Piran 2014 r过程导致GRB 130603B的推论

主要内容:
如果是大原子量的原子放射性衰变作为GRB 130603B的余辉辐射的话，那么原子量大于130的那些放射性元素可能主要就是这个过程产生的。

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Title:		Implications of GRB 130603B and its macronova for r-process nucleosynthesis
Authors:		Piran, Tsvi; Korobkin, Oleg; Rosswog, Stephan
Publication:		eprint arXiv:1401.2166
Publication Date:		01/2014
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, General Relativity and Quantum Cosmology, Nuclear Theory
Bibliographic Code:		2014arXiv1401.2166P

Abstract

The tentative identification of a Li-Paczynski macronova following the short GRB 130603B indicated that a few hundredths of a solar mass of neutron star matter were ejected and that this ejected mass has radioactively decayed into heavy r-process elements. If correct, this confirms long standing predictions (Eichler, Livio, Piran and Schramm 1989) that on the one hand, sGRBs are produced in compact binary mergers (CBMs) and on the other hand that these events are significant and possibly dominant sources of the heavy (A>130) r-process nuclei. Assuming that this interpretation is correct we obtain a lower limit of 0.02 m_sun on the ejected mass. Using the current estimates of the rate of sGRBs and with a beaming factor of 50, mergers associated with sGRBs can produce all the observed heavy r-process material in the Universe. We confront this conclusion with cosmochemistry and show that even though such events are rare, mixing is sufficient to account for the current homogeneous distribution of r-process material in the Galaxy. However, the appearance of significant amounts of Eu in some very low metallicity stars requires that some mergers took place very early on, namely with a very short time delay after the earliest star formation episodes. Alternatively, an additional early r-processsource may have contributed at that early stage. Finally, we note that evidence for short lived {244}^Pu in the very early solar system suggests that a merger of this kind took place within the vicinity of the solar system shortly (a few hundred million years) before its formation.

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Uhm 2014 在有密度跳变的时候的余辉动力学-又一篇基础动力学的文章

主要内容:
跳变可以是突然变密或者变稀。
在这些复杂的环境中，反向激波响应的变化更大，可以解释flares，dips，shallow decay等。

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Title:		Dynamics and Afterglow Light Curves of GRB Blast Waves Encountering a Density Bump or Void
Authors:		Uhm, Z. Lucas; Zhang, Bing
Publication:		eprint arXiv:1401.6758
Publication Date:		01/2014
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		32 pages, 17 figures, submitted to ApJ
Bibliographic Code:		2014arXiv1401.6758U

Abstract

We investigate the dynamics and afterglow light curves of gamma-ray burst (GRB) blast waves that encounter various density structures (such as bumps, voids, or steps) in the surrounding ambient medium. We present and explain the characteristic response features that each type of density structures in the medium leaves on the forward shock (FS) and reverse shock (RS) dynamics, for blast waves with either a long-lived or short-lived RS wave. We show that, when the ambient medium density drops, the blast waves exhibit in some cases a period of an actual acceleration (even during their deceleration stage), due to adiabatic cooling of blast waves. Comparing numerical examples that have different shapes of bumps or voids, we propose a number of consistency tests that correct modeling of blast waves needs to satisfy. Our model results successfully pass these tests. Employing a Lagrangian description of blast waves, we perform a sophisticated calculation of afterglow emission. We show that, as a response to density structures in the ambient medium, the RS light curves produce more significant variations than the FS light curves. Some observed features (such as re-brightenings, dips, or slow wiggles) can be more easily explained within the RS model. We also discuss on the origin of these different features imprinted on the FS and RS light curves.

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Liu 2014 GRB 131231A的高能辐射

主要内容:
可能来自外激波的同步自康普顿。

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Title:		GRB 131231A: Implications of the hard GeV emission
Authors:		Liu, Bin; Chen, Wei; Liang, Yun-Feng; Zhou, Bei; He, Hao-Ning; Tam, Pak-Hin Thomas; Shao, Lang; Jin, Zhi-Ping; Fan, Yi-Zhong;Wei, Da-Ming
Publication:		eprint arXiv:1401.7283
Publication Date:		01/2014
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		5 pages,4 figures
Bibliographic Code:		2014arXiv1401.7283L

Abstract

GRB 131231A was detected by the Large Area Telescope onboard Fermi Space Gamma-ray Telescope. The high energy gamma-ray ($> 100$ MeV) afterglow emission spectrum is as hard as $F_\nu \propto \nu^{-0.50\pm0.13}$ in the first $\sim 1300$ s after the trigger, and the most energetic photon has an energy $\sim 62$ GeV. Such a hard spectrum is at odds with the model of synchrotron radiation of the external forward shock. Instead, both its spectrum and temporal behavior are found to be consistent with the synchrotron self-Compton radiation of the forward shock-accelerated electrons. We show that the prospect for detecting GRB 131231A-like GRBs with Cherenkov Telescope Array (CTA) is quite promising, and with an exposure time of $\sim 0.5$ hour, the $25$ GeV, $40$ GeV, and $100$ GeV gamma-ray emission of such GRBs could be detected within $1$ hour, $4$ hours, and $12$ hours after the burst, respectively.

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Mizuno 2014 相对论性激波中的磁场放大--MHD模拟

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Title:		Magnetic Field Amplification and Saturation in Turbulence Behind a Relativistic Shock
Authors:		Mizuno, Yosuke; Pohl, Martin; Niemiec, Jacek; Zhang, Bing; Nishikawa, Ken-Ichi; Hardee, Philip E.
Publication:		eprint arXiv:1401.7080
Publication Date:		01/2014
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, General Relativity and Quantum Cosmology
Comment:		14 pages, 15 figures, accepted for publication in MNRAS
Bibliographic Code:		2014arXiv1401.7080M

Abstract

We have investigated via two-dimensional relativistic MHD simulations the long-term evolution of turbulence created by a relativistic shock propagating through an inhomogeneous medium. In the postshock region, magnetic field is strongly amplified by turbulent motions triggered by preshock density inhomogeneities. Using a long-simulation box we have followed the magnetic-field amplification until it is fully developed and saturated. The turbulent velocity is sub-relativistic even for a strong shock. Magnetic-field amplification is controled by the turbulent motion and saturation occurs when the magnetic energy is comparable to the turbulent kinetic energy. Magnetic-field amplification and saturation depend on the initial strength and direction of the magnetic field in the preshock medium, and on the shock strength. If the initial magnetic field is perpendicular to the shock normal, the magnetic field is first compressed at the shock and then can be amplified by turbulent motion in the postshock region. Saturation occurs when the magnetic energy becomes comparable to the turbulent kinetic energy in the postshock region. If the initial magnetic field in the preshock medium is strong, the postshock region becomes turbulent but significant field amplification does not occur. If the magnetic energy after shock compression is larger than the turbulent kinetic energy in the postshock region, significant field amplification does not occur. We discuss possible applications of our results to gamma-ray bursts and active galactic nuclei.

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Boylan 2014 短暴的offset

主要内容:
说矮星系不太可能是宿主信息（也就是说找不到宿主信息的还是来自于kick）

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Title:		Short gamma ray bursts: formation and offsets
Authors:		Boylan, C.; Li, Y.; Fan, X. L.; Heng, I. S.
Publication:		eprint arXiv:1401.7851
Publication Date:		01/2014
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		undergrad project, 7 pages, 3 figures, MNRAS style
Bibliographic Code:		2014arXiv1401.7851B

Abstract

Short gamma ray bursts have been observed a variety of galaxies types with varying angular offsets from the centre of their host galaxies. To investigate the properties of short gamma ray burst offsets, a sample of short gamma ray bursts with host galaxies has been gathered. Two formation channels proposed to explain the observed offsets of short gamma ray bursts from their host galaxies are discussed. The classification of short gamma ray bursts into these formation channels is demonstrated for short gamma ray bursts with host galaxies. The possibility of faint dwarf galaxies as host environments for the observed short gamma ray bursts is also investigated. However, by extrapolating the distribution of dwarf galaxies around the Milky Way to redshifts corresponding to the short gamma ray bursts, we show that it is unlikely that dwarf galaxies are the hosts of short gamma ray bursts.

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Behroozi 2014 短暴的kick

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Title:		Reinterpreting Short Gamma Ray Burst Progenitor Kicks and Time Delays Using the Host Galaxy-Dark Matter Halo Connection
Authors:		Behroozi, Peter S.; Ramirez-Ruiz, Enrico; Fryer, Christopher L.
Publication:		eprint arXiv:1401.7986
Publication Date:		01/2014
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		18 pages, ApJ submitted
Bibliographic Code:		2014arXiv1401.7986B

Abstract

Nearly 20% of short gamma-ray bursts (sGRBs) have no observed host galaxies. Combining this finding with constraints on galaxies' dark matter halo potential wells gives strong limits on the natal kick velocity distribution for sGRB progenitors. For the best-fitting velocity distribution, one in five sGRB progenitors receives a natal kick above 150 km/s, consistent with merging neutron star models but not with merging white dwarf binary models. This progenitor model constraint is robust to a wide variety of systematic uncertainties, including the sGRB progenitor time-delay model, the Swift redshift sensitivity, and the shape of the natal kick velocity distribution. We also use constraints on the galaxy-halo connection to determine the host halo and host galaxy demographics for sGRBs, which match extremely well with available data. Most sGRBs are expected to occur in halos near 10^12 Msun and in galaxies near 5 x 10^10 Msun (~L_*); unobserved faint and high-redshift host galaxies contribute a small minority of the observed hostless sGRB fraction. We find that sGRB redshift distributions and host galaxy stellar masses weakly constrain the progenitor time-delay model; the active vs. passive fraction of sGRB host galaxies may offer a stronger constraint. Finally, we discuss how searches for gravitational wave optical counterparts in the local Universe can reduce followup times using these findings.

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Eichler 2014 解决光球层热辐射的效率太低的问题

主要内容:
说如果在内部的热辐射往外走的时候，是基本不会被外层的shell挡住的，因为当光子追上外层的shell的时候，是在很远的地方，已经光学薄了。

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下面是示意图：

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Title:		Cloaked Gamma Ray Bursts
Authors:		Eichler, David
Publication:		eprint arXiv:1402.0245
Publication Date:		02/2014
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		accepted for publication in the Astrophysical Journal
Bibliographic Code:		2014arXiv1402.0245E

Abstract

It is suggested that many $\gamma$-ray bursts (GRBs) are cloaked by an ultra-relativistic baryonic shell that has high optical depth when the photons are manufactured. Such a shell would not fully block photons reflected or emitted from its inner surface, because the radial velocity of the photons can be less than that of the shell. This avoids the standard problem associated with GRBs that the thermal component should be produced where the flow is still obscured by high optical depth. The radiation that escapes high optical depth obeys the Amati relation. Observational implications may include a) anomalously high ratios of afterglow to prompt emission, such as may have been the case in the recently discovered PTF 11agg, and b) ultrahigh-energy neutrino pulses that are non-coincident with detectable GRB. It is suggested that GRB 090510, a short, very hard GRB with very little afterglow, was an {\it exposed} GRB, in contrast to those cloaked by baryonic shells. \end{abstract}

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Tunnicliffe 2014 无宿主星系的短暴

主要内容:
认为有一部分是双致密星被kick到星系外边去了。

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Title:		On the nature of the `hostless' short GRBs
Authors:		Tunnicliffe, R. L.; Levan, A. J.; Tanvir, N. R.; Rowlinson, A.; Perley, D. A.; Bloom, J. S.; Cenko, S. B.; O'Brien, P. T.;Cobb, B. E.; Wiersema, K.; Malesani, D.; de Ugarte Postigo, A.; Hjorth, J.; Fynbo, J. P. U.; Jakobsson, P.
Affiliation:		AA(Department of Physics, University of Warwick, Coventry CV4 7AL, UK; R.L.Tunnicliffe@warwick.ac.uk), AB(Department of Physics, University of Warwick, Coventry CV4 7AL, UK), AC(Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK), AD(Astronomical Institute, University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam, the Netherlands), AE(Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA), AF(Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA), AG(Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA), AH(Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK), AI(Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA), AJ(Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK), AK(Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark), AL(Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark), AM(Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark), AN(Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark), AO(Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhaga 5, IS-107 Reykjavik, Iceland)
Publication:		Monthly Notices of the Royal Astronomical Society, Volume 437, Issue 2, p.1495-1510 (MNRAS Homepage)
Publication Date:		01/2014
Origin:		OUP
Astronomy Keywords:		techniques: photometric, gamma-ray burst: individual: 090305A, gamma-ray burst: individual: 091109B, gamma-ray burst: individual: 110112A, gamma-ray burst: individual: 111020A, stars: neutron
Abstract Copyright:		2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
DOI:		10.1093/mnras/stt1975
Bibliographic Code:		2014MNRAS.437.1495T

Abstract

A significant proportion (˜30 per cent) of the short-duration gamma-ray bursts (SGRBs) localized by Swift have no detected host galaxy coincident with the burst location to deep limits, and also no high-likelihood association with proximate galaxies on the sky. These SGRBs may represent a population at moderately high redshifts (z ≳ 1), for which the hosts are faint, or a population where the progenitor has been kicked far from its host or is sited in an outlying globular cluster. We consider the afterglow and host observations of three `hostless' bursts (GRBs 090305A, 091109B and 111020A), coupled with a new observational diagnostic to aid the association of SGRBs with putative host galaxies to investigate this issue. Considering the well localized SGRB sample, 7/25 SGRBs can be classified as `hostless' by our diagnostic. Statistically, however, the proximity of these seven SGRBs to nearby galaxies is higher than is seen for random positions on the sky. This suggests that the majority of `hostless' SGRBs have likely been kicked from proximate galaxies at moderate redshift. Though this result still suggests only a small proportion of SGRBs will be within the Advanced Laser Interferometer Gravitational Wave Observatory horizon for neutron star-neutron star (NS) or neutron star-black hole (BH) inspiral detection (z ˜ 0.1), in the particular case of GRB 111020A a plausible host candidate is at z = 0.02.

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2013之重要事件

（仅包括我关心的）
1. GRB 130427A

2. GRB 130603B

3. FRB

4. AMS2公布初步数据了

5. IceCube的两个高能中微子

2014一开始就热闹啦

SN 2014J是距离地球第二近的超新星，除了1987A。是Ia型超新星中最近的，南极（貌似还放在国内试用着的？）望远镜又看到了“precursor”。看样子要被好好研究一番的。