伽玛暴(Gamma-Ray Burst)笔记。记录有关伽玛暴的新文章,另外也包括看的老文章、自己的想法、以及跟天文相关的一些东西。 Feel free to leave me a message by comments or by email.

星期日, 九月 20, 2009

2009.9.14-9.18 威尼斯shocking universe会议





会议网址: http://www.brera.inaf.it/sanservolo2009/index.html
他们说要提供ppt的, 不知道为什么也没上网.

以下是会议日程. 大致第一天Swift相关;第二天Fermi相关;第三天半天, 比较杂;第四天比较关注宇宙方面的如宿主星系, 高红移;第五天的也比较杂.

(时间表拷贝自网站上)

Sunday - September 13th
18:00 - 20:00Registration & Welcome Cocktail


Monday - September 14th
07:45 - 08:45Registration

ChairmanM. Feroci
08:45 - 09:00G. ChincariniWelcome
此人很像偷天陷阱里的男主角老头. 附剧照 http://posters.imdb.cn/jz/46852

09:00 - 09:35M. LyutikovGRB: observational progress and theoretical problems
主要内容大致有(这里以及以下都包含严重的偏见和记忆误差):
1. 一共有8个想080513这样的, 可能是短暴加一个tail;
2. 暴本身阶段的低频端的硬谱可能来自电子的分布;
3.说080916C的同步辐射模型是不行的

09:35 - 09:50I. SteeleOptical polarization measurements of GRB060418 and GRB090102
他们利物浦的望远镜加了偏振片, 这是两个观测. 其中060418的小于8%, 最令人惊讶的是090102的有10%, 而且致信度还很高!

09:50 - 10:05C. GuidorziThe controversial link between prompt optical and gammarays: temporal study of GRB 080319B
说这个暴的光变里有3.3s的周期现象.
下图是time lag

10:05 - 10:30Coffee Break
10:30 - 10:55S. BarthelmyGRB Prompt Emission and Swift-BAT
图左显示了三个仪器的分布和E_p的分布


1. 统计上, pulse的宽度 W~E_p^-0.4~z^0.4
2. 谱形上, cutoff power law的比Band的还多
3. 观测上, Swift的高红移的暴并没有更软 (这个可能说明E_p比较大, 即使红移比较高, 还是没看到peak的地方; 或者谱整个是一个比较好的幂律, 这样也不会看到变软; 或者, 当然最直接的解释应该是高红移的暴本身比较硬.)
4. 他们Swift在准备 sub-threshold, 就是不要那么强的伽玛光子信号就触发. 这样可以看到更多弱暴, 虽然会有很多误触发.
10:55 - 11:20S. KobayashiMagnetized Fireballs and Early Afterglows
11:20 - 11:45A. Pe'erObservations, theory and implications of thermal emission from gamma-ray bursts
他主要还是说他的Themal component
11:45 - 12:05L. AmatiSpectrum-energy correlation in GRB: status and perspectives
会议上有两个报告说Amati关系不对, 让他很郁闷. 在Tsvi的报告提问阶段都快结束后强烈要求发言, 终于给他机会, 说了很大一通. 最后说你们不能这样, 搞的让大家以为我这个关系真的就是错的样. Tsvi听了半天, 然后回了一句话, 闪人. 没听大明白, 大意是它是错的就是错的.

12:05 - 12:30J. RacusinJet Breaks and Energetics of Swift GRB X-ray Afterglows
12:30 - 12:45D. BurrowsChandra Searches for Jet Breaks





几类光变所占的比例.

12:45 - 13:00P. EvansConfronting GRB afterglow models with a complete set of XRT light curves and hardness ratios
13.00 - 14.20Lunch

ChairmanS. Barthelmy
14:20 - 14:45A. MacFadyenGRB Afterglow Lightcurves from Multi-Dimensional Simulations
14:45 - 15:10R. MarguttiGRB temporal structure: flares and short term variability
15:10 - 15:30R. YamazakiPrior Emission Model for the Plateau Phase in the X-ray Afterglow
15:30 - 15:55E. Del MonteThe observation of Gamma Ray Bursts with AGILE
15:55 - 16:10R. KlebesadelThe Discovery of Cosmic Gamma-Ray Bursts
此人算是伽玛暴的开山鼻祖, 1973?年发表了第一篇观测到伽玛暴的文章. 不知道会议组怎么这么有能耐, 居然能请到他来. 讲完后以及提问完后迎来了会上最长时间的掌声, 起码有一分钟. 具体内容不是很有意思, 提问还是蛮有意思的. Kouveliotou问他为什么那么晚才发文章, 他解释说忙, 还有因为计算机故障还是什么. 据说还有另外的版本, 说是因为军事机密问题, 不能发. (参见伽玛暴的发现的相关内容) 由于Vela是军事卫星, 主要目的是看前苏联有没有搞秘密核试验. 所以有人就问那你们到底看到了没有, 他坚决不泄密.



16:10 - 16:35Coffee Break
16:35 - 17:00F. DaigneThe prompt emission of gamma-ray bursts in the internal shock model
17:00 - 17:15S. SugitaTiming and spectral analysis of Short GRB and Multi-spiked Long GRB
17:15 - 17:30E. LiangSingle Power-Law Decaying XRT lightcurves and Implications for the Unified Origin of the X-rays
17:30 - 17:45P. RomingA Large Homogenous Sample of Optical GRB Afterglow Light Curves
17:45 - 18:00M. De PasqualeChromatic evolution in GRB afterglows
18:00 - 18:20S. CovinoOptical observations of GRB afterglows
18:20 - 18:35J. NousekStatus of the Swift Mission

Tuesday - September 15th

ChairmanP. Michelson
09:00 - 09:25N. OmodeiGamma-Ray Burst at HighEnergy: the Fermi LAT first observation of the shocking Universe
09:25 - 09:45N. KawaiPulse structures of GRB 080916C observed with Fermi LAT/GBM
09:45 - 10:05S. GuiriecGRB 090510, a short and hard burst detected by Fermi
10:05 - 10:25F. De PalmaGRB 090902B, a long GRB with High Energy emission detected with Fermi
10:25 - 11:00Coffee Break
11:00 - 11:20E. BissaldiGRB 090323 and GRB 090328: two ksec long high-energy GammaRay Bursts detected with Fermi
11:20 - 11:45B. PaciesasFermi GBM results
11:45 - 12:10M. BriggsSpectral Evolution of Three Short GRBs on Fine Timescales
12:10 - 12:30V. ConnaughtonHigh-Energy Spectral signatures of LAT-detected short gamma-ray bursts
12:30 - 12:55J. GranotSome Implications of Fermi High-Energy GRB Observations
12.55 - 14.20Lunch

ChairmanR. Bellazzini
14:20 - 14:45K. AsanoTheoretical Interpretation for Fermi LAT-detected Gamma-ray Bursts
14:45 - 15:10C. DermerEvidence for Ultra-High Energy Cosmic Ray Acceleration from Fermi Observations of GRBs




15:10 - 15:35P. MichelsonFermi LAT results



15:35 - 16:00B. AtwoodFermi-LAT Analysis to Maximize GRB Science
16:00 - 16:30Coffee Break
16:30 - 16:50D. KocevskiLAT Upper Limits to GRBs
16:50 - 17:05T. AuneConstraints on GeV-TeV Emission from the "nakedeye" GRB 080319B

17:05 - 17:30Y. FanInterpretation and implication of the non-detection of GeV spectrum excess by Fermi gamma-ray Space Telescope in most GRBs



17:30 - 17:45A. MelandriThe Rise and Fall of GRBs - Lorentz Factors and Fireball Shock Physics
17:45 - 18:10R. Barniol-DuranHigh energy photons from Fermi GRBs: Who would have thought that they were produced in the external shock?


19:15Visit at the S. Marco Basilica

Wednesday - September 16th

ChairmanP. Roming
09:00 - 09:30E. BergerThe Host Galaxies of Short GRBs: Implications for the Progenitors and Comparison to Long GRB Hosts
09:30 - 09:45F. VirgiliAre all short GRBs of compact star merger origin?
09:45 - 10:00P. D'AvanzoOptical spectroscopy of short GRB afterglows
10:00 - 10:20W. LeeThe role of winds and tidal tails from post merger disks in the production of outflows and late time flares in SGRBs
10:20 - 10:40Poster competition
10:40 - 11:10Coffee Break
11:10 - 11:40C. FryerNeutrinos and Gravitational Waves from Long Duration GRBs
11:40 - 12:05P. VreeswijkGRB optical afterglow spectroscopy and host galaxies: an unbiased approach
12:05 - 12:20D. PerleyThe Environments of Dark Gamma-Ray Bursts
12:20 - 12:35A. De Ugarte PostigoGRB 090313: X-shooter's first glimpse of a GRB
12:35 - 13:15K. HamaguchiNews on Eta-Carinae
13:15Lunch
13:45Free Afternoon - Social Trip to S. Francesco del Deserto island

Thursday - September 17th

ChairmanJ. Osborne
09:00 - 09:25S. SavaglioGamma-Ray Burst Host Galaxies and the High Redshift Universe
09:25 - 09:50A. FruchterEnvironments, Hosts, and their Implications for the Physics and Progenitors of GRBs
09:50 - 10:05E. LevesqueModeling the Host Galaxies of Long-Duration Gamma-Ray Bursts
10:05 - 10:20P. SchadyDust Extinction Properties within GRB Host Galaxies
10:20 - 10:35K. SvenssonThe host galaxies of core-collapse supernovae and gamma ray bursts
10:35 - 11:00Coffee Break
11:00 - 11:30A. SoderbergA Holistic View of the GRB-SN Connection
11:30 - 11:55M. Della ValleGRB-SN Connection: observational outcomes
11:55 - 12:15S. NagatakiGRB-SN Connection: Central Engine of Long GRBs and Explosive Nucleosynthesis
12:15 - 12:30A. KambleXRF080109/SN2008D : an investigation at radio frequencies
12:30 - 12:45R. ShenThe late jet in GRBs and its interactions with a supernova ejecta and a cocoon
12:45 - 13:00F. De ColleBipolar Supernova Explosions: Nucleosynthesis and the Role of Magnetic Fields
13.00 - 14.30Lunch

ChairmanN. Kawai
14:30 - 15:00P. KumarThe Physics of GRB Prompt Emission
15:00 - 15:30B. ZhangGRB prompt emission models: from low sigma to high sigma

15:30 - 16:00T. PiranTBA

16:00 - 16:30Coffee Break
16:30 - 16:45E. NakarIntroduction for a debate
16:45 - 17:20
Debate: where do we stand?
17:20 - 17:35A. LevanIlluminating the dark ages with GRB 090423
17:35 - 17:50R. SalvaterraGRB 090423 reveals an exploding star at the epoch of reionization
17:50 - 18:05D. FrailDiscovery of the Radio Afterglow from GRB 090423
18:05 - 18:20A. CucchiaraGRB 090429B as the second "extreme redshift" gamma-ray burst
18:20 - 18:45T. TotaniGRBs and High Redshift Universe: High Redshift Galaxies, Pop III Stars, and Reionization
20:30Social Dinner

Friday - September 18th

ChairmanK. Hurley
08:45 - 09:10C. KouveliotouMagnetar Observations with Fermi/GBM






09:10 - 09:25S. Dall'OssoMagnetars at birth as strong sources of Gravitation Wave Radiation
09:25 - 09:40Y. NakagawaSuzaku Observations of Short Bursts from SGR 0501+4516
09:40 - 10:10E. Ramirez-RuizCompact Objects in The Era of Celestial Cinematography
10:10 - 10:40Coffee Break
10:40 - 11:05V. D'EliaUVES-VLT High Resolution Spectroscopy of Gamma-Ray Burst afterglows: host galaxies and intervening absorbers
11:05 - 11:20S. VerganiStatistics and characteristics of MgII absorbers along GRB lines of sight observed with VLT-UVES
11:20 - 11:35S. CampanaCircumburst ambient surrounding GRBs in the X-ray band
11:35 - 11:50C. ThoeneGRB 090426 - a new class or a strange environment?
11:50 - 12:00I. HorvathGRB groups observed by BATSE, BeppoSAX and Swift
12:00 - 12:15D. Lopez-CamaraQuiescence and late time activity in collapsars due to critical angular momentum distributions
12:15 - 12:30G. BeskinDiscovery of the "central engine" manifestation in the Naked-Eye Burst prompt optical emission
12.30 - 14.00Lunch

ChairmanD. Burrows
14:00 - 14:25K. YamaokaSuzaku observations of GRB prompt emissions and X-ray afterglows
14:25 - 14:55C. BiancoThe extended afterglow luminosity evolution over the equitemporal surfaces
14:55 - 15:10F. GenetSteep decay phase and prompt emission models
15:10 - 15:25V. ManganoModeling the spectral evolution in the decaying tails of Swift GRBs
15:25 - 15:45S. InoueProbing UV radiation fields and magnetic fields in the era of first star formation through GeV γ-rays from very high-z GRBs
15:45 - 16:00P. RomanoSupergiant Fast X-ray Transients: the Swift monitoring program
16:00 - 16:45N. GehrelsConcluding Remarks

星期五, 九月 18, 2009

van Leeuwen, Joeri 2009 LOFAR的射电巡天

主要内容:
将要投入使用的射电阵, 可能可以探测到孤儿射电余辉.

精彩摘抄:


文章信息:

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· arXiv e-print (arXiv:0909.3212)
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Title:
Neutron Stars and Gamma Ray Bursts with LOFAR
Authors:
van Leeuwen, Joeri; LOFAR Transients Key Science Project, The
Publication:
eprint arXiv:0909.3212
Publication Date:
09/2009
Origin:
ARXIV
Keywords:
Astrophysics - Instrumentation and Methods for Astrophysics
Comment:
Proceedings of the "Frontiers of Space Astrophysics: Gamma Ray Bursts & Neutron Stars" meeting in Cairo/Alexandria, Egypt, April 2009. 4 Pages
Bibliographic Code:
2009arXiv0909.3212V

Abstract

LOFAR, the Low Frequency Array, is an innovative new radio telescope currently under construction in the Netherlands. With its continuous monitoring of the radio sky we expect LOFAR will detect many new transient events, including GRB afterglows and pulsating/single-burst neutron stars. We here describe all-sky surveys ranging from a time resolution of microseconds to a cadence span of years.
Bibtex entry for this abstract Preferred format for this abstract (see Preferences)

Lee, William H. 2009 数值模拟中子星-黑洞并合产生短暴

主要内容:


精彩摘抄:


文章信息:

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Title:
Short gamma-ray bursts from tidal capture and collisions of compact stars in globular clusters
Authors:
Lee, William H.; Ramirez-Ruiz, Enrico; van de Ven, Glenn
Publication:
eprint arXiv:0909.2884
Publication Date:
09/2009
Origin:
ARXIV
Keywords:
Astrophysics - High Energy Astrophysical Phenomena
Comment:
Submitted to ApJ
Bibliographic Code:
2009arXiv0909.2884L

Abstract

A new mechanism is proposed by which short gamma-ray burst (SGRB) production can be achieved. In this new paradigm, it is supposed that the compact objects contained within a globular cluster (GC) interact through close encounters, rather than being driven together by pure gravitational wave emission in existing binaries. Here we perform a careful assessment of the relevant processes and stellar dynamics within GCs as these undergo core collapse over cosmic time. We show that such events are frequent enough in their cores to be consistent both with current observational rate demands for SGRB production and with the widening range of observed redshifts of the associated hosts. Precise modeling of the hydrodynamics allows for a detailed description of the encounter, and our calculations show that there is in principle no problem in accounting for the global energy budget of a typical SGRB. The particulars of each collision, are variable in several aspects, and can lead to interesting diversity. First, the characteristics of the encounter are highly dependent on the impact parameter. This is in contrast to the merger scenario, where the masses of the compact objects dictate a typical length and luminosity scale for SGRB activity. Second, the nature of the compact star itself can produce very different outcomes. Finally, the presence of tidal tails in which material will fall back onto the central object at a later time is a robust feature of the present set of calculations. The mass involved in these structures is considerably larger than for binary mergers. It is thus possible, in principle, to account generically in this scenario for a prompt episode of energy release as well as for activity many dynamical time scales later. (abridged)
Bibtex entry for this abstract Preferred format for this abstract (see Preferences)

星期三, 九月 16, 2009

Bissaldi 2009 GRB 090902B的观测

主要内容:


精彩摘抄:
原始光变


处理后的高能光变, 有比较好的幂律形式, 很像外激波. (和另外一个暴090510很像)
谱, 高能有一个excess.

文章信息:

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Title:
Fermi Observations of GRB 090902B: A Distinct Spectral Component in the Prompt and Delayed Emission
Authors:
The Fermi/GBM collaboration; The Fermi/LAT Collaborations; The Swift Team
Publication:
eprint arXiv:0909.2470
Publication Date:
09/2009
Origin:
ARXIV
Keywords:
Astrophysics - High Energy Astrophysical Phenomena
Comment:
Submitted to ApJ Letters. Contact Authors: Elisabetta Bissaldi (ebs@mpe.mpg.de), James Chiang (jchiang@slac.stanford.edu), Francesco de Palma (francesco.depalma@ba.infn.it), Sheila McBreen (smcbreen@mep.mpg.de)
Bibliographic Code:
2009arXiv0909.2470T

Abstract

We report on the observation of the bright, long gamma-ray burst, GRB 090902B, by the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) instruments on-board the Fermi observatory. This was one of the brightest GRBs to have been observed by the LAT, which detected several hundred photons during the prompt phase. With a redshift of z = 1.822, this burst is among the most luminous detected by Fermi. Time-resolved spectral analysis reveals a significant power-law component in the LAT data that is distinct from the usual Band model emission that is seen in the sub-MeV energy range. This power-law component appears to extrapolate from the GeV range to the lowest energies and is more intense than the Band component both below $\sim$ 50 keV and above 100 MeV. The Band component undergoes substantial spectral evolution over the entire course of the burst, while the photon index of the power-law component remains constant for most of the prompt phase, then hardens significantly towards the end. After the prompt phase, power-law emission persists in the LAT data as late as 1 ks post-trigger, with its flux declining as $t^{-1.5}$. The LAT detected a photon with the highest energy so far measured from a GRB, $33.4_{-3.5}^{+2.7}$ GeV. This event arrived 82 seconds after the GBM trigger and $\sim$ 50 seconds after the prompt phase emission had ended in the GBM band. We discuss the implications of these results for models of GRB emission and for constraints on models of the Extragalactic Background Light.
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Postnov, K. A. 2009 双中子星并合产生的磁场和光度

主要内容:


精彩摘抄:


文章信息:

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Title:
Magnetic fileds of coalescing neutron stars and the luminosity funciton of short gamma-ray bursts
Authors:
Postnov, K. A.; Kuranov, A. G.
Publication:
eprint arXiv:0909.2502
Publication Date:
09/2009
Origin:
ARXIV
Keywords:
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:
LATEX, 25 pages, inc. 7 ps figures, Astron. Lett., in press
Bibliographic Code:
2009arXiv0909.2502P

Abstract

Coalescing neutron star binaries are believed to be the most reliable sources for ground-based detectors of gravitational waves and likely progenitors of short gamma-ray bursts. In the process of coalescence, magnetic fields of neutron stars can induce interesting observational manifestations and affect the form of gravitational wave signal. In this papaer we use the population synthesis method to model the expected distribution of neutron star magnetic fields during the coalescence under different assumptions on the initial parameters of neutron stars and their magnetic field evolution. We discuss possible elecotrmagnetic phenomena preceding the coalescence of magnetized neutron star binaries and the effect of magnetic field on the gravitational wave signal. We find that a log-normal (Gaussian in logarithms) distribution of the initial magnetic fields of neutron stars, which agrees with observed properties of radio pulsars, produces the distribution of the magnetic field energy during the coalescence that adequately describes the observed luminosity function of short gamma-ray bursts under different assumptions on the field evolution and initial parameters of neutron stars. This agreement lends further support to the model of coalescing neutron star binaries as progenitors of gamma-ray bursts.
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van Eerten, H. J. 2009 中等相对论余辉的数值模拟

主要内容:
速度是Huang 1999的3/4.

精彩摘抄:


文章信息:

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Title:
Gamma-ray burst afterglows from trans-relativistic blast wave simulations
Authors:
van Eerten, H. J.; Leventis, K.; Meliani, Z.; Wijers, R. A. M. J.; Keppens, R.
Publication:
eprint arXiv:0909.2446
Publication Date:
09/2009
Origin:
ARXIV
Keywords:
Astrophysics - High Energy Astrophysical Phenomena
Comment:
18 pages, 19 figures
Bibliographic Code:
2009arXiv0909.2446V

Abstract

We present a study of the intermediate regime between ultra-relativistic and nonrelativistic flow for gamma-ray burst afterglows. The hydrodynamics of spherically symmetric blast waves is numerically calculated using the AMRVAC adaptive mesh refinement code. Spectra and light curves are calculated using a separate radiation code that, for the first time, links a parametrisation of the microphysics of shock acceleration, synchrotron self-absorption and electron cooling to a high-performance hydrodynamics simulation. For the dynamics we find that the transition to the nonrelativistic regime generally occurs later than expected, that the Sedov-Taylor solution overpredicts the late time blast wave radius and that the analytical formula for the blast wave velocity from Huang (1999) overpredicts the late time velocity by a factor 4/3. For the radiation we find that the flux may differ up to an order of magnitude depending on the equation of state that is used for the fluid and that the counterjet leads to a clear rebrightening at late times for hard-edged jets. Simulating GRB030329 using predictions for its physical parameters from the literature leads to spectra and light curves that may differ significantly from the actual data, emphasizing the need for very accurate modelling. Predicted light curves at low radio frequencies for a hard-edged jet model of GRB030329 with opening angle 22 degrees show typically two distinct peaks, due to the combined effect of jet break, non relativistic break and counterjet.
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