[Okc-wp4] OKC EO seminar on 24th by Yang Hu

[Smaranika Banerjee]

Dear all,

Next week we will have EO seminar byYang Hu<https://oskarkleincentre.slack.com/team/U0681HXQ7KR>.

When and where: Thursday 24th, 13:15 in A5:1003

Title:
When CSM Outmasses Ejecta: the Case of Hydrogen-Rich Superluminous Supernovae 2021aaev

Abstract
Hydrogen-rich superluminous supernovae (SLSNe-II), characterised by their extreme peak luminosity (¡Ü -20 mag in optical), represent a rare subclass of supernovae (SNe). While a handful have been observed with medium- or high-resolution spectroscopy (most showing narrow H lines; SLSNe-IIn), two key questions persist: (1) Are SLSNe-IIn simply the luminous extreme of the SN IIn population? (2) What are the characteristic circumstellar medium (CSM) parameters that power SLSNe-IIn? Here, we present extensive photometric and spectroscopic observations of SN 2021aaev, a SLSN-IIn at z = 0.1557 with a rise time of 32.5 ¡À 1.0 days and a peak luminosity of -21.35 ¡À 0.03 mag (ATLAS o-band). Its early spectra resemble SNe IIn but reveal persistent flash-ionisation features lasting >1 week, marking it as the first SLSN-II flasher. Its late photospheric spectra diverge from typical SNe IIn and show similarity to SN 2017hcc (a SLSN-IIn), with the persistent narrow H¦Á up to +96 days since first light. Our analysis indicates interaction between 2-5 M¨‘ of ejecta and an extensive (¡Ý10^16 cm), heavy (¡Ý2 Mej) CSM. This makes SN 2021aaev a compelling case for understanding the diversity within SLSNe-II and the connection (or lack thereof) between SLSNe-IIn and SNe IIn.

See you all there.

Kind regards,
Smaranika (on behalf of organizers)

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Dr. Smaranika Banerjee
Astronomy Department, Stockholm University
Email: smaranika.banerjee at astro.su.se<mailto:smaranika.banerjee at astro.su.se>
Old email: smaranikab at astr.tohoku.ac.jp<mailto:smaranikab at astr.tohoku.ac.jp>
Website: https://sites.google.com/view/smaranikabanerjee/welcome?authuser=0
Zoom: https://stockholmuniversity.zoom.us/j/3760189321
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