检索结果-南通市图书馆

Supernova 1987A's Keyhole:A Long-lived Jet-pair in the Final Explosion Phase of Core-collapse Supernovae

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第7期24卷 89-94页

作者： noam Soker Department of Physics TechnionHaifa3200003Israel

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)*** doing so,I strengthen the claim that the jittering-jet explosion mechanism accounts for most,likely all,***“keyhole”structure comprises a northern low-intensity zone closed with a bright rim on its front and an elongated low-intensity nozzle in the *** 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 *** allows for a long-lived jet-launching *** 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.

关键词： stars massive-(stars)supernovae general-(stars)supernovae individual(SN 1987A)-ISM supernova remnants-stars jets

马普街5号住宅大楼——以色列特拉维夫-雅法

在线全文

学校读者我要写书评

暂无评论

世界建筑导报 2023年第3期38卷 84-87页

作者： Gidi Bar Orian Kfir Peled Nir Ovadia noam elkabetz Amit Geron(摄影) Bar Orian建筑师事务所

马普街5号是一栋方形的新建住宅大楼,位于特拉维夫白城中心马普街与Yehoash街道的拐角处--白城被联合国教科文组织列入世界遗产名录,因该地大量的包豪斯(Bauhaus)和折中主义建筑风格的建筑物而享誉世界。该建筑位于特拉维夫最理想的地... 详细信息

马普街5号是一栋方形的新建住宅大楼,位于特拉维夫白城中心马普街与Yehoash街道的拐角处--白城被联合国教科文组织列入世界遗产名录,因该地大量的包豪斯(Bauhaus)和折中主义建筑风格的建筑物而享誉世界。该建筑位于特拉维夫最理想的地区之一,其地块在大小和形状上(1.3德南(dunam:以色列单位))都异于寻常,是当地普通地块的三倍大,与特拉维夫地中海海滨大道相距约200米(600英尺)--正是在这样一个被忽视的空地上,Bar Orian接受了委托,要在此处构思和规划建设一栋新建筑。这片弃用的地块反而为其提供了一个极佳的机会,得以展示一栋向特拉维夫中东-地中海构造风格致敬的建筑,同时创造了一种新的当代视觉呈现。

关键词：建筑风格住宅大楼世界遗产名录海滨大道包豪斯构造风格联合国教科文组织马普

The class of supernova progenitors that result from fatal common envelope evolution

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 35-46页

作者： noam Soker Department of Physics Technion – Israel Institute of Technology Guangdong Technion Israel Institute of Technology

I construct the class of supernovae and supernova progenitors that result from fatal common envelope evolution(CEE). The fatal CEE progenitors are stellar binary systems where a companion spirals-in inside the envelope of a giant star and merges with the core. The companion can be a neutron star(NS;or a black hole) that destroys the core and by that forms a common envelope jets supernova(CEJSN), a white dwarf(WD) that merges with the core to form a massive WD that later might explode as a Type Ia supernova(the core degenerate scenario), or a main sequence companion. In the latter case the outcome might be a core collapse supernova(CCSN) of a blue giant, a CCSN of type IIb or of type Ib. In another member of this class two giant stars merge and the two cores spiral-in toward each other to form a massive core that later explodes as a CCSN with a massive circumstellar matter(CSM). I discuss the members of this class, their characteristics, and their common properties. I find that fatal CEE events account for ≈6%-10% of all CCSNe, and raise the possibility that a large fraction of peculiar and rare supernovae result from the fatal CEE. The study of these supernova progenitors as a class will bring insights on other types of supernova progenitors, as well as on the outcome of the CEE.

关键词： common envelope evolution(CEE) supernovae binary and multiple stars neutron stars white dwarfs

Supernovae Ia in 2017:a long time delay from merger/accretion to explosion

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2018年第4期61卷 7-16页

作者： noam Soker Department of Physics Technion-lsrael Institute of TechnologyHaifa 32000Israel Guangdong Technion Israel Institute of Technology shantou 515063China

I use recent observational and theoretical studies of type Ia supernovae(SNe Ia) to further constrain the viable SN Ia scenarios and to argue that there must be a substantial time delay between the end of the merger of the white dwarf(WD) with a companion or the end of mass accretion on to the WD and its terminal explosion. This merger/accretion to explosion delay(MED) is required to allow the binary system to lead to a more or less spherical explosion and to prevent a pre-explosion ionizing radiation. Considering these recent results and the required MED, I conclude that the core degenerate scenario is somewhat more favorable over the other scenarios, followed by the double degenerate scenario. Although the single degenerate scenario is viable as well, it is less likely to account for common(normal) SN Ia. As all scenarios require substantial MED, the MED has turned from a disadvantage of the core degenerate scenario to a challenge that theory should overcome. I hope that the requirement for a MED will stimulate the discussion of the different SN Ia scenarios and the comparison of the scenarios to each other.

关键词： supernovae supernova remnants cataclysmic binaries binary and multiple stars

Amplifying magnetic fields of a newly born neutron star by stochastic angular momentum accretion in core collapse supernovae

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第2期20卷 94-100页

作者： noam Soker Department of Physics Technion Guangdong Technion Israel Institute of Technology

I present a novel mechanism to boost magnetic field amplification of newly born neutron stars in core collapse *** this mechanism,that operates in the jittering jets explosion mechanism and comes on top of the regular magnetic field amplification by turbulence,the accretion of stochastic angular momentum in core collapse supernovae forms a neutron star with strong initial magnetic fields but with a slow *** varying angular momentum of the accreted gas,which is unique to the jittering jets explosion mechanism,exerts a varying azimuthal shear on the magnetic fields of the accreted mass near the surface of the neutron ***,I argue,can form an amplifying effect which I term the stochastic omega(Sω) *** the common αω dynamo the rotation has constant direction and value,and hence supplies a constant azimuthal shear,while the convection has a stochastic *** the Sω dynamo the stochastic angular momentum is different from turbulence in that it operates on a large scale,and it is different from a regular rotational shear in being *** basic assumption is that because of the varying direction of the angular momentum axis from one accretion episode to the next,the rotational flow of an accretion episode stretches the magnetic fields that were amplified in the previous episode.I estimate the amplification factor of the Sω dynamo alone to be ≈ 10.I speculate that the Sω effect accounts for a recent finding that many neutron stars are born with strong magnetic fields.

关键词： stars:neutron stars:magnetic field (stars:)supernovae:general

Imprints of the Jittering Jets Explosion Mechanism in the Morphology of the Supernova Remnant SNR 0540-69.3

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第3期22卷 186-193页

作者： noam Soker Department of Physics TechnionHaifa3200003Israel

I identify a point-symmetric structure in recently published VLT/MUSE velocity maps of different elements in a plane along the line of sight at the center of the supernova remnant SNR 0540-69.3,and argue that jittering jets that exploded this core collapse supernova shaped this point-symmetric *** four pairs of two opposite clumps that compose this point symmetric structure suggest that two to four pairs of jittering jets shaped the inner ejecta in this *** addition,intensity images of several spectral lines reveal a faint strip(the main jet-axis)that is part of this plane of jittering jets and its similarity to morphological features in a few other SNRs and in some planetary nebulae further suggests shaping by *** interpretation implies that in addition to instabilities,jets also mix elements in the ejecta of core collapse *** on the point-symmetric structure and under the assumption that jittering jets exploded this supernova,I estimate the component of the neutron star natal kick velocity on the plane of the sky to be■235 km s^(-1),and at an angle of■47°to the direction of the main jet-axis.I analyze this natal kick direction together with 12 other SNRs in the frame of the jittering jets explosion mechanism.

关键词： ISM:supernova remnants stars:jets (stars:)supernovae:general (stars:)supernovae:individual(SNR 0540-69.3)

Pre-explosion Helium Shell Flash in Type Ia Supernovae

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第9期22卷 98-105页

作者： noam Soker Department of Physics TechnionHaifa3200003Israel

I study the possibility that within the frame of the core degenerate(CD)scenario for type Ia supernovae(SNe Ia)the merger process of the core of the asymptotic giant branch(AGB)star and the white dwarf(WD)maintains an envelope mass of≈0.03 Mthat causes a later helium shell flash.I estimate the number of pre-explosion helium shell flash events to be less than a few per cent of all CD scenario SNe Ia.A helium shell flash while the star moves to the left on the HR diagram as a post-AGB star(late thermal pulse—LTP)or along the WD cooling track(very LTP—VLTP)causes the star to expand and become a“born again”AGB *** remnants exploding while still on the AGB form hydrogen-polluted peculiar SNe Ia,while an explosion inside an inflated born-again star results in an early flux excess in the light curve of the SN *** fraction of systems that might show an early flux excess due to LTP/VLTP is

关键词： stars:supernovae:general (stars:)white dwarfs (stars:)binaries(including multiple):close

Boosting Jittering Jets by Neutrino Heating in Core Collapse Supernovae

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第9期22卷 77-87页

作者： noam Soker Department of Physics TechnionHaifa3200003Israel

I estimate the energy that neutrino heating adds to the outflow that jets induce in the collapsing core material in core collapse supernovae(CCSNe), and find that this energy crudely doubles the energy that the jets deposit into the outer core. I consider the jittering jets explosion mechanism where there are several stochastic jet-launching episodes, each lasting for about 0.01–0.1 s. The collapsing core material passes through the stalled shock at about100 km and then slowly flows onto the proto-neutron star(NS). I assume that the proto-NS launches jittering jets,and that the jets break out from the stalled shock. I examine the boosting process by which the high-pressure gas inside the stalled shock, the gain region material, expands alongside the jets and does work on the material that the jets shock, the cocoon. This work is crudely equal to the energy that the original jets carry. I argue that the coupling between instabilities, stochastic rotation, magnetic fields, and jittering jets leads to most CCSN explosions. In other cases, the pre-collapse core is rapidly rotating and therefore ordered rotation replaces stochastic rotation and fixed jets replace jittering jets.

关键词： stars:supernovae:general stars:jets ISM:supernova remnants

The Role of Jets in Exploding Supernovae and in Shaping their Remnants

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第12期22卷 28-52页

作者： noam Soker Department of Physics TechnionHaifa3200003Israel

I review studies of core collapse supernovae(CCSNe) and similar transient events that attribute major roles to jets in powering most CCSNe and in shaping their ejecta. I start with reviewing the jittering jets explosion mechanism that I take to power most CCSN explosions. Neutrino heating does play a role in boosting the jets. I compare the morphologies of some CCSN remnants to planetary nebulae to conclude that jets and instabilities are behind the shaping of their ejecta. I then discuss CCSNe that are descendants of rapidly rotating collapsing cores that result in fixed-axis jets(with small jittering) that shape bipolar ejecta. A large fraction of the bipolar CCSNe are superluminous supernovae(SLSNe). I conclude that modeling of SLSN light curves and bumps in the light curves must include jets, even when considering energetic magnetars and/or ejecta interaction with the circumstellar matter(CSM). I connect the properties of bipolar CCSNe to common envelope jets supernovae(CEJSNe) where an old neutron star or a black hole spirals-in inside the envelope and then inside the core of a red supergiant. I discuss how jets can shape the pre-explosion CSM, as in Supernova 1987A, and can power pre-explosion outbursts(precursors)in binary system progenitors of CCSNe and CEJSNe. Binary interaction also facilitates the launching of postexplosion jets.

关键词： (stars:)supernovae:general ISM:supernova remnants stars:jets ISM:jets and outflows (stars:)binaries:general