1. E. Pian – LNGS, 13 Sep 2005 Elena Pian - INAF, Trieste Astronomical Observatory, Italy LNGS Summer Institute 2005 GRB: Modern Status

2. E. Pian – LNGS, 13 Sep 2005 Outline Connection between Supernovae and long GRBs / X-ray Flashes Swift: early GRB counterparts Short Gamma-Ray Bursts

3. E. Pian – LNGS, 13 Sep 2005 Bimodal distribution of GRB durations short long The progenitors of short bursts are still to be identified!!! Binary neutron stars? Kulkarni 2000

4. E. Pian – LNGS, 13 Sep 2005 Bloom et al. 1998,1999

5. E. Pian – LNGS, 13 Sep 2005 GRB host galaxies: EW of [O II] emission line Djorgovski 2001 SFR ~ 0.1-10 M /yr millimetric: up to ~500 M /yr O II 3727 Å

6. E. Pian – LNGS, 13 Sep 2005 z = 0.8 GRB990123 (z = 1.6) V ~ 23.5 GRB020405 (z = 0.695) GRB990510 (z = 1.6) V(host) = 28.5 ! GRB990712 z = 0.43

7. E. Pian – LNGS, 13 Sep 2005 Colors of host galaxies are very blue (compare, e.g., with Hubble Deep Field) Fruchter et al. 1999 GRB hosts

8. E. Pian – LNGS, 13 Sep 2005 Schaefer et al. 2002 Keck LRIS – Mirabal et al. 2003

9. E. Pian – LNGS, 13 Sep 2005 GRB980425 Supernova 1998bw (Type Ic) z = 0.0085

10. E. Pian – LNGS, 13 Sep 2005 GRB030329/SN 2003dh Si II 6355 Hjorth et al. 2003 z = 0.168 ESO VLT + FORS Photospheric velocity

11. E. Pian – LNGS, 13 Sep 2005 GRB021211/SN2002lt Della Valle et al. 2003

12. E. Pian – LNGS, 13 Sep 2005 Della Valle et al. 2003 z = 1.006 d

13. E. Pian – LNGS, 13 Sep 2005

14. GRB031202/SN2003lw z = 0.105 ESO VLT FORS Malesani et al. 2004

15. E. Pian – LNGS, 13 Sep 2005 z = 0.695 Galama et al. 2000 SN1998bw

16. E. Pian – LNGS, 13 Sep 2005 X-ray Flashes

17. E. Pian – LNGS, 13 Sep 2005 XRF030723 Fynbo et al. 2004 Tominaga et al. 2004 Soderberg et al. 2004

18. E. Pian – LNGS, 13 Sep 2005 Is there a unifying scheme for SNe and GRBs? Four clear cases of SN-GRB association have been detected spectroscopically, all are Type Ic SNe. In all of these, the SN is very powerful (high luminosity, large kinetic energy), i.e. it is a Hypernova (Paczynski 1998; Iwamoto et al. 1998) The rate of GRBs (taking into account collimation) corresponds to the relative rate of hypernovae with respect to the total number of Ic SNe (i.e. ~5%, Podsiadlowski et al. 2004) SNe with hypernova characteristics have been detected, although they are not accompanied by a GRB (SNe 1997dq, 1997ef, 2002ap, 2004aw…); see also IPN survey Do all hypernovae have jets and produce GRBs, so that only those aligned with the line of sight are detected? Can we test this unified scenario?

19. E. Pian – LNGS, 13 Sep 2005 Rates of GRBs and HNe These are lower than rate of SNe from massive stars: Podsiadlowski et al. 2004

20. E. Pian – LNGS, 13 Sep 2005 Type Ic SNe / Hypernovae Broad lines Large Kinetic Energy Hypernovae (only SN1998bw was associated with a GRB) Narrow lines normal KE (1 foe) Normal SN Ic Mazzali et al. 2002

21. E. Pian – LNGS, 13 Sep 2005 Signatures of asphericity in SN1998bw In nebular spectra of SN1998bw, Fe lines are broader than O lines A spherically symmetric explosion of a massive star would result in the opposite [FeII] 5200A [OI] 6300A SN 1998bw O Fe

22. E. Pian – LNGS, 13 Sep 2005 0.7 s 1.5 s 2D explosion : KE=11foe, M BH (final)=5.9M, M( 56 Ni)=0.11M Outflow Inflow Maeda et al. 2002

23. E. Pian – LNGS, 13 Sep 2005 56 Fe 16 O Spherical Aspherical FeII] 5200A [OI] 6300A SN 1998bw Aspherical explosion: confined nucleosynthesis Orientation 15 deg Maeda et al. 2002

24. E. Pian – LNGS, 13 Sep 2005 Another GRB/SN: SN2003dh The nebular spectrum shows a strong and narrow [O I]6300 line, like SN1998bw. Narrow-line model: v = 5000 km/s Broad-line model: v = 13000 km/s

25. E. Pian – LNGS, 13 Sep 2005 The bright Type Ic SN 2003jd Courtesy: K. Kawabata Discovered 25 Oct 2003; distance: 80 Mpc

26. E. Pian – LNGS, 13 Sep 2005 The bright Type Ic SN 2003jd SN 2003jd was as bright at peak as SN1998bw (Mv = -18.7) Early-time spectra had broad lines, similar to hypernova SN2002ap No GRB or XRF

27. E. Pian – LNGS, 13 Sep 2005 SN 2003jd: The [O I] 6300A line shows a double peak, suggesting an explosion similar to SN1998bw but viewed ~70° from the axis an aspherical SN viewed off-axis Mazzali et al. 2005, Science 308, 1284 Observations: Subaru+FOCAS, at 330 days Keck+LRIS, at 370 days Subaru

28. E. Pian – LNGS, 13 Sep 2005 Mg I] [Fe II][O I] [Ca II] Subaru+FOCAS Keck+LRIS SN2003jd: an aspherical supernova viewed off-axis Mazzali et al. 2005

29. E. Pian – LNGS, 13 Sep 2005 [O I] line: strong dependence on viewing angle Mazzali et al. 2005 [O I] nebular emission

30. E. Pian – LNGS, 13 Sep 2005 Was SN 2003jd also a GRB/HN? Radio and X-ray upper limits are not in contradiction with a GRB viewed off-axis X-ray radio Mazzali et al. 2005

31. E. Pian – LNGS, 13 Sep 2005 Swift Launched 20 Nov 2004

32. E. Pian – LNGS, 13 Sep 2005 Swift localization of GRBs

33. E. Pian – LNGS, 13 Sep 2005 Steep decline common Gets shallower around here Examples of Swift-XRT light curves Nousek et al. 2005

34. E. Pian – LNGS, 13 Sep 2005 Maiorano et al. 2004 GRB990123 Corsi et al. 2004 WFC PDS MECS 2-10 keV 15-28 keV

35. E. Pian – LNGS, 13 Sep 2005 GRB990123 (z = 1.6) Fruchter et al. 1999

36. E. Pian – LNGS, 13 Sep 2005 GRB041219a: Optical flash from internal shocks Akerlof et al. 1999; Vestrand et al. 2005 RAPTOR Internal shock ROTSE-I Reverse shock

37. E. Pian – LNGS, 13 Sep 2005 Optical Flashes Guidorzi et al. 2005

38. E. Pian – LNGS, 13 Sep 2005 GRB050502a z = 3.793 Liverpool 2m telescope + Robonet consortium Forward shock in ISM In variable density Environment Guidorzi et al. 2005

39. E. Pian – LNGS, 13 Sep 2005 BAT+XRT emission consistent with a single decay rate of 1.2±0.09 1 keV X-ray light curve GRB050509b (T 90 =0.04s) Gehrels et al. 2005

40. E. Pian – LNGS, 13 Sep 2005 Comparison with other X-ray transients

41. E. Pian – LNGS, 13 Sep 2005 GRB050509b Bloom et al. 2005 Host galaxy

42. E. Pian – LNGS, 13 Sep 2005 GRB050509b (z = 0.22) Upper limits on optical Flux are inconsistent With supernova Hjorth et al. 2005

43. E. Pian – LNGS, 13 Sep 2005 t -4 ν -1 GRB050724 looks long to BAT (T 90 =153s), but would be short to BATSE (<1s) GRB050724 (z = 0.257)

44. E. Pian – LNGS, 13 Sep 2005 Optical afterglow of the short GRB050724 (T = 0.25 s) Berger et al. 2005

45. E. Pian – LNGS, 13 Sep 2005 Host Galaxy of the Short GRB050724 (z = 0.257) Bloom et al. 2005 SFR < 0.03 Msun/yr

46. E. Pian – LNGS, 13 Sep 2005 Isotropic irradiated –ray energy vs redshift GRB/SN Short GRB GRB050904 z = 6.29

47. E. Pian – LNGS, 13 Sep 2005 SNe/GRB: the X-ray light curves Initial X-ray flux is Very different: afterglow-like emission in GRB-SNe? Kouveliotou et al. 2004 Pian et al. 2004

48. E. Pian – LNGS, 13 Sep 2005 X-ray properties of Core Collapse SNe Compare to predictions of standard (1foe) jet model for different orientations SNe follow the trend, but a universal jet cannot explain all SNe Pian et al., in prep.

49. E. Pian – LNGS, 13 Sep 2005 X-ray properties of Core Collapse SNe With normalisation GRB/SNe angles agree with results from optical spectra SN2003dh jet was stronger ? SN2002ap jet was very weak ? Alt: Differences in jet or in ISM properties?

50. E. Pian – LNGS, 13 Sep 2005

51. Properties of GRB/HNe: Photospheric velocities Velocity also seems to be proportional to global properties: GRB/SNe have the highest velocities

52. E. Pian – LNGS, 13 Sep 2005 Conclusions The nebular spectrum of the Type Ic energetic SN2003jd is different from that of SN1998bw: it exhibits a double-peaked [O I] emission line, which suggests an aspherical geometry and an equatorial view. This is consistent with the lack of a detected GRB, and could support a unified scenario for SNe and GRBs Are hypernovae the most aspherical SNe? Possibly, and this would be related to the presence of GRBs In this picture, X-ray flashes may be off-axis GRBs or weaker explosions Short GRBs have afterglows similar to those of long GRBs. They are Preferentially detected at lower redshifts, and in galaxies with scarce Star formation. The evidence that they are not associated with supernovae is increasing. They are probably double neutron star mergers Are hypernovae the only aspherical SNe Ic? No, normal Ic are polarized Optical flashes probe the early emission mechanisms and circumburst medium