Abstract
If a quark-nova occurs inside a collapsar, the interaction between the quark-nova ejecta (relativistic iron-rich chunks) and the collapsar envelope leads to features indicative of those observed in Gamma Ray Bursts. The quark-nova ejecta collides with the stellar envelope creating an outward moving cap (Γ∼1–10) above the polar funnel. Prompt gamma-ray burst emission from internal shocks in relativistic jets (following accretion onto the quark star) becomes visible after the cap becomes optically thin. Model features include (i) precursor activity (optical, X-ray,γ-ray), (ii) promptγ-ray emission, and (iii) afterglow emission. We discuss SN-less long duration GRBs, short hard GRBs (including association and nonassociation with star forming regions), dark GRBs, the energetic X-ray flares detected in Swift GRBs, and the near-simultaneous optical andγ-ray prompt emission observed in GRBs in the context of our model.
Highlights
Recent observations following the launch of the Swift satellite challenge the traditional models of GRBs (e.g., [1, 2])
We expect that the funnel’s opening angle in this case will be wider than in cases involving disks. This implies that (i) some short GRBs with no SN association should be found in star forming regions; (ii) they might be less numerous than long ones if low angular momentum progenitors are spars; (iii) they are less luminous and only the nearby one will be detectable; (iv) their spectrum should be harder since the QN ejecta will interact with a more dense SN ejecta; (v) X-ray precursors of SN-less GRBs or the early phase of the prompt GRB emission in SN-less GRBs should resemble emission from short GRBs
We explore the case of a QN going off inside a collapsar
Summary
Recent observations following the launch of the Swift satellite challenge the traditional models of GRBs (e.g., [1, 2]). We show how appealing to a quark-nova occurring inside a collapsar can lead to phenomenology reminiscent of that seen by Swift. The ejection of the outer layers of the NS is driven by the thermal fireball generated as the star cools from its birth temperature down to ∼7.7 MeV [7, 8]. We note that for low angular momentum progenitors, the combination of a high NS core density at birth and, most likely, fall-back material would drive the protoneutron star to a black hole.
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