Scienza dei GRBs dopo BeppoSAX & Swift

1. Scienzadei GRBs dopo BeppoSAX & Swift Gianpiero Tagliaferri INAF – OABr 13-16 Maggio, 2014

2. La scopertadei Gamma Ray Bursts • 1967-1973 satelliti Vela 4,5,6: cercanoraggiX e gamma per monitorareilrispetto del Geneva Limited Nuclear Test Ban Treaty del 1963 (nessun test nuclearenellospazio) • Scoperta di intensi flash di raggi Gamma di originecosmica: GAMMA RAY BURSTS (GRBs) (Klebesadel et al. 1973; Strong et al. 1974) • Centinaia di GRBs scoperti da varisatelliti • dagglianni 80. • - Nessuna idea sulladistanzadellesorgenti • I primimodellisibasavanosustelle a neutroni

3. CGRO : due tipi di GRBs • La durata dei GRBs ha una distribuzione bimodale (e.g. Briggs et al. 2002) • 0.1-1 s -> burst brevi • 10-100 s -> burst lunghi • I GRBs brevi hanno uno spettro più duro dei GRB lunghi(e.g. Fishman & Meegan, 1995;Tavani 1996)

4. BeppoSAX e l’eradegli afterglow, GRB970228: il primo afterglow otticoed X • Il rapido ripuntamento con i NFIs di BeppoSAX (8hr) ha permesso la scoperta di una sorgente brillante e sconosciuta • Un secondo puntamento 3 giorni dopo ha mostrato che la sorgente era più debole (Costa, et al., 1997) L’accuratezza della posizione X (~1 arcmin) ha portato all’identificazione con i telescopi da terra di una sorgente ottica che si indeboliva nel tempo Metzeger et al., 1997 I GRBs sono a distanze cosmologiche! (Van Paradijs, et al., 1997)

5. Gli spettri e le curve di luce degli afterglows: leggi di potenza • Fx(t) µ t-d, dx≈1.4 • Fx(n) µn-a, ax≈1.0

6. UVOT BAT BAT XRT UVOT XRT Spacecraft Spacecraft Il satellite Swift (USA, I, UK) Strumenti • BurstAlertTelescope (BAT) • Nuovi rivelatori CdZnTe • Scopre >100 GRBs per anno (dipende dalla logN-logS) • Il rivelatore di raggi gamma ad immagine più sensibile mai costruito • X-RayTelescope (XRT) • Posizione dei GRB al secondo d’arco • Spettroscopia CCD • Fotometria nel range 10-7-10-15 erg cm-2 s-1 • (UVOT) UV/Optical Telescope • Immagini al sub-arcsec • Spettroscopia con grism • Sensibilità alla 24thmag (1000 sec) • Finding chart per gli altri osservatori • Satellite • GRB scoperti a bordo in automatico • Ripuntamento automatico in 20 - 100 sec

7. >860 GRB 85% (91%) con scoperta di afterglow X ~60% con scoperta di afterglowottico >270 con redshift (41 prima di Swift) > 70 GRBsbrevilocalizzati (0 prima di Swift), piu’ di 20 con redshift) Short GRB Short GRB Fast Rise Exponential Decay Swift GRB Statistics

8. http://www.brera.inaf.it/Swift10/ 10 years of Swift

9. Un insieme delle curve di luce X di GRB visti da Swift Prompt (<Tp) PLDecay ОFlares ОEmission“Hump” O’Brien et al. 2006, ApJ 647, 1213

10. GRB050904: un tipicoesempio di GRB scoperto da Swift(a z=6.29 !!!)

11. GRBs ad alto redshift z = 6.29 GRB 050904 7 GRBs su 600 a z>5 z = 8.2 GRB 090423 Tagliaferri et al. 2005, Kawai et al. 2006 z = 9.4 GRB 090429B Salvaterra et al. 2009 Tanvir et al. 2009 Cucchiara et al. 2011

12. Universo lontano (quindi giovane) GRBs: le sorgenti ad alto-z più brillanti Metallicità z GRB Optical Brightness 9.4 090429B K = 19 @ 3 hrs 8.2 090423 K = 20 @ 20 min 6.7 080813 K = 19 @ 10 min 6.29 050904 J = 18 @ 3 hrs 5.6 060927 I = 16 @ 2 min 5.3 050814 K = 18 @ 23 hrs 5.11 060522 R = 21 @ 1.5 hrs Thöne et al. 2011 Savaglio 2006 Tasso di formazione stellare Kistler et al. 2009

13. GRB most important facts • GRB are cosmological (therefore large energetics, but how large? Depends on collimation ..; history of Star formation; beacon to study the Universe) • GRBs have large Γ(From GeV; msec variability; radio scintillation; theory) • Long & Short (but there are exceptions + extended emission) • SN connection (i.e. progenitors. But there are exceptions. Evidence can be gathered only from nearby, under-luminous GRBs, but see GRB130427A) • GW? (we do not have evidences so far, but with the Advanced-LIGO & -VIRGO short burst could be good candidate for the detection of GW)

14. GRBs a mystery or an opportunity? After more than 40 years we know a lot about GRB, still they are a big puzzle!! GRBs physics • What is the prompt? Which is the mechanism? • Who is the progenitor? (very massive star? Binary? Fast rotator? Coalescence? …) • What is left over? (BH? NS? nothing?) • Do we always have a SN associated to a long-GRB? • Why sometimes we have a precursor? What is it?

15. GRBs a mystery or an opportunity? After more than 40 years we know a lot about GRB, still they are a big puzzle!! GRBs as indicators • Are they a good tracer of SFR and star evolution? • Are they a good tracer of galaxy evolution and therefore of the history of the Universe? • Are they unbiased “illuminators” in & of the Universe? • Will they ever be good distance indicators? • GW UFFO SVOM

16. GRBs a mystery or an opportunity? After more than 40 years we know a lot about GRB, still they are a big puzzle!! So what do we need ideally, for the prompt? • Energy band: ≤1 keV – ≥50 MeV • Field of view: 2 steradiant • Sensitivity: ~1500 cm2 up to 10-20 keV; ~6000 cm2 up to 1 MeV • High time resolution (<1ms) • Good energy resolution (few hundreds eV <10 keV, 10-15% above) • X-ray polarisation

17. NIR spectrum for high z GRB

18. High resolution X-ray spectroscopy of high z GRB GRB afterglow at z=7 after 60s X-Rat Telescope on ORIGIN: 1000cm2, 2eV energy resolution

19. GRBs a mystery or an opportunity? After more than 40 years we know a lot about GRB, still they are a big puzzle!! So what do we need ideally, for the afterglow? • Fast repointing (<1min) • NIR telescope (1-1.5 m), good spectral resolution (R~3000) • X-ray imaging (few arcsec) and high energy resolution (few eV)

20. Global context - 2030 • Many of these will be concerned with time-domain phenomena (and high-z). • “The full realization of time domain studies is one of the most promising discovery areas of the decade.” - US Decadal review Tanvir, Paris presentation L2/L3

21. 2010 2020 2030 Swift ALMA Wide area, high energy is key to tying together many transient phenomena. Fast slewing, narrow field instruments enable detailed characterisation and follow-up. AdGW CTA JWST “The single most important message...is that we cannot afford to be without a satellite localizing GRBs in the era of 25-40 m optical/ IR telescopes” – Richard Ellis, summary of “Feeding the Giants” conference. LSST Euclid E-ELT SKA ATHENA Tanvir, Paris presentation L2/L3

22. Open questions in 2030 addressable via GRBs • Even post-JWST there will likely be crucial unsolved questions regarding formation of first stars and galaxies: • An increasing (dominant) proportion of high-z star formation appears to be taking place in intrinsically very faint galaxies, beyond the reach of JWST at z>8 ; the nature of those galaxies will hardly be known, but they will be GRB hosts. • Spectroscopy of even bright z>8 galaxies, with JWST and ELT will provide only limited information on global chemical evolution, which is key to understanding the earliest generations of stars; GRB afterglows will provide bright backlights for spectroscopy, and could give reliable redshifts even at z>13. • There may be no direct detections of population III sources; pop III collapsars predicted to produce GRB-like events. • Experiments such as LOFAR and SKA may tell us whenreionization occurred, but not directly how it occurred, which requires identifying the sources responsible and determining the escape fraction of ionizing radiation from them; GRBs allow us to map global star formation and study escape fraction and IGM neutral fraction via spectroscopy. Tanvir, Paris presentation L2/L3

23. Athena: the first stars and black holes Gamma Ray Burst at z=7 • When did the first generation of stars explode to form the first seed black holes and disseminate the first metals in the Universe? Jonker, O'Brien et al., 2013 arXiv1306.2336 • How do black holes grow and shape the Universe?

24. CONCLUSIONS • The study of GRB provides a lot of opportunity, nevertheless it is very unlikely that we will have a good mission in the next 10-15 years!! • But having a good GRB machine in the future is fundamental also for other research area (e.g. High-z, GW) • We have to work together with other communities (GW, transient, SNe, early Universe, SFR, metallicity & galaxy evolution ….) to strengthen our case and succeed in getting a good mission in the 2020-2030 timescale

25. CONCLUSIONS In any case we definitively need a high energy transient discovery mission in the period 2020-2030 good enough to work with E-ELT, JSWT, AdWG, SKA, CTA, LSST

26. http://www.brera.inaf.it/Swift10/ 10 years of Swift

27. BACK-UP

28. GAME: GRB and All Sky Monitor Experiment XRM: X-ray Monitor Si drift detectors (SDD) 1-50 keV 3srFCFoV Localisation <1 arcmin Sensitivity: 0.3 crab in 1s; 2 mCrab 50ks SGS: Soft Γ-Ray Spectrometer Phoswich scintillators 20-2000 keV 2.5 sr FWHM FoV Sensitivity 1 Crab in 1s 10 mCrab 1 day HXI: Hard X-ray Imager CZT detectors 10-200 keV 20ox20o FWHM FoV Localisation ~30 arcmin Sensitivity 1 Crab in 1s 10 mCrab 1 day

29. A-STAR accommodated on a rapid-slewing Myriade Evolutions platform for a Vega launch into a 30° low-earth orbit. Prompt alert downlink is via a HETE-like VHF subsystem. All sky survey pointings will be 20 mins each, resulting in 2 observations of every field per day and an exposure of 1 Msec per field per year. A-STAR 1 Swift XRT c/s is detectable in a single Lobster pointing. Julian Osborne (University of Leicester). Explosive Transients. Santorini. 15-20 Sept 2013 Lobster (Leicester + B/I/DK/PL/CH) Owl (IRAP, Toulouse & CEA, Saclay) FOV 17x52° Energy band 0.15-5.0 keV Positions 50% <30” Sensitivity 4x10-11 erg.cm-2.s in 103 s FOV 60x88° Energy band 4-150 keV Positions 2-10’ Sensitivity 2x10-10 erg.cm-2.s in 103 s

30. GAME: GRB and All Sky Monitor Experiment

31. Lobster wide-field focussing: Julian Osborne (University of Leicester). Explosive Transients. Santorini. 15-20 Sept 2013

32. Lobster development based on micro-channel optics in the MIXS instrument on ESA’s BepiColombo mission to Mercury Julian Osborne (University of Leicester). Explosive Transients. Santorini. 15-20 Sept 2013