Failed Gamma-Ray Bursts: Thermal Ultraviolet/Soft X-Ray Emission Accompanied by Peculiar Afterglows

Xu, Ming; Nagataki, Shigehiro; Huang, Yun‐Feng; Lee, S.-H.

doi:10.1088/0004-637x/746/1/49

Cited by 8 publications

(6 citation statements)

References 44 publications

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“…Due to these difficulties, the photospheric emission model is considered as one of the most promising alternative scenarios for the prompt emission mechanism (e.g., Thompson 1994;Eichler & Levinson 2000;Mészáros & Rees 2000;Lazzati et al 2009;Mizuta et al 2011;Nagakura et al 2011;Ruffini et al 2013;Xu et al 2012;Bégué et al 2013;Lundman et al 2013;Lazzati et al 2013). The photospheric emission is an inherent feature of the original fireball model in which the internally trapped photons that accelerate outflow to ultrarelativistic velocity are eventually released at the photosphere (Goodman 1986;Paczynski 1986).…”

Section: Introductionmentioning

confidence: 99%

“…Due to these difficulties, photospheric emission model is considered as one of the most promising alternative scenario for the prompt emission mechanism (e.g., Thompson 1994;Eichler & Levinson 2000;Mészáros & Rees 2000;Lazzati et al 2009;Mizuta et al 2011;Nagakura et al 2011;Ruffini et al 2011;Xu et al 2012;Bégué et al 2013;Lundman et al 2013a;Lazzati et al 2013).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spectral and Polarization Properties of Photospheric Emission From Stratified Jets

Ito¹,

Nagataki²,

Matsumoto³

et al. 2014

ApJ

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We explore the spectral and polarization properties of photospheric emissions from stratified jets in which multiple components, separated by sharp velocity shear regions, are distributed in lateral directions. Propagation of thermal photons injected at a high optical depth region are calculated until they escape from the photosphere. It is found that the presence of the lateral structure within the jet leads to the nonthermal feature of the spectra and significant polarization signal in the resulting emission. The deviation from thermal spectra, as well as the polarization degree, tends to be enhanced as the velocity gradient in the shear region increases. In particular, we show that emissions from multicomponent jet can reproduce the typical observed spectra of gamma-ray bursts irrespective of the position of the observer when a velocity shear region is closely spaced in various lateral (θ ) positions. The degree of polarization associated with the emission is significant (>few percent) at a wide range of observer angles and can be higher than 30%.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spectral and Polarization Properties of Photospheric Emission From Stratified Jets

Ito¹,

Nagataki²,

Matsumoto³

et al. 2014

ApJ

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“…These well-known difficulties in the internal shock model have lead researchers to reconsider photospheric emission (e.g., Thompson 1994;Eichler & Levinson 2000;Mészáros & Rees 2000;Lazzati et al 2009;Beloborodov 2011;Mizuta et al 2011;Nagakura et al 2011;Ruffini et al 2011;Xu et al 2012;Bégué et al 2013;Lundman et al 2013;Lazzati et al 2013), which is a natural consequence of the original fireball model (Goodman 1986;Paczynski 1986).…”

Section: Introductionmentioning

confidence: 99%

Photospheric Emission From Stratified Jets

Ito

Nagataki

Ono

et al. 2013

ApJ

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We explore photospheric emissions from stratified two-component jets, wherein a highly relativistic spine outflow is surrounded by a wider and less relativistic sheath outflow. Thermal photons are injected in regions of high optical depth and propagated until they escape at the photosphere. Due to the presence of shear in velocity (Lorentz factor) at the boundary of the spine and sheath region, a fraction of the injected photons are accelerated via a Fermi-like acceleration mechanism such that a high energy power-law tail is formed in the resultant spectrum. We show, in particular, that if a velocity shear with a considerable variance in the bulk Lorentz factor is present, the high energy part of observed Gamma-ray Bursts (GRBs) photon spectrum can be explained by this photon acceleration mechanism. We also show that the accelerated photons may also account for the origin of the extra hard power-law component above the bump of the thermal-like peak seen in some peculiar bursts (e.g., GRB 090510, 090902B, 090926A). It is demonstrated that time-integrated spectra can also reproduce the low energy spectrum of GRBs consistently due to a multi-temperature effect when time evolution of the outflow is considered. Finally, we show that the empirical E p -L p relation can be explained by differences in the outflow properties of individual sources.

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“…The non-thermal spectra of most of the observed GRBs are described by the Band function (Band et al 1993), of which two power laws are jointed at a break energy E p,obs in the νf ν spectrum. Three popular models of GRB prompt phase had been proposed so far, i.e., the internal shock model (Rees & Mészáros 1994;Narayan, Paczynski & Piran 1992), magnetic reconnection model (Giannios 2008;Zhang & Yan 2011;Beniamini & Granot 2016;Granot 2016) and photospheric model (Thompson 1994;Eichler & Levinson 2000;Mészáros & Rees 2000;Lazzati et al 2009;Beloborodov 2011;Pe'er & Ryde 2011;Mizuta et al 2011;Nagakura et al 2011;Ruffini et al 2013;Xu et al 2012;Bégué et al 2013;Lundman et al 2013;Lazzati et al 2013). The predicted features of all these three models can match the observations (Uhm & Zhang 2014;Pe'er, Mészáros & Rees 2005, 2006Abramowicz, Novikov & Paczynski 1991;Pe'er 2008).…”

Section: Introductionmentioning

confidence: 77%

Polarization of GRB Prompt Emission and its Application to POLAR's Data

Lan,

Wu,

Dai

2020

Preprint

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Synchrotron emission polarization is very sensitive to the magnetic field configuration. Recently, polarization of synchrotron emission with a mixed (SM) magnetic field in Gamma-ray burst (GRB) afterglow phase had been developed. Here, we apply these SM models to GRB prompt phase and compare their polarization properties with that of synchrotron emission in purely ordered (SO) magnetic field. We find that the polarization properties in a SM model are very similar to these in a corresponding SO model (e.g., synchrotron emission in a mixed magnetic field with an aligned ordered part (SMA) and synchrotron emission with a purely ordered aligned magnetic field (SOA)), only with a lower polarization degree (PD). We also discuss the statistical properties of the models. We find PDs of the simulated bursts are concentrated around 25% for both SOA and synchrotron emission in a purely ordered toroidal magnetic field (SOT), while they can range from 0% to 25% for SMA and synchrotron emission in a mixed magnetic field with a toroidal ordered part (SMT), depending on ξ B value, i.e., the ratio of magnetic reduction of the ordered magnetic field over that of random magnetic field. From statistics, if PDs of majority GRBs are non-zero, then it favours SO and SM models. Further, if there are some bright GRBs with a prominently lower PDs than that of the majority GRBs, it favours SOT (SMT) models; if all the bright GRBs have comparable PDs with the majority ones, it favours SOA (SMA) models. Finally, we apply our results to POLAR's data and find that ∼ 10% time-integrated PDs of the observed bursts favor SMA and SMT models, and ξ B parameter of these bursts is constrained to be around 1.135.

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Failed Gamma-Ray Bursts: Thermal Ultraviolet/Soft X-Ray Emission Accompanied by Peculiar Afterglows

Cited by 8 publications

References 44 publications

Spectral and Polarization Properties of Photospheric Emission From Stratified Jets

Spectral and Polarization Properties of Photospheric Emission From Stratified Jets

Photospheric Emission From Stratified Jets

Polarization of GRB Prompt Emission and its Application to POLAR's Data

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