Speaker
Description
We present photometric and spectroscopic observations of the Type Ic superluminous supernova SN2025imr at redshift z ≈ 0.09, distinguished by a pronounced post-peak stair-like decline in its light curve, in which the luminosity decreases in discrete steps rather than following a smooth decay, with the brightest epoch is detected at an absolute magnitude of approximately −22 mag. The dataset combines multi-band photometry from ZTF, UVOT, ATLAS, and the Lulin Observatory telescopes (LOT and SLT), along with multi-epoch spectroscopy from ZTF and ePESSTO+. While such stepped behavior may suggest circumstellar medium (CSM) interaction, the spectra show no corresponding signatures, such as narrow emission features. The absence of early-time data near maximum light limits constraints on the peak luminosity and phase. A comparison with other SLSNe exhibiting possible CSM interaction, particularly those with post-peak bumps, shows that most do not display a similar stepped declining morphology, indicating that SN2025imr may represent a distinct form of post-peak variability or an alternative powering mechanism.
| Participate the oral/poster presentation award competition | Yes |
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