1 / 23

THE COSMIC RAYS

THE COSMIC RAYS. Wolfgang Kundt Argelander Institute of Bonn University Vulcano, 29 May 2008. COSMIC-RAY BOOSTING.

moanna
Download Presentation

THE COSMIC RAYS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. THE COSMIC RAYS Wolfgang Kundt Argelander Institute of Bonn University Vulcano, 29 May 2008

  2. COSMIC-RAY BOOSTING • Not via multi-step accelerations, (in situ, Fermi 1, 2 , shock acceleration): Journal of Astrophysics and Astronomy142, 150-156 (1984). Note also: their highest energies would require excessive Bs. • Rather by single-step sweeping via corotating magnetic fields, (eE x B-force)  see modified Hillas plot  preferentially by magnetars, but also by the (coronas of the) central disks of active galaxies.

  3. The SPECTRUM of the COSMIC RAYS • peaks in power near the ionic rest energy, (a few GeV), • extends in particle energy up towards 1020.5 eV, • wants Galactic neutron stars as boosters, because of: • W = e # (E +  ×B)·dx = 1021eV ( ×B)12(x)6.5 , • i.e. via a single fall through a strong potential, near the inner edge of a n*´s accretion disk, which will indent deeply into its corotating magnetosphere. • Note that ions above 1018eV are not contained by the galaxy´s magnetic fields (for some 107 yr)  as are the lower-energy ones  hence abund vastly more near their sources. They require robust engines.

  4. THE GAMMA-RAY BURSTS Wolfgang Kundt, Vulcano, 29 May 2008

  5. GAMMA-RAY-BURST PROPERTIES HISTORY • FIRST DETECTION: 2 July 1967 • FIRST CONFERENCE: X-mas 1974 • FIRST REPEATER: 5 March 1979 • CONSENSUS (1980s): Galactic n** • PRESENT MODELS: Fusing binary neutron stars or black holes at cosmic • distances, without further detail • PREFERRED MODEL: as during 80s Wolfgang Kundt, 27. September 2006

  6. GAMMA-RAY-BURST PROPERTIES Burst Spectra log( S) 1 log(h/MeV) Wolfgang Kundt, 27. September 2006

  7. GAMMA-RAY-BURST PROPERTIES CONSTRAINTS (1) • No Pair Formation at Source: d < kpc / • Neutron-star Energetics: d < kpc  • Afterglow Brightness (at low ): d < 0.3 kpc / • Modest Proper Motion of SGR (& radio lobe): d  30pc • Tolerable Luminosity of SGR (k-Eddington): d  30pc • Resolved X-ray Afterglow (growing concentric rings)!? • No Long-Distance travel signatures!? [Mitrofanov, 96] •  Pre- and Post-cursors (offset by  hour)!? [X.Y.Wang & P.Mészáros (2007) discuss delays of 10s and 102s]. Wolfgang Kundt, 27. September 2006

  8. GAMMA-RAY-BURST PROPERTIES CONSTRAINTS (2) • Accreting Galactic dead-pulsar population should be detected (10-17 M/yr n*) ! • Thin-shell energy distribution: <dmax/dmin> = 2 ! • No-Host dilemma: Brad Schaefer et al, [97, 99] • Brightness Excess at high z ( 7): B. Schaefer [07] • Hardness Excess ( 1013 eV) ! • Duration Excess (hour) ! • Afterglow Brightnesses are z-independent !? • L(afterglow)  L(prompt): no beaming ?! Wolfgang Kundt, 27. September 2006

  9. CONSTRAINTS (3) GAMMA-RAY-BURST PROPERTIES • X-ray Afterglows don´t evolve (increasing ionization!) • X-ray Afterglows can fade slowly ( 125 d) ! • All host galaxies – when , and not fake – are peculiar, as a class ! [B.Cobb & Ch.Bailyn (2007), also GRB 070125]. • No Orphan Afterglows have been detected ! • Cavallo-Fabian-Rees limit on L/t • L(after)/L(prompt) ≅ 1 for GRB 060729 ! • The Mg II absorbers are 4-times overabundant (w.r.t. those of quasars), and time-variable (hours). • GRB 070201 has not been seen at g-waves (by LIGO). Wolfgang Kundt, 27. September 2006

  10. CONSTRAINTS (4) • Superluminally expanding radio afterglows, like for GRB 030329 [(4±1)c], and mystery spots [19c], would require pre-existing jet channels [G. Taylor et al (2005)]; similarly for SGR 1806-20 [B. Gaensler (2006)]. • GRB 080319B was the brightest known optical point source in the Universe, aleady 20 sec after outburst! • X-ray afterglow lightcurves show strong flares (<102), between minutes and days after outburst, as well as steep falls! [Chincarini et al (2007); also: Troia et al (2007)]. • Bright optical afterglow follows -ray intensity (GRB 080319B) within a few sec, between 13s and 60s after onset; similarly for GRB 990123.

  11. References • Aharonian, F., Ozernoy, L., 1979: Astron. Tzirk1072, 1 • Chincarini, G., et al (14 authors), 2006, The Messenger 123, 54-58 • Colgate, S.A., Petschek, A.G., 1981, Ap. J.248, 771-782 • Gehrels, N., et al (20 authors), 2006: Nature444, 1044-1046 • Grupe et al, 2007: Ap. J.662, 443-458 • Hjorth, J., et al (20 authors), 2006: The Messenger126, 16-18 • Kundt, W., 2005: Astrophysics, A New Approach • Kundt, W., Chang, H.-K., 1993: Astroph. Sp. Sci. 200, L151-L163 • Marsden, D., Rothschild, R.E., Lingenfelter, R.E., 1999: Ap. J.520, L107-110 • Schaefer, B.E., 1999: Ap.J.511, L79-L83 • Schaefer, B., 2007: Am.Astr.Soc.Meeting, 12 highest-z GRBs (52) too bright • Schmidt, W., 1978: Nature271, 525-527 • Song, Fu-Gao, Jan. 2008: astro-ph/0801.0780 • Sudilovsky, V., et al (6 authors), 2007: Ap. J. 669, 741-748 • Taylor,G.B., Frail,D.A., Berger,E., Kulkarni,S.R., 2004: Ap. J.609, L1-L4 • Vietri, M., Stella, L., Israel, G., 2007: astro-ph/0702598v1 • Zdziarski, A., 1984: A & A134, 301-305

  12. PREFERRED MODEL (1) • Most GRBs come from (n*s at distances) d  (0.1 , 0.2) kpc. • The nearest bursts, the SGRs, have distances d  10 pc. • The GRBs are emitted by throttled pulsars, whose magnetosphere is deeply indented by a low-mass accretion disk assembled from its CSM. These disks tend to be  the Milky Way. Their (anisotropic) emissions – by ricocheting, accreting `blades´ – peak near their disk plane, strengthening an isotropic appearance of the bursts in the sky. • The afterglows are light echos, or transient reflection nebulae. • Centrifugally ejected ion clouds escape transluminally, and show up redshifted in absorption against the burst impact´s light, mainly their receding sector. In extreme cases of large mass ejections (at small speeds), the afterglows can look like SN shells, by acting as photon bags.

  13. PREFERRED MODEL (2) • The short GRBs, of peak duration < 2 sec, result by accretion of a single blob (blade), of size of a terrestrial mountain; they are modul- ated by the throttled pulsar´s spin (of period 5s to 10s), and soften and tail off within some 102 sec. They form basic events, [Piran (2005)]. • The long GRBs are superpositions of short GRBs, cf. the July 1994 accretion by Jupiter of comet Shoemaker-Levy. • Part of the (hot) accreted blob rises to a large scale-height, and gets centrifugally ejected, as a transluminal, baryonic burst. • Occasionally, accretion onto a throttled pulsar can trigger additional high-energy activities, of much longer duration (than 103 sec). • SN-like afterglow lightcurves result because of SN-like ejections.

  14. GAMMA-RAY-BURST PROPERTIES Long Short Wolfgang Kundt, 27. September 2006

More Related