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Extreme stripped-envelope supernovae (SESNe), including Type Ic superluminous supernovae (SLSNe), broad-line Type Ic SNe (SNe Ic-BL), and fast blue optical transients (FBOTs), are widely believed to harbor a newborn fast-spinning highly-magnetized neutron star (``magnetar''), which can lose its rotational energy via spin-down processes to accelerate and heat the ejecta. The progenitor(s) of these magnetar-driven SESNe, and the origin of considerable angular momentum (AM) in the cores of massive stars to finally produce such fast-spinning magnetars upon core-collapse are still under debate. Popular proposed scenarios in the literature cannot simultaneously explain their event rate density, SN and magnetar parameters, and the observed metallicity. Here, we perform a detailed binary evolution simulation that demonstrates that tidal spin-up helium stars with efficient AM transport mechanism in close binaries can form fast-spinning magnetars at the end of stars' life to naturally reproduce the universal energy-mass correlation of these magnetar-driven SESNe. Our models are consistent with the event rate densities, host environments, ejecta masses, and energetics of these different kinds of magnetar-driven SESNe, supporting that the isolated common-envelope formation channel could be a major common origin of magnetar-driven SESNe. The remnant compact binary systems of magnetar-driven SESNe are progenitors of some galactic systems and gravitational-wave transients., Comment: Main text (17 pages, 5 Figures) and Supplementary Information (18 pages, 6 Figures, 2 tables)

Despite the fact that the progenitor of fast blue optical transients (FBOTs) is still up for debate, FBOTs are sometimes suggested to originate from the core-collapse of ultra-stripped stars and be powered by a spinning-down neutron star. Following this consideration, it is expected that the late-time evolution of the progenitor stars can leave important imprints in the circumstellar material (CSM) of the FBOTs, due to the strong mass loss of the stars. The interaction of the FBOT ejecta with the CSM can drive a long-lasting shock to generate radio emission, which thus enables us to probe the CSM properties through radio observation although such observations are still rare. Within the framework of the magnetar-powered model, Liu et al.(2022) fitted the multi-band optical light curves of 40 FBOTs and, hence, the statistical distributions of the FBOT magnetar and ejecta parameters were obtained. Based on these FBOT population results, we investigate the dependence of the radio emission on the mass-loss rate of the progenitors and evaluate the detectability of radio emission from FBOTs with current and future telescopes. It is found that the distribution of the peak time and peak luminosity of the emission at 8.4 GHz are primarily in the regions of $t_{\rm{peak},\nu}=10^{2.12\pm0.63}$ days and $L_{\rm{peak},\nu}=10^{28.73\pm0.83}$ erg s$^{-1}$ Hz$^{-1}$, respectively. A joint detection of the Zwicky Transient Facility and Very Large Array could achieve success in about 8.7% FBOTs of $z\leq1$. Furthermore, if considering a joint observation of the Chinese Space Station Telescope and Square Kilometer Array, this fraction can be increased to about 23.9%., Comment: 10 pages, 5 figures, submitted to ApJ

We fit the multi-band lightcurves of 40 fast blue optical transients (FBOTs) with the magnetar engine model. The mass of the FBOT ejecta, the initial spin period and polar magnetic field of the FBOT magnetars are respectively constrained to $M_{\rm{ej}}=0.18^{+0.52}_{-0.13}\,M_\odot$, $P_{\rm{i}}=9.4^{+8.1}_{-3.9}\,{\rm{ms}}$, and $B_{\rm p}=7^{+16}_{-5}\times10^{14}\,{\rm{G}}$. The wide distribution of the value of $B_{\rm p}$ spreads the parameter ranges of the magnetars from superluminous supernovae (SLSNe) to broad-line Type Ic supernovae (SNe Ic-BL; some are observed to be associated with long-duration gamma-ray bursts), which are also suggested to be driven by magnetars. Combining FBOTs with the other transients, we find a strong universal anti-correlation as $P_{\rm{i}}\propto{M_{\rm{ej}}^{-0.45}}$, indicating them could share a common origin. To be specific, it is suspected that all of these transients originate from collapse of extreme-stripped stars in close binary systems, but with different progenitor masses. As a result, FBOTs distinct themselves by their small ejecta masses with an upper limit of ${\sim}1\,M_\odot$, which leads to an observational separation in the rise time of the lightcurves $\sim12\,{\rm d}$. In addition, the FBOTs together with SLSNe can be separated from SNe Ic-BL by an empirical line in the $M_{\rm peak}-t_{\rm rise}$ plane corresponding to an energy requirement of a mass of $^{56}$Ni of $\sim0.3M_{\rm ej}$, where $M_{\rm peak}$ is the peak absolute magnitude of the transients and $t_{\rm rise}$ is the rise time., Comment: 15 pages, 5 figures, 2 tables, accepted by ApJL