1 / 30

Osservazioni multifrequenza dei GRB G. Tagliaferri (INAF – OABr)

Osservazioni multifrequenza dei GRB G. Tagliaferri (INAF – OABr). Astrofisica Gamma dallo Spazio in Italia: AGILE e GLAST 2-3 luglio 2007, ASDC-ESRIN, Frascati. CGRO Results:. GRBs are uniformly distributed! Fluence 10 -4 e i 10 -7 erg.

nibaw
Download Presentation

Osservazioni multifrequenza dei GRB G. Tagliaferri (INAF – OABr)

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. Osservazioni multifrequenza dei GRB G. Tagliaferri (INAF – OABr) Astrofisica Gamma dallo Spazio in Italia: AGILE e GLAST 2-3 luglio 2007, ASDC-ESRIN, Frascati

  2. CGRO Results: GRBs are uniformly distributed! Fluence 10-4 e i 10-7 erg • GRBs duration distribution is BIMODAL (Briggs et al. 2002, Kouveliotou et al. 1993) • 0.1-1 s -> Short bursts • 10-100 s -> Long bursts • Short GRBs are harder than long GRBs(e.g. Fishman & Meegan, 1995;Tavani 1996).

  3. High Energy Gamma Ray Emission EGRET discovered >30 MeV emission from GRBs Five GRBs found with spark chamber EGRET events in coincidence with a BATSE GRB GRB 910503 GRB 910601 - marginal GRB 930131 - Queen Beatrix GRB GRB 940217 - Hurley et al. extended emission GRB 940301

  4. Prompt Extended BATSE SD …... EGRET TASC EGRET Spark Chamber Hurley et al. 1994 Famous GRB 940217 T90 = 150 s S = 1.2 x 10-4 erg cm-2 100 MeV g's for >1 hr

  5. Queen Beatrix GRB 930131 T90 = 14 s (but short-hard main emission of ~1s - short GRB?) S = 1.2 x 10-5 erg cm-2 100 MeV g's past main prompt phase

  6. GRB941017 High Energy Component -18 to 14 sec 14 to 47 sec 47 to 80 sec 80-113 sec 113-211 sec Gonzalez, Dingus et al., 2003 BATSE + EGRET/TASC spectra show high-E component Different time evolution

  7. BeppoSAX:X-ray and Optical afterglow • Fast follow up with the BeppoSAX-NFIs (8hr) led to the discovery of a bright unknown X-ray source. • A second pointing 3 days after showed that source had faded. (Costa, et al., 1997) • Accurate (~1 arcmin) X-ray position led to the identification of a fading optical source from ground based telescopes (Van Paradijs, et al., 1997)

  8. The fireball model in a cartoon

  9. Instruments • Burst Alert Telescope (BAT) • New CdZnTe detectors • Detect ~100 GRBs per year • Most sensitive gamma-ray imager ever • X-Ray Telescope (XRT) • Arcsecond GRB positions • CCD spectroscopy • Photometry in the range 10-7-10-15 erg cm-2 s-1 • (UVOT) UV/Optical Telescope • Sub-arcsec imaging • Grism spectroscopy • 24th mag sensitivity (1000 sec) • Finding chart for other observers • Autonomous re-pointing, 20 - 100 sec • Onboard and ground triggers UVOT BAT BAT XRT UVOT Spacecraft XRT Spacecraft Spacecraft Swift(& HETE-II and INTEGRAL) Detected more than 250 GRB in 2.5 years

  10. XRT detects early steep decays Tagliaferri et al. 2005

  11. XRT: GRB050406, GRB050502B, …. Burrows et al. 2005, Falcone et al. 2006, Romano et al. 2006, Guetta et al. 2007, Pagani et al. 2007, Butler et al. 2007

  12. GRB050904: a very high redshift burst (z=6.29) Cusumano et al. 2006 Watson et al. 2006

  13. Multiple flares episodes: some examples GRB060111A GRB060210 Time since burst (s)

  14. Composite X-ray light curves for 40 GRBs: central activity last much longer than previously thought O’Brien et al. 2006 Chincarini et al. 2007 Willingale et al. 2007 but see also Dermer et al. 2007 Galli & Piro 2007

  15. GRB060124: triggering on a precursor Romano et al. 2006 See also GRB061121, Page et al. 2007

  16. GRB 050509B: HST Imaging 48 sources in XRT error circle Giant elliptical, random location probability ~10-4 L=1.5L* SFR<0.1 M yr-1 Error radius = 9.3 arcsec 4 HST Epochs May 14 to June 10 SN limit >27.2 mag Kulkarni et al. 2005

  17. GRB 050709: HETE Detection T90=70 ms T90=130 s Villasenor et al. 2005 X-ray and optical afterglow detected, no SN (Fox et al. 2005, Covino et al. 2006, Hjorth et al. 2005)

  18. GRB060614: a long GRB with no SN A very unsual burst: a long without a SN or a short masked as a long GRB? Eiso~8.4x1050 ergs Gehrels et al. 2006; Mangano et al. 2007 Della Valle et al. 2006, Fynbo et al. 2006

  19. Spectral lags vs peak Luminosity Is there an intermediate class of GRB between long and short? e.g. Queen Beatrix GRB? a new classification scheme suggested? type I and II, instead of short and long (Zhang et al. 2006) Difference between low-energy and high energy triggered GRBs? Gehrels et al. 2006

  20. Epeak– Eiso correlation Unfortunately Swift does not determine very well Epeak Amati et al. 2002, Ghirlanda et al. 2004

  21. GRB050416A α = 0.81 > 58 Days

  22. Jet, achromatic breaks? Very rare Panaitescu et al. 2006, Willingale et al. 2007

  23. GLAST & AGILE Performances GLAST AGILE ~50 GRBs/yr with LAT ~5-10 GRBs/yr with GRID ~arcmin-degree LAT ~arcmin-degree GRID; few arcmin SuperAGILE ~2 sr FOV LAT ~3 sr FOV AGILE; ~1 sr FOV SuperAGILE ~200 GRBs/yr with GBM 15˚ (<5˚ on gnd) GBM ~9sr FOV GBM

  24. GLAST/LAT Swift/BAT Two Wide-Field Instruments

  25. Swift - LAT Joint GRB Operations BAT - LAT Joint Pointing XRT/UVOT Follow-up • Rapid follow-up by Swift • will give arc-sec location and possibly photometric redshifts • XRT FOV 22x22 arcmin Orbits beat with a period of 12.9 days Assuming BAT FOV of 45 deg radius and LAT FOV of 65 deg On average LAT covers 28% of BAT FOV and BAT covers 13% of the LAT Calculation from David Band

  26. GLAST + Swift GRBs • ~10/yr LAT GRBs are in BAT FOV • ~25/yr SWIFT GRBs are in LAT FOV • Swift follow-up of GLAST GRBs (arcsec position, afterglow LCs + Spectra) • need ~10 arcmin position accuracy from LAT • GLAST follow-up of Swift GRBs (high energy extended emission)

  27. Results from follow-up: • GRB050904: star explosion at z=6.29!! • Prompt and afterglow properties are not peculiar • 10% of Swift GRBs expected at z>5(Salvaterra & Chincarini 2007, Bromm & Loeb 2006) Kawai et al. 2006, Totani et al. 2005 <z>~2.5 Tagliaferri et al. 2005

  28. Liverpool 2m, Faulkes telescopes, TAROT, ROTSE, PROMPT, ….

  29. Molinari et al., A&A in press tpeak = 122s T90 < tpeak tpeak = 165s 'thin shell' case

  30. Conclusions GRB MW observations are crucial for: Quoting from Zhang’s 2007 GRB review (astro/ph-0701520): “On the theoretical side the fireball model is not short of mechanisms to produce these High Energy photons. In fact, one could list over a dozen of mechanisms to produce HE photons from a relativistic fireball. The challenge is how to identify the correct mechanism at work.” Multiwavelength observations are probably the best way to achieve this. • Is there a counterpart at GeV energy of the flares and flat component seen in the X-ray light curves? • Is there a difference in the GRB selected in the KeV, MeV and GeV band? GRB properties depends from redshift? • Short and long GRB explode in different environments and their afterglows have different properties. Other differences in the GeV band? Intermediate objects? • Epeak-Eiso-Eγ correlation? Jet breaks?

More Related