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A Plethora of Pulsars

A Plethora of Pulsars. Roger W. Romani Stanford University Alice K. Harding GSFC for the Fermi LAT collaboration. Fermi LAT Pulsar Discoveries.

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A Plethora of Pulsars

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  1. A Plethora of Pulsars Roger W. Romani Stanford University Alice K. Harding GSFC for the Fermi LAT collaboration

  2. Fermi LAT Pulsar Discoveries • We announce today the discovery of 12 new pulsars found directly in the gamma-rays and 17 additional pulsars seen for the first time as gamma-ray emitters. • In the first 4 months of the mission, over 3 dozen pulsars detected! • confirmed 6 known EGRET pulsars (and several EGRET candidates) • Found 12 new young radio pulsars • Found 13 young pulsars pulsing in Gamma-rays alone • Found 7 ‘Millisecond’ Gamma-ray pulsars • This harvest tells us many things: • A unique probe into the heart of the pulsar machine • A new, less biased look at the fate of massive stars

  3. g-Ray Pulsars Known Before Today w/ New Fermi LAT Pulsar Discoveries

  4. The Pulsing g-ray Sky Pulses at 1/10th true rate

  5. g-only Pulsars:High Altitude Emission Traditional Polar Cap Emission High Altitude Gap Emission Conclusion: LAT g-ray PSR discoveries kill the classical Polar Cap picture

  6. What Pulses? Depends on where you look: • Basic outer gap predictions • Radio along B axis • g-ray along equator • 4 Possible cases • Both: Radio + g-ray PSR • Most famous objects • Radio-only PSR • fainter slot gap g? • Neither: no Radio, no g-ray • Thermal X-ray only • Hard to find! • Gamma:g-ray only • Geminga, CTA-1

  7. Fermi Probes the Power And now I see, with eye serene the very pulse of the machine; --Wm Wordsworth “She was a Phantom of Delight” Fermig-ray >10,000x Log (Power Radiated) Radio g-ray X-ray Radio Log (Photon Energy)

  8. Gamma-Ray Millisecond Pulsars with the Fermi Large Area Telescope Alice K. Harding NASA Goddard Space Flight for the Fermi LAT Collaboration • First clear detection of g-ray pulsations from a millisecond pulsar – 7 found • New population of g-ray pulsars has been established

  9. ms g-ray pulsars • Very different characteristics from the normal g-ray pulsars: • Spinning 100 times faster • Magnetic fields ~10,000 times lower • ~10,000 times older • “Recycled” pulsars spun-up by binary companion stars

  10. Spin-up of a millisecond pulsar

  11. Millisecond g-ray pulses PRELIMINARY Fermi g-ray Radio

  12. Summary points • Millisecond pulsars pulse in g-rays! • Six new g-ray ms pulsars discovered with Fermi • EGRET low-significance candidate (PSR J0218+4232) confirmed • Old recycled pulsars can accelerate particles to very high (TeV) energies • Fermi is seeing so far the nearby ms pulsar population • This may be the tip-of-the-iceberg with many more to be discovered

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