2023MNRAS.525.1498Z -
Mon. Not. R. Astron. Soc., 525, 1498-1519 (2023/October-2)
Evidence for mass-dependent peculiar velocities in compact object binaries: towards better constraints on natal kicks.
ZHAO Y., GANDHI P., DASHWOOD BROWN C., KNIGGE C., CHARLES P.A., MACCARONE T.J. and NUCHVANICHAKUL P.
Abstract (from CDS):
We compile a catalogue of low-mass and high-mass X-ray binaries, some recently reported binaries that likely host a neutron star (NS) or a black hole (BH), and binary pulsars (a pulsar and a non-degenerated companion) that have measured systemic radial velocities (γ). Using Gaia and radio proper motions together with γ, we integrate their Galactic orbits and infer their post-supernova (post-SN) 3D peculiar velocities ($v_\mathrm{pec }^{z=0}$ at Galactic plane crossing); these velocities bear imprints of the natal kicks that compact objects received at birth. With the sample totalling 85 objects, we model the overall distribution of $v_\mathrm{pec }^{z=0}$ and find a two-component Maxwellian distribution with a low- ($\sigma _v \approx 21\, \mathrm{km s^{-1}}$) and a high-velocity ($\sigma _v \approx 107\, \mathrm{km s^{-1}}$) component. A further comparison between distributions of binary subgroups suggests that binaries hosting high-mass donors/luminous companions mostly have $v_\mathrm{pec }^{z=0}\lesssim 100\, \mathrm{km s^{-1}}$, while binaries with low-mass companions exhibit a broader distribution that extends up to $\sim 400\, \mathrm{km s^{-1}}$. We also find significant anticorrelations of $v_\mathrm{pec }^{z=0}$ with binary total mass (Mtot) and orbital period (Porb), at over 99 per cent confidence. Specifically, our fit suggests $v_\mathrm{pec }^{z=0}\propto M_\mathrm{tot}^{-0.5}$ and $v_\mathrm{pec }^{z=0}\propto P_\mathrm{orb}^{-0.2}$. Discussions are presented on possible interpretation of the correlations in the context of kinematics and possible biases. The sample should enable a range of follow-up studies on compact object binary kinematics and evolution.
Abstract Copyright:
© 2023 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
parallaxes - proper motions - stars: black holes - stars: neutron - supernovae: general
Simbad objects:
92
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