Related papers: Origin of postmaximum bump in luminous type Ic SN …
Type Iax supernovae (SNe Iax) are thermonuclear explosions of white dwarfs, peculiar and underluminous compared to the normal type Ia supernovae. Observations of SNe Iax provide insight into the physics of white-dwarf explosions and suggest…
I explore observational effects of the cirsumstellar gas around superluminous supernova SN~2018ibb. High velocity Fe II narrow absorptions are reproduced in the model of fragmented cold dense shell. Unusual selective absorption in the…
We have performed intensive follow-up observations of a Type IIn/Ia-CSM SN (SN IIn/Ia-CSM), 2020uem, with photometry, spectroscopy, and polarimetry. In this paper, we report on the results of our observations focusing on…
At times later than 200 days, Type Ia SN light curves are dominated by the kinetic energy deposition from positrons created in the decay of $^{56}$Co. In this paper, the transport of positrons after emission are simulated, for deflagration…
Superhump amplitudes observed in dwarf novae during their superoutbursts depend on orbital inclination: the maximum amplitudes in systems with low inclinations are $A_\circ \approx 0.25$ mag., while at higher inclinations they increase from…
Contribution from the irradiated secondary component is detected in the light curves of five dwarf novae observed during superoutbursts. Their superhump light curves show that irradiation is modulated with the superhump phase. This…
Magnetar-powered supernova explosions are competitive models for explaining very luminous optical transits. However, these explosion models were mainly calculated in 1D. Radiation emitted from the magnetar snowplows into the previous…
The optical and ultra-violet broadband photometric and spectroscopic observations of the Type II supernova (SN) 2016gfy are presented. The $V$-band light curve (LC) shows a distinct plateau phase with a slope, $s_2$ $\sim$ 0.12 mag / 100 d…
Interaction of supernova (SN) ejecta with the optically thick circumstellar medium (CSM) of a progenitor star can result in a bright, long-lived shock breakout event. Candidates for such SNe include Type IIn and superluminous SNe. If some…
Many gamma-ray bursts are followed by periods of extended emission. At least in some cases, the burst afterglow may be powered by a rapidly rotating, highly-magnetised neutron star, which spins down due to electromagnetic and gravitational…
Recent observations suggest that some supernovae may be the result of an explosion into an optically thick circumstellar material, the product of pre-explosion mass-loss (wind) by the progenitor star. This scenario has been studied…
An excess of flux (i.e. a bump) in the early light curves of type Ia supernovae has been observed in a handful of cases. Multiple scenarios have been proposed to explain this. It has been shown that for at least one object (SN~2018oh) the…
We present the densely sampled early light curve of the Type II supernova (SN) 2023ixf, first observed within hours of explosion in the nearby Pinwheel Galaxy (Messier 101; 6.7 Mpc). Comparing these data to recently updated models of…
We analyze recent magnetar light-curve modeling of 38 hydrogen-poor superluminous supernovae (SLSNe), and find that the energies of the explosions themselves, that take place before the magnetar energy is released, are more than what the…
It is generally accepted that Anomalous X-ray Pulsars (AXPs) and Soft Gamma-ray Repeaters (SGRs) are magnetars, i.e. neutron stars with extremely high surface magnetic fields ($B > 10^{14}$ G). The origin of these high magnetic fields is…
We study the most luminous known supernova (SN) associated with a gamma-ray burst (GRB), SN 2011kl. The photospheric velocity of SN 2011kl around peak brightness is $21,000\pm7,000$ km s$^{-1}$. Owing to different assumptions related to the…
We present optical observations of the Type IIb supernova (SN) 2017ckj, covering approximately 180 days after the explosion. Its early-time multi-band light curves display no clear evidence of a shock-cooling tail, resembling the behavior…
We study optical counterparts of a new-born pulsar in a double neutron star system like PSR J0737-3039A/B. This system is believed to eject a small amount of mass of $\mathcal{O}(0.1M_{\odot})$ at the second core-collapse supernova. We…
We present calibrated photometric measurements of the earliest detections of nearby type Ia supernovae (SNe Ia). The set of ~30 new, unfiltered CCD observations delineate the early rise behavior of SNe Ia > 18 to 10 days before maximum.…
Type II supernovae (SNe) originate from the explosion of hydrogen-rich supergiant massive stars. Their first electromagnetic signature is the shock breakout, a short-lived phenomenon which can last from hours to days depending on the…