arXiv subjects

Noam Soker

Publications and source records attributed to Noam Soker.

At least 73 records · Page 4Linked to original sources

arXiv2025

XRISM observations of the cooling flow cluster A2029 support heating by mixing

I argue that the mixing-heating mechanism of the intracluster medium (ICM) is compatible with the new observations by the X-ray telescope XRISM that show the dispersion velocity in the cooling flow cluster of galaxies A2029 to be 169 km/s. Past jets from the central supermassive black hole induced turbulence; the velocity dispersion value indicates that the jets were powerful, as expected in the mixing-heating mechanism. Although the kinetic energy of the ICM turbulence that XRISM finds is short of heating the ICM and counter radiative cooling, the turbulence is fast enough to mix the hot shocked jets' material with the ICM on time scales shorter than the radiative cooling time. The support of the mixing-heating mechanism from determining the turbulent velocity I claim for A2029 is similar to the conclusion from the X-ray observations by the X-ray telescope Hitomi of the Perseus cluster.

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arXiv2025

On the response of massive main sequence stars to mass accretion and outflow at high rates

With a one-dimensional stellar evolution model, we find that massive main-sequence stars can accrete mass at very high mass accretion rates without expanding much if they lose a significant fraction of this mass from their outer layers simultaneously with mass accretion. We assume the accretion process is via an accretion disk that launches powerful jets from its inner zones. These jets remove the outer high-entropy layers of the mass-accreting star. This process operates in a negative feedback cycle, as the jets remove more envelope mass when the star expands. With the one-dimensional model, we mimic the mass removal by jets by alternative mass addition and mass removal phases. For the simulated models of 30Mo and 60Mo, the star does not expand much if we remove more than about half of the added mass in not-too-short episodes. This holds even if we deposit the energy the jets do not carry into the envelope. As the star does not expand much, its gravitational potential well stays deep, and the jets are energetic. These results are relevant to bright transient events of binary systems powered by accretion and the launching of jets, e.g., intermediate luminosity optical transients, including some luminous red novae, the grazing envelope evolution, and the 1837-1856 Great Eruption of Eta Carinae.

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arXiv2024

The two alternative explosion mechanisms of core-collapse supernovae: 2024 status report

In comparing the two alternative explosion mechanisms of core-collapse supernovae (CCSNe), I examine recent three-dimensional (3D) hydrodynamical simulations of CCSNe in the frame of the delayed-neutrino explosion mechanism (neutrino mechanism) and argue that these valuable simulations show that neutrino heating can supply a non-negligible fraction of the explosion energy but not the observed energies, hence cannot be the primary explosion mechanism. In addition to the energy crisis, the neutrino mechanism predicts many failed supernovae that are not observed. The most challenging issue of the neutrino mechanism is that it cannot account for point-symmetric morphologies of CCSN remnants, many of which were identified in 2024. These contradictions with observations imply that the neutrino mechanism cannot be the primary explosion mechanism of CCSNe. The alternative jittering-jets explosion mechanism (JJEM) seems to be the primary explosion mechanism of CCSNe; neutrino heating boosts the energy of the jittering jets. Even if some simulations show explosions of stellar models (but usually with energies below observed), it does not mean that the neutrino mechanism is the explosion mechanism. Jittering jets, which simulations do not include, can explode the core before the neutrino heating process does. Morphological signatures of jets in many CCSN remnants suggest that jittering jets are the primary driving mechanism, as expected by the JJEM.

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arXiv2024

Et tu, Brute?: The Crab Nebula also exploded by jittering jets

We identify a point-symmetrical morphology comprised of seven pairs of opposite bays in the core-collapse supernova (CCSN) remnant Crab Nebula, which is consistent with the jittering jets explosion mechanism (JJEM) of CCSNe. We use a recently published infrared image of the Crab Nebula and apply image analysis to fit seven pairs of bays in the Crab, each pair of two bays and a symmetry axis connecting them. The seven symmetry axes intersect close to the explosion site, forming a point-symmetrical structure. We explain the bays as clumps that move slower than the low-density ejecta that the pulsar accelerated. Jittering jets that exploded the Crab formed the clumps during the explosion process. This shows that jittering jets explode even very low-energy CCSNe, as the Crab is, adding to the solidification of the JJEM as the primary explosion mechanism of CCSNe.

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arXiv2024

Identifying jittering-jet-shaped ejecta in the Cygnus Loop supernova remnant

Analyzing images of the Cygnus Loop, a core-collapse supernova (CCSN) remnant, in different emission bands, we identify a point-symmetrical morphology composed of three symmetry axes that we attribute to shaping by three pairs of jets. The main jet axis has an elongated S shape, appearing as a faint narrow zone in visible and UV. We term it the S-shaped hose, and the structure of three symmetry lines, the point-symmetric wind rose. The two other lines connect a protrusion (an ear or a bulge) with a hole on the opposite side of the center (a nozzle or a cavity), structures that we identify in the X-ray, UV, visible, IR, and/or radio images. There is a well-known blowout at the southern end of the S-shaped hose, and we identify a possible opposite blowout at the northern end of the S-shaped hose. The point-symmetrical morphology of the Cygnus Loop is according to the expectation of the jittering jets explosion mechanism (JJEM) of CCSNe, where several to few tens of pairs of jets with stochastically varying directions explode the star. The three pairs of jets that shaped the wind-rose structure of the Cygnus Loop are the last energetic pairs of this series of jets. Our study further supports the JJEM as the main explosion mechanism of CCSNe.

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arXiv2024

Identifying a point-symmetrical morphology in the core-collapse supernova remnant W44

I identify a point-symmetrical morphology in the core-collapse supernova remnant (CCSNR) W44 compatible with shaping by three or more pairs of jets in the jittering jet explosion mechanism (JJEM). Motivated by recent identifications of point-symmetrical morphologies in CCSNRs and their match to the JJEM, I revisit the morphological classification of CCSNR W44. I examine a radio map of W44 and find the outer bright rim of the radio map to possess a point-symmetric structure compatible with shaping by two energetic pairs of opposite jets rather than an S-shaped morphology shaped by a precessing pair of jets. An inner pair of filaments might hint at a third powerful pair of jets. More pairs of jets were involved in the explosion process. This study adds to the growing evidence that the JJEM is the primary explosion mechanism of core-collapse supernovae.

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arXiv2024

Identifying a point-symmetric morphology in supernova remnant Cassiopeia A: explosion by jittering jets

We identify a point-symmetric morphology of the supernova remnant (SNR) Cassiopeia A compatible with shaping by at least two, and more likely more than four, pairs of opposite jets, as expected in the jittering jets explosion mechanism (JJEM) of core-collapse supernovae. Using an old Spitzer Telescope infrared map of argon, we identify seven pairs of opposite morphological features that we connect with lines that cross each other at the same point on the plane of the sky. The opposite morphological features include protrusions, clumps, filaments, and funnels in the main SNR shell. In addition to these seven symmetry axes, we find two tentative symmetry axes (lines). These lines form a point-symmetric wind-rose. We place this point-symmetric wind-rose on a new JWST and X-ray images of Cassiopeia A. We find other morphological features and one more symmetry axis that strengthen the identified point-symmetric morphology. Not all symmetry axes correspond to jets; e.g., some clumps are formed by the compression of ejecta between two jet-inflated lobes (bubbles). The robust point-symmetric morphology in the iconic Cassiopeia A SNR strongly supports the JJEM and poses a severe challenge to the neutrino-driven explosion mechanism.

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arXiv2024

The compact circumstellar material of SN 2024ggi: Another supernova with a pre-explosion effervescent zone and jet-driven explosion

I examine recent theoretical studies and observations of the recent core-collapse supernova (CCSN) SN 20224ggi and find that the likely explanation for its dense, compact circumstellar material is an effervescent model, where parcels or streams of gas are uplifted by stellar convection and pulsation and fall back. The effervescent zone exists alongside the regular wind from the red supergiant (RSG) progenitor of SN 2024ggi. I find that an extended wind-acceleration zone encounters some difficulties in accounting for the required CSM mass. Recent modelling finds the explosion energy of SN 2024ggi to be >1e51 erg, and up to 2e51 erg. I examine this explosion energy against a recent study of the delayed neutrino explosion mechanism and find that this mechanism might have some difficulties in accounting for the required energy. This might suggest that the explosion was caused by the jittering jets explosion mechanism (JJEM). This adds to other recent pieces of evidence supporting the JJEM, particularly point-symmetric CCSN remnants.

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arXiv2024

The jittering jets explosion mechanism (JJEM) in electron capture supernovae

We conduct one-dimensional stellar-evolution simulations of stars with zero age main sequence masses of $M_{ZAMS} = 8.8-9.45 M_\odot$ towards core collapse by electron capture, and find that the convective zone of the pre-collapse core can supply the required stochastic angular momentum fluctuations to set a jet-driven electron capture supernova (ECSN) explosion in the frame of the jittering jets explosion mechanism (JJEM). By our assumed criteria of a minimum convective specific angular momentum and an accreted mass during jet-launching of $M_{acc} \simeq 0.001-0.01 M_\odot$, the layer in the convective zone that when accreted launches the exploding jittering jets resides in the helium-rich zone. Depending on the model, this exploding layer is accreted at about a minute to a few hours after core collapse occurs, much shorter than the time the exploding shock crosses the star. The final (gravitational) mass of the neutron star (NS) remnant is in the range of $M_{NS} =1.25-1.43 M_\odot$.

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arXiv2024

Comparing jet-shaped point symmetry in cluster cooling flows and supernovae

I point out similarities between point-symmetric X-ray morphologies in cooling flow groups and clusters of galaxies, which are observed to be shaped by jets, and point-symmetric morphologies of eight core-collapse supernova (CCSN) remnants. I identify these similarities by qualitative eye inspection of multiwavelength images. I use these similarities to strengthen the jittering jet explosion mechanism (JJEM) of CCSNe, which predicts that the last pairs of jets to be launched by the newly born neutron star might shape some CCSN remnants to point-symmetric morphology. The point-symmetric morphologies in both types of objects are composed of two or more pairs of opposite bubbles (cavities), nozzles, some clumps, small protrusions (termed ears), and rims. The typically large volume of a CCSN remnant shaped by jets implies that the shaping jets carry an energy comparable to that of the ejecta, which in turn implies that jets exploded the remnant's massive star progenitor. The morphological similarities studied here add to the similarity of CCSN remnants, not only point-symmetric ones, to planetary nebulae shaped by jets. Together, these similarities solidify the JJEM as the main explosion mechanism of CCSNe. I consider the identification of point-symmetry in CCSNe, as expected by jet-shaping in the JJEM, to be the most severe challenge to the competing neutrino-driven explosion mechanism. I reiterate my earlier claim, but in a more vocal voice, that the main explosion mechanism of CCSNe is the JJEM.

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arXiv2024

Comments on: "Almost All Carbon/Oxygen White Dwarfs Can Support Double Detonations"

I critically review some claims in the paper ``Almost All Carbon/Oxygen White Dwarfs Can Support Double Detonations'' (arXiv:2405.19417). The claim of that paper that the community converges on a leading scenario of type Ia supernovae (SNe Ia), the double detonation scenario, is wrong, as hundreds of papers in recent years study five and more different SN Ia scenarios and their channels. Moreover, the finding by that paper that the double detonation scenario with the explosion of the secondary white dwarf (WD; the mass-donor WD) is common, i.e., the triple-detonation channel and the quadruple-detonation sub-channel, implies highly no-spherical explosions. The highly non-spherical explosions contradict the morphologies of many SN Ia remnants. I find that the results of that paper strengthen the claim that the double detonation scenario (with its channels) might account for a non-negligible fraction of peculiar SNe Ia but only for a very small fraction (or non at all) of normal SNe Ia.

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arXiv2024

Planetary nebula morphologies indicate a jet-driven explosion of SN 1987A and other core-collapse supernovae

I demonstrate the usage of planetary nebulae (PNe) to infer that a pair of jets shaped the ejecta of the core-collapse supernova (CCSN) SN 1987A. The main structure of the SN 1987A inner ejecta, the keyhole, comprised two low-intensity zones. The northern one has a bright rim on its front, while the southern one has an elongated nozzle. Earlier comparison of the SN 1987A keyhole with bubbles in the galaxy group NGC 5813 led to its identification as a jet-shaped rim-nozzle structure. Here, I present rim-nozzle asymmetry in planetary nebulae (PNe), thought to be shaped by jets, which solidify the claim that jets powered the ejecta of SN 1987A and other CCSNe. This finding for the iconic SN 1987A with its unique properties strengthens the jittering jets explosion mechanism (JJEM) of CCSNe. In a few hundred years, the CCSN 1987A will have a complicated structure with two main symmetry axes, one along the axis of the three circumstellar rings that two opposite 20,000-years pre-explosion jets shaped, and the other along the long axis of the keyhole that was shaped by the main (but not the only) jet pair of the exploding jets of SN 1987A in the frame of the JJEM.

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arXiv2024

Supernova 1987A's keyhole: A long-lived jet-pair in the final explosion phase of core-collapse supernovae

I further study the manner by which a pair of opposite jets shape the keyhole morphological structure of the core-collapse supernova (CCSN) SN 1997A, now the CCSN remnant (CCSNR) 1987A. By doing so, I strengthen the claim that the jittering-jet explosion mechanism (JJEM) accounts for most, likely all, CCSNe. The keyhole structure comprises a northern low-intensity zone closed with a bright rim on its front and an elongated low-intensity nozzle in the south. This rim-nozzle asymmetry is observed in some cooling flow clusters and planetary nebulae that are observed to be shaped by jets. I build a toy model that uses the planar jittering jets pattern, where consecutive pairs of jets tend to jitter in a common plane, implying that the accreted gas onto the newly born neutron star at the late explosion phase flows perpendicular to that plane. This allows for a long-lived jet-launching episode. This long-lasting jet-launching episode launches more mass into the jets that can inflate larger pairs of ears or bubbles, forming the main jets' axis of the CCSNR that is not necessarily related to a possible pre-collapse core rotation. I discuss the relation of the main jets' axis to the neutron star's natal kick velocity.

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arXiv2024

More luminous red novae that require jets

I study two intermediate luminosity optical transients (ILOTs) classified as luminous red novae (LRNe) and argue that their modeling with a common envelope evolution (CEE) without jets encounters challenges. LRNe are ILOTs powered by violent binary interaction. Although popular in the literature is to assume a CEE is the cause of LRNe, I here repeat an old claim that many LRNe are powered by grazing envelope evolution (GEE) events; the GEE might end in a CEE or a detached binary system. I find that the LRN AT 2021biy might have continued to experience mass ejection episodes after its eruption and, therefore, might not suffered a full CEE during the outburst. This adds to an earlier finding that a jet-less model does not account for some of its properties. I find that a suggested jet-less CEE model for the LRN AT 2019zhd does not reproduce its photosphere radius evolution. These results that challenge jet-less models of two LRNe strengthen a previous claim that jets play major roles in powering ILOTs and shaping their ejecta and that in many LRNe, the more compact companion launches the jets during a GEE.

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arXiv2024

Supernovae in 2023 (review): possible breakthroughs by late observations

I present a review of how late observations of supernovae, of the nebular phase, and much later of supernova remnants (SNRs), and their analysis in 2023 made progress towards possible breakthroughs in supporting the jittering jets explosion mechanism (JJEM) for core-collapse supernovae (CCSNe) and in introducing the group of lonely white dwarf (WD) scenarios for type Ia supernovae (SNe Ia). The new analyses of CCSN remnants (CCSNRs) reveal point-symmetric morphologies in a way unnoticed before in several CCSNRs. Qualitative comparison to multipolar planetary nebulae that are shaped by jets suggests that jets exploded these CCSNe, as predicted by the JJEM, but incompatible with the prediction of the delayed neutrino explosion mechanism. The spherical morphology of the ejecta Pa 30 of the historical type Iax supernova (SN Iax) of 1181 AD, which studies in 2023 revealed, is mostly compatible with the explosion of a lonely WD. Namely, at the explosion time, there is only a WD, without any close companion, although the WD was formed via a close binary interaction, i.e., binary merger. Identifying point-symmetry in SNR G1.9+0.3, a normal SN Ia and the youngest SN in the Galaxy, suggests an SN explosion of a lonely WD inside a planetary nebula (an SNIP). The group of lonely WD scenarios includes the core degenerate scenario and the double degenerate scenario with a merger to explosion delay (MED) time. SN Ia explosions of lonely WDs are common and might actually account for most (or even all) normal SNe Ia.

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arXiv2024

Explaining supernova remnant G352.7-0.1 as a peculiar type Ia supernova inside a planetary nebula

I identify a point-symmetric morphology of the supernova remnant (SNR) G352.7-0.1 and propose that the outer axially-symmetric structure is the remnant of a common envelope evolution (CEE) of the progenitor system, while the inner structure is the ejecta of a thermonuclear explosion triggered by the merger of a white dwarf (WD) and the core of an asymptotic giant branch (AGB) star. The main radio structure of SNR G352.7-0.1 forms an outer (large) ellipse. The bright X-ray emitting gas forms a smaller ellipse with a symmetry axis inclined to the symmetry axis of the large radio ellipse. The high abundance of iron and the energy of its X-ray lines suggest a type Ia supernova (SN Ia). The massive swept-up gas suggests a relatively massive progenitor system. I propose a scenario with progenitors of initial masses of M1=5-7Mo and M2=4-5 Mo. At a later phase, the WD remnant of the primary star and the AGB secondary star experience a CEE that ejects the circumstellar material that swept up more ISM to form the large elliptical radio structure. An explosion during the merger of the WD with the core of the AGB star triggered a super-Chandrasekhar thermonuclear explosion that formed the inner structure that is bright in X-ray. A tertiary star in the system caused the misalignment of the two symmetry axes. This study adds to the wide variety of evolutionary routes within the scenarios of normal and peculiar SNe Ia.

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arXiv2024

Jet - counter-jet asymmetry in the jittering jets explosion mechanism of supernovae

I identify a point-symmetric morphology composed of three pairs of ears (small lobes) in the X-ray images of the core-collapse supernova remnant (CCSNR) N63A and argue that this morphology supports the jittering jets explosion mechanism (JJEM). The opposite two ears in each of the three pairs of SNR N63A are not equal to each other as one is larger than the other. From the morphology of SNR N63A, I infer that this asymmetry is due to asymmetrical opposite jets at launching. Namely, the newly born neutron star that launches the jets that explode the star, does it in many cases with one jet more powerful than its counter-jet. I propose that this asymmetry results from that the accretion disk that launches the jets has no time to fully relax during a jet-launching episode. This implies that the disk has no time to fully relax to a thin disk and it is rather a thick accretion disk. As well, it implies that if the disk is born with two unequal sides as expected in the JJEM, then during a large fraction, or even all, of the jet-launching episode the two sides remain unequal. I also show that the magnetic reconnection timescale, which is about the timescale for the magnetic field to relax, is not much shorter than the jet-launching episode, therefore the two sides of the accretion disk might have a different magnetic structure. In most jet-launching episodes, the unequal sides of the accretion disk launch two opposite non-relativistic jets with different energy from each other.

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arXiv2024

The runaway velocity of the white dwarf companion in the double detonation scenario of supernovae

We consider the finite velocity of the ejecta of a type Ia supernova (SN Ia) in the double detonation (DDet) scenario with a white dwarf (WD) mass-donor companion, and find that the runaway velocity of the surviving (mass donor) WD is lower than its pre-explosion orbital velocity by about 8-11%. This implies that the fastest runaway WDs in the Galaxy, if come from the DDet scenario, require even more massive WDs than what a simple calculation that neglects the finite ejecta velocity gives. This extreme set of initial conditions makes such binaries less common. We also tentatively find that the inner ejecta deviates from spherical symmetry, but not to the degree that we can use observations to make any claim. Our findings support the claim that the DDet scenario leads mostly to peculiar SNe Ia but not to normal SNe Ia.

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