He, Hao-Ning 2009 短暴的高能辐射

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同步辐射的延伸或者SSC

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Title:		The early high-energy afterglow emission from Short GRBs
Authors:		He, Hao-Ning; Wang, Xiang-Yu
Publication:		eprint arXiv:0908.2580
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		5 pages, 5 figures. This is a slightly expanded version of the paper that will appear in Science in China Series G
Bibliographic Code:		2009arXiv0908.2580H

Abstract

We calculate the high energy afterglow emission from short Gamma-Ray Bursts (SGRBs) in the external shock model. There are two possible components contributing to the high energy afterglow: the electron synchrotron emission and the synchrotron self-Compton (SSC) emission. We find that for typical parameter values of SGRBs, the early high-energy afterglow emission in 10 MeV-10 GeV is dominated by the synchrotron emission. For a burst occurring at redshift z =0.1, the high-energy emission can be detectable by Fermi LAT if the blast wave has an energy E>=10^51 ergs and the fraction of energy in electrons is \epsilon_e>=0.1 . This provides a possible explanation for the high energy tail of SGRB 081024B.

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Bellm, Eric C. 2009 用RHESSI的数据测试伽玛暴为黑体谱的可能性

主要内容:
实际上是黑体+幂律

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Title:		RHESSI Tests of Quasi-Thermal Gamma-Ray Burst Spectral Models
Authors:		Bellm, Eric C.
Publication:		eprint arXiv:0908.2433
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		14 pages, 17 figures; submitted to ApJ
Bibliographic Code:		2009arXiv0908.2433B

Abstract

Prompt gamma-ray burst spectra evolve on short time scales, suggesting that time-resolved spectral fits may help diagnose the still unknown prompt emission mechanism. We use broad-band gamma-ray data from the RHESSI spacecraft to test quasi-thermal models with high signal-to-noise time-resolved spectra of nine bright gamma-ray bursts. In contrast to results reported in more narrow energy bands, the quality of the fits of quasi-thermal models is poor in relation to fits of the phenomenological Band function. Moreover, the best-fit parameters for the simplest quasi-thermal model, a black body plus a nonthermal power law, show significant dependence on the fit band. Models that replace the power law with more complicated nonthermal functions are not robust for the data considered here and decrease the physical relevance of the fit black body.

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Campisi, M. A. 2009 用宇宙学模拟的方法研究伽玛暴宿主星系的性质

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Title:		Properties of Long Gamma-Ray Burst Host Galaxies in Cosmological Simulation
Authors:		Campisi, M. A.; De Lucia, G.; Li, L. -X.; Mao, S.; Kang, X.
Publication:		eprint arXiv:0908.2427
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Comment:		The paper contains 14 figures and 2 tables. Accepted MNRAS
Bibliographic Code:		2009arXiv0908.2427C

Abstract

We use galaxy catalogues constructed by combining high-resolution N-body simulations with semi-analytic models of galaxy formation to study the properties of Long Gamma-Ray Burst (LGRB) host galaxies. We assume that LGRBs originate from the death of massive young stars and analyse how results are affected by different metallicity constraints on the progenitor stars. As expected, the host sample with no metallicity restriction on the progenitor stars provides a perfect tracer of the cosmic star formation history. When LGRBs are required to be generated by low-metallicity stars, they trace a decreasing fraction of the cosmic star formation rate at lower redshift, as a consequence of the global increase in metallicity. We study the properties of host galaxies up to high redshift (~9), finding that they typically have low-metallicity (Z<0.5>

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Gehrels, N. 2009 伽玛射线望远镜小综述

主要内容:
目前的望远镜有: INTEGRAL, Swift, Fermi-GLAST, RHESSI, Suzaku, and AGILE.

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Title:		Gamma-Ray Telescopes (in "400 Years of Astronomical Telescopes")
Authors:		Gehrels, N.; Cannizzo, J. K.
Publication:		eprint arXiv:0908.2606
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Comment:		11 pages, 6 figures/ in "400 Years of Astronomical Telescopes: A Review of History, Science and Technology", ed. B.R. Brandl, R. Stuik, & J.K. Katgert-Merkeli (Exp. Astron. 26, 111-122 [2009])
Bibliographic Code:		2009arXiv0908.2606G

Abstract

The last half-century has seen dramatic developments in gamma-ray telescopes, from their initial conception and development through to their blossoming into full maturity as a potent research tool in astronomy. Gamma-ray telescopes are leading research in diverse areas such as gamma-ray bursts, blazars, Galactic transients, and the Galactic distribution of aluminum-26.

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Krühler, T. 2009 GRB 080710的余辉观测

主要内容:
可能是一个偏轴的暴.

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Title:		The bright optical/NIR afterglow of the faint GRB 080710 - Evidence for a jet viewed off axis
Authors:		Krühler, T.; Greiner, J.; Afonso, P.; Burlon, D.; Clemens, C.; Filgas, R.; Kann, D. A.; Klose, S.; Küpcü Yoldas, A.; McBreen, S.; Olivares, F.; Rau, A.; Rossi, A.; Schulze, S.; Szokoly, G. P.; Updike, A.; Yoldas, A.
Publication:		eprint arXiv:0908.2250
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		9 pages, 4 figures, accepted by A and A
Bibliographic Code:		2009arXiv0908.2250K

Abstract

We investigate the optical/near-infrared light curve of the afterglow of GRB 080710 in the context of rising afterglows. Optical and near-infrared photometry was performed using the seven channel imager GROND and the Tautenburg Schmidt telescope. X-ray data were provided by the X-ray Telescope onboard the Swift satellite. The optical/NIR light curve of the afterglow of GRB 080710 is dominated by an initial increase in brightness, which smoothly turns over into a shallow power law decay. The initially rising achromatic light curve of the afterglow of GRB 080710 can be accounted for with a model of a burst viewed off-axis or a single jet in its pre deceleration phase and in an on-axis geometry. An unified picture of the afterglow light curve and prompt emission properties can be obtained with an off-axis geometry, suggesting that late and shallow rising optical light curves of GRB afterglows might be produced by geometric effects.

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Ukwatta, T. N. 2009 光变的谱时延和光度的关系

主要内容:
有关系, 光度越大, 时延越小. 指数关系是1.4

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Title:		Spectral Lags and the Lag-Luminosity Relation: An Investigation with Swift BAT Gamma-ray Bursts
Authors:		Ukwatta, T. N.; Stamatikos, M.; Dhuga, K. S.; Sakamoto, T.; Barthelmy, S. D.; Gehrels, N.; Norris, J. P.; Parke, W. C.
Publication:		eprint arXiv:0908.2370
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		18 Pages, 11 Figures and 5 Tables; Submitted to The Astrophysical Journal
Bibliographic Code:		2009arXiv0908.2370U

Abstract

Spectral lag, the time difference between the arrival of high-energy and low-energy photons, is a common feature in Gamma-ray Bursts (GRBs). Norris et al. 2000 reported a correlation between the spectral lag and the isotropic peak luminosity of GRBs based on a limited sample. More recently, a number of authors have provided further support for this correlation using arbitrary energy bands of various instruments. In this paper we report on a systematic extraction of spectral lags based on the largest Swift sample to date of 31 GRBs with measured redshifts. We extracted the spectral lags for all combinations of the standard Swift hard x-ray energy bands: 15-25 keV, 25-50 keV, 50-100 keV and 100-200 keV and plotted the time dilation corrected lag as a function of isotropic peak luminosity. The mean value of the correlation coefficient for various channel combinations is -0.67 with a chance probability of ~ 1.0 x 10^{-3}. In addition, the mean value of the power-law index is 1.4 +/- 0.3. Hence, our study lends support for the existence of a lag-luminosity correlation, albeit with large scatter.

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关于论文的贡献的衡量

既然现在干什么都要论文, 而且还有各种乱七八糟的规定, 还一类二类的刊物啥的. 那还不如干脆弄一个非常明了, 浅显易懂的算法. 比如:

计算一个人的学术成果, 看论文的话, 可以这样计算:
每篇文章的影响因子作为一个因子IF, 第一作者和通讯作者首先分别各瓜分1/4, 剩下的1/2由所有作者(包括第一作者和通讯作者)平分. 比如某人在IF=4的杂志发表文章, 第一作者, 但不是通讯作者(否则通讯作者的1/2也可以加过来), 共有三个作者. 那么此人此篇文章的得分为: (1/4+1/2*1/3)*4=5/3! 再把别的文章也加上, 就是此人的总得分. 在评比呀什么的都基本上可以有个量化比较了.
另外如果在论文中写明了谁的贡献多少的话, 按照论文中的计算.

这样学校要求学生毕业, 比如理科就要求这种得分=2之类的就可以了. 如果要细调的话, 也就是化学的要等于2.5, 数学的等于1.5之类的. 简单明了.

基金也可以有个类似这种值. 文章后挂了多少个基金, 每个就只能平分文章的分值的一部分.

Pe'er, Asaf 2009 火球相对论运动时候的演化

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Title:		Temporal Evolution of Thermal Emission from Relativistically Expanding Plasma
Authors:		Pe'er, Asaf
Affiliation:		AA(Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218; apeer@stsci.edu.; Giacconi Fellow.)
Publication:		The Astrophysical Journal, Volume 682, Issue 1, pp. 463-473. (ApJ Homepage)
Publication Date:		07/2008
Origin:		UCP
ApJ Keywords:		Gamma Rays: Theory, Plasmas, Radiation Mechanisms: Thermal, Radiative Transfer, Scattering, X-Rays: Bursts
Abstract Copyright:		(c) 2008: The American Astronomical Society
DOI:		10.1086/588136
Bibliographic Code:		2008ApJ...682..463P

Abstract

Propagation of photons in relativistically expanding plasma outflows characterized by steady Lorentz factor Γ is considered. Photons that are injected in regions of high optical depth are advected with the flow until they escape at the photosphere. Below the photosphere, the photons are coupled to the plasma via Compton scattering. I show here that as a result of the slight misalignment of the scattering electrons' velocity vectors, the (local) comoving photon energy decreases with radius as ɛ^'(r)~r^-2/3. This mechanism dominates the photon cooling in scenarios of faster adiabatic cooling of the electrons. I then show that the photospheric radius of a relativistically expanding plasma wind strongly depends on the angle to the line of sight, θ. For θ<~Γ^-1, the photospheric radius is θ-independent, while for θ>~Γ^-1, r_ph(θ)~θ². I show that the θ-dependence of the photosphere implies that for flow parameters characterizing gamma-ray bursts (GRBs), thermal photons originating from below the photosphere can be observed up to tens of seconds following the inner engine activity decay. I calculate the probability density function P(r,θ) of a thermal photon to escape the plasma at radius r and angle θ. Using this function, I show that following the termination of the internal photon injection mechanism, the thermal flux decreases as F^ob_BB(t)~t^-2, and that the decay of the photon energy with radius results in a power-law decay of the observed temperature, T^ob(t)~t^-2/3 at early times, which changes to t^-1/2 later. Detailed numerical results are in very good agreement with the analytical predictions. I discuss the consequences of this temporal behavior in view of the recent evidence for a thermal emission component observed during the prompt emission of GRBs.

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Giuliani, A. 2009 AGILE对GRB 090510的观测

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Title:		Agile Detection of Delayed Gamma-Ray Emission from the Short Gamma-Ray Burst GRB 090510
Authors:		Giuliani, A.; Fuschino, F.; Vianello, G.; Marisaldi, M.; Mereghetti, S.; Tavani, M.; Cutini, S.; Barbiellini, G.; Longo, F.; Moretti, E.; Feroci, M.; Del Monte, E.; Argan, A.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P. W.; Chen, A. W.; Contessi, T.; D'Ammando, F.; Costa, E.; De Paris, G.; Di Cocco, G.; Donnarumma, I.; Evangelista, Y.; Ferrari, A.; Fiorini, M.; Galli, M.; Gianotti, F.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Lipari, P.; Morselli, A.; Pacciani, L.; Pellizzoni, A.; Perotti, F.; Piano, G.; Picozza, P.; Pilia, M.; Pucella, G.; Prest, M.; Rapisarda, M.; Rappoldi, A.; Rubini, A.; Sabatini, S.; Scalise, E.; Striani, E.; Soffitta, P.; Trifoglio, M.; Trois, A.; Vallazza, E.; Vercellone, S.; Vittorini, V.; Zambra, A.; Zanello, D.; Pittori, C.; Verrecchia, F.; Santolamazza, P.; Giommi, P.; Colafrancesco, S.; Antonelli, L. A.; Salotti, L.
Publication:		eprint arXiv:0908.1908
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		Submitted to the Astrophysical Journal Letters on August 4, 2009
Bibliographic Code:		2009arXiv0908.1908G

Abstract

Short gamma-ray bursts (GRBs), typically lasting less than 2 s, are a special class of GRBs of great interest. We report the detection by the AGILE satellite of the short GRB 090510 which shows two clearly distinct emission phases: a prompt phase lasting ~ 200 msec and a second phase lasting tens of seconds. The burst is relatively intense in the 0.3-10 MeV range showing a spectrum of the prompt phase characterized by a large peak/cutoff energy near 3 MeV. Following the prompt phase, gamma-ray photons above 30 MeV were detected showing a power-law time decay of the flux of the type t^-1.3. The broad-band spectrum of this "delayed gamma-ray emission phase" is remarkably different from that of the prompt phase. It extends from sub-MeV to hundreds of MeV energies with a photon index alpha ~ 1.5. We present the timing and spectral data of GRB 090510 and briefly discuss its remarkable properties within the current models of gamma-ray emission of short GRBs.

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Fermi GBM/LAT Collaborations 2009 短暴GRB 090510的高能观测

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Title:		Testing Einstein's special relativity with Fermi's short hard gamma-ray burst GRB090510
Authors:		Fermi GBM/LAT Collaborations
Publication:		eprint arXiv:0908.1832
Publication Date:		08/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		Supplementary Material is available at http://gammaray.nsstc.nasa.gov/gbm/grb/GRB090510/supporting_material.pdf -- Corresponding authors: J. Granot (j.granot@herts.ac.uk), S. Guiriec (sylvain.guiriec@nasa.gov, sylvain.guiriec@lpta.in2p3.fr), M. Ohno (ohno@astro.isas.jaxa.jp) and V. Pelassa (pelassa@lpta.in2p3.fr)
Bibliographic Code:		2009arXiv0908.1832F

Abstract

Gamma-ray bursts (GRBs) are the most powerful explosions in the universe and probe physics under extreme conditions. GRBs divide into two classes, of short and long duration, thought to originate from different types of progenitor systems. The physics of their gamma-ray emission is still poorly known, over 40 years after their discovery, but may be probed by their highest-energy photons. Here we report the first detection of high-energy emission from a short GRB with measured redshift, GRB 090510, using the Fermi Gamma-ray Space Telescope. We detect for the first time a GRB prompt spectrum with a significant deviation from the Band function. This can be interpreted as two distinct spectral components, which challenge the prevailing gamma-ray emission mechanism: synchrotron - synchrotron self-Compton. The detection of a 31 GeV photon during the first second sets the highest lower limit on a GRB outflow Lorentz factor, of >1200, suggesting that the outflows powering short GRBs are at least as highly relativistic as those powering long GRBs. Even more importantly, this photon sets limits on a possible linear energy dependence of the propagation speed of photons (Lorentz-invariance violation) requiring for the first time a quantum-gravity mass scale significantly above the Planck mass.

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