1 / 16

GRB 091024 and ultra-long GRBs

GRB 091024 and ultra-long GRBs. Francisco Virgili , LJMU June 22, 2012 GRBs 2012 Liverpool. C. Mundell , A. Melandri , C. Guidorzi , R. Margutti , A. Gomboc , S . Kobayashi, V . Pal’shin , etc…. Outline. GRB 091024 case study Observations Analysis Temporal Spectral (limited)

neo
Download Presentation

GRB 091024 and ultra-long GRBs

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. GRB 091024 and ultra-long GRBs Francisco Virgili, LJMU June 22, 2012 GRBs 2012 Liverpool C. Mundell, A. Melandri, C. Guidorzi, R. Margutti, A. Gomboc, S. Kobayashi, V. Pal’shin, etc…

  2. Outline • GRB 091024 case study • Observations • Analysis • Temporal • Spectral (limited) • Energetics • Interpretation • Other ultra-long GRBs

  3. High-energy emission GBM bg subtracted lc Gruber+ 2011

  4. High-energy emission XRT starting at ~T0+53 min Evans+ 2009 BAT emission up to ~T0+483 s

  5. (Part of) What we do… x 2

  6. Optical Emission FTN LT KAIT Super-LOTIS SRO Gemini FTN LT KAIT Super-LOTIS SRO Gemini

  7. Temporal • 3 optical peaks (451 +/- 18 s; 2222 +214 s 5081 +306 s) • No correlation to gamma-ray peaks (~ 0s, 600s, 950 s) • Steep rise/fall of 1st peak

  8. Power spectrum analysis • Calculate fractional signal power density (fpd) for various time slices of the KW and BAT lc. • Find a variety of timescales, specifically 2 short timescales (0.5 and 1 s) and 2 long timescales (7 and 14s) R. Margutti+ 2008 (arxiv:0809.0189)

  9. PDS: Time slices • Same analysis as full signal but on three different regimes of the BAT lightcurve: -200:250 s 250:800 s 800:1200 s • Short var in 1st and 3rd emission episode • Longer timescales in period of quiescence

  10. PDS: Energy dependant • Vary over energy channels • Softest energy range has no short timescale component • Hardest scales show clear peak at low variability timescales

  11. Analysis: Spectral • Limited spectral information: • 1st episode: BAT+GBM • 2nd and 3rd: GBM only • Waiting on KW spectra (ideally GBM+KW) • All segments fit with CPL • 1st: α= -0.89, Ep=461 keV • -0.89, 522 keV (joint) • 2nd: -1.2, 311 keV • 3rd: -1.58, 388 keV • -1.57, 275 keV • -1.49, 472 keV Gruber+ 2011

  12. z and energetics • z=1.092 • Energetics: • Total Eiso: 6-8e53 erg • Most (2e53 erg) in last emission episode • Time-resolved: Most in very last peak • Amati: Consistent (Amati+ 2008)

  13. Other wavelengths? 1 100 100 Extend analysis from Mundell+ 2007, Melandri+ 2009 No radio data (sadly)…but if we did…

  14. Other Ultra-long GRBs • Table from V. Pal’shin • Also add GRB 110709B (B.B. Zhang’s talk), GRB 111209 (FTN obs)

  15. Summary and Future Work • Long-lived central engine activity (~500-600s in RF) • Similar variability timescales at early and late times • No correlation of gamma and optical emission • Different emission regions • Indicative of RS peak followed by FS emission in optical LC • Rise/fall slopes of 1st peak

  16. Summary and Future work • Comprehensive/broadband study of prompt and any afterglow emission of ultra-long GRBs • KW sample has many bursts with good spectral/temporal coverage

More Related