Context : GRB060614 observations by VLT and by Swift have infringed the traditionally accepted gamma-ray burst ( GRB ) collapsar scenario that purports the origin of all long duration GRBs from supernovae ( SN ) .
GRB060614 is the first nearby long duration GRB clearly not associated with a bright Ib/c SN .
Moreover , its duration ( T _ { 90 } \sim 100 s ) makes it hardly classifiable as a short GRB .
It presents strong similarities with GRB970228 , the prototype of a new class of “ fake ” short GRBs that appear to originate from the coalescence of binary neutron stars or white dwarfs spiraled out into the galactic halo .

Aims : Within the “ canonical ” GRB scenario based on the “ fireshell ” model , we test if GRB060614 can be a “ fake ” or “ disguised ” short GRB .
We model the traditionally termed “ prompt emission ” and discriminate the signal originating from the gravitational collapse leading to the GRB from the process occurring in the circumburst medium ( CBM ) .

Methods : We fit GRB060614 light curves in Swift ’ s BAT ( 15 - 150 keV ) and XRT ( 0.2 - 10 keV ) energy bands .
Within the fireshell model , light curves are formed by two well defined and different components : the proper-GRB ( P-GRB ) , emitted when the fireshell becomes transparent , and the extended afterglow , due to the interaction between the leftover accelerated baryonic and leptonic shell and the CBM .

Results : We determine the two free parameters describing the GRB source within the fireshell model : the total e ^ { \pm } plasma energy ( E _ { tot } ^ { e ^ { \pm } } = 2.94 \times 10 ^ { 51 } erg ) and baryon loading ( B = 2.8 \times 10 ^ { -3 } ) .
A small average CBM density \sim 10 ^ { -3 } particles/cm ^ { 3 } is inferred , typical of galactic halos .
The first spikelike emission is identified with the P-GRB and the following prolonged emission with the extended afterglow peak .
We obtain very good agreement in the BAT ( 15 - 150 keV ) energy band , in what is traditionally called “ prompt emission ” , and in the XRT ( 0.2 - 10 keV ) one .

Conclusions : The anomalous GRB060614 finds a natural interpretation within our canonical GRB scenario : it is a “ disguised ” short GRB .
The total time-integrated extended afterglow luminosity is greater than the P-GRB one , but its peak luminosity is smaller since it is deflated by the peculiarly low average CBM density of galactic halos .
This result points to an old binary system , likely formed by a white dwarf and a neutron star , as the progenitor of GRB060614 and well justifies the absence of an associated SN Ib/c .
Particularly important for further studies of the final merging process are the temporal structures in the P-GRB down to 0.1 s .