An Interpretation of the $h\nu_{peak}$ - $E_{iso}$ Correlation for GRB
  The $h\nu_{peak}/100 KeV \sim [E_{iso}/10^{52} \rm{erg}]^{1/2}$ correlation reported recently by Amati et al. (2002) and Lamb et al. (2003) for long GRB's can be interpreted as a viewing angle effect if the emitting region of the fireball is ring-shaped. 
David Eichler, Amir Levinson