1 / 98

Gamma-Ray Bursts: Recent Progress and Relation with Cosmology Dai Zigao Nanjing University

Gamma-Ray Bursts: Recent Progress and Relation with Cosmology Dai Zigao Nanjing University. Five eras 1) “Dark” era (1973-1991): discovery Klebesadel, Strong & Olson’s discovery (1973); 2) BATSE era (1992-1996): spatial distribution Meegan & Fishman’s discovery (1992),

aitana
Télécharger la présentation

Gamma-Ray Bursts: Recent Progress and Relation with Cosmology Dai Zigao Nanjing University

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. Gamma-Ray Bursts: Recent Progress and Relation with CosmologyDai ZigaoNanjing University

  2. Five eras 1) “Dark” era (1973-1991): discovery Klebesadel, Strong & Olson’s discovery (1973); 2) BATSE era (1992-1996): spatial distribution Meegan & Fishman’s discovery (1992), detection rate: ~1 to 3 /day, ~3000 bursts; 3) BeppoSAX era (1997-2000): afterglows van Paradijs, Costa, Frail’s discoveries (1997); 4) HETE-2 era (2001-2004): origin of long bursts Observations on GRB030329/SN2003dh 5) Swift era (2005-): early afterglows? short-GRB afterglows? subclasses? GRB cosmology? …

  3. Gamma-ray bursts are short-duration flashes of gamma rays occurring at cosmological distances.

  4. Gamma-Ray Bursts Temporal features: diverse and spiky light curves

  5. log GRB spectra: broken power laws with Ep of a few tens to hundreds of keV

  6. Sagar et al. (2001) achromatic break Afterglows: broken light curves suggest jets. Edge effect Sideways expansion

  7. Afterglow g-rays Inner Engine Relativistic Wind Internal Shocks External Shocks The Standard Internal-External Shock Model

  8. Gamma-ray bursts: recent progress

  9. 2004－2005年GRB组工作汇报（1）* Dai 2004, ApJ, 606, 1000 For the Crab Nebula (see Figure), the successful models were proposed byRees & Gunn (1974) and Kennel & Coroniti (1984): a relativistic wind from the Crab pulsar interacts with the supernova ejecta. Kennel & Coroniti (1984)

  10. Similarly, after GRB, a highly magnetized millisecond pulsar continues to produce a relativistic e-/e+ pair wind. The interaction of the wind with an outward-expanding fireball or jet implies a post-burst energy injection. • Thus, in an afterglow, a relativistic e-/e+ pair (possibly magnetized) wind from a millisecond magnetar is expected and its interaction with a post-burst fireball or jet produces a relativistic wind bubble, asa relativistic version of the Crab Nebula.

  11. Ambient gas (zone 1) Shocked ambient gas (zone 2) Shocked wind (zone 3) A relativistic e-e+ wind (zone 4) Forward shock (S2) Black hole Reverse shock (S1) Contact discontinuity Schematic sketch for the structure of a relativistic wind bubble

  12. The wind luminosity from a pulsar due to magnetic dipole radiation: This luminosity decays as:

  13. At the contact discontinuity (CD) surface, the similarity variable is Define a critical time at which  = 1, We obtain three temporal phases: Phase 1:t < tcr ( > 1); Phase 2:tcr < t < TM,0 ( = 1); Phase 3:t > TM,0.

  14. Phase 1 The Lorentz factor of zone 2 decays as the Blandford-McKee solution, The Lorentz factor of zone 3 declines as

  15. Phase 2 From energy conservation, the dynamics of the wind bubble is given by A solution of this equation is This temporal feature is consistent with Dai & Lu (1998, Phys. Rev. Lett., 81, 4301).

  16. Phase 3 The Lorentz factor of zone 2 still decays as γ2 t-3/8. But, zone 3 expands adiabatically because energy injection can be neglected (Lw t-2). Light curves Assuming synchrotron radiation as in the standard afterglow model, we obtain light curves of the emission from an ultra-relativistic wind bubble during three phases (see Figure).

  17. 2004－2005年GRB组工作汇报（2） Huang Yong-Feng et al. (2004, ApJ, 605, 300)：该文在意大利召开的第四次 “伽玛暴”国际学术会议上被Lamb、Kawai、Butler等人重点介绍。该工作证实了Huang et al. (2002, MNRAS, 332, 735)的推测。这两篇文章与Huang et al. (1999, MNRAS, 309, 513)一起为GRB和XRF及其余辉提供了清晰的统一图像。

  18. 2004－2005年GRB组工作汇报（3） Effect of the prompt radiative efficiency:Xu Lei & Dai Z.G. (2004, ChJAA, 4, 267)

  19. 2004－2005年GRB组工作汇报（4）* An Ep – Lγ,iso correlation of 2408 spectra of 91 BATSE bursts: Liang En-Wei, Dai Z.G. & Wu X.F. (2004, ApJ Letters , 606, L29)

  20. 2004－2005年GRB组工作汇报（5）* A bimodal distribution of the peak energy of 57 HETE-2 bursts: Liang En-Wei & Dai Z.G. (2004, ApJ Letters, 608, L9)

  21. 2004－2005年GRB组工作汇报（6）* Wu Xue-Feng, Dai Z.G. & Liang E.W. 2004, ApJ, 615, 359-365

  22. 2004－2005年GRB组工作汇报（7） Analytical generic model of afterglowsWu Xue-Feng, Dai Z.G., Huang Y.F. & Lu T. 2005, ApJ, 619, 968 ISM case Wind case

  23. 2004－2005年GRB组工作汇报（8） Fitting to polarization of GRB020813Wu Xue-Feng, Dai Z.G., Huang Y.F. & Lu T. 2005, MNRAS, in press

  24. 2004－2005年GRB组工作汇报（9）* A radio afterglow of the 2004 December 27 giant flare of the soft gamma repeater 1806-20 Wang X.Y., Wu X.F., Fan Y.Z., Dai Z.G. & Zhang B. 2005, ApJ Letters, in press (astro-ph/0502085) • Previous Giant Flares: • SGR 0526-66, 1979.3.5 • SGR 1900+14, 1998.8.27 • SGR 1806-20, 2004.12.27, detected by all the gamma-ray detectors

  25. A tremendous flaredetected by RHESSI Hurley et al. (2005), Nature, submitted, astro-ph/0502329 Precursor (before ~142 s): rise time ~45 ms & fall time ~150 ms

  26. Hurley et al. (2005): ~3.51046 ergs in 0.2 sec

  27. Pulsed tail Initial hard spike

  28. Summary: The Dec 27 Giant Flare (~15 kpc) Origin from amagnetar (with strength of ~1015G and period of several seconds): starquake magnetic reconnection  energy release  fireball

  29. Mazets et al., Nature, submitted: the reflected signal detected by Helicon-Coronas-F G1: 16.5–65 keV G2: 65–280 keV G3: 280–1060 keV

  30. Gaensler et al. (2005), Nature, accepted, astro-ph/0502393: a radio afterglow

  31. Cameron et al. (2005), Nature, submitted, astro-ph/0502428: a radio afterglow

  32. New information Size and polarization (Gaensler et al. 2005)

  33. Numerical fits: Wang et al. (2005, ApJ Letters, in press); Predicted by Huang, Dai & Lu (1998, Chin. Phys. Lett.)

  34. Early optical/infrared afterglow • However, heavy extinction AV~30 • Infrared observations

  35. 10 papers put to astro-ph (7 papers submitted to Nature) • 1. astro-ph/0502052 • Title: Giant Flares as Mini Gamma Ray BurstsAuthors: Ehud Nakar, Tsvi Piran, Re'em Sari • 2. astro-ph/0502085 • Title: An energetic blast wave from the December 27 giant flare of SGR1806-20Authors: X. Y. Wang, X. F. Wu, Y. Z. Fan, Z. G. Dai, B. ZhangComments: 10 pages, 2 figures, accepted by ApJ Letters, cited by Cameron et al. • 3. astro-ph/0502315 • Title: GEOTAIL observation of the SGR1806-20 Giant Flare: The first 600 msAuthors: Toshio Terasawa et al.Comments: 6 pages, 2 color figures, submitted to Nature • 4. astro-ph/0502320 • Title: Giant flare of SGR 1806-20 from a relativistic jetAuthors: Ryo Yamazaki, Kunihito Ioka, Fumio Takahara, Noriaki ShibazakiComments: 7 pages, 2 figures, submitted to Nature • 5. astro-ph/0502329 • Title: A tremendous flare from SGR1806-20 with implications for short-duration GRBs • Authors: K. Hurley et al. • Comments: 27 pages, 5 figures, submitted to Nature

  36. 6. astro-ph/0502393 Title: An expanding radio nebula produced by a giant flare from the magnetar SGR 1806-20 Authors: B. M. Gaensler et al. Comments: 13 pages, Nature, in press 7. astro-ph/0502428 Title: Discovery of a Radio Afterglow following the 27 December 2004 Giant Flare from SGR 1806-20 Authors: P. B. Cameron et al. Comments: 14 pages, 2 figures, submitted to Nature 8. astro-ph/0502541 Title: The Konus-Wind and Helicon-Coronas-F detection of the giant gamma-ray flare from the soft gamma-ray repeater SGR 1806-20 Authors: E.P.Mazets et al. Comments: 5 pages, 7 figures, submitted to Nature 9. astro-ph/0502577 Title: The first giant flare from SGR 1806-20: observations with the INTEGRAL SPI Anti-Coincidence Shield Authors: S. Mereghetti et al. Comments: submitted to ApJ Letters 10. astro-ph/0503030 Title: Gamma-Ray Observations of a Giant Flare from The Magnetar SGR 1806-20 Authors: D. M. Palmer et al. Comments: Nature, in press

  37. II. GRB Cosmology Studies on cosmic structure, evolution, and dark energy with gamma-ray bursts • High-z (even first-) star-formation rate • High-z intergalactic medium(reionization) • Cosmic expansion and dark energy Ciardi & Loeb 2000, ApJ, 540, 687

  38. WMAP observations on the CMB anisotropy:4% ordinary matter, 23% dark matter, and 73% dark energy. This is because the “sound” of the early universe—the relative abundances and sizes of the hot and cold spots in the CMB—depend on the composition of the universe and its shape.

  39. GRB 030329 - SN 2003dh; • High polarization of GRB 021206; • X-ray flashes; • Dark bursts; • Short bursts in the Swift era. 2003, Science, 302, 2042-2043

  40. GRB ? ? Dark energy Dark matter PHYSICS

  41. Couldgamma-ray burstsbe used to measurecosmology?

  42. Outline • Analytical foundation • Supernova cosmology • GRB cosmology • Comparison and prospect

  43. 1. Analytical foundation

  44. Einsteinequations Friedmann equations However, these equations cannot explain an assumed static, closed universe (Einstein 1917)!

  45. Einsteinequations with  Friedmann equations These equations can explain an assumed static universe, but this is in an unstable equilibrium.Eddington (1932) thought the observed Hubble expansion might well be just the first-order view of a universe accelerating from rest because of .

  46. Einstein’s comments on  After learning of Hubble’s (1929) work, he smote himself on the forehead and declared  “perhaps the biggest blunder of my life”. --- Gamow’s autobiography In 1932, he and DeSitter wrote about , “An increase in the precision of data derived from observations will enable us in the future to fix its sign and determine its value”. In a 1947 letter to Lemaitre, he wrote, “Since I introduced this term, I had always a bad conscience. … I am unable to believe that such an ugly thing should be realized in nature”.

  47. The checkered history of (Summarized by Perlmutter et al. 1999, PRL, 83, 670) • Advocated by Einstein to construct a static universe, but discarded after the discovery of the expansion; • Revived by Hoyle, Bondi, & Gold to solve an age crisis, but later resolved by a smaller Hubble constant; • Put forth to explain the abundance of quasars at z~2, but now known to be due to the evolution of quasars themselves.

  48. deceleration acceleration Krauss, L. M. 1999, Scientific American

More Related