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AGILE observations of Crab (and other pulsars)

AGILE observations of Crab (and other pulsars) A. Pellizzoni (INAF-OAC Cagliari) on behalf of AGILE Team & AGILE Pulsar Working Group. “Polarimetry days in Rome: Crab status, theory and prospects” October 16-17, 2008. AGILE Pulsar Working Group:

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AGILE observations of Crab (and other pulsars)

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  1. AGILE observations of Crab (and other pulsars) A. Pellizzoni (INAF-OAC Cagliari) on behalf of AGILE Team & AGILE Pulsar Working Group “Polarimetry days in Rome: Crab status, theory and prospects” October 16-17, 2008

  2. AGILE Pulsar Working Group: A.Pellizzoni (chair) AGILE Team: E.DelMonte, P.Caraveo, F.Fornari, S.Mereghetti, M.Feroci, E.Costa, M.Marisaldi, F.Fuschino, A. Argan, A. Trois,… Radio/X-ray Astronomers/Observers: A.Possenti, M.Pilia, M.Burgay, M.Kramer, A.Hotan, S.Johnston, P.Weltevrede, J.Halpern, I.Cognard, P.Esposito, J.Palfreyman, G.Hobbs, R.N. Manchester,… Radiotelescopes: EPTA (Jodrell Bank, Nancay), ATNF (Parkes) & Un. Of Tasmania (Mt.Pleasant) XMM-Newton X-ray Telescope

  3. Indian Space Research Organisation (ISRO) Italian Space Agency (ASI) PSLV-C8 India AGILE P/L 100 kg 1.8 m e t e r s AGILE S/C 200 kg Launched April 23, 2007

  4. Super-AGILE Imaging X 18-60 keV Field-of-View: ~1 sr Angular res.: 6 arcmin (loc.acc.2’) Energy res.: 8 keV Time res.: <5ms Sens.: 15 mCrab @ 20 keV AGILE – GRID (tracker + ACS + miniCalorimiter) Imaging 30 MeV – 50 GeV very large filed-of-view (>2.5 sr) Effective Area: 500 cm2 Angular res.: 1.2 deg @ 400 MeV Energy res.: DE/E=1 Sens: 10-7 ph/cm2/s >100 MeV AGILE P/L 100 kg 1.8 m e t e r s AGILE S/C 200 kg

  5. AGILE timing capabilities (absolute time tagging with accuracy near 1 microsecond) and sensitivity in the 30 MeV-30 GeV range, with simultaneous X-ray monitoring also in the 18-60 keV band makes it perfectly suited for the study of gamma-ray pulsars fully exploiting the EGRET heritage. Photon statistics-limited timing performances (few thousands counts)/(N light-curve bins) NMAX typically =100

  6. The AGILE Gamma-ray Sky (E>100 MeV)

  7. Known Gamma-ray Pulsars (E>100 MeV) J1057-5226 J1952+3252 Geminga Crab J1709-4429 Vela

  8. Known Gamma-ray Pulsars: fluxes (10-8 ph/cm2/s, E>100 MeV) 35 350 10 225 110 835

  9. Known Gamma-ray Pulsars: periods (ms) 197 39 237 33 102 89

  10. Known Gamma-ray Pulsars (E>100 MeV) Red: Guest Observer Program, yellow: AGILE Team J1057-5226 J1952+3252 Geminga Crab J1709-4429 Vela

  11. Known Gamma-ray Pulsars (E>100 MeV) Geminga Crab Vela

  12. FERMI EGRET AGILE

  13. AGILE continuously monitored known pulsars for months (and the counts statistics is still improving as more exposure time is gathered in the on-going program)… Vela data span is of about 250 days!

  14. In about 9 months of scientific life, AGILE reached EGRET exposure level in the Vela region (a good start!).

  15. Crab PSR GRID Gamma-rays X-rays SuperAGILE

  16. Crab PSR GRID Gamma-rays Current effective time resolution and phasing accuracy is about 200 ms (improving with count statistics) X-rays SuperAGILE

  17. Timing noise uncorrected Timing noise corrected 1 ms Pellizzoni et al. 2008

  18. Method: simultaneous radio coverage allows us to perform proper phasing accounting for timing noise in the folding process. We fit radio timing residuals with polynomial harmonic functions in addition to standard ephemeris parameters (pulsars frequency and its derivatives). This strongly improves the phasing precision and resolution (especially with >6 months long AGILE data spans) properly accounting for timing noise and then matching the *actual* shape of the pulsar light-curve in gamma-rays.

  19. Hobbs et al. 2004 Pellizzoni et al. 2008, ApJ, in press (astro-ph 0810.1516)

  20. PEPOCH: 54362 MJD P_RADIO = 0.033607554009 s P_AGILE = 0.033607553966 s P_RADIO - P_AGILE = 4.3e-11 Crab PSR P_search_res: 8e-11 s

  21. PEPOCH: 54362 MJD P_RADIO = 0.033607554009 s P_AGILE = 0.033607554006 s P_RADIO - P_AGILE = 3.3e-12 Crab PSR P_search_res: 8e-11 s

  22. Gamma-ray pulsar period fit Crab PSR Timing noise uncorrected Timing noise corrected: perfect radio-gamma matching even for long and noisy exposures

  23. Crab PSR Timing noise corrected Timing noise uncorrected (dashed) No light-curve “smearing” even in very long observations

  24. Crab 0.5<E<30 GeV AGILE E>100 MeV 0.7 ms bins SuperAGILE 18-60 keV Radio Pellizzoni et al. 2008

  25. Vela E>1 GeV E>100 MeV 0.9 ms res. 30<E<100 MeV Radio P2 a-b complex Pellizzoni et al. 2008

  26. Photon statistics-limited timing performances. SIMULATION <counts/bin> = 9 max counts/bin = 80 <50 ms effective time resolution (final) 200 ms effective time resolution (current)

  27. Gamma-ray emission from pulsar glitches? • Vela has shown 10 major glitches since 1969. • The chance occurrence of a strong Vela glitch in the wide AGILE field of view over three years of mission is 20%. • Starquake waves can “shake” magnetic fields generating strong electric fields which accelerate particles to relativistic energies, possibly emitting a burst of high-energy radiation (Ruderman, 1976, 1991; Alpar et al., 1994). • Cgglitch=1011hDn/n counts, • where h is the unknown conversion efficiency of the glitch energy to gamma-ray emission (Pellizzoni et al., 2008)

  28. Vela glitch=54,312.5+/-3 MJD E>50 MeV Small Vela glitch in August 2007: burst emission possibly detected by AGILE

  29. Vela glitch=54,312.5+/-3 MJD Cgglitch=1011hDn/n counts Dn/n=10-9 h=0.1 15 photons in 4 minutes E>50 MeV Small Vela glitch in August 2007: burst emission possibly detected by AGILE

  30. E>1 GeV E>100 MeV 2.4 ms 30<E<100 MeV X-rays (XMM) 2-10 keV Geminga complex? Pellizzoni et al. 2008

  31. B1706-44 E>30 MeV 2.6 ms Pellizzoni et al. 2008

  32. Results: structured energy-dependent peaks (more than two) are evident in the light curves. How many particle acceleration sites in the pulsars magnetospheres? And where? Multiple gap models may be invoked… find more in Pellizzoni et al., 2008.

  33. Crab 0.5<E<30 GeV AGILE E>100 MeV 0.7 ms bins SuperAGILE 18-60 keV Radio Pellizzoni et al. 2008

  34. Crab P1/P2 vaiabilitity? (nutation of the neutron star?) P3?? P1/P2 variability? ? Pellizzoni et al. 2008

  35. Crab P3 is coincident with the feature HFC2 that appears in the radio profile above 4 GHz. HFC2 polarization suggest that this peak may come from a lower emission region, near polar cap (Moffet & Hankins; 1996, 1999) 3.7s P1-P2: High-altitude gap (MAGIC)? P3: low altitude cascades? Pellizzoni et al. 2008

  36. (Moffet & Hankins; 1996, 1999)

  37. Crab P3 is coincident with the feature HFC2 that appears in the radio profile above 4 GHz. HFC2 polarization suggest that this peak may come from a lower emission region, near polar cap (Moffet & Hankins; 1996, 1999) 3.7s P1-P2: High-altitude gap (MAGIC)? P3: low altitude cascades? Pellizzoni et al. 2008

  38. Crab P3 from Giant Pulses? We can tag GPs from radio observations and fold at high-energy GPs events only… Pellizzoni et al. 2008

  39. Known Gamma-ray Pulsars (E>100 MeV) J1057-5226 J1952+3252 Geminga Crab J1709-4429 Vela

  40. Thank you! on behalf of AGILE Team & AGILE Pulsar Working Group: A.Pellizzoni (chair): apellizz@ca.astro.it AGILE Team: E.DelMonte, P.Caraveo, F.Fornari, S.Mereghetti, M.Feroci, E.Costa, M.Marisaldi, F.Fuschino, A. Argan, A. Trois,… Radio/X-ray Astronomers/Observers: A.Possenti, M.Pilia, M.Burgay, M.Kramer, A.Hotan, S.Johnston, P.Weltevrede, J.Halpern, I.Cognard, P.Esposito, J.Palfreyman, G.Hobbs, R.N. Manchester,… Radiotelescopes: EPTA (Jodrell Bank, Nancay), ATNF (Parkes) & Un. Of Tasmania (Mt.Pleasant) XMM-Newton X-ray Telescope

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