Gendre 2009 GRB 090102的奇怪余辉

主要内容:
目前的模型都不能很好地解释.

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Title:		Testing GRB models with the strange afterglow of GRB 090102
Authors:		Gendre, B.; Klotz, A.; Palazzi, E.; Kruhler, T.; Covino, S.; Afonso, P.; Antonelli, L. A.;Atteia, J. L.; D'Avanzo, P.; Boer, M.; Greiner, J.; Klose, S.
Publication:		eprint arXiv:0909.1167
Publication Date:		09/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		9 pages, 2 color figures, 2 b&w figures, 7 tables. Submitted to MNRAS
Bibliographic Code:		2009arXiv0909.1167G

Abstract

We present the observations of the afterglow of gamma-ray burst GRB 090102. We use optical data taken by the TAROT, REM, GROND, Palomar and NOT telescopes, and X-ray data taken by the XRT instrument on board the Swift spacecraft. This event features an unusual light curve. In X-rays, it presents a very monotonic decrease with no hint of temporal break from 0.005 to 6 days after the burst. In optical, the light curve presents a flattening after 1 ks. Before this break, the optical light curve is steeper than the X-ray one. In optical, no further break is observed up to 10 days after the burst. We tried to explain these observations in light of the standard fireball model, but we failed to do so. We then investigated several other models, like the cannonball model. We find that the explanation of the broad band data by any model requires a strong fine tuning when taking into account both optical and X-ray bands.

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Hakkila 2009 伽玛暴光变起始于同时

主要内容:
统计发现不同能段的pulse的起始时间是一样的, 说明伽玛暴的能量是一下子释放的, 而接着的谱演化等是由于辐射和降温导致的.

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Title:		Testing the Gamma-Ray Burst Pulse Start Conjecture
Authors:		Hakkila, Jon; Nemiroff, Robert J.
Publication:		eprint arXiv:0909.0755
Publication Date:		09/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		34 pages, 17 figures, 3 tables, accepted for publication in The Astrophysical Journal
Bibliographic Code:		2009arXiv0909.0755H

Abstract

We test the hypothesis that prompt gamma-ray burst pulse emission starts simultaneously at all energies (the Pulse Start Conjecture). Our analysis, using a sample of BATSE bursts observed with four channel, 64-ms data and performed using a pulse fit model, generally supports this hypothesis for the Long GRB class, although a few discrepant pulses belong to bursts observed during times characterized by low signal-to-noise, hidden pulses, and/or significant pulse overlap. The typical uncertainty in making this statement is <>

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Franckowiak, A. 2009 对IceCube的中微子观测的光学余辉观测方案

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还没有结果

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Title:		Optical follow-up of high-energy neutrinos detected by IceCube
Authors:		Franckowiak, A.; Akerlof, C.; Cowen, D. F.; Kowalski, M.; Lehmann, R.; Schmidt, T.; Yuan, F.; for the IceCube collaboration; for the ROTSE collaboration
Publication:		eprint arXiv:0909.0631
Publication Date:		09/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		4 pages, 2 figures, Proceedings of the 31st ICRC, Lodz, Poland, July 2009
Bibliographic Code:		2009arXiv0909.0631F

Abstract

Three-quarters of the 1 cubic kilometer neutrino telescope IceCube is currently taking data. Current models predict high-energy neutrino emission from transient objects like supernovae (SNe) and gammaray bursts (GRBs). To increase the sensitivity to such transient objects we have set up an optical follow-up program that triggers optical observations on multiplets of high-energy muon-neutrinos. We define multiplets as a minimum of two muon-neutrinos from the same direction (within 4 deg) that arrive within a 100 s time window. When this happens, an alert is issued to the four ROTSE-III telescopes, which immediately observe the corresponding region in the sky. Image subtraction is applied to the optical data to find transient objects. In addition, neutrino multiplets are investigated online for temporal and directional coincidence with gamma-ray satellite observations issued over the Gamma-Ray Burst Coordinate Network. An overview of the full program is given, from the online selection of neutrino events to the automated follow-up, and the resulting sensitivity to transient neutrino sources is presented for the first time.

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Asano, Katsuaki 2009 GRB 090510高能的强子模型

主要内容:
模拟发现要求的能量太高, 可能不行.

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Title:		Hadronic Models for the Extra Spectral Component in the short GRB 090510
Authors:		Asano, Katsuaki; Guiriec, Sylvain; Mészáros, Peter
Publication:		eprint arXiv:0909.0306
Publication Date:		09/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		11pages, 4 figures
Bibliographic Code:		2009arXiv0909.0306A

Abstract

A short gamma-ray burst GRB 090510 detected by {\it Fermi} shows an extra spectral component between 10 MeV and 30 GeV, an addition to a more usual low-energy ($<10$> Bibtex entry for this abstract Preferred format for this abstract (see Preferences)

Petropoulou, M. 2009 又一个余辉数值模拟

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Title:		On the multiwavelength emission from Gamma Ray Burst afterglows
Authors:		Petropoulou, M.; Mastichiadis, A.
Publication:		eprint arXiv:0909.0208
Publication Date:		09/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		12 pages, 9 figures, accepted for publication in Astronomy and Astrophysics
Bibliographic Code:		2009arXiv0909.0208P

Abstract

Aims: Drawing an analogy with Active Galactic Nuclei, we investigate the one-zone SSC model of Gamma Ray Bursts afterglows in the presence of electron injection and cooling both by synchrotron and SSC losses. Methods: We solve the spatially averaged kinetic equations which describe the simultaneous evolution of particles and photons, obtaining the multi-wavelength spectrum as a function of time. We back up our numerical calculations with analytical solutions of the equations using various profiles of the magnetic field evolution under certain simplifying assumptions. Results: We apply the model to the afterglow evolution of GRBs in a uniform density environment and examine the impact various parameters have on the multiwavelength spectra. We find that in cases where the electron injection and/or the ambient density is high, the losses are dominated by SSC and the solutions depart significantly from the ones derived in the synchrotron standard cases.

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Tchekhovskoy, Alexander 2009 MHD 模拟伽玛暴的jet

主要内容:
结果 \Gamma ~ 500, theta_j ~ 0.04.

可以详细看看他们的jet怎么演化的, 看能不能产生柱状的.

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Title:		Magnetohydrodynamic Simulations of Gamma-Ray Burst Jets: Beyond the Progenitor Star
Authors:		Tchekhovskoy, Alexander; Narayan, Ramesh; McKinney, Jonathan C.
Publication:		eprint arXiv:0909.0011
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Galaxy Astrophysics
Comment:		5 pages (emulateapj), 3 figures. Submitted to ApJL
Bibliographic Code:		2009arXiv0909.0011T

Abstract

Achromatic breaks in afterglow light curves of gamma-ray bursts (GRBs) arise naturally when the product of the jet's Lorentz factor \gamma and opening angle \Theta_j satisfies \gamma\Theta_j >> 1. Magnetohydrodynamic (MHD) simulations of collimated GRB jets generally give \gamma\Theta_j <~ 1, suggesting that MHD models are incapable of explaining jet breaks. We work within the collapsar paradigm and use axisymmetric relativistic MHD simulations to explore the effect of a finite stellar envelope on the structure of the jet. Our idealized models treat the jet-stellar envelope interface as a collimating rigid wall, which opens up outside the star to mimic loss of collimation. We find that the onset of deconfinement outside the star causes a burst of acceleration with negligible change in the opening angle. In our fiducial model with a stellar radius equal to 10^4.5 times that of the central compact object, the jet achieves an asymptotic Lorentz factor \gamma ~ 500 far outside the star and an asymptotic opening angle \Theta_j ~ 0.04 rad ~ 2 deg, giving \gamma\Theta_j ~ 20. These values are consistent with observations of typical long-duration GRBs, and explain the occurrence of jet breaks.

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Dreyer, Jens 2009 星暴和伽玛暴的关联

主要内容:
统计170个z小于0.03的星暴星系, 说这些星暴星系里可能每年有0.03个伽玛暴. 还以此可以推测中微子的探测率.

(伽玛暴/长暴都在星暴星系里吗?)

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Title:		The starburst-GRB connection
Authors:		Dreyer, Jens; Becker, Julia K.; Rhode, Wolfgang
Publication:		eprint arXiv:0909.0158
Publication Date:		09/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		4 pages, 4 figures, contribution to the 31st ICRC, Lodz, Poland, 2009
Bibliographic Code:		2009arXiv0909.0158D

Abstract

As starburst galaxies show a star formation rate up to several hundred times larger than the one in a typical galaxy, the expected supernova rate is higher than average. This in turn implies a high rate of long gamma ray bursts (GRBs), which are extreme supernova events. We present a catalog of 127 local starburst galaxies with redshifts of z<0.03.> Bibtex entry for this abstract Preferred format for this abstract (see Preferences)

Ghirlanda, G. 2009 GRB 090510的晚期GeV辐射可能是来自余辉

主要内容:
说LAT的余辉的高能. 不过看到这么光滑的光变, 应该确实是的. 但是减速时标只有0.3秒!

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Title:		The onset of the GeV afterglow of GRB 090510
Authors:		Ghirlanda, G.; Ghisellini, G.; Nava, L.
Publication:		eprint arXiv:0909.0016
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		4 pages, 3 figures, submitted to ApJ Letters
Bibliographic Code:		2009arXiv0909.0016G

Abstract

We study the emission of the short/hard GRB 090510 at energies > 0.1 GeV as observed by the Large Area Telescope (LAT) onboard the Fermi satellite. The GeV flux rises in time as t^2 and decays as t^-1.5 up to 200 s. The peak of the high energy flux is delayed by 0.2 s with respect to the main ~MeV pulse detected by the Fermi Gamma Burst Monitor (GBM). Its energy spectrum is consistent with F(E)=E^-1. The time behavior and the spectrum of the high energy LAT flux are strong evidences of an afterglow origin. We then interpret it as synchrotron radiation produced by the forward shock of a fireball having a bulk Lorentz factor Gamma ~ 2000. The afterglow peak time is independent of energy in the 0.1-30 GeV range and coincides with the arrival time of the highest energy photon (~ 30 GeV). Since the flux detected by the GBM and the LAT have different origins, the delay between these two components is not entirely due to possible violation of the Lorentz invariance. It is the LAT component by itself that allows to set a stringent lower limit on the quantum-gravity mass of 4.7 times the Planck mass.

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Margutti 2009 GRB090111的观测

主要内容:
谱非常软, 光子谱指数都到了5! 另外还有一个X射线的flare.

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Title:		GRB090111: extra soft steep decay emission and peculiar re-brightening
Authors:		Margutti, R.; Sakamoto, T.; Chincarini, G.; Guidorzi, C.; Mao, J.; Pasotti, F.; Burrows, D.;D'Avanzo, P.; Campana, S.; Barthelmy, S. D.; Gehrels, N.
Publication:		eprint arXiv:0908.4452
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		Accepted for publication by MNRAS
Bibliographic Code:		2009arXiv0908.4452M

Abstract

We present a detailed study of GRB090111, focusing on its extra soft power-law photon index Gamma>5 at the very steep decay phase emission (power-law index alpha=5.1, steeper than 96% of GRBs detected by Swift) and the following peculiar X-ray re-brightening. Our spectral analysis supports the hypothesis of a comoving Band spectrum with the the peak of the nu*F_nu spectrum evolving with time to lower values: a period of higher temporal variability in the 1-2 keV light-curve ends when the E_peak evolves outside the energy band. The X-ray re-brightening shows extreme temporal properties when compared to a homogeneous sample of 82 early flares detected by Swift. While an internal origin cannot be excluded, we show these properties to be consistent with the energy injection in refreshed shocks produced by slow shells colliding with the fastest ones from behind, well after the internal shocks that are believed to give rise to the prompt emission have ceased.

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Liu 2009 SGR的hyper flare可能是高能中微子背景的来源

主要内容:
用伽玛暴火球模型作为hyper flare的模型, 计算的中微子产生和观测差不多(而伽玛暴产生的这种中微子的诞生率不够).

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Title:		Diffuse high energy neutrinos and cosmic rays from hyperflares of soft-gamma repeaters
Authors:		Liu, Xue-Wen; Wu, Xue-Feng; Lu, Tan
Publication:		eprint arXiv:0908.4371
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		Accepted for publication in New Astronomy, 14 pages
Bibliographic Code:		2009arXiv0908.4371L

Abstract

We calculate the diffuse high energy (TeV - PeV) neutrino emission from hyperflares of Soft-Gamma Repeaters (SGRs), like the hyperflare risen from \astrobj{SGR 1806-20} on December 27 of 2004, within the framework of the fireball model. The fireball model for gamma-ray bursts (GRBs) can explain well the main features of this hyperflare and the subsequent multi-frequency terglow emission. The expected rate, $\sim 20-100$ Gpc$^{-3}$day$^{-1}$, of such hyperflares is well in excess of the GRBs rate. Our result shows that the contribution to the diffuse TeV-PeV neutrino background from such hyperflares is less than 10% of the contribution from GRBs. We also discuss the high energy cosmic rays (CRs) from these sources.

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