The Synchrotron-self-Compton Radiation Accompanying Shallow Decaying X-Ray Afterglow: the Case of GRB 940217

Wei, Da-Ming; Fan, Yi‐Zhong

doi:10.1088/1009-9271/7/4/06

Cited by 15 publications

(18 citation statements)

References 43 publications

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“…This interpretation, however, suggests β ∼ 1/2, which is inconsistent with the observation β ∼ 1.8 and thus is unlikely. Wei and Fan [147] suggest that the SSC of a modified forward shock can reproduce the data. Their numerical results are shown in Fig.…”

Section: Electromagnetic Cascade Of Tev γ-Raysmentioning

confidence: 94%

“…(from Ref. [147]) that inverse Compton from reverse shock is most likely to provide the right temporal behavior. Because of the very large energy emitted in hard γ-rays, the reverse shock has to be relativistic.…”

Section: Electromagnetic Cascade Of Tev γ-Raysmentioning

confidence: 98%

“…In both cases, an early flattening is expected in the high-energy afterglow light curve, as shown in Refs. [24,131,147,150,151]. Without these modifications, both E k and ε e take a constant value from the beginning.…”

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confidence: 99%

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High-energy γ-ray emission from gamma-ray bursts — before GLAST

2008

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Gamma-ray bursts (GRBs) are short and intense emission of soft γ-rays, which have fascinated astronomers and astrophysicists since their unexpected discovery in 1960s. The X-ray/optical/radio afterglow observations confirm the cosmological origin of GRBs, support the fireball model, and imply a long-activity of the central engine. The high-energy γ-ray emission (> 20 MeV) from GRBs is particularly important because they shed some lights on the radiation mechanisms and can help us to constrain the physical processes giving rise to the early afterglows. In this work, we review observational and theoretical studies of the high-energy emission from GRBs. Special attention is given to the expected high-energy emission signatures accompanying the canonical early-time X-ray afterglow that was observed by the Swift X-ray Telescope. We also discuss the detection prospect of the upcoming GLAST satellite and the current ground-based Cerenkov detectors. 95.30.Gv, 95.85.Pw, 98.70.Rz Gamma-ray bursts (GRBs) are brief intense flashes of Yi-Zhong FAN and Tsvi PIRAN, Front. Phys. China, 2008, 3(3) 307 ∼ 20 GeV. Similarly, inverse Compton of reverse shock photons with ∼ 1 eV by forwards shock electrons with a Lorentz factor of 10 4 will result in an IC component of ∼ 100 MeV. PACS numbersThe Large Area Telescope (LAT) onboard the Gamma Ray Large Area Space Telescope (GLAST; see http://glast.gsfc.nasa.gov/), to be launched soon, is expected to enhance high-energy detection rate significantly because of its larger effective area than that of EGRET. For a bright burst at a redshift z ∼ 1, LAT may collect ∼ 10 tens-MeV to GeV afterglow photons [24]. The estimate of the detectability of the prompt high-energy γ-rays is more difficult because the physical parameters involved in the internal shocks are still poorly constrained. Regardless of the uncertainties, preliminary calculations suggest a promising detection prospect for LAT [25,26].The high-energy emission from GRBs can help us to better understand the physical composition of the outflow, the radiation mechanisms, and the underlying physical processes shaping the early afterglow. Such goals, of course, are hard to achieve because of the rarity of the high-energy photons. However, with LAT, ∼ 10 3 highenergy photons could be detected from an extremely bright burst (for example, GRB 940217, GRB 030329 and GRB 080319B) and these can be used to constrain the models. With such a hope, we present in this work an overview of the theoretical studies of high-energy emission from GRBs.The structure of this review is as follows. We first discuss the observational aspects of high-energy emission of GRBs and afterglows in Section 2, and then the physical processes in Section 3. We discuss the high-energy emission processes in GRBs and afterglows, the interpretations of available high-energy observations and possible progresses in the next decade in Sections 4, 5 and 6, respectively.We begin with a short review of the observations of high- Space telescopesAmong space telescopes dedicated ...

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Section: Electromagnetic Cascade Of Tev γ-Raysmentioning

confidence: 94%

Section: Electromagnetic Cascade Of Tev γ-Raysmentioning

confidence: 98%

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High-energy γ-ray emission from gamma-ray bursts — before GLAST

2008

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“…A shallower afterglow decay showing a synchrotron spectrum can be explained with late-time energy injection in the outflow (Panaitescu 2006;Zhang et al 2006). In this case the VHE SSC flux temporal decay could be slowed in a way related to the time evolution of the energy injection (Wei & Fan 2007;Gou & Mészáros 2007;Galli & Piro 2007;Fan & Piran 2008). However, the lack of a similar behaviour at optical wavelengths do not fully support this possibility since energy injection should affect the afterglow evolution in any band.…”

Section: Synchrotron-self Compton During the Afterglowmentioning

confidence: 97%

MAGIC observation of the GRB 080430 afterglow

Aleksić¹,

Anderhub²,

Antonelli³

et al. 2010

A&A

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Context. Gamma-ray bursts are cosmological sources emitting radiation from the gamma-rays to the radio band. Substantial observational efforts have been devoted to the study of gamma-ray bursts during the prompt phase, i.e. the initial burst of high-energy radiation, and during the longlasting afterglows. In spite of many successes in interpreting these phenomena, there are still several open key questions about the fundamental emission processes, their energetics and the environment. Aims. Independently of specific gamma-ray burst theoretical recipes, spectra in the GeV/TeV range are predicted to be remarkably simple, being satisfactorily modeled with power-laws, and therefore offer a very valuable tool to probe the extragalactic background light distribution. Furthermore, the simple detection of a component at very-high energies, i.e. at ∼100 GeV, would solve the ambiguity about the importance of various possible emission processes, which provide barely distinguishable scenarios at lower energies. Methods. We used the results of the MAGIC telescope observation of the moderate resdhift (z ∼ 0.76) GRB 080430 at energies above about 80 GeV, to evaluate the perspective for late-afterglow observations with ground based GeV/TeV telescopes. Results. We obtained an upper limit of F 95% CL = 5.5 × 10 −11 erg cm −2 s −1 for the very-high energy emission of GRB 080430, which cannot set further constraints on the theoretical scenarios proposed for this object also due to the difficulties in modeling the low-energy afterglow. Nonetheless, our observations show that Cherenkov telescopes have already reached the required sensitivity to detect the GeV/TeV emission of GRBs at moderate redshift (z 0.8), provided the observations are carried out at early times, close to the onset of their afterglow phase.

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“…On the one hand, the physical origin of the shallow decay phase is still a mystery. Different models, such as the energy injection models [6,7,10,11], a combination of the GRB tail with delayed onset of the afterglow emission [12], off-beam jets [13,14], precursor activity [15], two-component jets [16,17], two-component emission model [18], varying microphysical parameters [15,16,[19][20][21] and so on, are hard to differentiate among each other from the X-ray observations [3]. On the other hand, some puzzling facts related to the shallow decay phase are revealed by Swift's observations, which can not be explained by the current models.…”

Section: Introductionmentioning

confidence: 99%

The plateau of gamma-ray burst: hint for the solidification of quark matter?

Dai

2011

Sci. China Phys. Mech. Astron.

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The origin of the shallow decay segment in γ-ray bursts' (GRB) early light curves remains a mystery, especially those cases with a long-lived plateau followed by an abrupt falloff. In this paper, we propose to understand the origins of the long-lived plateau by considering the solidification of newborn quark stars with latent heat released as energy injection to the GRB afterglow, and we suggest that an abrupt falloff would naturally appear after the plateau due to the energy injection cutoff. We estimated the total latent heat released during the phase transition of quark stars from liquid to solid states to be on the order of ∼ 10 51 ergs, which is comparable to the emission energy in the shallow decay segment. We also estimated the time scale of radiating the latent heat through thermal photon emission, and found that the time scale agrees with the observations. Based on our estimation, we analyzed the process of energy injection to GRB afterglow. We will show that the steady latent heat of quark star phase transition will continuously inject into the GRB afterglow in a form similar to that of a Poynting-flux-dominated outflow and naturally produce the shallow decay phase and the abrupt falloff after the plateau. We conclude that the latent heat of quark star phase transition is an important contribution to the shallow decay radiation in some GRB afterglows, and explains the long-lived plateau followed by an abrupt falloff, if pulsar-like stars are really (solid) quark stars. γ-rays: bursts, X-rays, neutron stars, elementary particles PACS: 97.60.Jd, 98.70.Rz, 21.65.Qr

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The Synchrotron-self-Compton Radiation Accompanying Shallow Decaying X-Ray Afterglow: the Case of GRB 940217

Cited by 15 publications

References 43 publications

High-energy γ-ray emission from gamma-ray bursts — before GLAST

High-energy γ-ray emission from gamma-ray bursts — before GLAST

MAGIC observation of the GRB 080430 afterglow

The plateau of gamma-ray burst: hint for the solidification of quark matter?

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