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Late time observations of GRB080319B. Nial Tanvir University of Leicester collaboration with Evert Rol, Andrew Levan, Andy Fruchter, Yoni Granot, Karl Svensson and others. GRB 080319B. Pi of Sky. Reached visual magnitude 5.3!. GRB 080319B. Redshift = 0.94. Amazing!. REM & Tortora. - PowerPoint PPT Presentation
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Late time observations Late time observations of GRB080319Bof GRB080319B
Nial TanvirNial Tanvir
University of LeicesterUniversity of Leicester
collaboration with Evert Rol, Andrew Levan, Andy Fruchter, Yoni Granot, Karl Svensson and
others
Reached visual magnitude 5.3!
Pi of Sky
Redshift = 0.94
REM & Tortora
Racusin et al. 2008Bloom et al. 2009
Was GRB 080319B exceptional in other ways?
Total energy (beaming corrected)?
Accompanying supernova?
Host galaxy?
Late time observations up to ~1 year post-burst.
HST/WFPC2 observations
T+19 days T+54 days T+107 days
Light curve (host subtracted photometry)
Light curve (host subtracted photometry)
Simple model:
1 =1.3, 2=2.35
=0.5
Sharp achromatic break at tb=11 days
Redder bands show late time excess.
Redder bands show late time excess.
Consistent with an additional supernova component reaching about 80% of the luminosity of SN 98bw (possibly slightly shorter duration).
i.e. similar to the properties of other GRB supernovae inferred from light curve “humps”.
Bright accompanying supernova and small host galaxy entirely typical of the very faintest GRBs!
Findings:
• Sharp, achromatic light-curve break at tb=11 days. If interpreted as a jet break, the implications for beaming corrected total energy depend on model, but most likely Etot <1052.5 erg.
• Accompanying supernova with magnitude similar to SN 98bw (best fit with a template somewhat fainter and redder).
• Dwarf host galaxy, which is at the faint end of the distribution of GRB hosts at comparable redshifts, and hence probably of lower metallicity.
Tanvir et al. ApJ submitted (arXiv:0812.1217)