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Les Pulsars gamma avec GLAST

Les Pulsars en rayons gamma avec le satellite Fermi David A. Smith, pour la collaboration Fermi LAT Centre d’Études Nucléaires de Bordeaux-Gradignan (CENBG / IN2P3 / CNRS) smith@cenbg.in2p3.fr. Les Pulsars gamma avec GLAST. David Smith

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Les Pulsars gamma avec GLAST

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  1. Les Pulsars en rayons gamma avec le satellite Fermi David A. Smith,pour la collaboration Fermi LAT Centre d’Études Nucléaires de Bordeaux-Gradignan (CENBG / IN2P3 / CNRS) smith@cenbg.in2p3.fr Les Pulsars gamma avec GLAST David Smith Centre d’Etudes Nucléaires de Bordeaux-Gradignan ( CENBG - in2p3 - CNRS ) Réunion de Collaboration Saclay, 15 Mars 2010

  2. Pre-launch preparations spawned post-launch successes • Blind period search • Invention of Time Differencing algorithm. Ziegler, Atwood, R. Johnson. • Practicing with EGRET data. • A priori lists of Compact Central Objects (CCOs), etc Parkinson, Wood… • Data Challenges! • Pulsar simulations. Population creation. Harding, Razzano • Pulsar search scripts. Parent, Caliandro, Guillemot, Razzano… • The radio and X-ray timing campaign See next slide • Testing and Fixing the satellite GPS clocks See slide after that • Testing the Timing code on real data Guillemot • Hereafter, I'm not going to try to name all the names, for fear of forgetting great contributions from excellent colleagues.

  3. Parkes (Australia) Jodrell Bank (England) Nançay (France) RXTE Campaign to time 224 high Edot pulsars. (best gamma-ray candidates, but unstable spin-down rate.) Nançay and Jodrell Bank "gave" us another 500 ephemerides. A&A 492, 293 (2008)

  4. Bad! Sub µs accuracy relative to UTC LAT on spacecraft above the floor Scintillator paddles Ground tests of Fermi clocks: Cosmic ray muons through LAT and standalone detector. GPS of Fermi LAT compared to a standalone GPS. Big bug found and fixed (millisecond sawtooth). Would have compromised g-MSP discovery See Lucas G. thesis, http://www.arxiv.org/abs/0910.4707,Figure IV.6, page 78. See also The On-orbit Calibrations for the Fermi Large Area TelescopeAbdo, A. A. et al. 2009, Astropart. Phys., 32, 193

  5. paper in progress • 400 bin zoom. • 1.6 ms pulsar. • theoretical neutron star speed limit is 1.4 ms • 2 bins is 8 µs ! • Mission req't was 10 µs, goal was 2 µs. • I didn't really think we'd need µs for MSPs… • By the way: g-radio phase-alignment!

  6. During L&EO • Pointed Observations During Early Operations • Aimed at 3EG J1835+5918 ("the next Geminga"), discovered CTA 1. LAT's huge FoV is nice. • And we aimed at Vela. • Acceptance validation • Discovery of the Sliding Shoulder • The EGRET 3, then 6 came quickly. • New young radio pulsars too! • Many young blind period search (g-selected) pulsars. • Often in unidentified EGRET sources… • And millisecond (recycled) radio pulsars came as well. • with many consequences… (From the "Vela II" paper)

  7. Fermi Pulsars at 1 ½ Years • Blind Period Search, and timing • Using known ephemerides ("PSUE") • Millisecond pulsars • Using known ephemerides • In globular clusters • Discovering radio MSPs in associated 1FGL sourcs • Other spin-off… • Objects where "no pulsar!" is important • non-gamma-bright Edot/d² pulsars : upper limit studies • Including in some SNR's. • The LMC • Current topics • More sensitive analysis • Going to lower energies • Distances… pulsar angles…

  8. Now 24 • Blind Period Pulsar Searches • Resultsexceed my high pre-launch hopes 16 pulsars discovered in a g-ray blind period search. Abdo, A. A. et al. 2009, Science, 325, 840  Search at candidate neutron star positions, from the LAT and/or from radio,X-ray, (optical).

  9. Together with i) radio-gamma offset and ii) exponential cut-off, the large number of Radio-quiet relative to Radio-loud is iii) the 3rd reason we think most high energy emission occurs far from the neutron star surface. radio emission cone g-ray emission fan beam (Until Fermi, "Geminga" was the only gamma-loud, radio-quiet pulsar.)

  10. Optical. Chandra ACIS. (Also a Swift image). Extensive characterisation of the pulsars and their environment.

  11. Some of the new pulsars are very near • (small dispersion measures, DM) • PSR J1741-2054 at 400 pc, with DM = 4.7 electrons pc/cm3 • Others amongst the most radio-faint known : • 3.4 µJy at 1.5 GHz with Arecibo pour PSR J1907+0602: A Radio-Faint Gamma-Ray Pulsar Powering a Bright TeV Pulsar Wind Nebula, Abdo, A. A. et al. 2010, ApJ, 711, 64 • (Timing localisation using Fermi LAT: < 0.2" in RA, 2" in dec.) • Fantastic synergy between the Fermi and the radio pulsar community • (X-ray synergy great too).

  12. Fermi LAT data now used to build accurate rotation ephemerides. This meeting: talk to Damien Parent. • Need less radio telescope time on gamma-bright, radio-faint objects. PSR J1124-5916 takes hours of Parkes time, compared to minutes for most targets. • High precision localisation using gamma timing. Few arc seconds. • Ap J in preparation… Paul Ray et al.

  13. P.S.U.E. • Pulsar Searches Using Ephemerides ™D. Parent • Results match high pre-launch hopes • Papers include: • PSRs J1048-5832 & J2229+6114. • PSR J1028-5819. • PSR J0205+6449. • "Six Parkes Polarized Pulsars". • 3 more in preparation. • Here: spectrum of PSR J0248+6021 • 100% of radio pulsars discovered at Nançay are LAT g-pulsars!

  14. PSR J2021+3651 First bright new young radio pulsar Abdo, A. A. et al. 2009, ApJ, 700, 1059 ¼ of Fermi papers to date have the word "PSR" or "Puls" in the title!

  15. The 7 CGRO Pulsars • Crab! • Lots of detail in the pulsar peaks. • Low energy analysis  nebula synchrotron component. • Geminga • High-precision phase-resolved spectroscopy is now the norm. • B1055-52, B1706-44, B1951+32 • Paper near submission. • B1509-58 • See next slide.

  16. PSR B1509-58 was seen with COMPTEL, OSSE, and BATSE but not by EGRET due to the low energy cut-off. • LAT low-energy pulsar analyses working better and better!

  17. Galactic EGRET unidentified sources: so far, all pulsars • Example 1: • 3EG J2033+4118 coincides with the TeV source near Cyg OB2. • Shocks between the winds of massive stars? T. Montmerle, ApJ 231, 95-110 (1979) M. Cassé & J. Paul, ApJ 237, 236-243 (1980) R. Mukherjee et al, ApJ 589, 487-494 (2003) • No! LAT PSR J2032+4127 • Example 2: • 3EG J2021+3716 coincides with the open cluster Berkeley 87. • A hadron accelerator driven by shocks from winds from WR star(s) ? • W. Bednarek MNRAS 382, 367 (2007) and references therein • No! radio PSR J2021+3651 in the "Dragonfly" PWN. • Example 3: • 3EG J2020+4017 associated with SNR g Cygni. Shock acceleration? • No! LAT PSR J2021+4044 Yet another example: 3EG J1028-5819 is indeed the recently discovered radio pulsar PSR J1028-5819, see • Abdo et al. 2009, ApJL, 695, L72 arXiv: 0903.1602 • All within 10° in Cygnus…The point is: of the large variety of proposed cosmic accelerators, the correct answer is "pulsar" in a majority of cases so far.

  18. Abdo, A. A. et al. 2009, ApJ, 699, 1171 Contact author: L. Guillemot, Bordeaux

  19. A Population of Gamma-Ray Millisecond Pulsars Seen with the Fermi LAT Abdo, A. A. et al. 2009, Science, 325, 848Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LATAbdo, A. A. et al. 2009, Science, 325, 840  Discovery of high-energy gamma-ray emission from the globular cluster 47 Tucanae with FermiAbdo, A. A. et al. 2009, Science, 325, 845  3 articles "pulsar" in this issue, another in October 2008. µQuasar Cy X-3 in November 2009. SNR W44 in January 2010.

  20. Knowing MSPs emit gamma-rays, look differently at Globular Clusters. "Made in Toulouse"

  21. = ~3 kpc Épaisseur du disque ~300 pc 200 à 400 milliards d'étoiles (incertitude dominée par les petites étoiles)

  22. Spin-off from the MSP discovery • Now up to 18 radio MSPs discovered in Fermi unassociated sources. • 5 of these now show gamma-ray pulses. • 13 PSUE MSP + 18 1FGL = 31 "gamma" MSPs = huge. • More MSPs to come: • Compact binary systems  strong accelerations  big parameter space for pulsation searches  lots of computer time  we've only just begun. • Many candidates… • Gravity wave shtick (see 3rd slide following) • Precision astrometry: mating galactic and extragalactic reference frames. • VLBI astrometry campaign for the gamma pulsars. Parallax, proper movement etc…in Europe: Agnes Fienga (Besancon) with Nancay, and Wouter Vlemmings from Effelsberg. (Fermi Cycle 3 proposal.)

  23. Radio pulsation searches in Fermi LAT unidentified sources: Algorithm: IF POWER-LAW AND/OR VARIABLE PROBABLY BLAZAR ELSE MAYBE PULSAR EMS1535 Elizabeth Ferrara and Eric Grove X-ray proposal

  24. Gamma-pulsations now seen EMS 1535 Nançay (Ismaël Cognard, Gregory Desvignes, & Gilles Theureau)

  25. Nature 463, 147, 14 January 2010 The new MSPs have different selection biases. Well-distributed on the sky.

  26. About the LAT pulsars • Currently: 62 pulsars with >5s pulsations • Generally (but not always), two peaks separated by ½ rotation. • Generally (but not always), gamma peak offset from radio. • Exponential cut-offs at ~1 to ~3 GeV. (notsuper-exponential) • Favors outer magnetospheric emission. • Edot's as low as 3E33 erg/s • As many gamma-selected as radio-selected! • Large numbers of g-MSPs. • 1st glance: MSPs look like young ones. • 2nd glance: fast ones quite different!

  27. 46 Pulsars in "1st Pulsar Catalog" (Ap J Suppl, in press)Here: Gamma-ray luminosity versus spindown power

  28. Things not seen

  29. Abdo, A. A. et al., Science, 2010 January 7 Gamma-pulsations don't mess up the SNR study.

  30. Observations of the Large Magellanic Cloud with Fermi • Abdo et al., A&A accepted. (Contact: J. Knodlseder, CESR – Toulouse) • Gamma-emission dominated by the 30 Doradus star forming region. • Cosmic rays on dust, similar to gammas in the Milky Way. • Weak (2.4 s) hint of pulsations from PSR J0540−6919: pulsar non-detection (so far) • +'s are ATNF pulsars. • 's indicate Wolf-Rayet stars

  31. So far, no gamma-ray signal, pulsed or steady, from Magnetars. ( a.k.a. AXP's, Anomalous X-ray Pulsars, which sometimes are SGR's, Soft Gamma-Ray Repeaters.)

  32. Need good understanding of: • Pulsar population • Pulsar emission

  33. Spin-down power Edot = 4p²Pdot/P3. Newborn ("young") pulsars “Recycled”, or millisecond pulsars From "Fermi Pulsar Catalog" Black dots: we have ephemeris, no gamma-pulsations seen. Grey dots: no pulsation search performed.

  34. Prospects, and work in progress

  35. Understanding all those little grey and black dots • Joanne Bogart & Tom Glanzman using RSP (=Routine Science Processing) pipeline to run gtlike at all 1900 ATNF pulsar positions. • If DC emission found, obtain good ephemerides and perform sensitive pulsation search. • Guillemot et al building 729 rotation ephemerides mixing TOAs from various radiotelescopes: Calculate upper limits for non-detections. • including 224 with Edot > 1E34 that we will put on the FSSC servers. • VLBI astrometry of Fermi pulsars should provide some better distances. • Galactic electron model being updated (NE2001). Our pulsars help. • Angles a, z of neutron star spin and magnetic axes (relative to Earth) necessary to interpret beams-not-seen. • Chandra imaging proposals in progress (Roger et al) • Radio polarization studies continuing… • Optical searches gaining momentum

  36. 9 - • Three ways to estimate those angles: • The rotation axis inclination  from PWN X-ray images. • Comparing gamma-ray pulse profiles with model predictions ("Atlas"). • a, b=(z-a) can come from radio polarization measurements and e.g. RVM = the Rotating Vector Model radio emission cone Image Model g-ray emission fan beam Watters et al. 2009, ApJ, 695, 1289

  37. Gamma-ray and Radio Properties of Six Pulsars Detected by the Fermi Large Area Telescope P. Weltevrede, A.A.Abdo, et al, (2010) ApJ, 708, 1426

  38. Cordes & Lazio 2002 isoDM contours 1 pc = 3.26 ly = 3.1E18 cm APOD = Astrophysical Picture of the Day

  39. The rate of new pulsars can be faster than T, due to • Analysis improvements • e.g. Matthew Kerr's likelihood approach to pulsed analysis • e.g. Pass 8 • Find dim pulsars in the off-pulse of bright ones. • Low-energy: Veronique Pelassa's GRB work being explored. • Blind period searches extending to the MSP domain. • Radio searches of unassociated 1FGL's yielding ephemerides. • And so forth. • We could hit a hundred by about Christmas… • Or next Easter…

  40. Exploring the gamma-ray Milky Way is like peeling an onion • Pulsars are the brightest. • Next come the off-pulse PWN and the SNR searches. • Winds… molecular clouds… binaries… may be hidden by these bright foregrounds. (link to Cyg V382 could go here) • Iterations with the diffuse background will enhance sensitivity for all. • For Fermi to see truly subtle signals over a 10-year mission requires mastering each of these "known" phenomena better & better.

  41. Thank you!

  42. Back-up slides

  43. The word caustic comes from the Greek καυστός, burnt, via the Latin causticus, burning. … the envelope of light raysreflected or refracted by a curved surface ... a curve of concentrated light. These shapes often have cusp singularities. (From wikipedia)

  44. From Alice K. Harding, NASA/GSFC

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