Oates 2009 UVOT observations

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Title:		A statistical study of gamma-ray burst afterglows measured by the Swift Ultra-violet Optical Telescope
Authors:		Oates, S. R.; Page, M. J.; Schady, P.; de Pasquale, M.; Koch, T. S.; Breeveld, A. A.; Brown, P. J.; Chester, M. M.; Holland, S. T.; Hoversten, E. A.; Kuin, N. P. M.; Marshall, F. E.; Roming, P. W. A.; Still, M.; Vanden Berk, D. E.; Zane, S.; Nousek, J. A.
Publication:		eprint arXiv:0901.3597
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		16 pages, 9 figures, accepted MNRAS
Bibliographic Code:		2009arXiv0901.3597O

Abstract

We present the first statistical analysis of 27 UVOT optical/ultra-violet lightcurves of GRB afterglows. We have found, through analysis of the lightcurves in the observer's frame, that a significant fraction rise in the first 500s after the GRB trigger, that all lightcurves decay after 500s, typically as a power-law with a relatively narrow distribution of decay indices, and that the brightest optical afterglows tend to decay the quickest. We find that the rise could either be produced physically by the start of the forward shock, when the jet begins to plough into the external medium, or geometrically where an off-axis observer sees a rising lightcurve as an increasing amount of emission enters the observers line of sight, which occurs as the jet slows. We find that at 99.8% confidence, there is a correlation, in the observed frame, between the apparent magnitude of the lightcurves at 400s and the rate of decay after 500s. However, in the rest frame a Spearman Rank test shows only a weak correlation of low statistical significance between luminosity and decay rate. A correlation should be expected if the afterglows were produced by off-axis jets, suggesting that the jet is viewed from within the half-opening angle theta or within a core of uniform energy density theta_c. We also produced logarithmic luminosity distributions for three rest frame epochs. We find no evidence for bimodality in any of the distributions. Finally, we compare our sample of UVOT lightcurves with the XRT lightcurve canonical model. The range in decay indices seen in UVOT lightcurves at any epoch is most similar to the range in decay of the shallow decay segment of the XRT canonical model. However, in the XRT canonical model there is no indication of the rising behaviour observed in the UVOT lightcurves.

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Cannizzo 2009 External Accretion Disk for the 4 segment of the light curves

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Title:		A New Paradigm for Gamma Ray Bursts: Long Term Accretion Rate Modulation by an External Accretion Disk
Authors:		Cannizzo, J. K.; Gehrels, N.
Publication:		eprint arXiv:0901.3564
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		8 pages, 1 figure, submitted to the Astrophysical Journal: 22 January 2009
Bibliographic Code:		2009arXiv0901.3564C

Abstract

We present a new way of looking at the very long term evolution of GRBs in which the disk of material surrounding the putative black hole powering the GRB jet modulates the mass flow, and hence the efficacy of the process that extracts rotational energy from the black hole and inner accretion disk. The pre-Swift paradigm of achromatic, shallow-to-steep "breaks" in the long term GRB light curves has not been borne out by detailed Swift data amassed in the past several years. We argue that, given the initial existence of a fall-back disk near the progenitor, an unavoidable consequence will be the formation of an "external disk" whose outer edge continually moves to larger radii due to angular momentum transport and lack of a confining torque. The mass reservoir at large radii moves outward with time and gives a natural power law decay to the GRB light curves. In this model, the different canonical power law decay segments in the GRB identified by Zhang et al. and Nousek et al. represent different physical states of the accretion disk. We identify a physical disk state with each power law segment.

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van Putten 2009 Non-thermal transient sources from rotating black holes

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Title:		Non-thermal transient sources from rotating black holes
Authors:		van Putten, Maurice H. P. M.; Gupta, Alok C.
Publication:		eprint arXiv:0901.1674
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		Accepted by MNRAS
Bibliographic Code:		2009arXiv0901.1674V

Abstract

Rotating black holes can power the most extreme non-thermal transient sources. They have a long-duration viscous time-scale of spin-down and produce non-thermal emissions along their spin-axis, powered by a relativistic capillary effect. We report on the discovery of exponential decay in BATSE light curves of long GRBs by matched filtering, consistent with a viscous time-scale, and identify UHECRs energies about the GZK threshold in linear acceleration of ion contaminants along the black hole spin-axis, consistent with black hole masses and lifetimes of FR II AGN. We explain the absence of UHECRs from BL Lac objects due to UHECR emissions preferably at appreciable angles away from the black hole spin-axis. Black hole spin may be key to unification of GRBs and their host environments, and to AGN and their host galaxies. Our model points to long duration bursts in radio from long GRBs without supernovae and gravitational-waves from all long GRBs.

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Enoto 2009 SGR 0501+4516的一个爆发的观测

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Title:		Suzaku Observation of the New Soft Gamma Repeater SGR 0501+4516 in Outburst
Authors:		Enoto, T.; Nakagawa, Y. E.; Rea, N.; Esposito, P.; Gotz, D.; Hurley, K.; Israel, G. L.; Kokubun, M.; Makishima, K.; Mereghetti, S.; Murakami, H.; Nakazawa, K.; Sakamoto, T.; Stella, L.; Tiengo, A.; Turolla, R.; Yamada, S.; Yamaoka, K.; Yoshida, A.; Zane, S.
Publication:		eprint arXiv:0901.3453
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Comment:		4 pages, 4 figures, accepted for publication in ApJL
Bibliographic Code:		2009arXiv0901.3453E

Abstract

We present the first Suzaku observation of the new Soft Gamma Repeater SGR 0501+4516, performed on 2008 August 26, four days after the onset of bursting activity of this new member of the magnetar family. The soft X-ray persistent emission was detected with the X-ray Imaging Spectrometer (XIS) at a 0.5-10 keV flux of 3.8E-11 erg/s/cm2, with a spectrum well fitted by an absorbed blackbody plus power-law model. The source pulsation was confirmed at a period of 5.762072+/-0.000002 s, and 32 X-ray bursts were detected by the XIS, four of which were also detected at higher energies by the Hard X-ray Detector (HXD). The strongest burst, which occurred at 03:16:16.9 (UTC), was so bright that it caused instrumental saturation, but its precursor phase, lasting for about 200 ms, was detected successfully over the 0.5-200 keV range, with a fluence of ~2.1E-7 erg/cm2 and a peak intensity of about 89 Crab. The entire burst fluence is estimated to be ~50 times higher. The precursor spectrum was very hard, and well modeled by a combination of two blackbodies. We discuss the bursting activity and X/gamma-ray properties of this newly discovered Soft Gamma Repeater in comparison with other members of the class.

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Hakkila 2009 pulse的统计关系用做红移指示器

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Title:		Gamma-Ray Burst Pulse Correlations as Redshift Indicators
Authors:		Hakkila, Jon; Fragile, P. Chris; Giblin, Timothy W.
Publication:		eprint arXiv:0901.3174
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extra-Galactic Astrophysics
Comment:		3 pages and 6 figures, to appear in the proceedings of the Sixth Huntsville Gamma-Ray Burst Symposium, edited by C.A. Meegan, N. Gehrels, and C. Kouveliotou
Bibliographic Code:		2009arXiv0901.3174H

Abstract

Correlations among pulse properties in the prompt emission of long GRBs can potentially be used as cosmological distance indicators to estimate redshifts of GRBs to which these pulses belong. We demonstrate application of this technique to a sample of GRBs for which redshifts are not known. We also study the scatter of predicted redshifts of pulses found within individual bursts. We explore the characteristics of this scatter in hopes of identifying systematic corrections and/or pulse subsets that can be used to increase the technique's reliability.

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Hakkila 2009 Lag, Duration, Peak Luminosity, Hardness, and Asymmetry间的统计关系

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Title:		Correlations between Lag, Duration, Peak Luminosity, Hardness, and Asymmetry in Long GRB Pulses
Authors:		Hakkila, Jon; Cumbee, Renata S.
Publication:		eprint arXiv:0901.3171
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extra-Galactic Astrophysics
Comment:		6 pages, 10 figures, 2 tables, to appear in the proceedings of the Sixth Huntsville Gamma-Ray Burst Conference 2008, edited by C.A. Meegan, N. Gehrels, and C. Kouveliotou
Bibliographic Code:		2009arXiv0901.3171H

Abstract

Continued study of the BATSE catalog verifies previously-identified correlations between pulse lag and pulse duration and corresponding anti-correlations between both properties and pulse peak flux for a large sample of Long GRB pulses; the study also finds correlations between pulse peak lags, pulse asymmetry, and pulse hardness. These correlations apparently can be used to delineate Long GRBs from Short ones. Correlated pulse properties represent constraints that can be used to guide theoretical modeling, whereas bulk prompt emission properties appear to be constructed by combining and smearing out pulse characteristics in ways that potentially lose valuable information.

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Cardone 2009 伽玛暴哈勃图: 数据更新

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Title:		An updated Gamma Ray Bursts Hubble diagram
Authors:		Cardone, V. F.; Capozziello, S.; Dainotti, M. G.
Publication:		eprint arXiv:0901.3194
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - Cosmology and Extra-Galactic Astrophysics
Comment:		14 pages, 7 figures, 4 tables, submitted to MNRAS
Bibliographic Code:		2009arXiv0901.3194C

Abstract

Gamma ray bursts (GRBs) have recently attracted much attention as a possible way to extend the Hubble diagram to very high redshift. To this aim, the luminosity (or isotropic emitted energy) of a GRB at redshift z must be evaluated from a correlation with a distance independent quantity so that one can then solve for the luminosity distance D_L(z) and hence the distance modulus mu(z). Averaging over five different two parameters correlations and using a fiducial cosmological model to calibrate them, Schaefer (2007) has compiled a sample of 69 GRBs with measured mu(z) which has since then been widely used to constrain cosmological parameters. We update here that sample by many aspects. First, we add a recently found correlation for the X - ray afterglow and use a Bayesian inspired fitting method to calibrate the different GRBs correlations known insofar assuming a fiducial LCDM model in agreement with the recent WMAP5 data. Averaging over six correlations, we end with a new GRBs Hubble diagram comprising 83 objects. We also extensively explore the impact of varying the fiducial cosmological model considering how the estimated mu(z) change as a function of the $(\Omega_M, w_0, w_a)$ parameters of the Chevallier - Polarski - Linder phenomenological dark energy equation of state. In order to avoid the need of assuming an {\it a priori} cosmological model, we present a new calibration procedure based on a model independent local regression estimate of mu(z) using the Union SNeIa sample to calibrate the GRBs correlations. This finally gives us a GRBs Hubble diagram made out of 69 GRBs whose estimated distance modulus mu(z) is almost independent on the underlying cosmological model.

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Sironi 2009 PIC数值模拟相对论性的磁场激波加速

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Title:		Particle Acceleration in Relativistic Magnetized Collisionless Pair Shocks: Dependence of Shock Acceleration on Magnetic Obliquity
Authors:		Sironi, Lorenzo; Spitkovsky, Anatoly
Publication:		eprint arXiv:0901.2578
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		25 pages, 22 figures, submitted to ApJ, high-resolution version available at http://www.astro.princeton.edu/~lsironi/ShockAccel.pdf
Bibliographic Code:		2009arXiv0901.2578S

Abstract

We investigate shock structure and particle acceleration in relativistic magnetized collisionless pair shocks by means of 2.5D and 3D particle-in-cell simulations. We explore a range of inclination angles between the pre-shock magnetic field and the shock normal. We find that only magnetic inclinations corresponding to "subluminal" shocks, where relativistic particles following the magnetic field can escape ahead of the shock, lead to particle acceleration. The downstream spectrum in such shocks consists of a relativistic Maxwellian and a high-energy power-law tail with exponential cutoff. For increasing magnetic inclination in the subluminal range, the high-energy tail accounts for an increasing fraction of particles (from ~1% to ~2%) and energy (from ~4% to ~12%). The spectral index of the power law increases with angle from -2.8+-0.1 to -2.3+-0.1. Particle energization is driven by the Diffusive Shock Acceleration process for nearly parallel shocks, and switches to Shock-Drift Acceleration for larger subluminal inclinations. For "superluminal" shocks, the downstream particle spectrum does not show any significant suprathermal tail. As seen from the upstream frame, efficient acceleration in relativistic (Lorentz factor gamma0 > 5) magnetized (sigma > 0.03) flows exists only for a very small range of magnetic inclination angles (<> Bibtex entry for this abstract Preferred format for this abstract (see Preferences)

Wagner 2009 伽玛暴, AGN的高能时延限制量子引力小综述

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Title:		Exploring Quantum Gravity with Very-High-Energy Gamma-Ray Instruments - Prospects and Limitations
Authors:		Wagner, Robert
Publication:		eprint arXiv:0901.2932
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		11 pages, 4 figures, proceedings of "Science with the New Generation of High Energy Gamma-Ray Experiments", Euganean Spa Area, Padova: October 8-10, 2008
Bibliographic Code:		2009arXiv0901.2932W

Abstract

Some models for quantum gravity (QG) violate Lorentz invariance and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the dispersion from short-duration substructures observed in gamma-rays emitted by gamma-ray bursts (GRBs) at cosmological distances have provided interesting bounds on Lorentz invariance violation (LIV). Recent observations of unprecedentedly fast flares in the very-high energy gamma-ray emission of the active galactic nuclei (AGNs) Mkn 501 in 2005 and PKS 2155-304 in 2006 resulted in the most constraining limits on LIV from light-travel observations, approaching the Planck mass scale, at which QG effects are assumed to become important. I review the current status of LIV searches using GRBs and AGN flare events, and discuss limitations of light-travel time analyses and prospects for future instruments in the gamma-ray domain.

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Ukwatta 2009 高红移"镜像"伽玛暴的可能性

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应该是没有.

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Title:		Investigating the Possibility of Screening High-z GRBs based on BAT Prompt Emission Properties
Authors:		Ukwatta, T. N.; Sakamoto, T.; Dhuga, K. S.; Parke, W. C.; Barthelmy, S. D.; Gehrels, N.; Stamatikos, M.; Tueller, J.
Publication:		eprint arXiv:0901.2928
Publication Date:		01/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		3 pages; Submitted to Proceedings of Huntsville 2008 Symposium on GRBs
Bibliographic Code:		2009arXiv0901.2928U

Abstract

Being able to quickly select among gamma-ray bursts (GRBs) seen by the Swift satellite those which are high-z candidates would give ground-based observers a better chance to determine a redshift for such distant GRBs. Information about these high-z GRBs is important in helping to resolve questions about the early universe such as the formation rate of high-z GRBs, the re-ionization period of the universe, the metallicity of the early universe, and the Hubble expansion. Initially using a sample of 51 GRBs with previously measured redshifts, we have developed high-z screening criteria employing the GRB spectral as well as temporal characteristics of the prompt emission from the Burst Alert Telescope (BAT) on Swift. Now that the sample has increased to 81 GRBs, we have revisited the screening criteria and our methodology. Our updated high-z screening criteria are presented in this paper.

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Baring 2009 Fermi可以用来限定辐射机制

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Probes of Diffusive Shock Acceleration using Gamma-Ray Burst Prompt Emission

Authors: Matthew G. Baring

(Submitted on 16 Jan 2009)

Abstract: The principal paradigm for gamma-ray bursts (GRBs) suggests that the prompt transient gamma-ray signal arises from multiple shocks internal to the relativistic expansion. This paper explores how GRB prompt emission spectra can constrain electron (or ion) acceleration properties at the relativistic shocks that pertain to GRB models. The array of possible high-energy power-law indices in accelerated populations is highlighted, focusing on how spectra above 1 MeV can probe the field obliquity in GRB internal shocks, and the character of hydromagnetic turbulence in their environs. When encompassing the MeV-band spectral break, fits to BATSE/EGRET burst data indicate that the preponderance of electrons responsible for the prompt emission reside in an intrinsically non-thermal population. This differs markedly from typical populations generated in acceleration simulations; potential resolutions of this conflict such as the action of self-absorption are mentioned. Spectral modeling also suggests that the synchrotron mechanism is favored over synchrotron self-Compton scenarios due to the latter's typically broad curvature near the peak. Such diagnostics will be enhanced by the broadband spectral coverage of bursts by the Fermi Gamma-Ray Space Telescope; the GBM will provide key information on the lower energy portions of the non-thermal particle population, while the LAT will constrain the power-law regime of particle acceleration.

Comments:	6 pages, 1 embedded figure, to appear in Proc. of the 6th Huntsville Gamma-Ray Burst Symposium, eds. C. A. Meegan, N. Gehrels, and C. Kouveliotou (AIP Conf. Proc., New York)
Subjects:	High Energy Astrophysical Phenomena (astro-ph.HE)
Cite as:	arXiv:0901.2535v1 [astro-ph.HE]

黑洞作为暗物质

想了一下, 从原初的产生- 初始密度很高的时候产生一批黑洞, 有的立马蒸发了, 有的继续吸积. 这将导致一个马太效应, 从某个质量为界线, 更小的黑洞由于蒸发快而无法留下来, 而更大的会吸积更多物质而长得很大, 从而大于一个很长的蒸发寿命, 导致现在并没有看到原初黑洞的蒸发. 因为现在没看到并不是当初没有, 而是质量很大, 现在还没蒸发. (这对初始质量和密度等都有限制)

黑洞的质量限制- 总质量要满足比重子物质多约十来倍的样子.

黑洞的半径限制- 在满足质量限制之后, 还要求我们不能看到到处都是原初黑洞, 而是基本上看不到. 这就要求在本星系团(或者星系)中黑洞的柱密度(或者说"光深")n sigma L<<1.

上asd上查一下(标题以 dark matter black hole为关键词)果然不少. 总体上看, 早期有直接标题说用黑洞/或者原初黑洞 作为暗物质候选体的, 而后来有提作为暗物质的组成部分, 以及仅仅是和暗物质,黑洞相关. 这说明很有可能这个模型遇到了不可克服的困难, 以至于后来就没什么人提了.

比较早的有:
Inflation and primordial black holes as dark matter
从这个模型对暴涨本身提出一些限制.

Constraints on massive black holes as dark matter candidates using Galactic globular clusters
考虑大致量黑洞作为DM的可能性(不在我的考虑范围内)

CAN PRIMORDIAL BLACK HOLES BE A SIGNIFICANT PART OF DARK MATTER?
这篇文章直接问黑洞能不能做暗物质, 但结论确实否定的.
他们得到了质量的范围在10^15到10^21g之间.
貌似没有考虑黑洞形成之后的成长, 不过方法应该是值得借鉴的.

Dark matter and stable bound states of primordial black holes
从牛顿引力和经典量子力学出发, 研究的是想氢原子那样的bounded黑洞系统, 辐射引力波. 认为可能是暗物质的一部分. (不相关)

Black hole remnants and dark matter
修改霍金辐射的温度, 说可以存在在普朗克质量上的黑洞. (有点weird)

Primordial Black Holes as Dark Matter: The Power Spectrum and Evaporation of Early Structures
考虑大质量的原初黑洞. 质量可能小于10^4M_sun, 数量大约10^3个. (不过也是大质量的黑洞, 暂时不在考虑范围内, 如果原初黑洞正常情况下长不到这么大的话)

Little Black Holes as Dark Matter Candidates with Feasible Cosmic and Terrestrial Interactions
此文想用Little black holes (LBH)解释"一切", 包括暗能量, 暗物质, 双星, 恒星, 行星的部分现象.
居然59页, 在会议文集上, 2005年出来, 没有一个引用. (估计是个民科, 呵呵)

Spherical gravitational collapse of annihilating dark matter and the minimum mass of cold darkmatter black holes
企图限制作为暗物质的黑洞的最小质量: 最后说可能此模型不对!
方法貌似比较靠谱.

Primordial black holes as dark matter
这篇文章几乎就是和我想的一样的, 而且最新. (可惜AIP会议论文, 不能下)

Augusto 2009 和伽玛暴成协的一些GeV muon辐射

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此文介绍了两个事例. 说在4 sigma的置信度上是存在的

奇怪的是此人有好多篇关于与伽玛暴成协的muon文章, 但是要么只在astroph上出现, 要么只在prd上出现. 没有ApJ等的文章.
如在ads上搜索的结果: results of Augusto


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Title:		Search for the GeV counterparts of two gamma ray bursts: Swift 317662 and Fermi bn081017474
Authors:		Augusto, C. R. A.; Navia, C. E.; Robba, M. B.; Tsui, K. H.
Affiliation:		AA(Instituto de Física, Universidade Federal Fluminense, 24210-346, Niterói, RJ, Brazil), AB(Instituto de Física, Universidade Federal Fluminense, 24210-346, Niterói, RJ, Brazil), AC(Instituto de Física, Universidade Federal Fluminense, 24210-346, Niterói, RJ, Brazil), AD(Instituto de Física, Universidade Federal Fluminense, 24210-346, Niterói, RJ, Brazil)
Publication:		Physical Review D, vol. 78, Issue 12, id. 122001 (PhRvD Homepage)
Publication Date:		12/2008
Origin:		APS
Abstract Copyright:		(c) 2008: The American Physical Society
DOI:		10.1103/PhysRevD.78.122001
Bibliographic Code:		2008PhRvD..78l2001A

Abstract

We examine the possibility of the ground observation of the GeV counterparts of two gamma ray bursts, the Swift GRB-080723 (Trigger=317662) and the Fermi GRB081017474 (trigger=bn081017474). The data come from two small directional muon telescopes at sea level inside the South Atlantic Anomaly region. This characteristic offers the muon telescopes a low rigidity of response to primary and secondary charged particles (≥0.4GV). In both cases, the GRB trigger coordinates are within the effective field of view of the vertical Tupi muon telescopes. There is a ground level enhancement (GLE) on the muon counting rate background, with a statistical significance above 4σ, 38.22 minutes after the Swift trigger occurrence, and there are at least two GLEs, with a significance above 4σ, at 7.2 minutes and 19.2 minutes after the Fermi trigger, respectively. We argue that the GeV counterpart of a keV GRB could be similar to the highest GRBs, observed by EGRET within BATSE’s field of view, where the high-energy emission arrives at the detector in fragments, and they are delayed and/or anticipated with respect to the keV-MeV burst. This behavior is observed in both cases. In short, the analysis suggests that they may be physically associated. Details and some implications of this possible association are reported in this work.

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Seiffert 2009 对河外射电背景的解释

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貌似没有解释这个额外的不是CMB, 也不是已知射电源的射电辐射到底是什么.

精彩摘抄:
上图是在不同频率处所对应的辐射流量(和温度成正比)和频率的关系. 下图说明拟合(唯象拟合)的误差很小.

其实CMB本身的图上就说明在射电波段不是那么好的黑体, 比2.73K的辐射多了那么一点点(注意<1ghz的地方), onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://arcade.gsfc.nasa.gov/images/cmb_intensity.gif">

文章信息:
Title: Interpretation of the Extragalactic Radio Background

Authors: M. Seiffert, D. J. Fixsen, A. Kogut, S. M. Levin, M. Limon, P. M. Lubin, P. Mirel, J. Singal, T. Villela, E. Wollack, C. A. Wuensche

(Submitted on 5 Jan 2009)

Abstract: We use absolutely calibrated data between 3 and 90 GHz from the 2006 balloon flight of the ARCADE 2 instrument, along with previous measurements at other frequencies, to constrain models of extragalactic emission. Such emission is a combination of the Cosmic Microwave Background (CMB) monopole, Galactic foreground emission, the integrated contribution of radio emission from external galaxies, any spectral distortions present in the CMB, and any other extragalactic source. After removal of estimates of foreground emission from our own Galaxy, and the estimated contribution of external galaxies, we present fits to a combination of the flat-spectrum CMB and potential spectral distortions in the CMB. We find 2 sigma upper limits to CMB spectral distortions of mu

Comments:	8 pages, 4 figures
Subjects:	Astrophysics (astro-ph)
Cite as:	arXiv:0901.0559v1 [astro-ph]

Fixsen 2009 ARCADE 2对河外天区的温度测量

主要内容:
在3.3GHz处, 比CMB的2.73K多了0.05K.
整体上有一个额外的比2.73K黑体辐射多出的温度 T=1.26K (nu/1GHz)^-2.6, 其中nu=(22MHz,10GHz).

那么: 如果换成流量, 根据F_nu\propto T nu^2 \propto nu^-0.6 ~ nu^-1/2. 像是某种冷却啊.

精彩摘抄:


文章信息:
ARCADE 2 Measurement of the Extra-Galactic Sky Temperature at 3-90 GHz

Authors: D. J. Fixsen, A. Kogut, S. Levin, M. Limon, P. Lubin, P. Mirel, M. Seiffert, J. Singal, E. Wollack, T. Villela, C. A. Wuensche

(Submitted on 5 Jan 2009)

Abstract: The ARCADE 2 instrument has measured the absolute temperature of the sky at frequencies 3, 8, 10, 30, and 90 GHz, using an open-aperture cryogenic instrument observing at balloon altitudes with no emissive windows between the beam-forming optics and the sky. An external blackbody calibrator provides an {\it in situ} reference. Systematic errors were greatly reduced by using differential radiometers and cooling all critical components to physical temperatures approximating the CMB temperature. A linear model is used to compare the output of each radiometer to a set of thermometers on the instrument. Small corrections are made for the residual emission from the flight train, balloon, atmosphere, and foreground Galactic emission. The ARCADE 2 data alone show an extragalactic rise of $50\pm7$ mK at 3.3 GHz in addition to a CMB temperature of $2.730\pm .004$ K. Combining the ARCADE 2 data with data from the literature shows a background power law spectrum of $T=1.26\pm 0.09$ [K] $(\nu/\nu_0)^{-2.60\pm 0.04}$ from 22 MHz to 10 GHz ($\nu_0=1$ GHz) in addition to a CMB temperature of $2.725\pm .001$ K.

Comments:	11 pages 5 figures Submitted to ApJ
Subjects:	Astrophysics (astro-ph)
Cite as:	arXiv:0901.0555v1 [astro-ph]

Kogut 2009 ARCADE 2对银河系的射电观测

主要内容:


精彩摘抄:


文章信息:
ARCADE 2 Observations of Galactic Radio Emission

Authors: A. Kogut, D. J. Fixsen, S. M. Levin, M. Limon, P. M. Lubin, P. Mirel, M. Seiffert, J. Singal, T. Villela, E. Wollack, C. A. Wuensche

(Submitted on 5 Jan 2009)

Abstract: We use absolutely calibrated data from the ARCADE 2 flight in July 2006 to model Galactic emission at frequencies 3, 8, and 10 GHz. The spatial structure in the data is consistent with a superposition of free-free and synchrotron emission. Emission with spatial morphology traced by the Haslam 408 MHz survey has spectral index beta_synch = -2.5 +/- 0.1, with free-free emission contributing 0.10 +/- 0.01 of the total Galactic plane emission in the lowest ARCADE 2 band at 3.15 GHz. We estimate the total Galactic emission toward the polar caps using either a simple plane-parallel model with csc|b| dependence or a model of high-latitude radio emission traced by the COBE/FIRAS map of CII emission. Both methods are consistent with a single power-law over the frequency range 22 MHz to 10 GHz, with total Galactic emission towards the north polar cap T_Gal = 0.498 +/- 0.028 K and spectral index beta = -2.55 +/- 0.03 at reference frequency 1 GHz. The well calibrated ARCADE 2 maps provide a new test for spinning dust emission, based on the integrated intensity of emission from the Galactic plane instead of cross-correlations with the thermal dust spatial morphology. The Galactic plane intensity measured by ARCADE 2 is fainter than predicted by models without spinning dust, and is consistent with spinning dust contributing 0.4 +/- 0.1 of the Galactic plane emission at 22 GHz.

Comments:	10 poges, 9 figures. Submitted to The Astrophysical Journal
Subjects:	Astrophysics (astro-ph)
Cite as:	arXiv:0901.0562v1 [astro-ph]

Singal 2009 射电背景辐射探测器ARCADE 2

主要内容:
相当于有了一个新的窗口. 3-90GHz

(不过不知道和地面的射电望远镜比, 有什么优势. 是地面的精于点状辐射体, 只能探测比地面背景等背景高的辐射吗?)

精彩摘抄:


文章信息:
The ARCADE 2 Instrument

Authors: J. Singal, D.J. Fixsen, A. Kogut, S. Levin, M. Limon, P. Lubin, P. Mirel, M. Seiffert, T. Villela, E. Wollack, C.A. Wuensche

(Submitted on 5 Jan 2009)

Abstract: The second generation Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE 2) instrument is a balloon-borne experiment to measure the radiometric temperature of the cosmic microwave background and Galactic and extra-Galactic emission at six frequencies from 3 to 90 GHz. ARCADE 2 utilizes a double-nulled design where emission from the sky is compared to that from an external cryogenic full-aperture blackbody calibrator by cryogenic switching radiometers containing internal blackbody reference loads. In order to further minimize sources of systematic error, ARCADE 2 features a cold fully open aperture with all radiometrically active components maintained at near 2.7 K without windows or other warm objects, achieved through a novel thermal design. We discuss the design and performance of the ARCADE 2 instrument in its 2005 and 2006 flights.

Comments:	11 pages, 12 figues, 3 tables. To accompany companion papers Kogut et al, Fixsen et al, and Seiffert et al
Subjects:	Astrophysics (astro-ph)
Cite as:	arXiv:0901.0546v1 [astro-ph]

Page 2009 GRB 080307的X射线光变

主要内容:


精彩摘抄:
企图认为第一个为暴本身, 后面的是余辉阶段.

不过我觉得这个给"平降阶段"提供了多样性的事例, 就是平降并不是真的降的比较缓慢, 也可以上升的.

文章信息:

rXiv:0901.2219 [ps, pdf, other]

Title: The unusual X-ray light-curve of GRB 080307: the onset of the afterglow?

Authors: K.L. Page (1), R. Willingale (1), P.T. O'Brien (1), N.R. Tanvir (1), J.P. Osborne (1), B. Zhang (2), S.T. Holland (3,4), A.J. Levan (5), A. Melandri (6), R.L.C. Starling (1), D. Bersier (6), D.N. Burrows (7), J.E. Geach (8), P. Maxted (9) ((1) University of Leicester, (2) University of Nevada, (3) GSFC, (4) USRA, (5) University of Warwick, (6) Liverpool John Moores University, (7) PSU, (8) Durham University, (9) Keele University)

Comments: 8 pages, 6 figures, accepted for publication in MNRAS

Subjects: Astrophysics (astro-ph)

Swift-detected GRB 080307 showed an unusual smooth rise in its X-ray light-curve around 100 seconds after the burst, at the start of which the emission briefly softened. This `hump' has a longer duration than is normal for a flare at early times and does not demonstrate a typical flare profile. Using a two component power-law-to-exponential model, the rising emission can be modelled as the onset of the afterglow, something which is very rarely seen in Swift-X-ray light-curves. We cannot, however, rule out that the hump is a particularly slow early-time flare, or that it is caused by upscattered reverse shock electrons.