1 / 53

GRBs and cosmology

Stockholm 1/9/2006 GLAST Collaboration meeting GRB symposium. GRBs and cosmology. Ghirlanda Giancarlo INAF- Osservatorio Astronomico di Brera. G. Ghisellini, C. Firmani, D. Lazzati, V. Avila-Reese, L. Nava, M. Nardini, F. Tavecchio. F(). Prompt emission spectrum. GRB Peak Energy

bree
Download Presentation

GRBs and cosmology

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. Stockholm 1/9/2006 GLAST Collaboration meeting GRB symposium GRBs and cosmology Ghirlanda Giancarlo INAF- Osservatorio Astronomico di Brera G. Ghisellini, C. Firmani, D. Lazzati, V. Avila-Reese, L. Nava, M. Nardini, F. Tavecchio

  2. F() Prompt emission spectrum GRB Peak Energy Epeak (i.e. where most of power comes out) Eiso = 4  dL(z)2 F(E,z,…) dE 1+z E

  3. Peak energy – Isotropic energy Correlation 9+2 BeppoSAX GRBs Epeak  Eiso0.5 Amati et al. 2002 Epeak(1+z) Rest Frame Eiso

  4. + 21 GRBs (Batse, Hete-II, Integral) Ghirlanda, Ghisellini, Lazzati 2004 Amati 2006 (most recent update) Epeak  Eiso0.5 X2=357/28 Epeak(1+z) Eiso

  5. The Skeptic list 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Ep-Eiso

  6. Huge isotropic equivalent energy! Assume Isotropy GRB typical Fluence (i.e. time int. flux) is 10-8 – 10-4 erg/cm2 (1keV – 10 MeV) GRB Global (isotropic) energetics 42 GRBs with z

  7. Afterglow light curve presents achromatic break Evidence that the GRB outflow is collimated within a jet with a certain opening angle AG break time Jet opening angle GRB 990510 – Israel et al. 1999

  8. + 21 GRBs (Batse, Hete-II, Integral) ? 1-cos(q) Ghirlanda, Ghisellini, Lazzati 2004 Epeak  Eiso0.5 Epeak(1+z)

  9. Peak energy vs. True energy cr2=1.27 Epeak  Etrue0.7 Ghirlanda, Ghisellini & Lazzati 2004 Epeak(1+z) Epeak(1+z)

  10. The Skeptic list Hidden variable jet (also sample variance) 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Ep-Eiso

  11. Outliers wrt the Ep-Eiso correlation view GRBs observed off-axis jet (Ramirez-Ruiz 2005, Yamazaki et al. 2004; Eichler & Levinson 2005) incident transmitted Klein-Nishina absorption t(E) Ghisellini et al. 2006 Pb: most luminous events (but @ z<0.1!!) Presence of absorbing material (Boettcher 1997, Dermer 1998, Barbiellini et al. 2004) incident Pb: Large amount of material may influence the afterglow (accel). + should explain why only in 2 cases transmitted incident transmitted

  12. Outliers wrt the Ep-Eiso correlation GRB 060218 SN 2006dh Z=0.033 (0.008 & 0.106) Eiso=9e49 erg Ep=6 keV See also NEWS & VIEWS at the end of the presentation! GRB 060218

  13. 060218 Outliers wrt the Ep-Eiso correlation 060218 If no XRT data (only BAT) Ep=50 keV ; Eiso=2.e49 erg It would have been the 3rd outlier!! 0-2600 sec 2000-2600 sec Strong H2S spectral evolution + Long duration (3000 sec) 0-200 sec Considerable soft X-ray emission i.e. lower Ep and larger Eiso Ghisellini et al. 2006

  14. Outliers wrt the Ep-Eiso correlation Dust scattering halo reconstructed flux Integral

  15. Outliers wrt the Ep-Eiso correlation Scattering material Spectral evolution

  16. The Skeptic list Hidden variable (jet) (also sample variance) 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Strong spectral evolution (or abs. material) Ep-Eiso Debate: Nakar & Piran 2005 + Band et al. 2005 vs Ghirlanda et al. 2005 + Bosnjak et al. 2006

  17. Selection effects of the Ep-Eiso (Eg) correlation TEST: 443 Long Batse GRBs with (independent) Pseudo-z estimated from the Lag-Lum correlation Ghirlanda et al. 2005 Pseudo-z GRBs define a correlation in the Ep-Eiso plane which is consistent with the same correlation found with the few spec-z GRBs (see also angle distribution) Recently the update of the sample to 41 (Amati et al. 2006) makes the corr more roboust.

  18. The Skeptic list Hidden variable (jet) (also sample variance) 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Strong spectral evolution (or abs. material) Ep-Eiso Consistent with large burst population. If any sel effect is only the angle (as expected)

  19. … towards “GRBs as standard candles” …

  20. Perlmutter 1998 Similar to Supernovae Ia “Stretching”: the slower the brighter

  21. E=1051 erg Luminosity distance Stretch-lum (SNIa) Ep-Eg correlation (GRB) Luminosity distance redshift E=1051 erg Luminosity distance The correlation reduces the scatter of GRBs in the Hubble Diagram GRBs can be used as cosmological RULERS ! redshift

  22. Ghirlanda et al. 2006 A&A

  23. Homogeneous density Nava L. et al. 2006

  24. Wind density profile n=r-2 Linear! “Lorentz invariant” Ng~const~1057 Nava et al. 2006

  25. Linear is even better for cosmology Ghirlanda et al. 2006 A&A

  26. The Skeptic list Hidden variable (jet) (also sample variance) 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Strong spectral evolution (or abs. material) Ep-Eiso Consistent with large burst population jet Ep-Eg 6) Correlations are model dependent std cndl

  27. A completely empirical correlation between prompt (Ep, Eiso) and afterglow properties (tbreak) (Liang & Zhang 2005) Nava L. et al. 2006

  28. Model dependent: uniform jet + homogeneous density Model dependent: uniform jet + wind density Through simple algebra it can be verified that the model dependent correlations are consistent with the empirical correlation! (Nava et al. 2006) EMPIRICAL

  29. … still not convinced ? … A new correlation between Liso, Ep, T0.45 Good fit Consistent with other corr ONLY PROMPT EMISSION PROPERTIES Firmani et al. 2006

  30. Cosmological Constraints with the Liso-Ep-T0.45 correlation 156 SN Ia 156 SN Ia 19 GRBs 19 GRBs Firmani et al. 2006a

  31. 115 SN Ia GRBs + Legacy SNIa 19 GRBs + 115 SN Ia 68% CL 68% CL GRB+SN prefer CDM 68% CL Firmani et al. 2006b

  32. The Skeptic list Hidden variable (jet) (also sample variance) 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Strong spectral evolution (or abs. material) Ep-Eiso Consistent with large burst population jet Ep-Eg 6) Correlations are model dependent 2 model independent correlations testify the possible use of GRBs as standard candles std cndl

  33. Model dependent correlations GRBs can be used as standard candles! Model independent correlations

  34. News & Views:SN shock breakout in GRB060218/SN2006aj ? UV ~ n2 X-ray  black body SN shock breakout GRB060218/SN2006aj XRT UVOT BUT If 1 single UV-X BB L>1048erg/sec  Erad>1051 erg [Ekin(SN)~1051 erg] If UV-BB is SN shock breakout Vphot>c If X-BB is SN shock breakout Vphot~3000 km/s (too small) Ghisellini, Ghirlanda & Tavecchio 2006 MNRAS submitted (astro-ph/0608555)

  35. GRB060218/SN2006aj Opt-UV to X-ray emission is Synchrotron-Self Compton (with self absorption) up to 105 sec GG,GG,FT astro-ph/0608555

  36. The Thermal Black Body in X-ray (20-50% of the tot flux up to 7000 sec) could be: 1) The leftover of the fireball accel. 2) The conversion of internal energy (e.g. B reconn.) below the photospheric radius) GG,GG,FT astro-ph/0608555

  37. Backup slides

  38. … what about the future? 150 Fake GRBs Z(SFR), tbreak,Ep,Eiso Following the wind Ep-Eg correlation Ghirlanda et al. 2006

  39. VERY PROMISING!! Ghirlanda et al.2006 A&A Ghirlanda et al. 2006 JOP Review, GRB Special Issue

  40. jet The Skeptic list Hidden variable (jet) (also sample variance) 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Strong spectral evolution (or abs. material) Ep-Eiso Consistent with large burst population 4) Jet breaks are not achromatic 5) No preference for wind from obs Ep-Eg 6) Correlations are model dependent std cndl

  41. Complex light curve with many, superimposed, flares Jet break is a smooth transition Still computed with fixed micro-physical parameters Falcone et al. 2006 Cusumano et al. 2006

  42. The Skeptic list Hidden variable (jet) (also sample variance) 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Strong spectral evolution (or abs. material) Ep-Eiso Consistent with large burst population jet 4) Jet breaks are not achromatic 5) No preference for wind from obs Complex X-ray (see also point 8) Ep-Eg 6) Correlations are model dependent std cndl

  43. Panaitescu et al. 2006

  44. The Skeptic list Hidden variable (jet) (also sample variance) 1) Large dispersion 2) Presence of 2 outliers 3) Possible selection effects Strong spectral evolution (or abs. material) Ep-Eiso Consistent with large burst population jet 4) Jet breaks are not achromatic 5) No preference for wind from obs Complex X-ray (see also point 8) Ep-Eg Variable micro-physics 6) Correlations are model dependent std cndl

  45.  , Surf. Jet half opening angle Relativistc beaming: emitting surface  1/ Log(F) Jet break Log(t) Jet effect  >> 1/  1/

  46. If angle distribution is uniform

  47. If angle distribution is peaked Small q, brighter

  48. with z with pseudo-z Ghirlanda et al. 2005, MNRAS

  49. … and its evolution (even darker) Flat Universe: Wtot=1,WM=0.27 P=(w0+w’z)rc2 Firmani, Ghisellini, Ghirlanda & Avila-Reese, 2005

More Related