Searcharxiv⌕ Search

arXiv subjects

Hans-Thomas Janka

Publications and source records attributed to Hans-Thomas Janka.

At least 37 records · Page 2Linked to original sources
arXiv2023

Supernova Simulations Confront SN 1987A Neutrinos

We return to interpreting the historical SN~1987A neutrino data from a modern perspective. To this end, we construct a suite of spherically symmetric supernova models with the Prometheus-Vertex code, using four different equations of state and five choices of final baryonic neutron-star (NS) mass in the 1.36-1.93 M$_\odot$ range. Our models include muons and proto-neutron star (PNS) convection by a mixing-length approximation. The time-integrated signals of our 1.44 M$_\odot$ models agree reasonably well with the combined data of the four relevant experiments, IMB, Kam-II, BUST, and LSD, but the high-threshold IMB detector alone favors a NS mass of 1.7-1.8 M$_\odot$, whereas Kam-II alone prefers a mass around 1.4 M$_\odot$. The cumulative energy distributions in these two detectors are well matched by models for such NS masses, and the previous tension between predicted mean neutrino energies and the combined measurements is gone, with and without flavor swap. Generally, our predicted signals do not strongly depend on assumptions about flavor mixing, because the PNS flux spectra depend only weakly on antineutrino flavor. While our models show compatibility with the events detected during the first seconds, PNS convection and nucleon correlations in the neutrino opacities lead to short PNS cooling times of 5-9 s, in conflict with the late event bunches in Kam-II and BUST after 8-9 s, which are also difficult to explain by background. Speculative interpretations include the onset of fallback of transiently ejected material onto the NS, a late phase transition in the nuclear medium, e.g., from hadronic to quark matter, or other effects that add to the standard PNS cooling emission and either stretch the signal or provide a late source of energy. More research, including systematic 3D simulations, is needed to assess these open issues.

astro-ph.HE↗
arXiv2023

End-to-end kilonova models of neutron-star mergers with delayed black-hole formation

We investigate the nucleosynthesis and kilonova properties of binary neutron-star (NS) merger models which lead to intermediate remnant lifetimes of ~0.1-1seconds until black-hole (BH) formation and describe all components of material ejected during the dynamical merger phase, NS-remnant evolution, and final viscous disintegration of the BH torus after gravitational collapse. To this end we employ a combination of hydrodynamics, nucleosynthesis, and radiative-transfer tools to achieve a consistent end-to-end modeling of the system and its observables. We adopt a novel version of the Shakura-Sunyaev scheme allowing to vary the approximate turbulent viscosity inside the NS remnant independently of the surrounding disk. We find that asymmetric progenitors lead to shorter remnant lifetimes and enhanced ejecta masses, although the viscosity affects the absolute values of these characteristics. The integrated production of lanthanides and heavier elements in such binary systems is sub-solar, suggesting that the considered scenarios contribute in a sub-dominant fashion to r-process enrichment. One reason is that BH-tori formed after delayed collapse exhibit less neutron-rich conditions than typically found, and often assumed in previous BH-torus models, for early BH formation. The outflows in our models feature strong anisotropy as a result of the lanthanide-poor polar neutrino-driven wind pushing aside lanthanide-rich dynamical ejecta. Considering the complexity of the models, the estimated kilonova light curves show promising agreement with AT2017gfo after times of several days, while the remaining inconsistencies at early times could possibly be overcome in binary configurations with a more dominant neutrino-driven wind relative to the dynamical ejecta.

astro-ph.HE↗
arXiv2023

Fast Neutrino Flavor Conversion in Core-Collapse Supernovae: A Parametric Study in 1D Models

We explore the impact of small-scale flavor conversions of neutrinos, the so-called fast flavor conversions (FFCs), on the dynamical evolution and neutrino emission of core-collapse supernovae (CCSNe). In order to do that, we implement FFCs in the spherically symmetric (1D) CCSN simulations of a 20 solar-mass progenitor model parametrically, assuming that FFCs happen at densities lower than a systematically varied threshold value and lead to an immediate flavor equilibrium consistent with lepton number conservation. We find that besides hardening the electron neutrino and antineutrino spectra, which helps the expansion of the shock by enhanced postshock heating, FFCs can cause significant, nontrivial modifications of the energy transport in the SN environment via increasing the heavy-lepton neutrino luminosities. In our non-exploding models this results in extra cooling of the layers around the neutrinospheres, which triggers a faster contraction of the proto-neutron star and hence, in our 1D models, hampers the CCSN explosion. Although our study is limited by the 1D nature of our simulations, it provides valuable insights into how neutrino flavor conversions in the deepest CCSN regions can impact the neutrino release and the corresponding response of the stellar medium.

astro-ph.HE↗
arXiv2022

Low-Energy Supernovae Severely Constrain Radiative Particle Decays

The hot and dense core formed in the collapse of a massive star is a powerful source of hypothetical feebly-interacting particles such as sterile neutrinos, dark photons, axion-like particles (ALPs), and others. Radiative decays such as $a\to2γ$ deposit this energy in the surrounding material if the mean free path is less than the radius of the progenitor star. For the first time, we use a supernova (SN) population with particularly low explosion energies as the most sensitive calorimeters to constrain this possibility. These SNe are observationally identified as low-luminosity events with low ejecta velocities and low masses of ejected $^{56}$Ni. Their low energies limit the energy deposition from particle decays to less than about 0.1 B, where $1~{\rm B~(bethe)}=10^{51}~{\rm erg}$. For 1-500 MeV-mass ALPs, this generic argument excludes ALP-photon couplings $G_{aγγ}$ in the $10^{-10}$-$10^{-8}~{\rm GeV}^{-1}$ range.

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↗
arXiv2022

Dynamical ejecta of neutron star mergers with nucleonic weak processes II: Kilonova emission

The majority of existing results for the kilonova (or macronova) emission from material ejected during a neutron-star (NS) merger is based on (quasi-)one-zone models or manually constructed toy-model ejecta configurations. In this study we present a kilonova analysis of the material ejected during the first ~10ms of a NS merger, called dynamical ejecta, using directly the outflow trajectories from general relativistic smoothed-particle hydrodynamics simulations including a sophisticated neutrino treatment and the corresponding nucleosynthesis results, which have been presented in Part I of this study. We employ a multi-dimensional two-moment radiation transport scheme with approximate M1 closure to evolve the photon field and use a heuristic prescription for the opacities found by calibration with atomic-physics based reference results. We find that the photosphere is generically ellipsoidal but augmented with small-scale structure and produces emission that is about 1.5-3 times stronger towards the pole than the equator. The kilonova typically peaks after 0.7-1.5days in the near-infrared frequency regime with luminosities between 3-7x10^40erg/s and at photospheric temperatures of 2.2-2.8x10^3K. A softer equation of state or higher binary-mass asymmetry leads to a longer and brighter signal. Significant variations of the light curve are also obtained for models with artificially modified electron fractions, emphasizing the importance of a reliable neutrino-transport modeling. None of the models investigated here, which only consider dynamical ejecta, produces a transient as bright as AT2017gfo. The near-infrared peak of our models is incompatible with the early blue component of AT2017gfo.

astro-ph.HE↗
arXiv2022

Fast Neutrino Conversion in Hydrodynamic Simulations of Neutrino-Cooled Accretion Disks

The outflows from neutrino-cooled black-hole (BH) accretion disks formed in neutron-star mergers or cores of collapsing stars are expected to be neutron-rich enough to explain a large fraction of elements created by the rapid neutron-capture (r-) process, but their precise chemical composition remains elusive. Here, we investigate the role of fast neutrino flavor conversion, motivated by the findings of our post-processing analysis that shows evidence of electron-neutrino lepton-number (ELN) crossings deep inside the disk, hence suggesting possibly non-trivial effects due to neutrino flavor mixing. We implement a parametric, dynamically self-consistent treatment of fast conversion in time-dependent simulations and examine the impact on the disk and its outflows. By activating the, otherwise inefficient, emission of heavy-lepton neutrinos, fast conversions enhance the disk cooling rates and reduce the absorption rates of electron-type neutrinos, causing a reduction of the electron fraction in the disk by 0.03-0.06 and in the ejected material by 0.01-0.03. The r-process yields are enhanced by typically no more than a factor of two, rendering the overall impact of fast conversions modest. The kilonova is prolonged as a net result of increased lanthanide opacities and enhanced radioactive heating rates. We observe only mild sensitivity to the disk mass, the condition for the onset of flavor conversion, and to the considered cases of flavor mixing. Remarkably, parametric models of flavor mixing that conserve the lepton numbers per family result in an overall smaller impact than models invoking three-flavor equipartition, often assumed in previous works.

astro-ph.HE↗
arXiv2022

Pulsational pair-instability supernovae: gravitational collapse, black-hole formation, and beyond

We investigate the final collapse of rotating and non-rotating pulsational pair-instability supernova progenitors with zero-age-main-sequence masses of 60, 80, and 115$\mathrm{M}_\odot$ and iron cores between 2.37$\mathrm{M}_\odot$ and 2.72$\mathrm{M}_\odot$ by 2D hydrodynamics simulations. Using the general relativistic NADA-FLD code with energy-dependent three-flavor neutrino transport by flux-limited diffusion allows us to follow the evolution beyond the moment when the transiently forming neutron star (NS) collapses to a black hole (BH), which happens within 350$-$580 ms after bounce in all cases. Because of high neutrino luminosities and mean energies, neutrino heating leads to shock revival within $\lesssim$250 ms post bounce in all cases except the rapidly rotating 60$\mathrm{M}_\odot$ model. In the latter case, centrifugal effects support a 10% higher NS mass but reduce the radiated neutrino luminosities and mean energies by $\sim$20% and $\sim$10%, respectively, and the neutrino-heating rate by roughly a factor of two compared to the non-rotating counterpart. After BH formation, the neutrino luminosities drop steeply but continue on a 1$-$2 orders of magnitude lower level for several 100 ms because of aspherical accretion of neutrino and shock-heated matter, before the ultimately spherical collapse of the outer progenitor shells suppresses the neutrino emission to negligible values. In all shock-reviving models BH accretion swallows the entire neutrino-heated matter and the explosion energies decrease from maxima around 1.5$\times$10$^{51}$erg to zero within a few seconds latest. Nevertheless, the shock or a sonic pulse moves outward and may trigger mass loss, which we estimate by long-time simulations with the PROMETHEUS code. We also provide gravitational-wave signals.

astro-ph.HE↗
arXiv2021

Neutrino absorption and other physics dependencies in neutrino-cooled black-hole accretion disks

Black-hole (BH) accretion disks formed in compact-object mergers or collapsars may be major sites of the rapid-neutron-capture (r-)process, but the conditions determining the electron fraction (Y_e) remain uncertain given the complexity of neutrino transfer and angular-momentum transport. After discussing relevant weak-interaction regimes, we study the role of neutrino absorption for shaping Y_e using an extensive set of simulations performed with two-moment neutrino transport and again without neutrino absorption. We vary the torus mass, BH mass and spin, and examine the impact of rest-mass and weak-magnetism corrections in the neutrino rates. We also test the dependence on the angular-momentum transport treatment by comparing axisymmetric models using the standard alpha-viscosity with viscous models assuming constant viscous length scales (l_t) and three-dimensional magnetohydrodynamic (MHD) simulations. Finally, we discuss the nucleosynthesis yields and basic kilonova properties. We find that absorption pushes Y_e towards ~0.5 outside the torus, while inside increasing the equilibrium value Y_e^eq by ~0.05-0.2. Correspondingly, a substantial ejecta fraction is pushed above Y_e=0.25, leading to a reduced lanthanide fraction and a brighter, earlier, and bluer kilonova than without absorption. More compact tori with higher neutrino optical depth, tau, tend to have lower Y_e^eq up to tau~1-10, above which absorption becomes strong enough to reverse this trend. Disk ejecta are less (more) neutron-rich when employing an l_t=const. viscosity (MHD treatment). The solar-like abundance pattern found for our MHD model marginally supports collapsar disks as major r-process sites, although a strong r-process may be limited to phases of high mass-infall rates, Mdot>~ 2 x 10^(-2) Msun/s.

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↗
arXiv2021

The infancy of core-collapse supernova remnants

We present 3D hydrodynamic simulations of neutrino-driven supernovae (SNe) with the PROMETHEUS-HOTB code, evolving the asymmetrically expanding ejecta from shock breakout until they reach the homologous expansion phase after roughly one year. Our calculations continue the simulations for two red supergiant (RSG) and two blue supergiant (BSG) progenitors by Wongwathanarat et al., who investigated the growth of explosion asymmetries produced by hydrodynamic instabilities during the first second of the explosion and their later fragmentation by Rayleigh-Taylor instabilities. We focus on the late time acceleration and inflation of the ejecta caused by the heating due to the radioactive decay of $^{56}$Ni to $^{56}$Fe and by a new outward-moving shock, which forms when the reverse shock from the He/H-shell interface compresses the central part of the ejecta. The mean velocities of the iron-rich ejecta increase between 100 km/s and 350 km/s ($\sim$8-30\%), and the fastest one percent of the iron accelerates by up to $\sim$1000 km/s ($\sim$20-25\%). This 'Ni-bubble effect', known from 1D models, accelerates the bulk of the nickel in our 3D models and causes an inflation of the initially overdense Ni-rich clumps, which leads to underdense, extended fingers, enveloped by overdense skins of compressed surrounding matter. We also provide volume and surface filling factors as well as a spherical harmonics analysis to characterize the spectrum of Ni-clump sizes quantitatively. Three of our four models give volume filling factors larger than 0.3, consistent with what is suggested for SN 1987A by observations.

astro-ph.SR↗
arXiv2020

Stellar Collapse Diversity and the Diffuse Supernova Neutrino Background

The diffuse cosmic supernova neutrino background (DSNB) is observational target of the gadolinium-loaded Super-Kamiokande (SK) detector and the forthcoming JUNO and Hyper-Kamiokande detectors. Current predictions are hampered by our still incomplete understanding of the supernova (SN) explosion mechanism and of the neutron star (NS) equation of state and maximum mass. In our comprehensive study we revisit this problem on grounds of the landscapes of successful and failed SN explosions obtained by Sukhbold et al. and Ertl et al. with parametrized one-dimensional neutrino engines for large sets of single-star and helium-star progenitors, with the latter serving as proxy of binary evolution effects. Besides considering engines of different strengths, leading to different fractions of failed SNe with black-hole (BH) formation, we also vary the NS mass limit, the spectral shape of the neutrino emission, and include contributions from poorly understood alternative NS-formation channels such as accretion-induced or merger-induced collapse events. Since the neutrino signals of our large model sets are approximate, we calibrate the associated degrees of freedom by using state-of-the-art simulations of proto-neutron star cooling. Our predictions are higher than other recent ones because of a large fraction of failed SNe with long delay to BH formation. Our best-guess model predicts a DSNB electron-antineutrino-flux of 28.8^{+24.6}_{-10.9} cm^{-2}s^{-1} with 6.0^{+5.1}_{-2.1} cm^{-2}s^{-1} in the favorable measurement interval of [10,30] MeV, and 1.3^{+1.1}_{-0.4} cm^{-2}s^{-1} with electron-antineutrino energies > 17.3 MeV, which is roughly a factor of two below the current SK limit. The uncertainty range is dominated by the still insufficiently constrained cosmic rate of stellar core-collapse events.

astro-ph.HE↗
arXiv2020

Fast neutrino flavor conversion, ejecta properties, and nucleosynthesis in newly-formed hypermassive remnants of neutron-star mergers

Neutrinos emitted in the coalescence of two neutron stars affect the dynamics of the outflow ejecta and the nucleosynthesis of heavy elements. In this work, we analyze the neutrino emission properties and the conditions leading to the growth of flavor instabilities in merger remnants consisting of a hypermassive neutron star and an accretion disk during the first 10 ms after the merger. The analyses are based on hydrodynamical simulations that include a modeling of neutrino emission and absorption effects via the "Improved Leakage-Equilibration-Absorption Scheme" (ILEAS). We also examine the nucleosynthesis of the heavy elements via the rapid neutron-capture process (r-process) inside the material ejected during this phase. The dominant emission of $\barν_e$ over $ν_e$ from the merger remnant leads to favorable conditions for the occurrence of fast pairwise flavor conversions of neutrinos, independent of the chosen equation of state or the mass ratio of the binary. The nucleosynthesis outcome is very robust, ranging from the first to the third r-process peaks. In particular, more than $10^{-5}$ $M_\odot$ of strontium are produced in these early ejecta that may account for the GW170817 kilonova observation. We find that the amount of ejecta containing free neutrons after the $r$-process freeze-out, which may power early-time UV emission, is reduced by roughly a factor of 10 when compared to simulations that do not include weak interactions. Finally, the potential flavor equipartition between all neutrino flavors is mainly found to affect the nucleosynthesis outcome in the polar ejecta within $\lesssim 30^\circ$, by changing the amount of the produced iron-peak and first-peak nuclei, but it does not alter the lanthanide mass fraction therein.

astro-ph.HE↗
arXiv2020

Neutrino emission characteristics of black hole formation in three-dimensional simulations of stellar collapse

Neutrinos are unique probes of core-collapse supernova dynamics, especially in the case of black hole (BH) forming stellar collapses, where the electromagnetic emission may be faint or absent. By investigating two 3D hydrodynamical simulations of BH-forming stellar collapses of mass 40 and 75 M_sun, we identify the physical processes preceding BH formation through neutrinos, and forecast the neutrino signal expected in the existing IceCube and Super-Kamiokande detectors, as well as in the future generation DUNE facility. Prior to the abrupt termination of the neutrino signal corresponding to BH formation, both models develop episodes of strong and long-lasting activity by the spiral standing accretion shock instability (SASI). We find that the spiral SASI peak in the Fourier power spectrum of the neutrino event rate will be distinguishable at 3 sigma above the detector noise for distances up to O(30) kpc in the most optimistic scenario, with IceCube having the highest sensitivity. Interestingly, given the long duration of the spiral SASI episodes, the spectrograms of the expected neutrino event rate carry clear signs of the evolution of the blue spiral SASI frequency as a function of time, as the shock radius and post-shock fluid velocity evolve. Due to the high accretion luminosity and its large-amplitude SASI-induced modulations, any contribution from asymmetric (dipolar or quadrupolar) neutrino emission associated with the lepton emission self-sustained asymmetry (LESA) is far subdominant in the neutrino signal.

astro-ph.HE↗
arXiv2020

NS 1987A in SN 1987A

The possible detection of a compact object in the remnant of SN 1987A presents an unprecedented opportunity to follow its early evolution. The suspected detection stems from an excess of infrared emission from a dust blob near the compact object's predicted position. The infrared excess could be due to the decay of isotopes like 44Ti, accretion luminosity from a neutron star or black hole, magnetospheric emission or a wind originating from the spindown of a pulsar, or thermal emission from an embedded, cooling neutron star (NS 1987A). It is shown that the last possibility is the most plausible as the other explanations are disfavored by other observations and/or require fine-tuning of parameters. Not only are there indications the dust blob overlaps the predicted location of a kicked compact remnant, but its excess luminosity also matches the expected thermal power of a 30 year old neutron star. Furthermore, models of cooling neutron stars within the Minimal Cooling paradigm readily fit both NS 1987A and Cas A, the next-youngest known neutron star. If correct, a long heat transport timescale in the crust and a large effective stellar temperature are favored, implying relatively limited crustal n-1S0 superfluidity and an envelope with a thick layer of light elements, respectively. If the locations don't overlap, then pulsar spindown or accretion might be more likely, but the pulsar's period and magnetic field or the accretion rate must be rather finely tuned. In this case, NS 1987A may have enhanced cooling and/or a heavy-element envelope.

astro-ph.HE↗
arXiv2020

Magnetar formation through a convective dynamo in protoneutron stars

The release of spin-down energy by a magnetar is a promising scenario to power several classes of extreme explosive transients. However, it lacks a firm basis because magnetar formation still represents a theoretical challenge. Using the first three-dimensional simulations of a convective dynamo based on a protoneutron star interior model, we demonstrate that the required dipolar magnetic field can be consistently generated for sufficiently fast rotation rates. The dynamo instability saturates in the magnetostrophic regime with the magnetic energy exceeding the kinetic energy by a factor of up to 10. Our results are compatible with the observational constraints on galactic magnetar field strength and provide strong theoretical support for millisecond protomagnetar models of gamma-ray burst and superluminous supernova central engines.

astro-ph.HE↗
arXiv2019

High angular resolution ALMA images of dust and molecules in the SN 1987A ejecta

We present high angular resolution (~80 mas) ALMA continuum images of the SN 1987A system, together with CO $J$=2 $\!\rightarrow\!$ 1, $J$=6 $\!\rightarrow\!$ 5, and SiO $J$=5 $\!\rightarrow\!$ 4 to $J$=7 $\!\rightarrow\!$ 6 images, which clearly resolve the ejecta (dust continuum and molecules) and ring (synchrotron continuum) components. Dust in the ejecta is asymmetric and clumpy, and overall the dust fills the spatial void seen in H$α$ images, filling that region with material from heavier elements. The dust clumps generally fill the space where CO $J$=6 $\!\rightarrow\!$ 5 is fainter, tentatively indicating that these dust clumps and CO are locationally and chemically linked. In these regions, carbonaceous dust grains might have formed after dissociation of CO. The dust grains would have cooled by radiation, and subsequent collisions of grains with gas would also cool the gas, suppressing the CO $J$=6 $\!\rightarrow\!$ 5 intensity. The data show a dust peak spatially coincident with the molecular hole seen in previous ALMA CO $J$=2 $\!\rightarrow\!$ 1 and SiO $J$=5 $\!\rightarrow\!$ 4 images. That dust peak, combined with CO and SiO line spectra, suggests that the dust and gas could be at higher temperatures than the surrounding material, though higher density cannot be totally excluded. One of the possibilities is that a compact source provides additional heat at that location. Fits to the far-infrared--millimeter spectral energy distribution give ejecta dust temperatures of 18--23K. We revise the ejecta dust mass to $\mathrm{M_{dust}} = 0.2-0.4$M$_\odot$ for carbon or silicate grains, or a maximum of $<0.7$M$_\odot$ for a mixture of grain species, using the predicted nucleosynthesis yields as an upper limit.

astro-ph.HE↗
arXiv2019

Effects of the standing accretion-shock instability and the lepton-emission self-sustained asymmetry in the neutrino emission of rotating supernovae

Rotation of core-collapse supernovae (SNe) affects the neutrino emission characteristics. By comparing the neutrino properties of three three-dimensional SN simulations of a 15 M_sun progenitor (one non-rotating model and two models rotating at different velocities), we investigate how the neutrino emission varies with the flow dynamics in the SN core depending on the different degrees of rotation. The large-amplitude sinusoidal modulations due to the standing accretion-shock instability (SASI) are weaker in both the rotating models than in the non-rotating case. The SN progenitor rotation reduces the radial velocities and radial component of the kinetic energy associated with convection interior to the proto-neutron star. This effect seems to disfavor the growth of the hemispheric neutrino-emission asymmetries associated with the lepton-emission self-sustained asymmetry (LESA). An investigation of the multipole expansion of the neutrino luminosity and the electron neutrino lepton number flux shows a dominant quadrupolar mode in rotating SN models. Our findings highlight the power of using neutrinos as probes of SN hydrodynamics.

astro-ph.HE↗