1. XRF 060218 associated with SN 2006aj Nature, Val 442 Aug.31 issues Campana et al. p.1008 Pian et al. P. 1011 Soderberg et al. p.1014 Paolo et al. p.1018

2. Contents Gamma-ray burst (GRB) and X-ray flash (XRF) XRF 060218 (associated with SN 2006aj) Progenitor of XRF (neutron star driven?)

3. GRBs Origin ….. Long soft bursts (T>2s)-----Type Ic SN Short hard bursts (T<2s)-----merging between compacts objects Flash gamma-ray emissions with E~10^51erg

4. XRFs

5. What origin of XRFs off axis long GRBs intrinsically dimmer and softer bursts than GRBs GRBs The less luminosity and soft emissions because of XRFs VS.

6. XRF 060218 (today’s report) Unusually long bursts detected by Swift

7. V, B, U, UVW1, UVM1, UVW2 Host galaxy at z~0.033 -secondary nearby burst XRF 060218

8. SN2006aj XRF 060218 is associated with SN 2006 aj. SN 2006aj is type Ic (owing to a lack of hydrogen and helium lines) What is the progenitor of SN 2006aj???

9. Off axis GRB or intrinsically dim explosion Associated with GRBs

10. Light curve in the radio bands will rule out the off axis GRB model, which predicts much bright radio emissions. XRF 060218 Intrinsically dim explosion

11. Neutron star driven XRF Spectra of SN 2006aj can be fitted by synthetic model with M~25Solar mass Neutron star driven?

12. Harrison et al.(99) Break time ⇒ Jet angle