| Gamma-ray burst supernovae: From Central Engines to Cosmological Probes |
| Zach Cano |
| IAA-CSIC, Granada, Spain |
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This talk will focus on two main topics: (1) the role of GRB-SNe as cosmological probes and (2) the physical processes
that power the luminosity of GRB-SNe and ULGRB 111209A and its accompanying SN 2011kl.
In part (1) I will demonstrate that GRB-SNe have a luminosity-decline relation akin to that of SNe Ia, and discuss the physical origins of this relation. I will then present how they can be used as cosmological probes and provide estimates of the Hubble constant via empirically derived, model-independent distances to several GRB-SNe. I will then demonstrate how these can be used to calibrate the high-energy properties of all long-duration GRBs, thus providing a complementary cosmological probes over an unprecidented redshift range of 0.00867 < z < 9.4. For part (2) I will address the question of what powers the luminosity of GRB-SNe. Do the same physical mechanism(s) also power the luminosity of ultra-long GRB-SNe such as GRB 111209A / SN 2011kl? ULGRB-SN 2011kl represents a unique link between superluminous supernovae and LGRB-SNe: its peak bolometric light is intermediate between LGRB-SNe and SLSNe, and it has been shown that, like many SLSNe, the SN itself may be powered by a magnetar central engine, rather than CSM interaction or radioactive heating. I will present an analytical model that considers energy arising from a magnetar central engine. When fitting this model to the optical and X-ray LCs of five GRB-SNe and one ULGRB-SNe, while the early AG-dominated phase are well described with our model, the predicted SN luminosity is underluminous by a factor of 3-17. I interpret this as compelling evidence that additional sources of heating must be present to power an LGRB-SN, which I argue must be radioactive heating. In contrast, I will show that ULGRB 111209A / SN 2011kl was powered entirely by a magnetar central engine, including the AG and the SN, and I derive values of the initial spin period, B-field and spin-down timescales commensurate with those obtained in other studies of SN 2011kl. |