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Tsurugi Takata

Publications and source records attributed to Tsurugi Takata.

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Rotation-induced Relaxation of Supernova Constraints on Axionlike Particles

We study how rotation modifies the constraints on MeV-scale axion-like particles (ALPs) coupled to photons derived from SN 1987A. We constrain the ALP parameter space based on both the energy-loss argument and the gamma-ray limits, and examine how these constraints are affected by stellar rotation. Adopting initial angular velocities of ${\Omega}_{0} = 0.0 and 1.0 rad s^{-1}$ in the iron core, we carry out two-dimensional core-collapse supernova simulations for three progenitor models - a $14 + 9M_{\odot}$ binary and $13M_{\odot}$ and $18M_{\odot}$ single stars with solar metallicity - and estimate ALP emission rates through post-processing. We find that rotation suppresses ALP emission by reducing the core temperature via centrifugal support. Rotation also reduces the neutrino luminosity, but the suppression of ALP emission is more effective, leading to relaxed constraints within a simplified criterion based on the energy-loss argument. This relaxation is particularly pronounced in the rotating $18M_{\odot}$ model, where a substantial decrease in the central temperature occurs at $t_{pb} = 0.8 - 1 s$. In this simplified criterion, such rapid temporal variations in temperature indicate that the resulting constraints depend sensitively on both the evaluation time and the underlying supernova model. For a gamma-ray limit from the SN 1987A observation, rotation has a negligible impact on the constraint. This is because the ALP-induced gamma-ray fluence observed at Earth is proportional to the fourth power of the ALP-photon coupling constant, making the constraint relatively insensitive to the rotational suppression of ALP emission.

astro-ph.HE

Progenitor Dependence of Neutrino-driven Supernova Explosions with the Aid of Heavy Axion-like Particles

We perform spherically symmetric simulations of core-collapse supernovae with the aid of heavy axion-like particles (ALPs) which interact with photons and redistribute energy within supernova matter. We explore a wide ALP parameter space that includes MeV-scale ALP mass $m_{\,a}$ and the ALP-photon coupling constant $g_{\,a γ} \sim 10^{\,-10} \, \rm{GeV}^{\,-1}$ , employing three progenitor models with zero-age main-sequence mass of $11.2\,M_\odot$, $20.0\,M_\odot$, and $25.0\,M_\odot$. We find a general trend that, given $m_{\,a}\lesssim 300\,$MeV, heavier ALPs are favorable for the shock wave to be successfully revived, aiding the onset of the neutrino-driven explosion. However, if ALPs are heavier than $\sim 400\,$MeV, the explosion is failed or weaker than that for the models with smaller $m_{\,a}$, because of an insufficient temperature inside the supernova core to produce heavy ALPs. The maximum temperature in the core depends on the initial progenitor structure. Our simulations indicate that the high-temperature environment in the collapsing core of massive progenitors leads to a significant impact of ALPs on the explodability.

astro-ph.HE