Related papers: How much radioactive nickel does ASASSN-15lh requi…

[Abridged] We present UV/optical observations of PS16aqv (SN 2016ard), a Type I superluminous supernova (SLSN-I) classified as part of our search for low-$z$ SLSNe. PS16aqv is a fast evolving SLSNe-I that reached a peak absolute magnitude…

We present nebular-phase imaging and spectroscopy for the hydrogen-poor superluminous supernova SN 2015bn, at redshift z=0.1136, spanning +250-400 d after maximum light. The light curve exhibits a steepening in the decline rate from 1.4…

ASASSN-18am/SN 2018gk is a newly discovered member of the rare group of luminous, hydrogen-rich supernovae (SNe) with a peak absolute magnitude of $M_V \approx -20$ mag that is in between normal core-collapse SNe and superluminous SNe.…

We present photometric and spectroscopic follow-up observations of the highly luminous Type Ibn supernova ASASSN-14ms, which was discovered on UT 2014-12-26.61 at $m_V \sim 16.5$. With a peak absolute $V$-band magnitude brighter than…

We present photometry and spectroscopy of the slowly evolving superluminous Type IIn SN2015da. SN2015da is extraordinary for its very high peak luminosity, and also for sustaining a high luminosity for several years. Even at 8\,yr after…

So called superluminous supernovae have been recently discovered in the local Universe. It appears possible that some of them originate from stellar explosions induced by the pair instability mechanism. Recent stellar evolution models also…

We present the detection of persistent soft X-ray radiation with L_x ~ 10^41-10^42 erg/s at the location of the extremely luminous, double-humped transient ASASSN-15lh as revealed by Chandra and Swift. We interpret this finding in the…

At late phases the powering of supernova light curves is often provided by the decay of radioactive elements synthesized in the explosions. This is unambiguously revealed when the light curve decline follows the half life time of the…

Observations from the last decade have indicated the existence of a general class of superluminous supernovae (SLSNe), in which the peak luminosity exceeds 10^{44} erg/s. Here we focus on a subclass of these events, where the light curve is…

We examine the pair-instability origin of superluminous supernova 2018ibb. As the base model, we use a non-rotating stellar model with an initial mass of 250 Msun at about 1/15 solar metallicity. We consider three versions of the model as…

We present and discuss ultraviolet and optical photometry from the Ultraviolet/Optical Telescope and X-ray limits from the X-Ray Telescope on Swift and imaging polarimetry and ultraviolet/optical spectroscopy with the Hubble Space Telescope…

We report comprehensive multi-wavelength observations of a peculiar Type Ia-like supernova ("SN Ia-pec") ASASSN-15pz. ASASSN-15pz is a spectroscopic "twin" of SN 2009dc, a so-called "Super-Chandrasekhar-mass" SN, throughout its evolution,…

We present extensive photometric and spectroscopic observations of the peculiar Type Ia supernova (SN Ia) 2022vqz. It shares many similarities with the SN 2002es-like SNe Ia, such as low luminosity ($M_{B,\rm max}=-18.11\pm0.16$ mag) and…

Superluminous supernovae are among the most energetic stellar explosions in the Universe, but their energy sources remain an open question. Here we present long-term observations of one of the closest examples of the hydrogen-poor subclass…

We perform a systematic study of the $^{56}$Ni mass ($M_{\rm Ni}$) of 27 stripped envelope supernovae (SESNe) by modeling their light-curve tails, highlighting that use of ``Arnett's rule'' overestimates $M_{\rm Ni}$ for SESN by a factor of…

We present a series of ground-based photometry and spectroscopy of the superluminous Type IIn supernova (SN) ASASSN-15ua, which shows evidence for strong interaction with pre-existing dense circumstellar material (CSM). Our observations…

We present optical and ultraviolet (UV) observations of a luminous type Ia supernova (SN Ia) SN 2015bq characterized by the early flux excess. This SN reaches a B-band absolute magnitude at $M_B = -19.68 \pm 0.41$ mag and a peak bolometric…

The interaction of a supernova with a circumstellar medium (CSM) can dramatically increase the emitted luminosity by converting kinetic energy to thermal energy. In 'superluminous' supernovae (SLSNe) of Type IIn -- named for narrow hydrogen…

SN 2006gy radiated far more energy in visual light than any other supernova so far, and potential explanations for its energy demands have implications for galactic chemical evolution and the deaths of the first stars. It remained bright…

It was recently proposed that exotic particles can trigger a new stellar instability which is analogous to the e-e+ pair instability if they are produced and reach equilibrium in the stellar plasma. In this study, we construct axion…