1. L. Piro - ILIAS meeting - 20081 Gamma-Ray Bursts Luigi Piro Istituto Astrofisica Spaziale Fisica Cosmica - Roma INAF

2. L. Piro - ILIAS meeting - 20082 Summary GRB: the breakthroughs of the last decade GRB: the breakthroughs of the last decade Main theoretical and observational background Main theoretical and observational background Clues to the progenitors Clues to the progenitors Open issues Open issues Cosmological Perspectives Cosmological Perspectives

3. L. Piro - ILIAS meeting - 20083 BeppoSAX: GRB in the afterglow Era Launch: Apr. 30, 1996 Launch: Apr. 30, 1996 End ops: April 30, 2002 End ops: April 30, 2002 Discovery of the afterglows of GRB Discovery of the afterglows of GRB Discovery of the extragalactic distances Discovery of the extragalactic distances Progenitor: Association with SN and star formation in distant galaxies Progenitor: Association with SN and star formation in distant galaxies Dark GRB’s and X-ray flashes Dark GRB’s and X-ray flashes Cosmology with GRB Cosmology with GRB

4. L. Piro - ILIAS meeting - 20084 GRB970228: the 1st X-ray and O afterglow A second pointing 3 days after the GRB: fading X-ray counterpart (Costa et al 1997) Optical fading source (van Paradijs et al 1997) Fast follow up with NFI in 8 hrs: a bright unknown X- ray source

5. L. Piro - ILIAS meeting - 20085 Internal vs external shock: prompt & afterglow emission In contrast with the afterglow, the prompt emission is characterized by strong hard- to-soft spectral evolution from X- to Gamma rays (e.g. GRB960720 Piro et al 1997) In contrast with the afterglow, the prompt emission is characterized by strong hard- to-soft spectral evolution from X- to Gamma rays (e.g. GRB960720 Piro et al 1997)

6. L. Piro - ILIAS meeting - 20086 The fireball model 10 6 cm   t -1 10 16 cm 10 13 cm t aft X-ray afterglow  RB t GRB

7. L. Piro - ILIAS meeting - 20087 Afterglow spectrum: fireball model Galama et al 98

8. L. Piro - ILIAS meeting - 20088 GRB970508: direct evidence of fireball Discovery of the radio afterglow Discovery of the radio afterglow Direct evidence of a relativistic expanding source by radio scintillation induced by electrons in the Galaxy ISM (3 uarcsec) Direct evidence of a relativistic expanding source by radio scintillation induced by electrons in the Galaxy ISM (3 uarcsec)

9. L. Piro - ILIAS meeting - 20089 The progenitors of GRB NS-NS (BH-NS & BH-WD) travel far from their formation sites before producing GRB’s (Fryer et al 2000) => “clean environment” The nature of the progenitor can be inferred from the environment NS- NS merging NS- NS merging Collapsar Hypernovae/collapsar evolve much faster, going off in their formation site => “mass-rich environment”

10. L. Piro - ILIAS meeting - 200810 Progenitors and hosts Fryer, Woosley and Hartmann 1999

11. L. Piro - ILIAS meeting - 200811 The fading OT of GRB990123

12. L. Piro - ILIAS meeting - 200812 Host galaxies of long GRBs: Normal (spiral) showing star formation Host galaxies of long GRBs: Normal (spiral) showing star formation most GRB within the half-light radius of the galaxy: star- formation sites and massive progenitors most GRB within the half-light radius of the galaxy: star- formation sites and massive progenitors

13. L. Piro - ILIAS meeting - 200813 X-ray absorption in the GRB local environment X-ray absorption column densities in the afterglow: NH=10 21-22 cm -2 (Stratta et al 2000, Campana et al 2006) Consistent with Giant molecular clouds

14. L. Piro - ILIAS meeting - 200814 GRB-SN connection GB980425: in the BeppoSAX error box: SN1998bw (Pian et al. 99,Kulkarni et al, Galama et al al 98). Exploded within 1 day from the GRB. Chance P=1E-4 GB980425: in the BeppoSAX error box: SN1998bw (Pian et al. 99,Kulkarni et al, Galama et al al 98). Exploded within 1 day from the GRB. Chance P=1E-4

15. L. Piro - ILIAS meeting - 200815 GRB-Sn: 030329 Sn contribution should appear when the power-law GRB afterglow has decreased (Bloom et al 98: GRB980326) Sn contribution should appear when the power-law GRB afterglow has decreased (Bloom et al 98: GRB980326) GRB030329: The nearest (and the brightest in HETE2 GRB) z=0.168 (Greiner et al, VLT) GRB030329: The nearest (and the brightest in HETE2 GRB) z=0.168 (Greiner et al, VLT) SN spectrum (similar to 1998bw) emerging at about 10 days (Matheson et al 03, Hjorth et al 03). SN spectrum (similar to 1998bw) emerging at about 10 days (Matheson et al 03, Hjorth et al 03).

16. L. Piro - ILIAS meeting - 200816 GRB (high  ) XRF (low  ) Sub energetic X-ray flashes Woosley et al Collapsar model

17. L. Piro - ILIAS meeting - 200817 Jet vs spherical expansion: break in the afterglow light curve t1t1 t2t2 t3t3 t4t4 t5t5 F t t4t4 Jet Spher.    (t 4 )=  The break must be achromatic

18. L. Piro - ILIAS meeting - 200818 Simultaneous O and X-ray light curves of GB990510 Break in the O at t= 1day (Harrison et al 99) Break in the O at t= 1day (Harrison et al 99) BeppoSAX light curve compatible with break ( Kuulkers et al 2000, Pian et al01) but not required (Piro et al.00) BeppoSAX light curve compatible with break ( Kuulkers et al 2000, Pian et al01) but not required (Piro et al.00) SWIFT data show a variety of behaviour, achromatic breaks are a small fraction. SWIFT data show a variety of behaviour, achromatic breaks are a small fraction. 1 10 T-T0(days)

19. L. Piro - ILIAS meeting - 200819 X-ray flashes A New class discovered by BSAX and confirmed by HETE2: about 40% GRB’s with no or very faint or gamma-ray emission A New class discovered by BSAX and confirmed by HETE2: about 40% GRB’s with no or very faint or gamma-ray emission high redshift GRBs high redshift GRBs off-axis events off-axis events Subenergetic events, more numerous than normal GRBs Subenergetic events, more numerous than normal GRBs Heise et al 2001

20. L. Piro - ILIAS meeting - 200820 XRF host galaxies 2 of XRF localized by BSAX and followed up by Chandra, 2 of XRF localized by BSAX and followed up by Chandra, more redshift by SWIFT at z<3 (Gendre, Galli, LP, 2007) more redshift by SWIFT at z<3 (Gendre, Galli, LP, 2007) XRF GRB

21. L. Piro - ILIAS meeting - 200821 GRB seen off axis: GW trigger + orphan Opt/X-ray afterglows 10 6 cm   t -1 10 16 cm 10 13 cm  RB t GRB t aft X-ray afterglow

22. L. Piro - ILIAS meeting - 200822 Dark GRBs BeppoSAX showed that >90% GRB are followed by X-ray afterglows. Confirmed by SWIFT. However only about 40% have optical afterglows. BeppoSAX showed that >90% GRB are followed by X-ray afterglows. Confirmed by SWIFT. However only about 40% have optical afterglows. High z (z>5) events ? High z (z>5) events ?

23. L. Piro - ILIAS meeting - 200823 Short GRB’s Short GRB’s About 25% of GRB’s have durations <1 sec,down to few msec. No counterpart so far. Different progenitors (NS-NS mergers)? About 25% of GRB’s have durations <1 sec,down to few msec. No counterpart so far. Different progenitors (NS-NS mergers)? Paciesas et al 99 T 90 =40 ms Gehrels et al 05 GRB050509B

24. L. Piro - ILIAS meeting - 200824 Entering SWIFT

25. L. Piro - ILIAS meeting - 200825 HOST GALAXIES OF SHORT BURSTS: Elliptical AND Spiral GRB050509 GRB050724 GRB050709 GRB050813 GRB050906

26. L. Piro - ILIAS meeting - 200826 Temporal evolution for mergers Fryer, Woosley and Hartmann 1999

27. L. Piro - ILIAS meeting - 200827 Redshift distribution of long- & short- GRBs However, suggestions that at least 25% of short-GRBs are at z>0.7 (Berger et al. 2006) ( if they did not travel long distances from their HG)

28. L. Piro - ILIAS meeting - 200828 X-ray light curves of SHBs X-ray light curves of SHBs

29. L. Piro - ILIAS meeting - 200829 X-ray to prompt γ-ray fluence One explanation (but not unique): lower density in short GRBs

30. L. Piro - ILIAS meeting - 200830 1) Electromagnetic window:  Afterglow: properties of the environment (host galaxy, density,..)  SN features  Long: Yes (outliers?)  Short. NO 2) Gravitational waves by GRBs: Binary merger: a)in-spiral b) merger, c) ring down For collapsars NO inspiral THE GRB PROGENITORS LONG=COLLAPSAR SHORT=NS-NS mergers The tell tale feature from GW

31. L. Piro - ILIAS meeting - 200831 Time delay GW-GRB Collapsar case (e.g. Waxman and Meszaros 2003): Collapsar case (e.g. Waxman and Meszaros 2003): the jet inside the star can be subrelativistic the jet inside the star can be subrelativistic The jet stream needs to be maintained for several tens of seconds to overcome the pressure inside the star (cork effect) The jet stream needs to be maintained for several tens of seconds to overcome the pressure inside the star (cork effect) NS-NS mergers NS-NS mergers Much shorter Much shorter

32. L. Piro - ILIAS meeting - 200832 GRBs by VIRGO and LIGO bh-ns m 1 =12 M  m 2 =1.4 M  - - - in-spiral -  -merger ring-down Collapsar m 1 = m 2 =1 M  - - - - merger - - - - merger Initial Virgo Upgraded Virgo 2300 Mpc 280 Mpc 62 Mpc Upgraded Virgo Virgo 110 Mpc 27 Mpc 23 Mpc GRB 980425 d=40 Mpc GRB020618 D=130Mpc GRB050709 D=650Mpc

33. L. Piro - ILIAS meeting - 200833 1  0.5  Precursors, flares and central engine X-ray precursor X-ray precursor Hard prompt emission Hard prompt emission X-ray flare at 300 s with spectrum similar to the late afterglow X-ray flare at 300 s with spectrum similar to the late afterglow Piro et al. 05, ApJ.

34. L. Piro - ILIAS meeting - 200834 The canonical X-ray light curve after SWIFT Prompt: IS Prompt: IS, curvature emission Flattening: refreshed shocks, off axis jet, …. External shock (classical power law) Jet break X-ray flares

35. L. Piro - ILIAS meeting - 200835 X-ray Flares SWIFT: Burrows et al (2005) BeppoSAX: Piro et al (2005) Signature of long duration activity of the central engine SWIFT: about 40% X-ray afterglows showing X-ray flares on time scales >100 sec (Chincarini et al 2007)

36. L. Piro - ILIAS meeting - 200836 GRB050904: z=6.3 Kawai et al 2005 Kawai et al 2005 SWIFT X-ray data (Cusumano et al, Campana et al., Gendre et al) SWIFT X-ray data (Cusumano et al, Campana et al., Gendre et al) GRBs in the dark Universe

37. L. Piro - ILIAS meeting - 200837 GRBs as cosmological beacons GRBs as cosmological beacons measure the cosmic history of metals in GRB regions and their host galaxies measure the cosmic history of metals in GRB regions and their host galaxies pinpoint the formation of early population of luminous sources ignited in the dark Universe (z>7) pinpoint the formation of early population of luminous sources ignited in the dark Universe (z>7) Solve the missing baryon problem residing in the cosmic web filaments Solve the missing baryon problem residing in the cosmic web filaments

38. L. Piro - ILIAS meeting - 200838 Conclusions Progenitors Progenitors circumstantial evidence associating long events to Massive star (collapsar) and short events to mergers. circumstantial evidence associating long events to Massive star (collapsar) and short events to mergers. GW can be crucial GW can be crucial Central engine Central engine Still to be really understood (BH+AD) Still to be really understood (BH+AD) X-ray flares (and their GeV counterparts with AGILE and GLAST) as evidence of long duration engine (fragmented AD) X-ray flares (and their GeV counterparts with AGILE and GLAST) as evidence of long duration engine (fragmented AD) Fireball model Fireball model General agreement, but too simplistic: General agreement, but too simplistic: Jet breaks not so common as expected Jet breaks not so common as expected X-ray and optical appear to be decoupled X-ray and optical appear to be decoupled Cosmological Perspectives Cosmological Perspectives GRB can probe throughout the Universe from present era to dark ages GRB can probe throughout the Universe from present era to dark ages

39. L. Piro - ILIAS meeting - 200839 Conclusions for GW GW provide direct information on the central engine GW provide direct information on the central engine Good prospect of detections from nearby GRB with advanced LIGO/VIRGO using EM trigger Good prospect of detections from nearby GRB with advanced LIGO/VIRGO using EM trigger Rate should be 100 times larger than EM burst, due to collimation (EM counterpart: XRF and Orphan afterglows) Rate should be 100 times larger than EM burst, due to collimation (EM counterpart: XRF and Orphan afterglows) In the future GW could provide the trigger and coarse (1 deg position) to carry out fast follow up observations in X-rays with mission like EDGE to detect the orphan afterglows of GRB jets pointing away from earth In the future GW could provide the trigger and coarse (1 deg position) to carry out fast follow up observations in X-rays with mission like EDGE to detect the orphan afterglows of GRB jets pointing away from earth