Taking a Broad View of Prompt Emission

1. Taking a Broad View of Prompt Emission Contemporaneous emission at eV and ~0.1 MeV Sarah Yost, for the ROTSE Collaboration Venice, June 2006

2. Key Points • prompt : contemporaneous with -rays • importance of broadband view • prompt less understood • synchrotron emission? • afterglow onset • reverse shock • diversity of prompt broadband spectral shapes • diversity of prompt optical lightcurves

3. I. Spectral Indices in Play  (at low  end) OPT- F 

4. Spectral Regions 1/3 : to peak (1-p)/2 : slow cool 2 : abs. -p/2 : above cooling

5. Spectral Regions 1/3 : to peak -1/2 : fast cool 2 : abs. -p/2 : above cooling  : expectations OPT- : can’t be any value

6. betweenoptical,vs.in  

7.  between optical,vs. in 

8.  between optical,vs. in  1/3 :to peak  -1/2 : fast cool  (1-p)/2 : slow cool  -p/2 : above cooling

9. Relative Spectra

10. Relative Spectra

11. Prompt Component(s) • afterglow rise • Swift X-ray: afterglow not just extension of GRB F 

12. II. Prompt Optical Behaviour

13. Prompt Optical Behaviour NOT correlated with GRB optical flux just above GRB spectrum () extrapolation

14. Prompt Optical Behaviour NOT correlated with GRB • optical flux below GRB spectrum () extrapolation • requires GRB spectral rollover

15. Prompt Optical Behaviour also seen as an IR flash T-T(GRB) (sec) ... but correlated with GRB in some cases. Vestrand et al 2005

16. Broadband Shape Peak: Anything Goes • high-E -rays (990123) • <~ optical (051111) • between optical, -rays • optical correlation (041219A), flux level below -ray extrapolation • not constant during GRB • cases with afterglow flux below -ray extrapolation (050401, 050319)

17. Summary • no single pattern (, peak of F, afterglow) • model(s) must be flexible • dearth of reverse shock signatures, 990123 exceptional • afterglow already established during GRB • 2nd prompt component • evidence in optical as well as X-ray that afterglow≠ GRB extension