Leonard E Parker

Center for Gravitation, Cosmology & Astrophysics

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Leonard E Parker Center for Gravitation, Cosmology and Astrophysics

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The Leonard E Parker Center for Gravitation, Cosmology and Astrophysics is supported by NASA, the National Science Foundation, UW-Milwaukee College of Letters and Science, and UW-Milwaukee Graduate School. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of these organizations.

Home Computers Discover New Pulsar through Einstein@Home

Pulsar Discovery by Global Volunteer Computing B. Knispel et al. (including B. Allen, D. Hammer, M.A. Papa, and X. Siemens) (Paper)

For the first time, home computers enrolled in Einstein@Home (E@H), a volunteer distributed computing project, have discovered a new pulsar. Members of the public enroll their home or office computers ("hosts"), which automatically download "workunits" from the servers, carry out analyses when idle, and return results. E@H's primary goal is to detect gravitational waves from rapidly-spinning neutron stars in data collected by the LIGO and Virgo detectors. However, about 35% of E@H compute cycles are dedicated to the search for pulsars in radio data collected by the PALFA project at the Arecibo Observatory in Puerto Rico. The newly discovered pulsar (PSR J2007+2722) marks the first discovery within the Einstein@Home project.

Artist's impression of PSR J2007+2722, view from the side. The rotation (white) and magnetic (yellow) axes and the line of sight (blue arrow) are visible. The beam intensity is represented by the yellow ring. The observed pulse profile (shown below the animation) is created as the radio emission cone moves into and out of the line of sight. Credit: Max-Planck-Institut fur Gravitationsphysik

The pulsar has a frequency of 40.8 Hz and was found in PALFA data collected in February 2007. It was re-detected by another PALFA survey observation and follow-up observations were performed by the Green Bank Telescope (USA), the Lovell Telescope at Jodrell Bank Observatory (UK), the radio telescope at Effelsberg (Germany), the Westerbork Synthesis Radio Telescope (The Netherlands) and Arecibo.

Initial observations indicate that it is likely a disrupted recycled pulsar. A disrupted recycled pulsar originates when a pulsar in a binary system spins up (spins faster or "recycles") as it accretes (or accumulates) matter from its binary partner star. When that star explodes in a supernova, the system is disrupted and the pulsar is no longer confined to the binary system. This leaves the pulsar isolated and very fast-spinning. With such high frequency (40.8 Hz), this is likely the fastest-spinning disrupted recycled pulsar yet identified.


The pulse profile of the newly discovered pulsar, J2007+2722, as measured by the Green Bank Telescope at 1.5 GHz. The pulse is very wide, measuring 224 degrees between the outer half-maxima. Credit: B. Knispel et al.

J2007+2722 has a relatively weak magnetic field. It is not in a supernova remnant or globular cluster and has no counterpart in x-ray or gamma-ray point-source catalogs. Based on the dispersion measure, the distance to the pulsar is 5.3 kpc. The wide pulse and initial polarization observations indicate that the pulsar likely has nearly aligned magnetic and spin axes.

All data analyzed via E@H is sent to two different host computers so that calculations can be verified. The computers that first identified the potential pulsar are owned by Chris and Helen Colvin (Ames, Iowa, USA) and Daniel Gebhardt (Universitat Mainz, Germany). E@H will continue harnessing the power of home computers in the hope of making many more discoveries in the future.

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