New constraints on the Bray conservation-of-momentum natal kick model from multiple distinct observations

Understand

Natal supernova kicks, the linear momentum compact remnants receive during their formation, are an essential part of binary population synthesis (BPS) models.

• Although these kicks are well-supported by evidence, their underlying distributions and incorporation into BPS models is uncertain.
• In this work, we investigate the nature of natal kicks using a previously proposed analytical prescription where the strength of the kick is given by $v_\text{k}=\alpha\frac{m_\text{ejecta}}{m_\text{remnant}}+\beta~\text{km s}^{-1}$, for free parameters $\alpha$ and $\beta$.
• We vary the free parameters over large ranges of possible values, comparing these synthetic populations simultaneously against four constraints: the merger rate of compact binary neutron star (BNS) systems, the period-eccentricity distribution of galactic BNSs, the velocity distribution of single-star pulsars, and the likelihood for low-ejecta mass supernovae to produce low-velocity kicks.