Gao 2011 暴本身光变里发现两成分信号

主要内容:
他们利用SFC方法，而不是功率密度谱的方法，得到如果SFC方法应用后有一个谷意味着存在双成分（一个快的，一个慢的）信号，然后他们发现在选的266个BATSE暴中有93个暴有。

这个可以想想中间的原因。

难道就是那个看到的大的整体光变叠加一些小的毛刺？

精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1103.0074)

· References in the Article

·

· Translate This Page

Title:		Evidence Of Superposed Variability Components In GRB Prompt Emission Lightcurves
Authors:		Gao, He; Zhang, Binbin; Zhang, Bing
Publication:		eprint arXiv:1103.0074
Publication Date:		02/2011
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		12 pages, 5 figures, 1 table
Bibliographic Code:		2011arXiv1103.0074G

Abstract

Gamma-ray bursts (GRBs) have variable lightcurves. Although most models attribute the observed variability to one physical origin (e.g. central engine activity, clumpy circumburst medium, relativistic turbulence), some models invoke two physically distinct variability components. We develop a method, namely, the stepwise filter correlation (SFC) method, to decompose the variability components in a GRB lightcurve. Based on a low-pass filter technique, we progressively filter the high frequency signals from the lightcurve, and then perform a correlation analysis between each adjunct pair of filtered lightcurves. Our simulations suggest that if a mock lightcurve contains a "slow" variability component superposed on a rapidly varying time sequence, the correlation coefficient as a function of the filter frequency would display a prominent "dip" feature around the frequency of the slow component. Through simulations, we prove that this method is robust to catch the superposition signals that are otherwise not easy to retrieve based on other methods (e.g. the power density spectrum analysis method). We apply this new method to 266 BATSE bright GRBs. We find that 93 bursts have clear evidence of such a superposition effect. We perform a statistical analysis of the identied variability components, and discuss the physical implications for GRB physics.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Vieregg 2011 对GRB090107A超高能中微子的限制

主要内容:


精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1102.3206)

· References in the Article

·

· Translate This Page

Title:		The First Limits on the Ultra-high Energy Neutrino Fluence from Gamma-ray Bursts
Authors:		Vieregg, A. G.; Palladino, K.; Allison, P.; Baughman, B. M.; Beatty, J. J.; Belov, K.; Besson, D. Z.; Bevan, S.;Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Detrixhe, M.; De Marco, D.; Dowkontt, P. F.;DuVernois, M.; Gorham, P. W.; Grashorn, E. W.; Hill, B.; Hoover, S.; Huang, M.; Israel, M. H.; Javaid, A.;Liewer, K. M.; Matsuno, S.; Mercurio, B. C.; Miki, C.; Mottram, M.; Nam, J.; Nichol, R. J.; Romero-Wolf, A.;Ruckman, L.; Saltzberg, D.; Seckel, D.; Varner, G. S.; Wang, Y.
Publication:		eprint arXiv:1102.3206
Publication Date:		02/2011
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		4 pages, 2 figures, submitted to ApJ
Bibliographic Code:		2011arXiv1102.3206V

Abstract

We set the first limits on the ultra-high energy (UHE) neutrino fluence at energies greater than 10^9 GeV from gamma-ray bursts (GRBs) based on data from the second flight of the ANtarctic Impulsive Transient Antenna (ANITA). During the 31 day flight of ANITA-II, 26 GRBs were recorded by Swift or Fermi. Of these, we analyzed the 12 GRBs which occurred during quiet periods when the payload was away from anthropogenic activity. In a blind analysis, we observe 0 events on a total background of 0.0044 events in the combined prompt window for all 12 low-background bursts. We also observe 0 events from the remaining 14 bursts. We place a 90% confidence level limit on the E^-4 prompt neutrino fluence of 2.5x10^17 GeV^3/cm^2 between 10^8 and 10^12 GeV from GRB090107A. This is the first reported limit on the UHE neutrino fluence from GRBs above 10^9 GeV, and the strongest limit above 10^8 GeV.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

van Eerten 2011 提供各种各样的光变曲线

主要内容:
根据不同的参数，用的方法是：High-Resolution Hydrodynamical Jet Simulations

http://cosmo.nyu.edu/afterglowlibrary/

精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1102.2863)

· References in the Article

·

· Translate This Page

Title:		An on-line library of afterglow light curves
Authors:		van Eerten, H. J.; MacFadyen, A. I.; Zhang, W.
Publication:		eprint arXiv:1102.2863
Publication Date:		02/2011
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		4 pages, 2 figures. Second of two contributions to proceedings GRB2010 Maryland conference. Editors: McEnery, Racusin and Gehrels. The data from this paper is publicly available from http://cosmo.nyu.edu/afterglowlibrary/
Bibliographic Code:		2011arXiv1102.2863V

Abstract

Numerical studies of gamma-ray burst afterglow jets reveal significant qualitative differences with simplified analytical models. We present an on-line library of synthetic afterglow light curves and broadband spectra for use in interpreting observational data. Light curves have been calculated for various physics settings such as explosion energy and circumburst structure, as well as differing jet parameters and observer angle and redshift. Calculations gave been done for observer frequencies ranging from low radio to X-ray and for observer times from hours to decades after the burst. The light curves have been calculated from high-resolution 2D hydrodynamical simulations performed with the RAM adaptive-mesh refinement code and a detailed synchrotron radiation code. The library will contain both generic afterglow simulations as well as specific case studies and will be freely accessible at http://cosmo.nyu.edu/afterglowlibrary . The synthetic light curves can be used as a check on the accuracy of physical parameters derived from analytical model fits to afterglow data, to quantitatively explore the consequences of varying parameters such as observer angle and for accurate predictions of future telescope data.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Bissaldi 2011 GBM亮暴的谱

主要内容:
从253个中选了52个（34长，18短），GBM甚至比BATSE都包含更多的短暴。确认了短暴比长暴更硬。

精彩摘抄:

居然有这样一个统计关系！估计没什么意义，就是时间越长，流量越大，意思就是观测到的基本上所有的暴都大致上每秒钟得到差不多的能量（这个是这样的吗？）。如果每个暴的流量密度都差不多这个说法是粗糙，但是统计关系还“不错“，说明其他看起来还不错的统计关系实际上也没什么意义。

文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1101.3325)

· References in the Article

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		First-year Results of Broadband Spectroscopy of the Brightest Fermi-GBM Gamma-Ray Bursts
Authors:		Bissaldi, Elisabetta; von Kienlin, Andreas; Kouveliotou, Chryssa; Briggs, Michael S.; Connaughton, Valerie;Greiner, Jochen; Gruber, David; Lichti, Giselher; Bhat, P. N.; Burgess, J. Michael; Chaplin, Vandiver; Diehl, Roland;Fishman, Gerald J.; Fitzpatrick, Gerard; Foley, Suzanne; Gibby, Melissa; Giles, Misty; Goldstein, Adam;Guiriec, Sylvain; van der Horst, Alexander J.; Kippen, Marc; Lin, Lin; McBreen, Sheila; Meegan, Charles A.;Paciesas, William S.; Preece, Robert D.; Rau, Arne; Tierney, Dave; Wilson-Hodge, Colleen
Publication:		eprint arXiv:1101.3325
Publication Date:		01/2011
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		40 pages, 11 figures, 3 tables, Submitted to ApJ
Bibliographic Code:		2011arXiv1101.3325B

Abstract

We present here our results of the temporal and spectral analysis of a sample of 52 bright and hard gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM) during its first year of operation (July 2008-July 2009). Our sample was selected from a total of 253 GBM GRBs based on each event peak count rate measured between 0.2 and 40MeV. The final sample comprised 34 long and 18 short GRBs. These numbers show that the GBM sample contains a much larger fraction of short GRBs, than the CGRO/BATSE data set, which we explain as the result of our (different) selection criteria and the improved GBM trigger algorithms, which favor collection of short, bright GRBs over BATSE. A first by-product of our selection methodology is the determination of a detection threshold from the GBM data alone, above which GRBs most likely will be detected in the MeV/GeV range with the Large Area Telescope (LAT) onboard Fermi. This predictor will be very useful for future multiwavelength GRB follow ups with ground and space based observatories. Further we have estimated the burst durations up to 10MeV and for the first time expanded the duration-energy relationship in the GRB light curves to high energies. We confirm that GRB durations decline with energy as a power law with index approximately -0.4, as was found earlier with the BATSE data and we also notice evidence of a possible cutoff or break at higher energies. Finally, we performed time-integrated spectral analysis of all 52 bursts and compared their spectral parameters with those obtained with the larger data sample of the BATSE data. We find that the two parameter data sets are similar and confirm that short GRBs are in general harder than longer ones.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Bromberg 2011 光球层内的辐射中介激波的辐射

主要内容:
应该算是内激波的一种补充形式。在光球层处，利用光子作为中介进行无碰撞加速，可以得到幂律的形式的谱，直到KN极限。之后应该是指数下降，如果这样的话，就应该可以解释多数的GBM暴了。

精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1101.4232)

· References in the Article

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		Sub-Photospheric Emission from Relativistic Radiation Mediated Shocks in GRBs
Authors:		Bromberg, Omer; Mikolitzky, Ziv; Levinson, Amir
Publication:		eprint arXiv:1101.4232
Publication Date:		01/2011
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		27 pages, 5 figures
Bibliographic Code:		2011arXiv1101.4232B

Abstract

It is proposed that the prompt emission observed in bursts that exhibit a thermal component originates from relativistic radiation mediated shocks that form below the photosphere of the GRB outflow. It is argue that such shocks are expected to form in luminous bursts via collisions of shells that propagate with moderate Lorentz factors $\Gamma\lesssim 500$. Faster shells will collide above the photosphere to form collisionless shocks. We demonstrate that in events like GRB 090902B a substantial fraction of the explosion energy is dissipated below the photosphere, in a region of moderate optical depth $\tau\lesssim300$, whereas in GRB 080916C the major fraction of the energy dissipates above the photosphere. We show that under conditions anticipated in many GRBs, such relativistic radiation mediated shocks convect enough radiation upstream to render photon production in the shock transition negligible, unlike the case of shock breakout in supernovae. The resulting spectrum, as measured in the shock frame, has a relatively low thermal peak, followed by a broad, nonthermal component extending up to the KN limit.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Nakar 2010 双致密星并合后的射电遗迹几乎一定存在

主要内容:


精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1102.1020)

· References in the Article

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		Radio Remnants of Compact Binary Mergers - the Electromagnetic Signal that will follow the Gravitational Waves
Authors:		Nakar, Ehud; Piran, Tsvi
Publication:		eprint arXiv:1102.1020
Publication Date:		02/2011
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, General Relativity and Quantum Cosmology
Bibliographic Code:		2011arXiv1102.1020N

Abstract

The question "what is the observable electromagnetic (EM) signature of a compact binary merger?" is an intriguing one with crucial consequences to the quest for gravitational waves (GW). Compact binary mergers are prime sources of GW, targeted by current and next generation detectors. Numerical simulations have demonstrated that these mergers eject energetic sub-relativistic (or even relativistic) outflows. This is certainly the case if the mergers produce short GRBs, but even if not, significant outflows are expected. The interaction of such outflows with the surround matter inevitably leads to a long lasting radio signal. We calculate the expected signal from these outflows (our calculations are also applicable to short GRB orphan afterglows) and we discuss their detectability. We show that the optimal search for such signal should, conveniently, take place around 1.4 GHz. Realistic estimates of the outflow parameters yield signals of a few hundred $\mu$Jy, lasting a few weeks, from sources at the detection horizon of advanced GW detectors. Followup radio observations, triggered by GW detection, could reveal the radio remnant even under unfavorable conditions. Upcoming all sky surveys can detect a few dozen, and possibly even thousands, merger remnants at any give time, thereby providing robust merger rate estimates even before the advanced GW detectors become operational. In fact, the radio transient RT 19870422 fits well the overall properties predicted by our model and we suggest that its most probable origin is a compact binary merger radio remnant.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Granot 2010 伽马暴的喷流

主要内容:
书的一章。

精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1012.5101)

· References in the Article

· Citations to the Article (1) (Citation History)

· Refereed Citations to the Article

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		Jets and Gamma-Ray Burst Unification Schemes
Authors:		Granot, Jonathan; Ramirez-Ruiz, Enrico
Publication:		eprint arXiv:1012.5101
Publication Date:		12/2010
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		46 pages, 12 figures; book chapter, to appear in "Gamma-ray Bursts" (CUP)
Bibliographic Code:		2010arXiv1012.5101G

Abstract

There are several lines of evidence indicating that the ultra-relativistic outflows powering gamma-ray bursts (GRBs) are collimated into narrow jets. However, these are indirect, and the jet structure is rather poorly constrained. What is more, the jet dynamics have still not been investigated in detail. It has been suggested that the observed variety between different long duration events, ranging from bright spectrally hard GRBs, to dimmer and spectrally softer X-ray flashes (XRFs) may be largely due to different viewing angles (or lines of sight) relative to rather similar relativistic jets. Here we describe the current state of knowledge on these topics, explain some of the most relevant physics behind some of the basic principles, and discuss prospects for the future.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Harry 2010 一种相干的引力波探测方法

主要内容:


精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1012.4939)

· References in the Article

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		A targeted coherent search for gravitational waves from compact binary coalescences
Authors:		Harry, Ian; Fairhurst, Stephen
Publication:		eprint arXiv:1012.4939
Publication Date:		12/2010
Origin:		ARXIV
Keywords:		General Relativity and Quantum Cosmology, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		21 pages, 14 figures
Bibliographic Code:		2010arXiv1012.4939H

Abstract

We present the details of a method for conducting a targeted, coherent search for compact binary coalescences. The search is tailored to be used as a followup to electromagnetic transients such as Gamma Ray Bursts. We derive the coherent search statistic for Gaussian detector noise and discuss the benefits of a coherent, multi-detector search over coincidence methods. To mitigate the effects of non-stationary data, we introduce a number of signal consistency tests, including the null SNR, amplitude consistency and several $\chi^{2}$ tests. We demonstrate the search performance on Gaussian noise and on data from LIGO's fourth science run and verify that the signal consistency tests are capable of removing the majority of noise transients and the search gives an efficiency comparable to that achieved in Gaussian noise.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Fong 2010 短暴 GRB 100117A的光学余辉和宿主星系

主要内容:


精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1012.4009)

· References in the Article

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		The Optical Afterglow and z=0.92 Early-type Host Galaxy of the Short GRB 100117A
Authors:		Fong, Wen-fai; Berger, Edo; Chornock, Ryan; Tanvir, Nial R.; Levan, Andrew J.; Graham, John F.; Fruchter, Andrew S.;Cucchiara, Antonino; Fox, Derek B.
Publication:		eprint arXiv:1012.4009
Publication Date:		12/2010
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		Submitted to ApJ; emulateapj style; 15 pages, 1 table, 9 figures
Bibliographic Code:		2010arXiv1012.4009F

Abstract

We present the discovery of the optical afterglow and early-type host galaxy of the short-duration GRB 100117A. The faint afterglow is detected 8.3 hr after the burst with r_AB = 25.46 +/- 0.20 mag. Follow-up optical and near-IR observations uncover a coincident compact red galaxy, identified as an early-type galaxy at a photometric redshift of z~0.6-0.9 (2-sigma) with a mass of 3x10^10 M_Sun, an age of ~1 Gyr, and a luminosity of L_B~0.5L_star. Spectroscopic observations of the host reveal a notable break corresponding to the Balmer 4000-Angstrom break at z~0.9, and stellar population spectral evolution template fits indicate z~0.915, which we adopt as the redshift of the host, with stellar population ages of ~1-3 Gyr. From a possible weak detection of [OII]-3727 emission at z=0.915 we infer an upper bound on the star formation rate of ~0.1 M_Sun per yr, leading to a specific star formation rate of <0.004 per Gyr. Thus, GRB 100117A is only the second short burst to date with a secure early-type host (the other being GRB 050724 at z=0.257) and it has one of the highest short GRB redshifts. The offset between the host center and the burst position, 470 +/- 310 pc, is the smallest to date. Combined with the old stellar population age, this indicates that the burst likely originated from a progenitor with no significant kick velocity. However, from the brightness of the optical afterglow we infer a relatively low density of n~3x10^-4 cm^-3 when epsilon_e and epsilon_B = 0.1. The combination of an optically faint afterglow and host suggest that previous such events may have been missed, thereby potentially biasing the known short GRB host population against z>1 early-type hosts.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Zhang 2010 电子在弯曲磁场中的同步曲率自康普顿辐射

主要内容:


精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:1012.3485)

· References in the Article

· Also-Read Articles (Reads History)

·

· Translate This Page

Title:		Synchro-Curvature Self-Compton Radiation of Electrons in Curved Magnetic Fields
Authors:		Zhang, Bo; Dai, Zi-Gao
Publication:		eprint arXiv:1012.3485
Publication Date:		12/2010
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		9 pages, 11 figures, accepted for publication in MNRAS
Bibliographic Code:		2010arXiv1012.3485Z

Abstract

In this paper we present the spectrum of synchro-curvature self-Compton (SCSC) radiation of relativistic electrons with a power-law distribution of Lorentz factors. We find that the resulting spectrum is significantly different from that of either synchrotron self-Compton or curvature self-Compton radiation if both the curvature radius of the magnetic field and the cyclotron radius of the electrons are within some proper ranges. The effects of electrons' cooling and drifting, the low-energy self absorption in seed spectra, and the Klein-Nishina cutoff are also discussed, in order to get an accurate picture. We take gamma-ray bursts (GRBs) as our example environment for discussions. The results would be considered as a universal approach of the self-Compton emission of relativistic electrons moving in curved magnetic fields, and thus could be applied to many astrophysical phenomena, including GRBs, active galactic nuclei (AGNs), and pulsars.

---

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)