2018MNRAS.474.2551S

We present optical photometric (up to ∼410 d since B_max) and spectroscopic (up to ∼157 d since B_max) observations of a Type Iax supernova (SN) 2014dt located in M61. SN 2014dt is one of the brightest and closest (D ∼ 20 Mpc) discovered Type Iax SN. It best matches the light-curve evolution of SN 2005hk and reaches a peak magnitude of M_B ∼ -18.13 ± 0.04 mag with Δm₁₅ ∼ 1.35 ± 0.06 mag. The early spectra of SN 2014dt are similar to other Type Iax SNe, whereas the nebular spectrum at 157 d is dominated by narrow emission features with less blending as compared to SNe 2008ge and 2012Z. The ejecta velocities are between 5000 and 1000 km s^–1, which also confirms the low-energy budget of Type Iax SN 2014dt compared to normal Type Ia SNe. Using the peak bolometric luminosity of SN 2005hk, we estimate the ⁵⁶Ni mass of ∼0.14 M_☉. The striking similarity between SN 2014dt and SN 2005hk implies that a comparable amount of ⁵⁶Ni would have been synthesized in the explosion of SN 2014dt.