Dust mass and dust production efficiencies on the redshift frontier

In order to clarify the dust production in the early Universe, we constrain the dust mass in high-redshift (z ≳ 5) galaxies using the upper limits obtained by ALMA. We perform fitting to the rest-frame UV-far-infrared spectral energy distribution (SED) of a giant Lyα emitter, Himiko, at z = 6.6 and a composite SED of z > 5 Lyman break galaxies (LBGs). For Himiko, we obtain a high dust temperature > 70 K. This high dust temperature puts a strong upper limit on the total dust mass M_d ≲ 2 × 10⁶ M_⊙, and the dust mass produced per supernova (SN) m_d,SN ≲ 0.1 M⊙. Such a low m_d,SN suggests significant loss of dust by reverse shock destruction or outflow. For the LBG sample, we only obtain an upper limit for m_d,SN as ∼2 M_⊙. This clarifies the importance of observing UV-bright objects (like Himiko) to constrain the dust production by SNe.