Klotz 2009 GRB 081126的光学和伽玛辐射

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貌似有联系，时延8.4秒

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Title:		Correlated optical and gamma emissions from GRB 081126
Authors:		Klotz, Alain; Gendre, B.; Atteia, J. L.; Boër, Michel; Coward, David M.; Imerito, Alan C.
Publication:		eprint arXiv:0904.4786
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		4 pages, to be published in ApJ; Astrophysical Journal Letters 697 (2009) L18
Bibliographic Code:		2009arXiv0904.4786K

Abstract

We present an analysis of time-resolved optical emissions observed from the gamma-ray burst GRB 081126 during the prompt phase. The analysis employed time-resolved photometry using optical data obtained by the TAROT telescope, using BAT data from the Swift spacecraft, and time-resolved spectroscopy at high energies from the GBM instrument onboard the Fermi spacecraft. The optical emission of GRB 081126 is found to be compatible with the second gamma emission pulse shifted by a positive time lag of 8.4 $\pm$ 3.9 s. This is the first well-resolved observation of a time lag between optical and gamma emissions during a gamma-ray burst. Our observations could potentially provide new constraints on the fireball model for gamma-ray burst early emissions. Furthermore, observations of time lags between optical and gamma ray photons provides an exciting opportunity to constrain quantum gravity theories.

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Dermer 的高能书

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介绍的挺全的， 包括辐射机制（康普顿，同步。。。），粒子加速机制（一阶，二阶费米加速），光子和粒子间的三种碰撞，黑洞。

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星系谱的黑体拟合

曾想用多个黑体的叠加拟合星系的谱， 这样就可以进而得到星系中恒星的分布vs恒星种类（或者面积）。 见笔记。

下图是找到了两个比较全的星系的谱， 不过看起来合黑体比较接近，而不是想像中的幂律之类的谱， 所以上面的方法可能没什么意义。

Lee 2009 短暴flare的一个可能机制：中微子冷却主导盘的态转变

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Title:		Phase transitions and He-synthesis driven winds in neutrino cooled accretion disks: prospects for late flares in short gamma-ray bursts
Authors:		Lee, William H.; Ramirez-Ruiz, Enrico; Diego-Lopez-Camara
Publication:		eprint arXiv:0904.3752
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		Submitted to ApJ Letters
Bibliographic Code:		2009arXiv0904.3752L

Abstract

We consider the long term evolution of debris following the tidal disruption of compact stars in the context of short gamma ray bursts (SGRBs). The initial encounter impulsively creates a hot, dense, neutrino-cooled disk capable of powering the prompt emission. After a long delay, we find that powerful winds are launched from the surface of the disk, driven by the recombination of free nucleons into alpha-particles. The associated energy release depletes the mass supply and eventually shuts off activity of the central engine. As a result, the luminosity and mass accretion rate deviate from the earlier self-similar behavior expected for an isolated ring with efficient cooling. This then enables a secondary episode of delayed activity to become prominent as an observable signature, when material in the tidal tails produced by the initial encounter returns to the vicinity of the central object. The time scale of the new accretion event can reach tens of seconds to minutes, depending on the details of the system. The associated energies and time scales are consistent with those occurring in X-ray flares.

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Fukue 2009 数值模拟相对论喷流光深为1处的辐射

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是各向同性的. 此人有解析节的文章在2008年.

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Title:		Relativistic Variable Eddington Factor in a Relativistic Plane-Parallel Flow
Authors:		Fukue, J.
Publication:		eprint arXiv:0904.3369
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		9 pages, 8 figures. PASJ, 62 (2009), in press
Bibliographic Code:		2009arXiv0904.3369F

Abstract

We examine the behavior of the variable Eddington factor for a relativistically moving radiative flow in the vertical direction. We adopt the "one-tau photo-oval" approximation in the comoving frame. Namely, the comoving observer sees radiation coming from a closed surface where the optical depth measured from the observer is unity; such a surface is called a one-tau photo-oval. In general, the radiative intensity emitted by the photo-oval is non-uniform and anisotropic. Furthermore, the photo-oval surface has a relative velocity with respect to the comoving observer, and therefore, the observed intensity suffers from the Doppler effect and aberration. In addition, the background intensity usually depends on the optical depth. All of these introduce the anisotropy to the radiation field observed by the comoving observer. As a result, the relativistic Eddington factor $f$ generally depends on the optical depth $\tau$, the four velocity $u$, and the velocity gradient $du/d\tau$. % In the case of a plane-parallel vertical flow, we found that the relativistic variable Eddington factor $f$ generally decreases as the velocity gradient increases, but it increases as the velocity increases for some case. When the comoving radiation field is uniform, it is well approximated by $3f \sim 1/[ 1+ ({16}/{15})(-{du}/{\gamma d\tau}) +(-{du}/{\gamma d\tau})^{1.6-2} ]$. When the radiation field in the inertial frame is uniform, on the other hand, it is expressed as $f = (1+3\beta^2)/(3+\beta^2$). These relativistic variable Eddington factors can be used in various relativistic radiatively-driven flows, such as black-hole accretion flows, relativistic astrophysical jets and outflows, and relativistic explosions like gamma-ray bursts.

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Sudilovsky 2009 尘埃状MgII的吸收

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结论是不重要

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Title:		Dusty MgII Absorbers: Implications for the GRB/Quasar Incidence Discrepancy
Authors:		Sudilovsky, Vladimir
Publication:		eprint arXiv:0904.3227
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Comment:		11 pages, 4 figures. ApJ Accepted
Bibliographic Code:		2009arXiv0904.3227S

Abstract

There is nearly a factor of four difference in the number density of intervening MgII absorbers as determined from gamma-ray burst (GRB) and quasar lines of sight. We use a Monte-Carlo simulation to test if a dust extinction bias can account for this discrepancy. We apply an empirically determined relationship between dust column density and MgII rest equivalent width to simulated quasar sight-lines and model the underlying number of quasars that must be present to explain the published magnitude distribution of SDSS quasars. We find that an input MgII number density dn/dz of 0.273 +- 0.002 over the range 0.4 <= z <= 2.0 and with MgII equivalent width W_0 >= 1.0 angstroms accurately reproduces observed distributions. From this value, we conclude that a dust obstruction bias cannot be the sole cause of the observed discrepancy between GRB and quasar sight-lines: this bias is likely to reduce the discrepancy only by ~10%

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Zhang 2009 GRB 080916C可能有Poynting流的证据

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高能没有任何热成份, 说明不是完全由重子组成.

"a thermal component as predicted by the baryonic models" 有重子就一定有热成份吗? 为什么?


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Title:		Evidence of a non-baryonic composition in GRB 080916C
Authors:		Zhang, Bing; Pe'er, Asaf
Publication:		eprint arXiv:0904.2943
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		ApJL, submitted
Bibliographic Code:		2009arXiv0904.2943Z

Abstract

The composition of gamma-ray burst (GRB) ejecta is still a mystery. The standard model invokes an initially hot "fireball" composed of baryonic matter. Here we analyze the broad band spectra of GRB 080916C detected by the Fermi satellite. The featureless Band-spectrum of all five epochs as well as the detections of >~ 10 GeV photons in this burst place a strong constraint on the prompt emission radius >~ 10^{15} cm, independent on the details of the emission process. The lack of the detection of a thermal component as predicted by the baryonic models strongly suggests that a significant fraction of the outflow energy is initially not in the "fireball" form, but is likely in a Poynting flux entrained with the baryonic matter. The ratio between the Poynting and the baryonic flux is at least ~(15-20).

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Lazzati 2009 光球辐射可以效率很高

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数值模拟, 不过这个结论是容易理解的, 主要光学薄半径和coasting半径相当, 就可以辐射效率很高了.

但是有个问题是光球辐射是黑体谱, 怎么转换成观测到的非热谱呢? 文中给了点儿定性的解释, 说是康普顿散射.

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Title:		Very high efficiency photospheric emission in long duration gamma-ray bursts
Authors:		Lazzati, Davide; Morsony, Brian J.; Begelman, Mitch
Publication:		eprint arXiv:0904.2779
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		4 pages, uses emulateapj and apjfonts (both included). 4 color figures. Submitted to ApJL
Bibliographic Code:		2009arXiv0904.2779L

Abstract

We numerically analyze the evolution of a long-duration gamma-ray burst jet as it leaves the progenitor star and propagates to the photospheric radius, where radiation can be released. We find that the interaction of the relativistic material with the progenitor star has influences well beyond the stellar surface. Tangential collimation shocks are observed throughout the jet evolution, out to about 100 stellar radii, which is the whole range of our simulation. We find that the jet is internally hot at the photospheric radius and we compute the photospheric emission. The photosphere is a very efficient radiator, capable of converting more than half of the total energy of the jet into radiation. We show that bright photospheres are a common feature of jets born inside massive progenitor stars and that this effect can explain the high radiative efficiency observed in long-duration bursts.

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Qi 2009 超新星和伽玛暴限制宇宙学常数

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暗能量的状态方程好像大于-1

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Title:		Deviation from the Cosmological Constant or Systematic Errors?
Authors:		Qi, Shi; Lu, Tan; Wang, Fa-Yin
Publication:		eprint arXiv:0904.2832
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		4 pages, 4 figures
Bibliographic Code:		2009arXiv0904.2832Q

Abstract

Motivated by the fact that both SNe Ia and GRBs seem to prefer a dark energy EOS greater than -1 at redshifts $z \gtrsim 0.5$, we perform a careful investigation on this situation. We find that the deviation of dark energy from the cosmological constant at redshifts $z \gtrsim 0.5$ is large enough that we should pay close attention to it with future observational data. Such a deviation may arise from some biasing systematic errors in the handling of SNe Ia and/or GRBs or more interestingly from the nature of the dark energy itself.

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关于黑体辐射强度是一切辐射的上限

有这么一个限制, 就是在给定温度的情况下, 一个物体辐射的强度最大(当然重点是说那些非热辐射, 或者是观测到的任意辐射)只能是该温度下的黑体辐射的强度.
见示意图.

但是对于和观测频率对应着一个温度, 这个温度下的黑体辐射和那个非热辐射有什么关系呢? 貌似没有关系, 可大可小.
(另外关于这个图为什么可以这么大, 确实还是很容易改的, 只要耐心读一下html源文件. 其中有这么些东东:
width: 400px; height: 283px; (我把这个乘以了2)
src=.../McSpiaY66YE/s400/BB-no-thermal.png (我s400/去掉了))


另外, 也不是所有的都是可大可小的. 有这么一种情况: 星系的谱, 它们实际上是很多黑体的合成 (注意星系--以恒星为单元--对光子实际上是光学薄的, 哎, 这个好像没关系). 那么对于任意一个频率的强度, 即上图的非热谱, 都主要来自于星系中一部分恒星的贡献, 那么, 把所有恒星面积当做面积, 改频率作为温度的黑体辐射就一定会比看到那个所谓非热谱在那个点上的强度大. 这也是个限制啊.

Lemoine 2009 极端相对论激波中的电磁不稳定性

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Title:		On electromagnetic instabilities at ultra-relativistic shock waves
Authors:		Lemoine, Martin; Pelletier, Guy
Publication:		eprint arXiv:0904.2657
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		12 pages, 1 figure
Bibliographic Code:		2009arXiv0904.2657L

Abstract

(Abridged) This paper addresses the issue of magnetic field generation in a relativistic shock precursor through micro-instabilities. The level of magnetization of the upstream plasma turns out to be a crucial parameter, notably because the length scale of the shock precursor is limited by the Larmor rotation of the accelerated particles in the background magnetic field and the speed of the shock wave. We discuss in detail and calculate the growth rates of the following beam plasma instabilities seeded by the accelerated and reflected particle populations: for an unmagnetized shock, the Weibel and filamentation instabilities, as well as the Cerenkov resonant longitudinal and oblique modes; for a magnetized shock, in a generic oblique configuration, the Weibel instability and the resonant Cerenkov instabilities with Alfven, Whisler and extraordinary modes. All these instabilities are generated upstream, then they are transmitted downstream. The modes excited by Cerenkov resonant instabilities take on particular importance with respect to the magnetisation of the downstream medium since, being plasma eigenmodes, they have a longer lifetime than the Weibel modes. We discuss the main limitation of the wave growth associated with the length of precursor and the magnetisation of the upstream medium. We also characterize the proper conditions to obtain Fermi acceleration. We recover some results of most recent particle-in-cell simulations and conclude with some applications to astrophysical cases of interest, pulsar winds and gamma-ray burst external shock waves in particular. (Abridged)

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Stamatikos 2009 GRB Astrophysics in the Swift Era and Beyond

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Title:		GRB Astrophysics in the Swift Era and Beyond
Authors:		Stamatikos, Michael
Publication:		eprint arXiv:0904.2755
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		5 pages, 1 figure. Contributed to the Proceedings of the 2nd Heidelberg Workshop: High-Energy Gamma-rays and Neutrinos from Extra-Galactic Sources (Max Planck Institute for Nuclear Physics)
Bibliographic Code:		2009arXiv0904.2755S

Abstract

Gamma-ray Bursts (GRBs) are relativistic cosmological beacons of transient high energy radiation whose afterglows span the electromagnetic spectrum. Theoretical expectations of correlated neutrino emission position GRBs at an astrophysical nexus for a metamorphosis in our understanding of the Cosmos. This new dawn in the era of experimental (particle) astrophysics and cosmology is afforded by current facilities enabling the novel astronomy of high energy neutrinos, in concert with unprecedented electromagnetic coverage. In that regard, GRBs represent a compelling scientific theme that may facilitate fundamental breakthroughs in the context of Swift, Fermi and IceCube. Scientific synergy will be achieved by leveraging the combined sensitivity of contemporaneous ground-based and satellite observatories, thus optimizing their collective discovery potential. Hence, the advent of GRB multi-messenger astronomy may cement an explicit connection to fundamental physics, via nascent cosmic windows, throughout the next decade.

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Xiao 2009 长时延的暴来自附近的猜测不成立

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通过对18个长时延的Swift暴的分析, (其中17个的红移大于0.5)认为以前猜测长时延的暴来自本地是不对的, 从而LIGO也不能看到其引力波辐射.

(奇怪的是关于这个结论只需要红移就搞定了, 不知道为什么作者还加了很多别的分析手段如和cluster是否靠近等.)

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Title:		Are Swift Long-Lag Gamma-Ray Bursts in the Local Supercluster?
Authors:		Xiao, Limin; Schaefer, Bradley E.
Publication:		eprint arXiv:0904.2566
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		14 pages, 1 figure, ApJ accepted
Bibliographic Code:		2009arXiv0904.2566X

Abstract

A sample of 18 long-lag (tau_{lag} > 1 s) Gamma-Ray Bursts (GRBs) has been drawn from our catalog of all Swift long GRBs. Four different tests are done on this sample to test the prediction that a large fraction of long-lag GRBs are from our Local Supercluster. The results of these four tests come out that: (1) the distribution of these GRBs shows no tendency towards the Supergalactic plane; (2) the distribution shows no tendency towards the Virgo or Coma Cluster; (3) no associated bright host galaxies (m <=15) in the Local Supercluster are found for any of the 18 GRBs; (4) 17 of these 18 GRBs have redshifts of z>0.5, which are too far to be in the Local Supercluster. All these results disproved the hypothesis that any significant fraction of long-lag GRBs are from Local Supercluster. Hence these long-lag GRBs can not be counted in the calculation of LIGO detection rates. An explanation of why we can detect long-lag GRBs at high redshift is presented.

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Rea 2009 SGR 0501+4516的首次爆发

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burst 本身


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Title:		The first outburst of the new magnetar candidate SGR 0501+4516
Authors:		Rea, Nanda; Israel, GianLuca; Turolla, Roberto; Esposito, Paolo; Mereghetti, Sandro; Gotz, Diego; Zane, Silvia; Tiengo, Andrea; Hurley, Kevin; Feroci, Marco; Still, Martin; Yershov, Vladimir; Winkler, Christoph; Perna, Rosalba; Bernardini, Federico; Ubertini, Pietro; Stella, Luigi; Campana, Sergio; van der Klis, Michiel; Woods, Peter M.
Publication:		eprint arXiv:0904.2413
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		16 pages; accepted for publication in MNRAS
Bibliographic Code:		2009arXiv0904.2413R

Abstract

We report here on the outburst onset and evolution of the new Soft Gamma Repeater SGR 0501+4516. We monitored the new SGR with XMM-Newton starting on 2008 August 23, one day after the source became burst-active, and continuing with 4 more observations, with the last one on 2008 September 30. Combining the data with the Swift-XRT and Suzaku data, we modelled the outburst decay over 160 days, and we found that the source flux decreased exponentially with a timescale of t_c=23.8 days. In the first XMM-Newton observation a large number of short X-ray bursts were observed, the rate of which decayed drastically in the following observations. We found large changes in the spectral and timing behavior of the source during the outburst, with softening emission as the flux decayed, and the non-thermal soft X-ray spectral component fading faster than the thermal one. Almost simultaneously to our XMM-Newton observations (on 2008 August 29 and September 2), we observed the source in the hard X-ray range with INTEGRAL, which clearly detected the source up to ~100keV in the first pointing, while giving only upper limits during the second pointing, discovering a variable hard X-ray component fading in less than 10 days after the bursting activation. We performed a phase-coherent X-ray timing analysis over about 160 days starting with the burst activation and found evidence of a strong second derivative period component (\ddot{P} = -1.6(4)x10^{-19} s/s^{-2}). Thanks to the phase-connection, we were able to study the the phase-resolved spectral evolution of SGR 0501+4516 in great detail. We also report on the ROSAT quiescent source data, taken back in 1992 when the source exhibits a flux ~80 times lower than that measured during the outburst, and a rather soft, thermal spectrum.

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Grindlay 2009 探测高红移伽玛暴的探测器EXIST

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类似Swift, 但都有所扩展(没有紫外, 有光学). 可以很快地定红移

预计2017年发射

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一些参数


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Title:		GRB Probes of the High-z Universe with EXIST
Authors:		Grindlay, Jonathan; the EXIST Team
Publication:		eprint arXiv:0904.2210
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Comment:		7 pages, 5 figures, 1 table; to appear in Proc. Huntsville Gamma-ray Burst Symposium, AIPC (C. Meegan, N. Gehrels and C. Kouveliotou, eds.), in press
Bibliographic Code:		2009arXiv0904.2210G

Abstract

The Energetic X-ray Imaging Survey Telescope (EXIST) mission concept is optimized for study of high-z GRBs as probes of the early Universe. With a High Energy Telescope (HET) incorporating a 4.5m^2 5-600keV (CZT; 0.6mm pixels) detector plane for coded aperture imaging a 90deg x 70deg (>10% coding fraction) field of view with 2' resolution and <20">5 sigma sources, EXIST will perform rapid (<200sec) r =" 3000" r ="30">7, EXIST will open a new era in studies of the early Universe as well as carry out a rich program of AGN and transient-source science. An overview of the GRB science objectives and a brief discussion of the overall mission design and operations is given, and example high-z GRB IRT spectra are shown. EXIST is being proposed to the Astro2010 Decadal Survey as a 5 year Medium Class mission that could be launched as early as 2017.

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Calura 2009 GRB 050830 宿主星系的恒星形成历史

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Title:		The Star Formation History of the GRB 050730 Host Galaxy
Authors:		Calura, Francesco
Affiliation:		AA(Dipartimento di Astronomia, Universita' di Trieste, via G. B. Tiepolo 11, 34131 TRIESTE - ITALY fcalura@oats.inaf.it)
Publication:		Low-Metallicity Star Formation: From the First Stars to Dwarf Galaxies, Proceedings of the International Astronomical Union, IAU Symposium, Volume 255, p. 217-223
Publication Date:		12/2008
Origin:		CUP
Keywords:		Gamma rays: bursts, Galaxies: high-redshift, Galaxies: abundances, ISM: general
Abstract Copyright:		(c) 2008: Copyright © International Astronomical Union 2008
DOI:		10.1017/S174392130802485X
Bibliographic Code:		2008IAUS..255..217C

Abstract

The long GRB 050730 observed at redshift z ~ 4 allowed the determination of the elemental abundances for a set of different chemical elements. We use detailed chemical evolution models taking into account also dust production to constrain the star formation history of the host galaxy of this long GRB. For the host galaxy of GRB 050730, we derive also some dust-related quantities and the specific star formation rate, namely the star formation rate per unit stellar mass. Finally, we compare the properties of the GRB host galaxy with those of Quasar Damped Lyman Alpha absorbers.

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Murase 2009 附近超高能宇宙射线光子

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Title:		Ultra-High-Energy Photons as a Probe of Nearby Transient Ultra-High-Energy Cosmic-Ray Sources and Quantum Gravity
Authors:		Murase, Kohta
Publication:		eprint arXiv:0904.2087
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		5 pages, 3 figures
Bibliographic Code:		2009arXiv0904.2087M

Abstract

Detecting neutrinos and photons is crucial to identify the sources of ultra-high-energy cosmic rays (UHECRs), especially for transient sources. We focus on ultra-high-energy gamma-ray emission from transient sources such as gamma-ray bursts, since > EeV gamma rays are more direct evidence of UHECRs than PeV neutrinos and GeV-TeV gamma rays. We demonstrate that coincident detections of around 1-100 events can be expected by current and future UHECR detectors such as Auger and JEM-EUSO, and the detection probability is higher than that of neutrinos for nearby transient sources at <> Bibtex entry for this abstract Preferred format for this abstract (see Preferences)

Parsons 2009 短暴的环境也比较致密

主要内容:
按说短暴的环境应该是IGM, 但是余辉拟合的密度都比较大.

此文提了个模型解释为什么比较大.

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Title:		Short Gamma Ray Bursts and their Afterglow Signatures in Dense Stellar Systems
Authors:		Parsons, Rion K.; Ramirez-Ruiz, Enrico; Lee, William H.
Publication:		eprint arXiv:0904.1768
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		9 pages, 3 figures, submitted to ApJ
Bibliographic Code:		2009arXiv0904.1768P

Abstract

The hypothesis that short GRBs arise from the coalescence of binary compact stars has recently gained support. With this comes the expectation that the afterglow should bear the characteristic signature of a tenuous intergalactic medium (IGM). However, fits to the observational data suggest that some detected afterglows arise in relatively dense gaseous environments rather than in the low density IGM. Here we show that considering the effect of red giant winds in the core of a star cluster may resolve this paradox if short GRB progenitors are contained in such an environment and close encounters rather than pure gravitational wave emission brings the compact objects together. Clear confirmation is provided here of the important notion that the morphology and visibility of short gamma-ray burst remnants are determined largely by the state of the gas in the cluster's core.

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