Central engines of Gamma Ray Bursts. Magnetic mechanism in the collapsar model.

Barkov, Maxim V.; Komissarov, S. S.

doi:10.1063/1.3076747

Cited by 6 publications

(5 citation statements)

References 27 publications

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“…At the initial stage of the simulation spherically symmetric accretion occurs and the magnetic flux accumulates on the horizon of the BH. At the moment when the magnetic flux exceeds the critical value (see Barkov & Komissarov 2008a;Komissarov & Barkov 2009, for more details), the BZ mechanism gets activated and a magnetically driven jet is launched. The accumulation phase can be clearly seen in Fig.…”

Section: Numerical Resultsmentioning

confidence: 99%

Direct wind accretion and jet launch in binary systems

Barkov

Khangulyan

2012

Monthly Notices of the Royal Astronomical Society

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In this paper, we study the wind accretion on to a rotating black hole in a close binary system that harbours a young massive star. It is shown that the angular momentum of the accreted stellar wind material is not sufficient for the formation of an accretion disc. However, in the conditions considered, the Blanford–Znajek mechanism can be activated, and thus powerful jets can be launched in the direction of the rotation axis of the black hole. Importantly, no observational signatures of accretion, as are typically seen from the thermal X‐ray emission of accretion discs, are expected in the suggested scenario. Here, the properties of the generated jet are studied numerically in the framework of a two‐dimensional general relativity magnetohydrodynamical approach. Because of the accumulation of the magnetic flux at the black hole horizon, the jet power is expected to be modulated on a subsecond time‐scale. Although the intervals between the jet active phases depend on the magnetic flux that escapes from the black hole horizon (which can be modelled self‐consistently only using a three‐dimensional code), a general estimate of the averaged jet power is obtained. It is shown that for the black hole rotation, expected in a stellar binary system (the dimensionless rotation parameter a= 0.5), approximately 5 per cent of the accreted rest energy can be channelled into the jets. In the case of the faster rotation of the black hole, the efficiency is expected to be significantly higher (e.g. for the dimensionless rotation parameter a= 0.95, the jet carries approximately 20 per cent of the accreted rest energy). In the specific case of the gamma‐ray binary system LS 5039, the obtained jet luminosity can be responsible for the observed GeV radiation if Doppler boosting is invoked, which can enhance the apparent flux from the system.

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Section: Numerical Resultsmentioning

confidence: 99%

Direct wind accretion and jet launch in binary systems

Barkov

Khangulyan

2012

Monthly Notices of the Royal Astronomical Society

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“…Evidence has emerged that at least some HNe are accompanied by gamma-ray bursts (GRBs) (Galama et al 1998;van Paradijs et al 2000;Stanek et al 2003;Malesani et al 2004;Woosley & Bloom 2006). The two most popular models to explain the connection between the collapse of a massive star and a GRB, the collapsar model of MacFadyen & Woosley (1999);MacFadyen et al (2001); Woosley & Heger (2003); Barkov & Komissarov (2008) and the magnetar model (e.g., LeBlanc & Wilson 1970;Wheeler et al 2000;Akiyama et al 2003;Burrows et al 2007;Komissarov & Barkov 2007;Obergaulinger & Aloy 2017), would also necessitate intrinsically aspherical HNe. A key ingredient in both of these models is a rapidly rotating progenitor, so HNe from these sources may also provide a natural explanation for larger HN rates in the past, as rapid rotation in stars is predicted to be more common at low metallicity (Woosley & Bloom 2006;Woosley & Heger 2006;Stacy et al 2011;Stacy & Bromm 2013).…”

Section: Early Evolution and Extremely Metal Poor Starsmentioning

confidence: 99%

The Chemical Evolution of Iron-Peak Elements with Hypernovae

Grimmett,

Karakas,

Heger

et al. 2019

Preprint

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We calculate the mean evolution of the iron-peak abundance ratios [(Cr,Mn,Co,Zn)/Fe] in the Galaxy, using modern supernova and hypernova chemical yields and a Galactic Chemical Evolution code that assumes homogeneous chemical evolution. We investigate a range of hypernova occurrence rates and are able to produce a chemical composition that is a reasonable fit to the observed values in metal-poor stars. This requires a hypernova occurence rate that is large (50%) in the early Universe, decreasing throughout evolution to a value that is within present day observational constraints ( 1%). A large hypernova occurence rate is beneficial to matching the high [Zn/Fe] observed in the most metal-poor stars, although including hypernovae with progenitor mass ≥ 60 M is detrimental to matching the observed [(Mn,Co)/Fe] evolution at low [Fe/H]. A significant contribution from HNe seems to be critical for producing supersolar [(Co,Zn)/Fe] at low metallicity, though more work will need to be done in order to match the most extreme values. We also emphasise the need to update models for the enrichment sources at higher metallicity, as the satisfactory recovery of the solar values of [(Cr,Mn,Co,Zn)/Fe] still presents a challenge.

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“…We observe these jets as gamma ray bursts [38]. While there are competing theories about the origin of jets, numerical studies indicate that it is more likely that astrophysical jets are the result of the BZ mechanism rather than the Penrose mechanism or accretion disk braking [36,38,40] , for at least some sets of parameters.…”

Section: Introductionmentioning

confidence: 95%

“…We will assume that the collapsar model [26][27][28], whereby the iron core of a progenitor star collapses into a black hole, describes some of the observed long gamma ray bursts and is followed by jet emission which is powered by the Blandford-Znajeck (BZ) mechanism [29][30][31][32][33][34][35][36][37][38][39][40][41][42]. We observe these jets as gamma ray bursts [38].…”

Section: Introductionmentioning

confidence: 99%

Implications of a dark sectorU(1)for gamma ray bursts

et al. 2014

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We discuss the implications for gamma ray burst studies of a dark unbroken U (1)D sector that couples predominantly through gravity to the visible sector. The dominant dark matter component remains neutral under U (1)D. The collapsar model is assumed to explain the origin of long gamma ray bursts. The main idea is that, by measuring the change in stellar black hole spin during the duration of the GRB, one can make inferences about the existence of a dark matter accretion disk. This could potentially provide evidence for the existence for a U (1)D sector.

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Central engines of Gamma Ray Bursts. Magnetic mechanism in the collapsar model.

Cited by 6 publications

References 27 publications

Direct wind accretion and jet launch in binary systems

Direct wind accretion and jet launch in binary systems

The Chemical Evolution of Iron-Peak Elements with Hypernovae

Implications of a dark sectorU(1)for gamma ray bursts

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