Binary population synthesis models for core-collapse gamma-ray burst progenitors

Abstract

Long-duration gamma-ray bursts (GRBs) are understood to be the final fate for a subset of massive, stripped envelope, rapidly rotating stars. Beyond this, our knowledge of the progenitor systems is limited. Using the BPASS (Binary Population and Spectral Synthesis) stellar evolution models, we investigate the possibility that some massive stars in binaries can maintain the angular momentum required for jet production, while still loosing their outer envelope through winds or binary interactions. We find that a total hydrogen mass of M H < 5 × 10 −4 M and a helium ejecta mass fraction of F He < 0.20 provide the best thresholds for the supernova II/Ibc and Ib/Ic divisions respectively. Tidal interactions in binaries are accounted for by applying a tidal algorithm to post-process the stellar evolution models output by BPASS. We show that the observed volumetric gamma-ray burst rate evolution can be recreated using two distinct pathways and plausible distributions for burst parameters. In the first pathway, stars are spun up by mass accretion into a quasi-homogeneous state. In the second, tides maintain rotation where otherwise the star would spin down. Both lead to type Ic supernova progenitors, and a metallicity distribution consistent with the GRB host galaxy population. The inferred core angular momentum threshold for jet production is consistent with theoretical requirements for collapsars, given the assumptions made in our model. We can therefore reproduce several aspects of core collapse supernova/GRB observation and theory simultaneously. We discuss the predicted observable properties of GRB progenitors and their surviving companions.

Evolutionary roads leading to low effective spins, high black hole masses, and O1/O2 rates for LIGO/Virgo binary black holes

“…4.1) can significantly modify our conclusions about the natal spins of merging binary compact objects resulting from isolated evolution. However,we do not include quasi-homogeneous evolution scenarios discussed by Chrimes et al (2020).…”

Applications of Stellar Population Synthesis in the Distant Universe

“…The best estimate of multiple fraction at intermediate masses (5-9 M ) is 76% ± 8%, and this considerable range of uncertainty theoretically permits binary interactions to extend ionising photon production toward later times (a higher binary fraction towards lower masses) or to shorten the ionising lifetimes (a lower close binary fraction). Some constraints on this can be derived from the populations of stripped envelope supernovae or interacting neutron star binaries, although other uncertainties (for example, on the residual surface hydrogen fraction permitted for stripped supernovae, or the surface stellar wind strength; see [178]) may be degenerate with those on the binary fraction itself.…”

Constraining the intrinsic population of long gamma-ray bursts: Implications for spectral correlations, cosmic evolution, and their use as tracers of star formation

“…At first order, assuming the effect of metallicity is a simple threshold on the LGRB production efficiency from stars, this could suggest that the cosmic evolution of the LGRB rate scenario is more plausible. One should keep in mind however that the effects of metallicity may be more subtle such as modifying the stellar IMF (La Barbera et al 2013) or the fraction of binary progenitors (Fryer & Heger 2005;de Mink et al 2009;Podsiadlowski et al 2010;Chrimes et al 2020). The potential dependence of LGRB progenitors properties on metallicity could very well lead not only to an evolution of the stellar efficiency to produce LGRB, η(z), but also to an evolution of the LGRB properties.…”

“…Another possibility is that the effect of metallicity is more complicated than a simple threshold. Indeed, metallicity can also play an indirect role by influencing the stellar IMF (e.g., La Barbera et al 2013) or the fraction of binary progenitors (Chrimes et al 2020).…”