[Paper Review] Quark Nova Signatures in Super-luminous Supernovae

M. Kostka, Nico Koning+3 more|arXiv (Cornell University)|Jun 29, 2012

Gamma-ray bursts and supernovae3 citations

TL;DR

This paper proposes that dual-shock quark novae (dsQNe) can explain the extreme luminosity and diverse light curves of super-luminous supernovae (SLSNe). By modeling energy injection from a quark nova explosion following a core-collapse supernova, the authors show that time delays between the SN and QN explosions—ranging from days to years—can naturally account for the observed variety in SLSN light curve morphology, including peak brightness and decay width. The model also reproduces the singular Hα spectral profile seen in three SLSNe and predicts unique chemical abundance signatures and double X-ray bursts.

ABSTRACT

Recent observational surveys have uncovered the existence of super-luminous supernovae (SLSNe). While several possible explanations have been put forth, a consensus description for SLSNe has yet to be found. In this work we study the light curves of eight SLSNe in the context of dual-shock quark novae. We find that progenitor stars in the range of 25-35 $M_{\sun}$ provide ample energy to power each light curve. An examination into the effects of varying the physical properties of a dual-shock quark nova on light curve composition is undertaken. We conclude that the wide variety of SLSN light curve morphologies can be explained predominantly by variations in the length of time between supernova and quark nova. Our analysis shows that a singular H$α$ spectral profile found in three SLSNe can be naturally described in the dual-shock quark nova scenario. Predictions of spectral signatures unique to the dual-shock quark nova are presented.

Motivation & Objective

• To investigate whether dual-shock quark novae (dsQNe) can explain the energetics and light curve diversity of super-luminous supernovae (SLSNe).
• To determine the role of time delay between core-collapse supernova and quark nova in shaping SLSN light curve morphology.
• To test the model's ability to reproduce observed spectral features, particularly the singular Hα profile in three SLSNe.
• To predict unique observational signatures such as chemical abundance anomalies and double X-ray bursts from dsQNe.

Proposed method

• The study models light curves of eight SLSNe using a dual-shock quark nova (dsQN) energy injection mechanism, assuming energy deposition from a quark nova following a core-collapse supernova.
• Radiative transfer coefficients are formulated using equations (1) and (2) to simulate continuum emission, with a fit suggesting recombination-like emission processes.
• The model varies the time delay between the supernova and quark nova explosions to assess its impact on light curve shape, peak magnitude, and decay rate.
• Spectral features are modeled by combining contributions from the inner shell (thermal broadening) and the diffuse envelope (absorption features), particularly for Hα.
• Chemical abundance predictions are derived from spallation of SN envelope layers by QN ejecta, depending on the time delay and envelope density.
• X-ray burst predictions are based on shock breakout from both SN and QN, with overlapping or distinct peaks depending on time delay.

Experimental results

Research questions

• RQ1 Can the dual-shock quark nova model reproduce the light curves of diverse SLSNe with varying peak magnitudes and decay widths?
• RQ2 How does the time delay between the supernova and quark nova explosions affect the morphology of SLSN light curves?
• RQ3 Can the model explain the singular Hα spectral profile observed in SN 2006gy, SN 2006tf, and SN 2007bi?
• RQ4 What unique chemical abundance signatures are predicted by the dsQN model due to spallation of SN envelope layers?
• RQ5 Can the dsQN model account for the observed X-ray burst characteristics, including double-peaked emission?

Key findings

• Progenitor stars in the 25–35 M☉ mass range provide sufficient energy to power the observed SLSN luminosities in the dsQN model.
• The time delay between the supernova and quark nova is the dominant factor shaping SLSN light curve morphology: shorter delays produce brighter, narrower peaks, while longer delays yield fainter, broader light curves.
• The model successfully reproduces the singular Hα profile in three SLSNe, with the broad emission due to thermal broadening from the inner shell and the blue-side absorption due to envelope diffusion.
• For short time delays, spallation destroys the 56Ni layer, producing sub-56Ni elements like Ti, V, Cr, and Mn, and enriching the outer layers with Fe.
• For longer time delays, spallation of the C/O layer leads to an overabundance of lithium in the remnant, a unique chemical signature of the dsQN scenario.
• The model predicts two distinct X-ray bursts from shock breakout of both the SN and QN, with overlapping or separated peaks depending on the time delay.