Les Pulsars gamma avec GLAST avec le satellite Fermi Le ciel en rayons gamma avec le satellite Fermi David A. Smith Centre d’Études Nucléaires de Bordeaux-Gradignan smith@cenbg.in2p3.fr David Smith Centre d’Etudes Nucléaires de Bordeaux-Gradignan ( CENBG - in2p3 - CNRS ) Institut de Physique Nucléaire de Lyon 6 mars 2015
Hello, Salut! ce qui serait bien: - une planche générique FERMI, choisir parmi les planches 3 à 6, ou m’en demander une autre. - les pulsars FERMI radio-quiet découverts en gamma, ils sont présentés de différentes manières sur les planches 7 à 10. à toi de choisir… - les détections radio des FERMI radio-quiets (ou est-ce que c'est Lucas qui aurait ça?) - la "figure 3 de 2PC", S1400 vs distance La Fig 3 (planche 11) est je pense la meilleure façon de présenter les très rares détections en radio (*). la moitié droite de la Figure du proposal, dans a.tar joint au mail Est-ce que tu as ça sur étagère? Et, au même prix: planches 12 à 24 qui peuvent éventuellement t’aider à montrer que le faisceau gamma ressemble à ceci, par là, tandis que le faisceau radio a une autre forme et est ailleurs. Tu peux mettre 12 à 24 à la poubelle sans arrière pensée. Je me chargerai de - FR606 - beam-width as function of frequency: je me baserai sur Thorsett 1991 ApJ, Chen 2014 ApJ, et Hassall 2012 ApJ, sauf si vous avez mieux. Merci! Jean-Mathias You’re welcome! David (je m’attends à une itération éventuelle avec toi, où tu me demanderas de répondre à tes requêtes différemment, ou bien tu me demanderas d’autres choses). (et je m’attends aussi au plaisir de voir tes planches pour te faire des compliments et p’tet des suggestions.) (* Tiens! Il y a eu une ou deux nouvelles détections depuis que j’ai utilisé la Fig 3 récemment. Je vais te la mettre à jour, dans la journée.)
Formerly "GLAST" June 11, 2008 7ième ! 3 PSR J2021+3651 Abdo et al. 2009, ApJ, 700, 1059 7ième ! Formerly "GLAST" 3
Large Area Telescope 30 MeV to 300 GeV GBM 2nd instrument Gamma-ray burst monitor The whole sky, 8 times per day
Milky Way is gamma bright: 72 months of data >1 GeV. Pass 8, from August 4, 2008 through August 4, 2014. LAT rocking angle <52° and zenith angle <100°. Milky Way is gamma bright: GeV and TeV cosmic rays (mostly protons) hit gas & dust to make pions, then p° gg and p± m±n e±nn, e± g’s. Point sources in the plane are mostly pulsars. Off the plane, mostly blazars (and some millisecond pulsars)
3FGL 3rd LAT source catalog Acero et al 3FGL 3rd LAT source catalog Acero et al. 2015, ApJS accepted http://arxiv.org/abs/1501.02003 3033 total sources (>4s) Red: Firm I.D. (232, mostly pulsars) Blue: ‘Association’ (> ⅓ of sources, mostly blazars.) Black: No I.D. ( < ~⅓ of sources) Un Id’s == Gold mine!
2nd Pulsar Catalog: “2PC”, ApJ Suppl. 208 17 (2013) Catalog contents online at http://fermi.gsfc.nasa.gov/ssc/data/access/lat/2nd_PSR_catalog/ Described in loving detail in Appendix B. 46 pulsars in “1PC” (6 months data), Abdo et al., ApJS 187 460-494 (2010)
117(+8) 2PC pulsars. Now 172 (+ ~30) 1st outside Galaxy. Update of 2PC Fig 1. 1st outside Galaxy. Double pulsar, J0737. In globular clusters. Uncertainties in Shklovskii correction. 117(+8) 2PC pulsars. Now 172 (+ ~30)
Update of 2PC Fig 2. The MSPs are faint: low Ė low Lg nearby big latitude spread. (larger scale height, too.) The Fermi “treasure map” has allowed deeper, repeated (scintillation! eclipsing!) radio searches than radio surveys. ¼ of known MSPs discovered in unidentified Fermi sources. Some new radio MSPs ‘good timers’ suitable for gravity wave searches.
``Anatomically correct’’ Milky Way. Reid et al, ApJ 700, 137 (2009) Not an MSP in the Galactic center. MSP in a globular cluster above the center. 2PC Fig 4. Radio-quiet pulsars have no DM (Dispersion Measure): assign limit at MW edge (using NE2001).
Diagonal : 100 µJy-kpc² pseudo-luminosity. Four gamma blind-search pulsars detected in radio. Define “quiet” as S1400 < 30 µJy. Fermi allows probe of radio parameter space. 2PC Fig 3. Diagonal : 100 µJy-kpc² pseudo-luminosity.
LAT shows, g-ray beams are mostly wide: radio emission cone g-ray emission fan beam Radio pulsars have a limited range of magnetic (a) and overall (z) inclinations: the radio beam must sweep the Earth. LAT shows, g-ray beams are mostly wide: many young, radio-quiet pulsars. MSPs have a smaller light-cylinder. The magnetic field lines are cut close in, making broader radio beams. No radio-quiet MSPs yet. Expect few or none.
Large gamma-ray sample: test models for a broad range of magnetic (a) and overall (z) inclinations. The caricature of a thermal X-ray pulse profile is the aberrated sinusoïd from a hot polar cap: g’s strikingly different. radio emission cone g-ray emission fan beam vs phase . Cut across some line-of-sight . Fan-like beam. Here, “slot gap” model. Model by Alice Harding
Luminous Orbiting Bananas LOBs: Luminous Orbiting Bananas radio emission cone g-ray emission fan beam Profile shapes depend on P, Ė, a, b, etc. Here: “Atlas II”, ApJ 714, 810 (2010). Gap size scales 1/Ė.
Sky distribution of intensity vacuum dipole Pulsar inclination a = 300 a = 600 a = 900 z = 450 z = 750 z = 900 Slot gap Observer angle z Outer gap Phase
Profile example: PSR J2240+5832 (see also Theureau et al. 2011, A&A, 525, A94) Black – weighted gamma-ray profiles. Blue – fit Red – phase-aligned radio profile. Gray – ‘off-peak’ phase range Horizontal dash – local gamma-ray b’grd d = d = ‘radio lag’ D = D = ‘peak separation’ H-test pulse significance 2PC Fig A-8.
Gamma-ray pulse profile shapes LAT Second Pulsar Catalog, Abdo et al., in prep.
Pulsar spectral ‘signature’. b 2PC online. b=1 high altitude curvature radiation. (strong magnetic fields near surface "absorb" gammas.) G100 : integral energy flux >100 MeV Pulsar spectral ‘signature’. (Most sources, e.g. blazars, have power law spectra with little or no curvature.)
Mais! Ce qui est rare est loin (donc faible). “The dark corners of parameter space” – see not just the bright ones (nearby; hi Ė, perhaps due to strong BS; favorable a,z ; low background regions) but also a sampling that allows model tests for atypical parameters. Mais! Ce qui est rare est loin (donc faible). Ce qui est loin est à basse latitude* donc, niveau de fond élévé. Et donc… sonder l’existence de populations actuellement inconnues demande du temps. T? oui, aussi. Surtout, analyses raffinées… * En supposant la même distribution en Zgal.
Magnetic field geometry Retarded vacuum dipole (Deutsch 1954) - No charges, no currents Force-free magnetosphere (Spitkovsky 2006) - No particle acceleration
Increasingly realistic models
Fermi LAT sees pulsations for 7 of these 9. Chandra X-ray images of the PWN can give the angle of the pulsar rotation axis relative to the Earth line-of-sight. Fermi LAT sees pulsations for 7 of these 9. Great X-ray PWN review: Kargaltsev & Pavlov, arXiv:0801.2602. Fermi sees PSRs in >20 of 40 PWNs. Image Model 9 - Ng & Romani et al. 2008
Three ways to discover gamma-ray pulsars 1. “PSUE” = “Pulsar Search Using Ephemerides”: Phase-fold gamma-rays using rotation parameters of a known pulsar. Weights from spectrumpoint-spread-function eliminate ~few trials over ROI & energy cuts. But… spectra tricky for faint pulsars. Except Geminga, all Fermi PSUE’s from radio, not X-rays. green dots ●: young red triangles ▲: MSPs 2. Deep radio search at UnId gamma positions : 60 MSPs, off the plane. ~Few young, and/or accidental coincidences. Can take a year before PSUE allows pulsed gamma detection. Golden triangles ∆: no g pulsations yet. 3. Blind period search in gamma-rays at target* positions : blue squares ■ 41 young PSRs. One MSP, J1311-3430 (near-sighted). Only 4 radio detections. * Targets: early in mission, e.g. X-ray CCO’s. Later, UnId gamma sources. Now also deep X-ray and optical companion searches.
Blazars (AGNs) are variable, with power-law spectra. 2FGL catalog Blazars (AGNs) are variable, with power-law spectra. Pulsars are steady, with cut-off spectra. (New – ignore cut-offs.) Nançay Ray et al, arXiv:1205.3089 LAT sources are well-localized.