the data from this survey for her M.Sc. thesis. This work is being done in collaboration with Don Backer and Ramachandran at UC Berkeley.
• Continuing involvement with the Parkes Multibeam Galactic Plane pulsar survey, a collaboration of about 12 people led by Andrew Lyne and Dick Manchester. We have used the 13-beam 21-cm receiver on the 64-m Parkes telescope to survey the Galactic Plane, and are still confirming candidates and following up new pulsars (over 700 so far!), recently including several new binary systems. Possibly the most exciting binary to come out of the survey to date is...
• PSR J1740-3052: a young pulsar in an eccentric 8-month orbit with a companion of at least 11 solar masses. There is a late-type star coincident with the pulsar, but for a variety of reasons we believe the companion is more likely to be a B-star. I monitor this pulsar at multiple frequencies with the GBT and now have a good picture of the dispersion measure changes with orbital phase. The long-term timing should also give us an idea of the spin mass quadrupole properties of the companion. And just to be safe, we're getting some Gemini-South and VLT data to test the hypothesis that the late-type star is not the companion.
• PSR 1828-11: another young pulsar, but this one is isolated and appears to be undergoing free precession, as its profile shape and spin properties display correlated periodic changes. This is the first solid evidence of free precession in a pulsar, and I am currently working with Andrew Lyne and others at Jodrell Bank to model the 2-dimensional shape of the pulsar emission beam.
• PSR B1534+12: a close cousin of the famous PSR B1913+16, this pulsar also permits tests of strong-field gravity, including Shapiro-delay-based tests that are unique to it and complementary to the test obtained from PSR B1913+16. I started timing this pulsar for my PhD thesis and have kept on because the science keeps getting more precise -- we now see a significant difference between the pulsar and companion masses, with the pulsar being slightly lighter. Furthermore, we see evidence for long-term profile evolution due to geodetic precession of the pulsar's spin axis and have just recently compared the size of this effect to the changes caused by special-relativistic aberration (on an orbital timescale), resulting in the first-ever measurement of the geodetic precession rate in a strong-field system. Now we want to try the same thing on the newly-discovered double-pulsar system...
• Long-term timing projects: I'm involved with timing several millisecond and binary pulsars at Arecibo and the GBT, trying to derive better binary parameters and neutron-star masses, and set limits on the stochastic gravitational wave background. The data can also be used for polarization studies, single-pulse work and studies of the interstellar medium. For the Arecibo observations, we have used the 10-MHz "Mark IV" coherent dedispersion system that I built for my Ph. D. thesis, but are now switching over to ASP.
• Thinking ahead: While I was at Green Bank I coordinated the science case for a beam-forming array system on the GBT. This would provide a 7- or 13-beam 21cm receiver which would do for the Northern sky what the Parkes multibeam system has done for the South, and will hopefully be ready to go in about 5 years. In the longer term, there are the LAR and SKA to think about.

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