arXiv subjects

Petr Baklanov

Publications and source records attributed to Petr Baklanov.

14 recordsLinked to original sources

arXiv2026

Helium superluminous SN 2021bnw : an explosion of a massive star with a pre-outburst

Superluminous supernovae (SLSNe) remain an intriguing topic in supernova (SN) transient astronomy. While the majority of SLSNe are shown to be explained by energy streaming from the newly born magnetar, there are others which are powered by different mechanisms. We analyse the pseudo-bolometric light curve of the nearby helium-rich SLSN 2021bnw. We built models and run hydrodynamics radiative-transfer simulations with STELLA. Our best-fit models include 15-22.5 Msun of ejecta enriched with 1.7 Msun of 56 Ni and carrying energy of 4 foe, and colliding w ith 7 Msun of circumstellar matter which match the observed light curve very well. The early data can be explained as cooling of an expanding shell with the mass of 0.5 Msun and kinetic energy of 0.7 foe. We tend to exclude a pulsational pair-instability (PPISN) origin for SLSN 2021bnw. Instead we conclude that SLSN 2021bnw was preferably a core-collapse explosion of a star with the initial mass of not less than 61 Msun aided by magnetorotational effects.

astro-ph.HE↗

arXiv2024

SN 2023ixf -- an average-energy explosion with circumstellar medium and a precursor

Abridged: The fortunate proximity of the SN2023ixf allowed astronomers to follow its evolution from almost the moment of the collapse of the progenitor's core. SN2023ixf can be explained as an explosion of a massive star with an energy of 0.7e51 erg, however with a greatly reduced envelope mass, probably because of binary interaction. In our radiative-transfer simulations, the SN ejecta of 6 Msun interact with circumstellar material (CSM) of ~0.6 Msun extending to 1.e15 cm, which results in a light curve (LC) peak matching that of SN2023ixf. The origin of this required CSM might be gravity waves originating from convective shell burning, which could enhance wind-like mass-loss during the late stages of stellar evolution. The steeply rising, low-luminosity flux during the first hours after observationally confirmed non-detection, however, cannot be explained by the collision of the energetic SN shock with the CSM. Instead, we considered it as a precursor that we could fit by the emission from ~0.5 Msun of matter that was ejected with an energy of 1.e49 erg a fraction of a day before the main shock of the SN explosion reached the surface of the progenitor. The source of this energy injection into the outermost shell of the stellar envelope could also be dynamical processes related to the convective activity in the progenitor's interior or envelope. Alternatively, the early rise of the LC could point to the initial breakout of a highly non-spherical SN shock or of fast-moving, asymmetrically ejected matter that was swept out well ahead of the SN shock, potentially in a low-energy, nearly relativistic jet. We also discuss that pre-SN outbursts and LC precursors can be used to study or to constrain energy deposition in the outermost stellar layers by the decay of exotic particles, such as axions, which could be produced simultaneously with neutrinos in the newly formed, hot neutron star.

astro-ph.HE↗

arXiv2024

Primary and secondary source of energy in the superluminous supernova 2018ibb

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 input for radiative transfer simulations done with the STELLA and ARTIS codes: with 25 Msun of 56Ni, 34 Msun of 56Ni, and a chemically mixed case with 34 Msun of 56Ni. We present light curves and spectra in comparison to the observed data of SN 2018ibb, and conclude that the pair-instability supernova model with 34 Msun of 56Ni explains broad-band light curves reasonably well between -100 and 250 days around the peak. Our synthetic spectra have many similarities with the observed spectra. The luminosity excess in the light curves and the blue-flux excess in the spectra can be explained by an additional energy source, which may be interaction of the SN ejecta with circumstellar matter. We discuss possible mechanisms of the origin of the circumstellar matter being ejected in the decades before the pair-instability explosion.

astro-ph.HE↗

arXiv2022

The circumstellar material around the Type IIP SN 2021yja

The majority of Type II-plateau supernovae (SNe IIP) have light curves that are not compatible with the explosions of stars in a vacuum; instead, the light curves require the progenitors to be embedded in circumstellar matter (CSM). We report on the successful fitting of the well-observed SN IIP 2021yja as a core-collapse explosion of a massive star with an initial mass of ~15 Msun and a pre-explosion radius of 631 Rsun. To explain the early-time behaviour of the broad-band light curves, the presence of 0.55 Msun CSM within ~2x10^14 cm is needed. Like many other SNe IIP, SN 2021yja exhibits an early-time flux excess including ultraviolet wavelengths. This, together with the short rise time (<2 days) in the gri bands, indicates the presence of a compact component in the CSM, essentially adjacent to the progenitor. We discuss the origin of the pre-existing CSM, which is most likely a common property of highly convective red supergiant envelopes. We argue that the difficulty in fitting the entire light curve with one spherical distribution indicates that the CSM around the SN 2021yja progenitor was asymmetric.

astro-ph.HE↗

arXiv2022

Low-luminosity type IIP supernovae: SN 2005cs and SN 2020cxd as very low-energy iron core-collapse explosions

SN 2020cxd is a representative of the family of low-energy, underluminous Type IIP supernovae (SNe), whose observations and analysis were recently reported by Yang et al. (2021). Here we re-evaluate the observational data for the diagnostic SN properties by employing the hydrodynamic explosion model of a 9 MSun red supergiant progenitor with an iron core and a pre-collapse mass of 8.75 Msun. The explosion of the star was obtained by the neutrino-driven mechanism in a fully self-consistent simulation in three dimensions (3D). Multi-band light curves and photospheric velocities for the plateau phase are computed with the one-dimensional radiation-hydrodynamics code STELLA, applied to the spherically averaged 3D explosion model as well as spherisized radial profiles in different directions of the 3D model. We find that the overall evolution of the bolometric light curve, duration of the plateau phase, and basic properties of the multi-band emission can be well reproduced by our SN model with its explosion energy of only 0.7x10^50 erg and an ejecta mass of 7.4 Msun. These values are considerably lower than the previously reported numbers, but they are compatible with those needed to explain the fundamental observational properties of the prototype low-luminosity SN 2005cs. Because of the good compatibility of our photospheric velocities with line velocities determined for SN 2005cs, we conclude that the line velocities of SN 2020cxd are probably overestimated by up to a factor of about 3. The evolution of the line velocities of SN 2005cs compared to photospheric velocities in different explosion directions might point to intrinsic asymmetries in the SN ejecta.

astro-ph.SR↗

arXiv2021

A Model for Fast Blue Optical Transient AT2018Cow: Circumstellar Interaction of a Pulsational Pair-instability Supernova

The Fast Blue Optical Transient (FBOT) ATLAS18qqn (AT2018cow) has a light curve as bright as superluminous supernovae but rises and falls much faster. We model this light curve by circumstellar interaction of a pulsational pair-instability (PPI) supernova (SN) model based on our PPISN models studied in previous work. We focus on the 42 $M_\odot$ He star (core of a 80 $M_{\odot}$ star) which has circumstellar matter of mass 0.50 $M_\odot$. With the parameterized mass cut and the kinetic energy of explosion $E$, we perform hydrodynamical calculations of nucleosynthesis and optical light curves of PPISN models. The optical light curve of the first $\sim$ 20 days of AT2018cow is well-reproduced by the shock heating of circumstellar matter for the $42 ~M_{\odot}$ He star with $E = 5 \times 10^{51}$ erg. After day 20, the light curve is reproduced by the radioactive decay of 0.6 $M_\odot$ $^{56}$Co, which is a decay product of $^{56}$Ni in the explosion. We also examine how the light curve shape depends on the various model parameters, such as CSM structure and composition. We also discuss (1) other possible energy sources and their constraints, (2) origin of observed high-energy radiation, and (3) how our result depends on the radiative transfer codes. Based on our successful model for AT2018cow and the model for SLSN with the CSM mass as large as $20 ~M_\odot)$, we propose the working hypothesis that PPISN produces SLSNe if CSM is massive enough and FBOTs if CSM is less than $\sim 1 ~M_\odot$.

astro-ph.HE↗

arXiv2021

Synthetic observables for electron-capture supernovae and low-mass core collapse supernovae

Stars in the mass range from 8 to 10 solar masses are expected to produce one of two types of supernovae (SNe), either electron-capture supernovae (ECSNe) or core-collapse supernovae (CCSNe), depending on their previous evolution. Either of the associated progenitors retain extended and massive hydrogen-rich envelopes, the observables of these SNe are, therefore, expected to be similar. In this study we explore the differences in these two types of SNe. Specifically, we investigate three different progenitor models: a solar-metallicity ECSN progenitor with an initial mass of 8.8 solar masses, a zero-metallicity progenitor with 9.6 solar masses, and a solar-metallicity progenitor with 9 solar masses, carrying out radiative transfer simulations for these progenitors. We present the resulting light curves for these models. The models exhibit very low photospheric velocity variations of about 2000 km/s, therefore, this may serve as a convenient indicator of low-mass SNe. The ECSN has very unique light curves in broad bands, especially the U band, and does not resemble any currently observed SN. This ECSN progenitor being part of a binary will lose its envelope for which reason the light curve becomes short and undetectable. The SN from the 9.6 solar masses progenitor exhibits also quite an unusual light curve, explained by the absence of metals in the initial composition. The artificially iron polluted 9.6 solar masses model demonstrates light curves closer to normal SNe IIP. The SN from the 9 solar masses progenitor remains the best candidate for so-called low-luminosity SNe IIP like SN 1999br and SN 2005cs.

astro-ph.SR↗

arXiv2020

Strongly lensed SN Refsdal: refining time delays based on the supernova explosion models

We explore the properties of supernova (SN) "Refsdal" - the first discovered gravitationally lensed SN with multiple images. A large magnification provided by the galactic-scale lens, augmented by the cluster lens, gave us a unique opportunity to perform a detailed modelling of a distant SN at z=1.5. We present results of radiation hydrodynamics modelling of SN Refsdal. According to our calculations, the SN Refsdal progenitor is likely to be a more massive and energetic version of SN 1987A, i.e. a blue supergiant star with the following parameters: the progenitor radius $R_0 = (50 \pm 1) R_{\odot}$, the total mass $M_{tot}= (25\pm 2) M_{\odot}$, the radioactive $^{56}$Ni mass $M_{^{56}\mathrm{Ni}} = (0.26 \pm 0.05) \,M_{\odot}$, and the total energy release $E_{burst}=(4.7 \pm 0.8)\times10^{51}$ erg. Reconstruction of SN light curves allowed us to obtain time delays and magnifications for the images S2-S4 relative to S1 with higher accuracy than previous template-based estimates of Rodney \& et al. (2016). The measured time delays are $Δt_{S2-S1} = 9.5^{+2.6}_{-2.7} $ days, $Δt_{S3-S1} = 4.2^{+2.3}_{-2.3} $ days, and $Δt_{S4-S1} = 30^{+7.8}_{-8.2} $ days. The obtained magnification ratios are $μ_{S2/S1}= 1.14 \pm 0.02$, $μ_{S3/S1} = 1.01 \pm 0.02 $, and $μ_{S4/S1} = 0.35\pm 0.02$. We estimate the Hubble constant $H_0 = 68.6^{+13.6}_{-9.7}$ km s$^{-1}$ Mpc$^{-1}$ via re-scaling the time delays predicted by different lens models to match the values obtained in this work. With more photometric data on the fifth image SX, we will be able to further refine the time delay and magnification estimates for SX and obtain competitive constraints on $H_0$.

astro-ph.HE↗

arXiv2020

The influence of line opacity treatment in STELLA on supernova light curves

We systematically explore the effect of the treatment of line opacity on supernova light curves. We find that it is important to consider line opacity for both scattering and absorption (i.e. thermalisation which mimics the effect of fluorescence.) We explore the impact of degree of thermalisation on three major types of supernovae: Type Ia, Type II-peculiar, and Type II-plateau. For that we use radiative transfer code STELLA and analyse broad-band light curves in the context of simulations done with the spectral synthesis code ARTIS and in the context a few examples of observed supernovae of each type. We found that the plausible range for the ratio between absorption and scattering in the radiation hydrodynamics code STELLA is (0.8-1):(0.2-0), i.e. the recommended thermalisation parameter is 0.9.

astro-ph.HE↗

arXiv2020

Shock breakouts from red supergiants: analytical and numerical predictions

Shock breakout (SBO) signal is the first signature of the supernova explosion apart from gravitational waves and neutrinos. Observational properties of SBO, such as bolometric luminosity and colour temperature, connect to the supernova progenitor and explosion parameters. Detecting SBO or SBO-cooling will constrain the progenitor and explosion models of collapsing stars. In the light of recently launched eROSITA telescope, the rate for detection of SBO is a few events during a year. In the current study, we examine the analytic formulae derived by Shussman et al. (2016). We use four red supergiant models from their study, while running explosions with the radiation hydrodynamics code STELLA. We conclude that there is a good agreement between analytic and numerical approaches for bolometric luminosity and colour temperature during SBO. The analytic formulae for the SBO signal based on the global supernova parameters can be used instead of running time-consuming numerical simulations. We define spectral range where analytic formulae for the SBO spectra are valid. We provide improved analytical expression for the SBO spectral energy distribution. We confirm dependence of colour temperature on radius derived by analytical studies and suggest to use early time observations to confine the progenitor radius. Additionally we show the prediction for the SBO signal from red supergiants as seen by eROSITA instrument.

astro-ph.HE↗

arXiv2018

Quark deconfinement as supernova explosion engine for massive blue-supergiant stars

Blue-supergiant stars develop into core-collapse supernovae --- one of the most energetic outbursts in the universe --- when all nuclear burning fuel is exhausted in the stellar core. Previous attempts failed to explain observed explosions of such stars which have a zero-age main sequence mass of 50~M$_\odot$ or more. Here we exploit the largely uncertain state of matter at high density, and connect the modeling of such stellar explosions with a first-order phase transition from nuclear matter to the quark-gluon plasma. The resulting energetic supernova explosions can account for a large variety of lightcurves, from peculiar type II to super-luminous events. The remnants are neutron stars with quark matter core, known as hybrid stars, of about 2~M$_\odot$ at birth. A galactic event of this kind could be observable due to the release of a second neutrino burst. Its observation would confirm such a first-order phase transition at densities relevant for astrophysics.

astro-ph.HE↗

arXiv2016

Pulsational Pair-Instability Model for Superluminous Supernova PTF12dam: Interaction and Radioactive Decay

Being a superluminous supernova (SLSN), PTF12dam can be explained by a $^{56}$Ni-powered model, a magnetar-powered model or an interaction model. We propose that PTF12dam is a pulsational pair instability supernova, where the outer envelope of a progenitor is ejected during the pulsations. Thus, it is powered by double energy source: radioactive decay of $^{56}$Ni and a radiative shock in a dense circumstellar medium. To describe multicolor light curves and spectra we use radiation hydrodynamics calculations of STELLA code. We found that light curves are well described in the model with 40M$_{\odot}$ ejecta and 20-40M$_{\odot}$ circumstellar medium. The ejected $^{56}$Ni mass is about 6M$_{\odot}$ which results from explosive nucleosynthesis with large explosion energy (2-3)$\cdot$10$^{52}$ ergs. In comparison with alternative scenarios of pair-instability supernova and magnetar-powered supernova, in interaction model all the observed main photometric characteristics are well reproduced: multicolor light curves, color temperatures, and photospheric velocities.

astro-ph.HE↗

arXiv2015

Hydrogenless Superluminous Supernova PTF12dam in the Model of an Explosion inside an Extended Envelope

A model of a supernova explosion inside a dense extended hydrogenless envelope is proposed to explain the properties of the light curve for one of the superluminous supernovae PTF12dam. It is argued in the literature that the flux of this supernova rises too fast to be explained by the explosion model due to the instability associated with the electron-positron pair production (pair-instability supernova, PISNe), but it is well described by the models with energy input by a magnetar. We show that the PTF12dam-type supernovae can be explained without a magnetar in a model with a radiative shock in a dense circumstellar envelope that does not require an excessively large explosion energy.

astro-ph.HE↗

arXiv2012

Direct Determination of Hubble Parameter Using Type IIn Supernovae

We introduce a novel approach, a Dense Shell Method (DSM), for measuring distances for cosmology. It is based on original Baade idea to relate absolute difference of photospheric radii with photospheric velocity. We demonstrate that this idea works: the new method does not rely on the Cosmic Distance Ladder and gives satisfactory results for the most luminous Type IIn Supernovae. This allows one to make them good primary distance indicators for cosmology. Fixing correction factors for illustration, we obtain with this method the median distance of 68^{+19}_{-15} (68%CL) Mpc to SN 2006gy and median Hubble parameter 79^{+23}_{-17} (68%CL) km/s/Mpc.

astro-ph.CO↗