van Marle 2007 rapid rotating progenitor enviroment

主要内容:


精彩摘抄:
we find a strong deviation of the circumstellar density profile in the polar direction from the 1/R^2 density profile normally associated with stellar winds close to the star.

Solid: mass density; dashed: energy density

文章信息:

arXiv:0711.4807 [ps, pdf, other]

Title: The circumstellar medium around a rapidly rotating, chemically homogeneously evolving, possible gamma-ray burst progenitor

Authors: Allard Jan van Marle, Norbert Langer, Sung-Chul Yoon, Guillermo Garcia-Segura

Comments: accepted by Astronomy & Astrophysics

Subjects: Astrophysics (astro-ph)

Rapidly rotating, chemically homogeneously evolving massive stars are considered to be progenitors of long gamma-ray bursts. We present numerical simulations of the evolution of the circumstellar medium around a rapidly rotating 20 Msol star at a metallicity of Z=0.001. Its rotation is fast enough to produce quasi-chemically homogeneous evolution. While conventionally, a star of 20 Msol would not evolve into a Wolf-Rayet stage, the considered model evolves from the main sequence directly to the helium main sequence. We use the time-dependent wind parameters, such as mass loss rate, wind velocity and rotation-induced wind anisotropy from the evolution model as input for a 2D hydrodynamical simulation. While the outer edge of the pressure-driven circumstellar bubble is spherical, the circumstellar medium close to the star shows strong non-spherical features during and after the periods of near-critical rotation. We conclude that the circumstellar medium around rapidly rotating massive stars differs considerably from the surrounding material of non-rotating stars of similar mass. Multiple blue-shifted high velocity absorption components in gamma-ray burst afterglow spectra are predicted. As a consequence of near critical rotation and short stellar evolution time scales during the last few thousand years of the star's life, we find a strong deviation of the circumstellar density profile in the polar direction from the 1/R^2 density profile normally associated with stellar winds close to the star.

Koers 2007 High-energy nertrinos from GRB

主要内容:
due to meson and muon acceleration.

精彩摘抄:
extending as a single power law up to ~10^3 TeV. This greatly improves the detection prospects.

文章信息:

arXiv:0711.4791 [ps, pdf, other]

Title: Enhanced high-energy neutrino emission from choked gamma-ray bursts due to meson and muon acceleration

Authors: Hylke B. J. Koers, Ralph A. M. J. Wijers

Comments: 4 pages, 1 figure, revtex4

Subjects: Astrophysics (astro-ph)

It has been suggested that a potentially large fraction of supernovae could be accompanied by relativistic outflows that stall below the stellar surface. In this letter we point out that internal shocks that are believed to accelerate protons to very high energies in these flows will also accelerate secondary mesons and muons. As a result the neutrino spectrum from meson and muon decay is expected to be much harder compared to previous estimates, extending as a single power law up to ~10^3 TeV. This greatly improves the detection prospects.

Wang 2007 BZ-MC-BP Model

主要内容:


精彩摘抄:


文章信息:

arXiv:0711.4408 [ps, pdf, other]

Title: BZ-MC-BP Model for Jet Production from Black Hole Accretion Disc

Authors: Ding-Xiong Wang, Yong-Chun Ye, Yang Li, Zhao-Jiang Ge

Comments: 9 pages, 6 figures, accepted by MNRAS

Subjects: Astrophysics (astro-ph)

Three energy mechanisms invoking large-scale magnetic fields are incorporated in a model to interpret jet production in black hole (BH) systems, i.e., the Blandford-Znajek (BZ), the magnetic coupling (MC) and Blandford-Payne (BP) processes. These energy mechanisms can coexist in BH accretion disc based on the magnetic field configurations constrained by the screw instability, provided that the BH spin and the power-law index indicating the variation of the magnetic field at an accretion disc are greater than some critical values. In this model the jets are driven by the BZ process in the Poynting flux regime and by the BP process in the hydromagnetic regime, being consistent with the spine/sheath jet structure observed in BH sources of stellar and supermassive size.

Rossi 2007 detectability of radio orphan afterglows

主要内容:
Considering the detectability by assuming that the jets are not top-hat.

精彩摘抄:


文章信息:

arXiv:0711.4096 [ps, pdf, other]

Title: "Orphan" afterglows in the Universal Standard Jet Model for gamma-ray bursts

Authors: Elena M. Rossi (JILA), Rosalba Perna (JILA), Frédéric Daigne (IAP)

Comments: 10 pages, 7 figures. MNRAS submitted

Subjects: Astrophysics (astro-ph)

The paucity of reliable achromatic breaks in Gamma-Ray Burst afterglow light curves motivates independent measurements of the jet aperture. Orphan afterglow (OA) searches, especially at radio wavelengths, have long been the classic alternative. These survey data have been interpreted assuming a uniformly emitting jet with sharp edges (``top-hat'' jet), in which case the ratio of nearly isotropic afterglows to GRBs scales with the jet solid angle. We consider, instead, an almost isotropic outflow with a luminosity that decreases across the emitting surface. The total GRB energy can be lower than for an isotropic top-hat jet, and the current lack of positive detections can be more easily explained. In particular, we adopt the universal structured jet (USJ) model, that reproduces the observed afterglow phenomenology to the same extent as the top-hat jet. We compute, within the framework of the USJ, the number and rate of orphan afterglows expected in all-sky snapshot observations as a function of the survey sensitivity. We find that the current (negative) results for OA searches are in agreement with our expectations. In radio and X-ray bands this was mainly due to the low sensitivity of the surveys, while in the optical band the sky-coverage was not sufficient. A comparison with the top-hat model is also performed. In general we find that X-ray surveys are poor tools for OA searches, if the jet is structured. On the other hand, the FIRST radio survey and future instruments like the Allen Telescope Array (in the radio band) and especially GAIA and Pan-Starrs (in the optical band) will have excellent chances, not only to detect OAs, but also to put strong constraints on the jet models.

Shao 2007 dust echo for GRB afterglow

主要内容:
They can fit the X-ray afterglow now. That is to say, the X-ray afterglow comes from dust echo of Wind bubble.

精彩摘抄:

sketch
fitting

文章信息:

arXiv:0711.3800 [ps, pdf, other]

Title: Echo Emission From Dust Scattering and X-Ray Afterglows of Gamma-Ray Bursts

Authors: L. Shao (1 and 2), Z. G. Dai (1), N. Mirabal (3) ((1)Nanjing University, China, (2)University of Colorado, USA, (3)Columbia University, USA)

Comments: 25 pages, 3 figures, 2 tables. Accepted for publication in ApJ

Subjects: Astrophysics (astro-ph)

We investigate the effect of X-ray echo emission in gamma-ray bursts (GRBs). We find that the echo emission can provide an alternative way of understanding X-ray shallow decays and jet breaks. In particular, a shallow decay followed by a "normal" decay and a further rapid decay of X-ray afterglows can be together explained as being due to the echo from prompt X-ray emission scattered by dust grains in a massive wind bubble around a GRB progenitor. We also introduce an extra temporal break in the X-ray echo emission. By fitting the afterglow light curves, we can measure the locations of the massive wind bubbles, which will bring us closer to finding the mass loss rate, wind velocity, and the age of the progenitors prior to the GRB explosions.

Schanne 2007 ECLAIRs space GRB telescope

主要内容:
ECLAIRs, trigger GRBs in almost real time. Will be launched in 2012.

精彩摘抄:


文章信息:

arXiv:0711.3754 [pdf]

Title: The trigger function of the space borne gamma-ray burst telescope ECLAIRs

Authors: S. Schanne, B. Cordier, D. Gotz, A. Gros, P. Kestener, H. Le Provost, B. L'Huillier, M. Mur

Comments: 4 pages, proceedings of the "30^th International Cosmic Ray Conference (ICRC)", 3-12 July 2007, Merida, Yucatan, Mexico

Subjects: Astrophysics (astro-ph)

Gamma-ray bursts (GRB) sign energetic explosions in the Universe, occurring at cosmological distances. Multi-wavelength observations of GRB allow to study their properties and to use them as cosmological tools. In 2012 the space borne gamma-ray telescope ECLAIRs is expected to provide accurate GRB localizations on the sky in near real-time, necessary for ground-based follow-up observations. Led by CEA Saclay, France, the project is currently in its technical design phase. ECLAIRs is optimized to detect highly red-shifted GRB thanks to a 4 keV low energy threshold. A coded mask telescope with a 1024 cm^2 detection plane of 80x80 CdTe pixels permanently observes a 2 sr sky field. The on-board trigger detects GRB using count-rate increase monitors on multiple time-scales and cyclic images. It computes sky images in the 4-50 keV energy range by de-convolving detector plane images with the mask pattern and localizes newly detected sources with <10>

Starling 2007 spectral evolution of GRB 070616

主要内容:


精彩摘抄:


文章信息:

arXiv:0711.3753 [ps, pdf, other]

Title: Swift captures the spectrally evolving prompt emission of GRB 070616

Authors: R.L.C. Starling (1), P.T. O'Brien, R. Willingale, K.L. Page, J.P. Osborne, M. De Pasquale, Y.E. Nakagawa, N.P.M. Kuin, K. Onda, J.P. Norris, T.N. Ukwatta, N. Kodaka, D.N. Burrows, J.A. Kennea, M.J. Page, M. Perri, C.B. Markwardt ((1) University of Leicester, UK)

Comments: 13 pages, 11 figures (2 in colour), MNRAS accepted

Subjects: Astrophysics (astro-ph)

The origins of Gamma-ray Burst prompt emission are currently not well understood and in this context long, well-observed events are particularly important to study. We present the case of GRB 070616, analysing the exceptionally long-duration multipeaked prompt emission, and later afterglow, captured by all the instruments on-board Swift and by Suzaku WAM. The high energy light curve remained generally flat for several hundred seconds before going into a steep decline. Spectral evolution from hard to soft is clearly taking place throughout the prompt emission, beginning at 285 s after the trigger and extending to 1200 s. We track the movement of the spectral peak energy, whilst observing a softening of the low energy spectral slope. The steep decline in flux may be caused by a combination of this strong spectral evolution and the curvature effect. We investigate origins for the spectral evolution, ruling out a superposition of two power laws and considering instead an additional component dominant during the late prompt emission. We also discuss origins for the early optical emission and the physics of the afterglow. The case of GRB 070616 clearly demonstrates that both broadband coverage and good time resolution are crucial to pin down the origins of the complex prompt emission in GRBs.

Moretti 2007 spectra of Swift early afterglow

主要内容:


精彩摘抄:
Although the data do not allow an unequivocal interpretation, the importance of this analysis consists in the fact that we show that a simple power law model or a Band model are insufficient to describe the X-ray spectra of a small homogeneous sample of GRBs at the end of their prompt phase.

文章信息:

arXiv:0711.3739 [ps, pdf, other]

Title: When GRB afterglows get softer, hard components come into play

Authors: A. Moretti (1), R. Margutti (1,2), F. Pasotti (1,2), A.P. Beardmore (3), S. Campana (1), G. Chincarini (2,1), S. Covino (1), O. Godet (3), C. Guidorzi (2,1) J.P. Osborne (3), P. Romano (2,1), G. Tagliaferri (1) ((1) INAF-OAB; (2) U. Bicocca; (3) U. Leicester)

Comments: 10 pages, accepted for publication in A&A

Subjects: Astrophysics (astro-ph)

We aim to investigate the ability of simple spectral models to describe the GRB early afterglow emission. We performed a time resolved spectral analysis of a bright GRB sample detected by the Swift Burst Alert Telescope and promptly observed by the Swift X-ray Telescope,with spectroscopically measured redshift in the period April 2005 -- January 2007. The sample consists of 22 GRBs and a total of 214 spectra. We restricted our analysis to the softest spectra sub--sample which consists of 13 spectra with photon index > 3. In this sample we found that four spectra, belonging to GRB060502A, GRB060729, GRB060904B, GRB061110A prompt--afterglow transition phase, cannot be modeled neither by a single power law nor by the Band model. Instead we find that the data present high energy (> 3 keV, in the observer frame) excesses with respect to these models. We estimated the joint statistical significance of these excesses at the level of 4.3 sigma. In all four cases, the deviations can be modeled well by adding either a second power law or a blackbody component to the usual synchrotron power law spectrum. The additional power law would be explained by the emerging of the afterglow, while the blackbody could be interpreted as the photospheric emission from X-ray flares or as the shock breakout emission. In one case these models leave a 2.2 sigma excess which can be fit by a Gaussian line at the energy the highly ionized Nickel recombination. Although the data do not allow an unequivocal interpretation, the importance of this analysis consists in the fact that we show that a simple power law model or a Band model are insufficient to describe the X-ray spectra of a small homogeneous sample of GRBs at the end of their prompt phase.

Spruit 2007 Review on the origin of NS magnetic fields

主要内容:
Three popular scenarios: 1. fossil magnetic field (almost excluded); 2. generated internally in the protostars; 3. generated in the collapsing.

精彩摘抄:


文章信息:

arXiv:0711.3650 [pdf, other]

Title: Origin of neutron star magnetic fields

Authors: H.C. Spruit

Comments: Review to appear in "40 years of pulsars", ed. A. Cumming, AIP

Subjects: Astrophysics (astro-ph)

Possible origins of the magnetic fields of neutron stars include inheritance from the main sequence progenitor and dynamo action at some stage of evolution of progenitor. Inheritance is not sufficient to explain the fields of magnetars. Energetic considerations point to differential rotation in the final stages of core collapse process as the most likely source of field generation, at least for magnetars. A runaway phase of exponential growth is needed to achieve sufficient field amplification during relevant phase of core collapse; it can probably be provided by a some form of magnetorotational instability. Once formed in core collapse, the field is in danger of decaying again by magnetic instabilities. The evolution of a magnetic field in a newly formed neutron star is discussed, with emphasis on the existence of stable equilibrium configurations as end products of this evolution, and the role of magnetic helicity in their existence.

Troja 2007 short bursts progenitors

主要内容:
NS-BH, NS-NS

精彩摘抄:


文章信息:

arXiv:0711.3034 [ps, pdf, other]

Title: Different progenitors of short hard gamma-ray bursts

Authors: Eleonora Troja, Andrew R. King, Paul T. O'Brien, Nicola Lyons, Giancarlo Cusumano

Comments: 5 pages, 2 figures, accepted for publication in MNRAS

Subjects: Astrophysics (astro-ph)

We consider the spatial offsets of short hard gamma-ray bursts (SHBs) from their host galaxies. We show that all SHBs with extended duration soft emission components lie very close to their hosts. We suggest that NS-BH binary mergers offer a natural explanation for the properties of this extended duration/low offset group. SHBs with large offsets have no observed extended emission components and are less likely to have an optically detected afterglow, properties consistent with NS-NS binary mergers occurring in low density environments.

Staff 2007 quark nova for GRB early X-ray afterglow

主要内容:


精彩摘抄:


文章信息:

arXiv:0711.3005 [ps, pdf, other]

Title: Gamma Ray Burst engine activity within the quark nova scenario: Prompt emission, X-ray Plateau, and sharp drop-off

Authors: Jan Staff, Brian Niebergal, Rachid Ouyed

Comments: 4 pages, submitted to ApJL

Subjects: Astrophysics (astro-ph)

We present a three-stage model for a long GRB inner engine to explain the prompt gamma ray emission, and interpret recent Swift satellite observations of early X-ray afterglow plateaus followed by a sharp drop off or a shallow power law decay. The three stages involves a neutron star phase, a quark star (QS) and a black hole phase as described in Staff et al. (2007). We find that the QS stage allows for more energy to be extracted from neutron star to QS conversion as well as from ensuing accretion onto the QS. The QS accretion phase naturally extends the engine activity and can account for both the prompt emission and irregular early X-ray afterglow activity. Following the accretion phase, the QS can spin-down by emission of a baryon-free outflow. The magnetar-like magnetic field strengths resulting from the NS to QS transition provide enough spin-down energy, for the correct amount of time, to account for the plateau in the X-ray afterglow. In our model, a sharp drop-off following the plateau occurs when the QS collapses to a BH during the spin-down, thus shutting-off the secondary outflow. We applied our model to GRB 070110 and GRB 060607A and found that we can consistently account for the energetics and duration during the prompt and plateau phases.

Dermer 2007 GRB and AGN origin of UHECR

主要内容:


精彩摘抄:
Greisen-Zatsepin-Kuzmin (GZK) cutoff at 10^20 eV.

文章信息:

arXiv:0711.2804 [ps, pdf, other]

Title: On Gamma Ray Burst and Blazar AGN Origins of the Ultra-High Energy Cosmic Rays in Light of First Results from Auger

Authors: Charles D. Dermer (NRL)

Comments: 25 pages, 16 figs, invited talk at Merida Yucatan ICRC

Subjects: Astrophysics (astro-ph)

The discoveries of the GZK cutoff with the HiRes and Auger Observatories and the discovery by Auger of clustering of >~60 EeV ultra-high energy cosmic rays (UHECRs) towards nearby <~75 Mpc) AGNs along the supergalactic plane establishes the astrophysical origin of the UHECRs. The likely sources of the UHECRs are gamma-ray bursts and radio-loud AGNs because: (1) they are extragalactic; (2) they are sufficiently powerful; (3) acceleration to ultra-high energies can be achieved in their relativistic ejecta; (4) anomalous X-ray and $\gamma$-ray features can be explained by nonthermal hadron acceleration in relativistic blast waves; and (5) sources reside within the GZK radius. Two arguments for acceleration to UHE are presented, and limits on UHECR ion acceleration are set. UHECR ions are shown to be able to survive without photodisintegrating while passing through the AGN scattered radiation field, even if launched deep in the broad line region. UHECR injection throughout cosmic time fits the measured energy spectrum of UHECRs, at least for protons. Local UHECR proton and ion interaction and energy-loss mean free paths are calculated using an empirical fit to the extragalactic background light (EBL) at IR and optical energies. Minimum intergalactic magnetic (IGM) fields ~1e-11 G are derived from clustering assuming specific source origins, e.g., Cen A, nearby AGNs, or GRBs for the super-GZK CRs seen with Auger. Besides distinct cosmic-ray induced gamma-ray signatures that should be observed with the Gamma ray Large Area Space Telescope (GLAST), source and GZK neutrino detections and the arrival distribution of UHECR in direction and time can finally decide the sources of cosmic rays at the highest energies.

Giannios 2007 Poynting-flux-dominated gamma-ray burst energy dissipation

主要内容:


精彩摘抄:


文章信息:

arXiv:0711.2632 [ps, pdf, other]

Title: Prompt GRB emission from gradual energy dissipation

Authors: Dimitrios Giannios (Max Planck Institute for Astrophysics)

Comments: 9 pages, 3 figures, A&A, submitted

Subjects: Astrophysics (astro-ph)

I calculate the emission expected from a Poynting-flux-dominated gamma-ray burst (GRB) flow in which energy is dissipated gradually by magnetic reconnection. In this picture, the energy of the radiating particles is determined by heating and cooling balance (slow heating model). Detailed radiative transfer calculations show that, at Thomson optical depths of order of unity, the dominant radiative process is inverse Compton scattering. Synchrotron-self-absorbed emission and inverse Compton dominate in the Thomson thin parts of the flow. The electrons stay thermal throughout the dissipation region because of Coulomb collisions (Thomson thick part of the flow) and exchange of synchrotron photons (Thomson thin part). The resulting spectrum naturally explains the observed sub-MeV break of the GRB emission and the spectral slopes above and below the break. The model predicts that the gamma-ray power-law tail has a high-energy cutoff typically at the ~0.1-1 GeV energy range that should be observable with GLAST. The model also predicts a prompt emission component in the optical and UV associated with the GeV emission. Observations of the prompt emission of GRB 061121 that cover the energy range from the optical to ~1 MeV are explained by the model.

Horiuchi 2007 Neutrinos from reverse shock

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精彩摘抄:


文章信息:

arXiv:0711.2580 [ps, pdf, other]

Title: High-energy neutrinos from reverse shocks in gamma-ray burst progenitors

Authors: Shunsaku Horiuchi (Tokyo University), Shin'ichiro Ando (Caltech)

Comments: 11 pages, 7 figures, 2 tables, submitted to PRD

Subjects: Astrophysics (astro-ph)

Highly relativistic jets are a key element of current gamma-ray burst models, where the jet bulk kinetic energy is converted to radiation energy at optically thin shocks. High-energy neutrinos are expected from photomeson interactions of protons accelerated in the same shocks. Here we revisit the early evolution of a relativistic jet, while the jet is still inside the star. We study propagation of mildly relativistic and ultrarelativistic jets through a type Ib progenitor, and follow reverse shocks as the jets cross the star. We show that protons can be accelerated to ~10^4 GeV at reverse shocks, and efficiently produce mesons, and the mesons experience significant cooling, suppressing subsequent neutrino emission on decay. We show, however, that the neutrino yield from the reverse shock is still reasonably large, especially for low-luminosity and long-duration bursts, where meson cooling is less severe.
From a choked burst with isotropic equivalent energies of 10^{53}-10^{54} erg at 10 Mpc, we expect ~2-25 neutrino events at IceCube. We discuss implications of our results in the context of neutrinos from choked jets, which are completely shock heated and do not break out of the star.

Li 2007 Prompt optical emission

主要内容:
Model: prompt internal shock is high optical depth for optical band. So they give a model that these emissions come from the residual collisions at larger radii. The residual collision is the shells merged in the prompt era, and these merged shells collide later.

精彩摘抄:


文章信息:
arXiv:0711.2379 [ps, pdf, other]
Title: Prompt optical emission from residual collisions in GRB outflows
Authors: Zhuo Li, Eli Waxman
Comments: 4 pages, 1 fig, ApJL submitted
Subjects: Astrophysics (astro-ph)
The prompt $\gamma$-ray emission in $\gamma$-ray bursts is believed to be produced by internal shocks within a relativistic unsteady outflow. The recent detection of prompt optical emission accompanying the prompt $\gamma$-ray emission appears to be inconsistent with this model since the out flowing plasma is expected to be highly optically thick to optical photons. We show here that fluctuations in flow properties on short, $\sim1$ ms, time scale, which drive the $\gamma$-ray producing collisions at small radii, are expected to lead to "residual" collisions at much larger radii, where the optical depth to optical photons is low. The late residual collisions naturally account for the relatively bright optical emission. The apparent simultaneity of $\gamma$-ray and optical emission is due to the highly relativistic speed with which the plasma expands. Residual collisions may also account for the X-ray emission during the early "steep decline" phase, where the radius is inferred to be larger than the $\gamma$-ray emission radius. Finally, we point out that inverse-Compton emission from residual collisions at large radii is expected to contribute significantly to the emission at high energy, and may therefore "smear" the pair production spectral cut-off.

Taboada 2007 Correlating prompt GRB photons with neutrinos

主要内容:


精彩摘抄:


文章信息:

arXiv:0711.2277 [ps, pdf, other]

Title: Correlating prompt GRB photons with neutrinos

Authors: Ignacio Taboada, Michelangelo V. D'Agostino

Subjects: Astrophysics (astro-ph)

It is standard in theoretical neutrino astrophysics to use a broken power law approximation, based on the Band function, to describe the average photon flux of the prompt emission of Gamma-Ray Bursts. We will show that this approximation overestimates the contribution of high energy gamma-rays (and underestimates low energy gamma-rays). As a consequence models that rely on this approximation overestimate neutrino event rate by a factor of approx 2 depending on Earth's column density in the direction of the GRB. Furthermore the characteristic energy of neutrinos that trigger a km^3 detector is typically 10^{16} eV, higher than previously predicted. We also provide a new broken power law approximation to the Band function and show that it properly represents the photon spectra.

Gendre 2007 X-ray lighcures at 1 day, cluster

主要内容:
GRB sources can be divided in three classes, namely optical and X-ray bright afterglows, optical and X-ray dim ones, and optically bright -X-ray dim ones.

They also give a way to estimate redshift.

精彩摘抄:


文章信息:

arXiv:0711.2222 [ps, pdf, other]

Title: X-ray afterglow light curves : toward standard candle ?

Authors: B. Gendre (1, 2), A. Galli (1, 3), M. Boer (4) ((1) IASF-Roma, Roma, Italy; (2) Bicocca University, Milano, Italy; (3) INFN-Trieste, Trieste, Italy; (4) Observatoire de Haute Provence (CNRS), Saint Michel l'Observatoire, France)

Comments: 13 pages, 10 color figures, 1 b&w figure. Submitted to ApJ

Subjects: Astrophysics (astro-ph)

We investigate the clustering of afterglow light curves observed at X-ray and optical wavelengths. We have constructed a sample of 34 bursts with known distance and X-ray afterglow. This sample includes bursts observed by BeppoSAX, XMM-Newton, Chandra, and SWIFT. We correct the light curves for cosmological effects and compare the observed X-ray fluxes one day after the burst. We check for correlations between the observed flux and the burst spectral and temporal properties. We confirm the previous result of Boer and Gendre (2000) that X-ray afterglow light curves cluster in luminosity, even when we consider the last SWIFT data. We observe this clustering only for the afterglow light curves; the inclusion of prompt-related data broaden the distribution. The same clustering is observed for the optical light curves; GRB sources can be divided in three classes, namely optical and X-ray bright afterglows, optical and X-ray dim ones, and optically bright -X-ray dim ones. We argue that this clustering is related to the fireball total energy, the external medium density, the fraction of fireball energy going in relativistic electrons and magnetic fields. These parameters can be either fixed to a standard value, or correlated. We finally propose a method for the estimation of the GRB source redshift based on the observed X-ray flux one day after the burst and optical properties. Using this method, we compute a redshift of 1.4 +/- 0.2 for GRB 980519 and of 1.9 +/- 0.3 for GRB 040827. We tested this method on three recently detected SWIFT GRBs with known redshift, and found it in good agreement with the reported distance from optical spectroscopy.

Wang 2007 GRB for UHE cosmic rays

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精彩摘抄:


文章信息:

arXiv:0711.2065 [ps, pdf, other]

Title: On the Origin and Survival of UHE Cosmic-Ray Nuclei in GRBs and Hypernovae

Authors: Xiang-Yu Wang, Soebur Razzaque, Peter Meszaros

Subjects: Astrophysics (astro-ph)

The chemical composition of the ultra-high-energy (UHE) cosmic rays serves as an important clue for their origin. Recent measurements of the elongation rates by the Pierre Auger Observatory hint at the possible presence of heavy or intermediate mass nuclei in the UHE cosmic rays. Gamma-ray bursts (GRBs) and hypernovae have been suggested as possible sources of the UHE cosmic rays. Here we derive the constraints on the physical conditions under which UHE heavy nuclei, if they are accelerated in these sources, can survive in their intense photon fields. We find that in the GRB external shock and in the hypernova scenarios, UHE nuclei can easily survive photo-disintegration. In the GRB internal shock scenario, UHE nuclei can also survive, provided the dissipation radius and/or the bulk Lorentz factor of the relativistic outflow are relatively large, or if the low-energy self-absorption break in the photon spectrum of the prompt emission occurs above several KeV. In internal shocks and in the other scenarios, intermediate-mass UHE nuclei have a higher probability of survival against photo-disintegration than UHE heavy nuclei such as Fe.

Pe'er 2007 wind reverse shock with ISM

主要内容:
NOT the reverse shock of GRB jet, but the wind from WR-star. This wind will react with ISM and reverse shock can give a rise in the GRB afterglow.

This paper is a clue for the environment of long GRBs. 考虑暴周环境的时候可以从这篇文章开始。

精彩摘抄:


文章信息:

Title:		The Signature of a Wind Reverse Shock in Gamma-Ray Burst Afterglows
Authors:		Pe'er, Asaf; Wijers, Ralph A. M. J.
Affiliation:		AA(Astronomical Institute ``Anton Pannekoek'', Kruislaan 403, 1098SJ Amsterdam, Netherlands; apeer@science.uva.nl.), AB(Astronomical Institute ``Anton Pannekoek'', Kruislaan 403, 1098SJ Amsterdam, Netherlands; apeer@science.uva.nl.)
Publication:		The Astrophysical Journal, Volume 643, Issue 2, pp. 1036-1046. (ApJ Homepage)
Publication Date:		06/2006
Origin:		UCP
ApJ Keywords:		Gamma Rays: Bursts, Gamma Rays: Theory, Plasmas, Radiation Mechanisms: Nonthermal, Shock Waves
Abstract Copyright:		(c) 2006: The American Astronomical Society
DOI:		10.1086/500969
Bibliographic Code:		2006ApJ...643.1036P

Abstract

Explosions of massive stars are believed to be the source of a significant fraction of gamma-ray bursts (GRBs). If this is indeed the case, then the explosion blast wave propagates into a complex density structure, composed of a stellar wind bounded by two shock waves-a wind reverse shock and a forward shock. As the explosion blast wave reaches R₀, the radius of the wind reverse shock, it splits into two shock waves-a reverse and a forward shock wave. We show that the reverse shock thus produced is not strong; therefore, full analytical treatment is required in calculating its properties. We calculate the dynamics of the flow and the evolution of the blast waves in all of the different stages. We show that the fluid Lorentz factor at r>R₀ is equal to 0.725 times the blast wave Lorentz factor as it reaches R₀ and is time (and r) independent as long as the blast wave reverse shock exists. Following the calculation of the blast wave evolution, we calculate the radiation expected in different energy bands. We show that about a day after the main explosion, as the blast wave reaches R₀, the observed afterglow flux starts to rise. It rises by a factor of about 2 in a few hours, during which the blast wave reverse shock exists, and then declines. We show that the power-law index describing the light-curve time evolution is different at early (before the rise) and late times and is frequency dependent. We present light curves in the different energy bands for this scenario.

Giannios 2007 magnetized reverse shock

主要内容:
Optical flashes may come from the magnetized reverse shock, not the normal reverse shock.

精彩摘抄:


文章信息:
arXiv:0711.1980 [ps, pdf, other]

Title: On the existence of a reverse shock in magnetized GRB ejecta

Authors: D. Giannios, P. Mimica, M. A. Aloy

Comments: 8 pages, 1 figure, A&A submitted

Subjects: Astrophysics (astro-ph)

The role of magnetic fields in gamma-ray burst (GRB) flows remains controversial. The study of the early afterglow phases and, in particular, of the reverse shock dynamics and associated emission offers a promising probe of the magnetization of the ejecta. In this paper, we derive the conditions for the existence of a reverse shock in arbitrarily magnetized ejecta that decelerate interacting with external medium of constant density. We show, in contrast to previous estimates, that ejecta with magnetization larger than unity are not crossed by a reverse shock for a large fraction of the parameter space relevant for GRB flows. Allowing for shell spreading, there is always a relativistic or mildly relativistic reverse shock forming in sigma_o < 0.3 ejecta. Thereby, we conclude that the paucity of optical flashes, believed to be a distinctive signature of a reverse shock, may be explained by the existence of dynamically important magnetic fields in the ejecta.

Angular momentum transation -- matter exchange

http://grblogscn.blogspot.com/2006/11/blog-post_25.html
Here is some aspects on the angular momentum transition. Another idea that the taking photons as the origin of viscousness, is also failed.

Now, one more another idea: particles to act the actor of viscousness. The transfer of particles (by thermal random movement? or some other methods) will bring the angular momentum from inner to outside.

Ichiki 2007 Probe intergalactic B using GRB high energy photons

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arXiv:0711.1589 [ps, pdf, other]

Title: Probing the Nature of the Weakest Intergalactic Magnetic Fields with the High Energy Emission of Gamma-Ray Bursts

Authors: Kiyotomo Ichiki, Susumu Inoue, Keitaro Takahashi

Comments: 19 pages, 9 figures

Subjects: Astrophysics (astro-ph)

We investigate the delayed, secondary GeV-TeV emission of gamma-ray bursts and its potential to probe the nature of intergalactic magnetic fields. Geometrical effects are properly taken into account for the time delay between primary high energy photons and secondary inverse Compton photons from electron-positron pairs, which are produced in $\gamma$-$\gamma$ interactions with background radiation fields and deflected by intervening magnetic fields. The time-dependent spectra of the delayed emission are evaluated for a wide range of magnetic field strengths and redshifts. The typical flux and delay time of secondary photons from bursts at $z \sim 1$ are respectively $\sim 10^{-8}$ GeV cm$^{-2}$ s$^{-1}$ and $\sim 10^4$ s if the field strengths are $\sim 10^{-18}$ G, as might be the case in intergalactic void regions. We find crucial differences between the cases of coherent and tangled magnetic fields, as well as dependences on the field coherence length.

Zhang 2007 a new luminosity/redshift indicator

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arXiv:0711.1411 [ps, pdf, other]

Title: Testing a new luminosity/redshift indicator for $\gamma$-ray bursts

Authors: Zhi-Bin Zhang, Guang-Zhong Xie

Comments: 7 pages, 6 figures and 1 table; Comments are welcome

Subjects: Astrophysics (astro-ph)

We have tested a relative spectral lag (RSL) method suggested earlier as a luminosity/redshift (or distance) estimator, using the generalized method by Schaefer & Collazzi. We find the derivations from the luminosity/redshift-RSL (L/R-RSL) relation are comparable with the corresponding observations. Applying the luminosity-RSL relation to two different GRB samples, we find that there exist no violators from the generalized test, namely the Nakar & Piran test and Li test. We also find that about 36 per cent of Schaefer's sample are outliers for the L/R-RSL relation within 1$\sigma$ confidence level, but no violators at 3$\sigma$ level within the current precision of L/R-RSL relation. An analysis of several potential outliers for other luminosity relations shows they can match the L/R-RSL relation well within an acceptable uncertainty. All the coincident results seem to suggest that this relation could be a potential tool for cosmological study.

De Rujula 2007 introduction to Cosmic rays and GRBs

主要内容:
A review for their cannon ball model.

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文章信息:

arXiv:0711.0970 (cross-list from hep-ph) [ps, pdf, other]

Title: An introduction to Cosmic Rays and Gamma-Ray Bursts, and to their simple understanding

Authors: A. De Rujula

Comments: Contribution to La Thuile 2007. 36 pages, 15 figures

Subjects: High Energy Physics - Phenomenology (hep-ph); Astrophysics (astro-ph)

I review the subjects of non-solar cosmic rays (CRs) and long-duration gamma-ray bursts (GRBs). Of the various interpretations of these phenomena, the one best supported by the data is the following. Accreting compact objects, such as black holes, are seen to emit relativistic puffs of plasma: `cannonballs' (CBs). The inner domain of a rotating star whose core has collapsed resembles such an accreting system. This suggests that core-collapse supernovae (SNe) emit CBs, as SN1987A did. The fate of a CB as it exits a SN and travels in space can be studied as a function of the CB's mass and energy, and of `ambient' properties: the encountered matter- and light- distributions, the composition of the former, and the location of intelligent observers. The latter may conclude that the interactions of CBs with ambient matter and light generate CRs and GRBs, all of whose properties can be described by this `CB model' with few parameters and simple physics. GRB data are still being taken in unscrutinized domains of energy and timing. They agree accurately with the model's predictions. CR data are centenary. Their precision will improve, but new striking predictions are unlikely. Yet, a one-free-parameter description of all CR data works very well. This is a bit as if one discovered QED today and only needed to fit $\alpha$.

Abbott 2007 No gravitational wave observed from GRB 070201

主要内容:
From LIGO. Implies that the short burst GRB 070201 may not came from double NSs merger.

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文章信息:

arXiv:0711.1163 [ps, pdf, other]

Title: Implications for the Origin of GRB 070201 from LIGO Observations

Authors: B. Abbott, et al, for the LIGO Scientific Collaboration

Comments: 10 pages 5 figures 1 table

Subjects: Astrophysics (astro-ph)

We analyzed the available LIGO data coincident with GRB 070201, a short duration hard spectrum gamma-ray burst whose electromagnetically determined sky position is coincident with the spiral arms of the Andromeda galaxy (M31). Possible progenitors of such short hard GRBs include mergers of neutron stars or a neutron star and black hole, or soft gamma-ray repeater (SGR) flares. These events can be accompanied by gravitational-wave emission. No plausible gravitational wave candidates were found within a 180 s long window around the time of GRB 070201. This result implies that a compact binary progenitor of GRB 070201, with masses in the range 1 M_sun <>99% confidence. Indeed, if GRB 070201 were caused by a binary neutron star merger, we find that D <>

Demianski 2007 Cosmological models in scalar tensor theories

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arXiv:0711.1043 [ps, pdf, other]

Title: Cosmological models in scalar tensor theories of gravity and observations: a class of general solutions

Authors: M.Demianski, E. Piedipalumbo, C.Rubano, P. Scudellaro

Comments: 26 pages,23 figures, accepted for publication in A&A

Subjects: Astrophysics (astro-ph)

We consider cosmological models in scalar tensor theories of gravity that describe an accelerating universe, and we study a family of inverse power law potentials, for which exact solutions of the Einstein equations are known. We also compare theoretical predictions of our models with observations. For this we use the following data: the publicly available catalogs of type Ia supernovae and high redshift Gamma Ray Bursts, the parameters of large scale structure determined by the 2-degree Field Galaxy Redshift Survey (2dFGRS), and measurements of cosmological distances based on the Sunyaev-Zel'dovich effect, among others.

Sato 2007 T_brk-L_X relation

主要内容:
Only for the values at the break time when shallow decay phase is ending. So the parameters needed is very few. From the relation, pseudo-redshift can be given.

That is to say, for more luminous bursts, the break time is larger. If we take a breaking time as the decelerating time, then, for more energetic burst (with more kinetic energy), the decelerating time is larger.

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T_brk中含z


文章信息:

arXiv:0711.0903 [ps, pdf, other]

Title: A Possible New Distance Indicator -Correlation between the duration and the X-ray luminosity of the shallow decay phase of Gamma Ray Bursts-

Authors: R. Sato, K. Ioka, K. Toma, T. Nakamura, J. Kataoka, N. Kawai, T. Takahashi

Comments: 28 pages, 7 figures, 4 tables. Submitted to ApJ

Subjects: Astrophysics (astro-ph)

We investigated the characteristics of the shallow decay phase in the early Xray afterglows of GRBs observed by Swift X-Ray Telescope (XRT) during the period of January 2005 to December 2006. We found that the intrinsic break time at the shallow-to-normal decay transition in the X-ray light curve Tbrk^0 is moderately well correlated with the isotropic X-ray luminosity in the end of the shallow decay phase (LX,end) as Tbrk^0 = (9.39+/-0.64)*10^3s(LX,end/10^47 ergs/s)^(-0.71+/-0.03), while Tbrk^0 is weakly correlated with the isotropic gamma-ray energy of the prompt emission Egamma,iso. Using Tbrk^0 - LX,end relation we have determined the pseudo redshifts of 33 GRBs. We compared the pseudo redshifts of 11 GRBs with measured redshifts and found the rms error to be 0.17 in log z. From this pseudo redshift, we estimate that ~15% of the Swift GRBs have z > 5. The advantages of this distance indicator is that (1) it requires only X-ray afterglow data while other methods such as Amati and Yonetoku correlations require the peak energy (Ep) of the prompt emission, (2) the redshift is uniquely determined without redshift degeneracies unlike the Amati correlation, and (3) the redshift is estimated in advance of deep follow-ups so that possible high redshift GRBs might be selected for detailed observations.

Auriemma 2007 constraints on CPT vialation review

主要内容:
Introduced the basic method on how to do the constraints -- purturbation expansion.

Including the work on GRBs, which is the Lorentz Violation to constrain the quantum gravity.

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文章信息:

arXiv:0711.0504 [ps, pdf, other]

Title: CPT violations in Astrophysics and Cosmology

Authors: G. Auriemma

Comments: 13 pages, Invited Paper to the Frascati Workshop 2007 Vulcano (Italy), May 28 - June 2, 2007

Subjects: Astrophysics (astro-ph)

In this paper it is given a brief review of the current limits on the magnitude of CPT and Lorentz Invariance violations, currently predicted in connection with quantum gravity and string/M-theory, that can be derived from astrophysical and cosmological data. Even if not completely unambiguous, these observational tests of fundamental physics are complementary to the ones obtained by accelerator experiments and by ground or space based direct experiments, because potentially can access very high energies and large distances.

García-Berro 2007 Review on constrain on fundamental constants by astronomy

主要内容:
e gravitational constant, on the fine structure constant and on the proton-to-electron mass ratio are reviewed.

And the astronomical objects include:
\alpha (fine structure constant): earth, sloar system, quasars, CMB, big bang nucleosynthesis
G: Earth, Earth-Moon, Radar and Laser, stellar, CMB, big bang nucleosynthesis
\mu (m_p/m_e): Geochemical, quasar spectroscopy

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文章信息:

Astronomical measurements and constraints on the variability of fundamental constants

期刊	Astronomy and Astrophysics Review
出版社	Springer Berlin / Heidelberg
ISSN	0935-4956 (Print) 1432-0754 (Online)
期	Volume 14, Number 2 / 2007年3月
文章类型	Paper
DOI	10.1007/s00159-006-0004-8
页	113-170

E. García-Berro¹ , J. Isern² and Y. A. Kubyshin^{3, 4}
Abstract We review the present status of how astronomical observations allow to constrain the evolution of fundamental constants of nature. The main observational constraints on the variation of the gravitational constant, on the fine structure constant and on the proton-to-electron mass ratio are reviewed. We also elaborate on some theoretical schemes which naturally lead to such variations.

Keywords Gravitation - Cosmology: miscellaneous - Cosmology: theory - Cosmology: early Universe

Evans 2007 techniques to analyse Swift-XRT data

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arXiv:0711.0433 [ps, pdf, other]

Title: Automatic analysis of Swift-XRT data

Authors: P. A. Evans, L.G. Tyler, A.P. Beardmore, J. P. Osborne (University of Leicester)

Comments: 4 pages, 2 figures, to appear in the proceedings of ADASS XVII (ASP Conference Series)

Subjects: Astrophysics (astro-ph)

The Swift spacecraft detects and autonomously observes ~100 Gamma Ray Bursts (GRBs) per year, ~96% of which are detected by the X-ray telescope (XRT). GRBs are accompanied by optical transients and the field of ground-based follow-up of GRBs has expanded significantly over the last few years, with rapid response instruments capable of responding to Swift triggers on timescales of minutes. To make the most efficient use of limited telescope time, follow-up astronomers need accurate positions of GRBs as soon as possible after the trigger. Additionally, information such as the X-ray light curve, is of interest when considering observing strategy. The Swift team at Leicester University have developed techniques to improve the accuracy of the GRB positions available from the XRT, and to produce science-grade X-ray light curves of GRBs. These techniques are fully automated, and are executed as soon as data are available.

Esposito 2007 Suzaku observation on SGR 1806-20

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arXiv:0711.0306 [ps, pdf, other]

Title: The first Suzaku observation of SGR 1806-20

Authors: P. Esposito, A. Tiengo, S. Zane, R. Turolla, S. Mereghetti, D. Gotz, G.L. Israel, N. Rea

Comments: 3 pages, 1 figure. Proceedings of the conference "40 Years of Pulsars, Millisecond Pulsars, Magnetars and More", Montreal, August 12-17 2007. AIP, in press

Subjects: Astrophysics (astro-ph)

The soft gamma-ray repeater SGR 1806-20 has been attracting a lot of attention owing to the fact that in December 2004 it emitted the most powerful giant flare ever observed. Here we present the results of the first Suzaku observation of SGR 1806-20, that seems to have reached a state characterized by a flux close to the pre-flare level and by a relatively soft spectrum. Despite this, the source remained quite active, as testified by several short bursts observed by Suzaku. We discuss the broadband spectral properties of SGR 1806-20 in the context of the magnetar model, considering its recent theoretical developments.

Coward 2007 bias of GRBs without measured redshift on the redshift distribution

主要内容:
Adding the bias for GRB without measured redshifts, the distribution will follow the SFR distribution.

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arXiv:0711.0242 [ps, pdf, other]

Title: Where are the missing gamma ray burst redshifts?

Authors: D. M. Coward, D. Guetta, R. R. Burman, A. Imerito

Comments: 5 pages, submitted to MNRAS

Subjects: Astrophysics (astro-ph)

In the redshift range z = 0-1, the gamma ray burst (GRB) redshift distribution should increase rapidly because of increasing differential volume sizes and strong evolution in the star formation rate. This feature is not observed in the Swift redshift distribution and to account for this discrepancy, a dominant bias, independent of the Swift sensitivity, is required. Furthermore, despite rapid localization, about 40-50% of Swift and pre-Swift GRBs do not have a measured redshift. We employ a heuristic technique to extract this redshift bias using 66 GRBs localized by Swift with redshifts determined from absorption or emission spectroscopy. For the Swift and HETE+BeppoSAX redshift distributions, the best model fit to the bias in z <> 2. To achieve this high KS probability requires increasing the GRB rate density in small z compared to the high-z rate. This provides further evidence for a low-luminosity population of GRBs that are observed in only a small volume because of their faintness.

Zhilyaev 2007 GRB 050922C optical

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arXiv:0711.0038 [ps, pdf, other]

Title: Detection of an oscillatory phenomenon in optical transient counterpart of GRB090522C from observations on Peak Terskol

Authors: B.E. Zhilyaev, M.V. Andreev, A.V. Sergeev, V.B. Petkov

Comments: 8 pages, 8 figures, Proceedings of the Conference "Near-Earth Astronomy - 2007", 3-7 September 2007, Terskol settlement, Kabardino-Balkaria, Russia

Subjects: Astrophysics (astro-ph)

22 Sep 2005 Swift-BAT triggered and located GRB050922C. The light curve shows the intense broad peak with $T_{90}$ of $(5 \pm 1)$ s. The Nordic Optical Telescope has obtained spectra of the afterglow with several absorption features corresponding to a redshift of $z = 2.17 \pm 0.03$. Observation of optical transient of GRB050922C was carried out in the R-band with the 60-cm telescope equipped with a CCD on Peak Terskol (North Caucasus). The OT magnitude was fading from R $\approx 16$ to $\approx 17.5$. Detection of an oscillatory phenomenon in the R post-burst light curve is described in this work. Analysis of the R data reveals coherent harmonic with a period of $0.0050 \pm 0.0003$ days (7.2 min) during observing run of about 0.05 days ($\sim 70$ min). Amplitude of oscillations is about 0.05 magnitude. The simplest model suggests that GRB050922C may result from tidal disruption of a white dwarf star by a black hole of about one thousand solar mass. The periodicity in the light curve can be identified with relativistic precession of an accretion disc.

Lipunov 2007 MASTER optical data 2005-2006

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arXiv:0711.0037 [ps, pdf, other]

Title: Optical Observations of Gamma-Ray Bursts, the Discovery of Supernovae 2005bv, 2005ee, and 2006ak, and Searches for Transients Using the "MASTER" Robotic Telescope

Authors: V. M. Lipunov, V.G.Kornilov, A.V.Krylov, N.V.Tyurina, A. A. Belinskii, E. S. Gorbovskoi, D. A. Kuvshinov, P. A. Gritsyk, G.A.Antipov, G. V. Borisov, A. V. Sankovich, V.V.Vladimirov, V. I.Vybornov, A. S. Kuznetsov

Comments: 30 pages, 18 figures, 9 tables

Journal-ref: Astronomicheskii Zhurnal, 2007, Vol. 84, No. 12, pp. 1110-1134

Subjects: Astrophysics (astro-ph)

We present the results of observations obtained using the MASTER robotic telescope in 2005 -- 2006, including the earliest observations of the optical emission of the gamma-ray bursts GRB 050824 and GRB 060926. Together with later observations, these data yield the brightness-variation law $t^{-0.55\pm0.05}$ for GRB 050824. An optical flare was detected in GRB 060926 -- a brightness enhancement that repeated the behavior observed in the X-ray variations. The spectrum of GRB 060926 is found to be $F_E \approx E^{-\beta}$, where $\beta = 1.0\pm0.2$. Limits on the optical brightnesses of 26 gamma-ray bursts have been derived, 9 of these for the first time. Data for more than 90% of the accessible sky down to $19^m$ were taken and reduced in real time during the survey. A database has been composed based on these data. Limits have been placed on the rate of optical flares that are not associated with detected gamma-ray bursts, and on the opening angle for the beams of gamma-ray bursts. Three new supernovae have been discovered: SN 2005bv (type Ia) -- the first to be discovered on Russian territory, SN 2005ee -- one of the most powerful type II supernovae known, and SN 2006ak (type Ia). We have obtained an image of SN 2006X during the growth stage and a light curve that fully describes the brightness maximum and exponential decay. A new method for searching for optical transients of gamma-ray bursts detected using triangulation from various spacecraft is proposed and tested.

Tsutsui 2007 redshift dependent time lag-luminosity relation

主要内容:
Gave a revised relation including redshift. It looks better.

This implies that the GRB evolves with redshift.

精彩摘抄:
the original relation
revised relation


文章信息:

arXiv:0710.5864 [ps, pdf, other]

Title: Redshift Dependent Lag-Luminosity Relation in 565 BASTE Gamma Ray Bursts

Authors: Ryo Tsutsui, Takashi Nakamura, Daisuke Yonetoku, Toshio Murakami, Sachiko Tanabe, Yoshiki Kodama

Subjects: Astrophysics (astro-ph)

We compared redshifts $z_Y$ from Yonetoku relation and $z_{lag}$ from the lag-luminosity relation for 565 BASTE GRBs and were surprised to find that the correlation is very low. Assuming that the luminosity is a function of both $z_Y$ and the intrinsic spectral lag $\tau_{lag}$, we found a new redshift dependent lag-luminosity relation as $L=7.5\times 10^{50}{\rm erg/s}(1+z)^{2.53}\tau_{lag}^{-0.282}$ with the correlation coefficient of 0.77 and the chance probability of $7.9\times 10^{-75}$. To check the validity of this method, we examined the other luminosity indicator, Amati relation, using $z_Y$ and the observed fluence and found the correlation coefficient of 0.92 and the chance probability of $5.2\times 10^{-106}$. Although the spectral lag is computed from two channels of BATSE, our new lag-luminosity relation suggests that a possible lag-luminosity relation in the \swift era should also depend on redshift.