Survival probabilities in time-dependent random walks

Nakar, Ehud; Hod, Shahar

doi:10.1103/physreve.70.016116

Cited by 30 publications

(47 citation statements)

References 25 publications

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“…The low value of E p may suggest that it belongs to the long-duration class; however, it is becoming clear that hardness cannot be used to reliably distinguish between the two classes (for further discussion see Nakar 2007). Similarly, while the negative lag inferred for XRF 050416a may suggest an SHB classification, examples do exist of long-duration BATSE bursts with negative lags (Norris & Bonnell 2006).…”

Section: Is Xrf 050416a a Short Burst?mentioning

confidence: 92%

A Spectacular Radio Flare from XRF 050416a at 40 Days and Implications for the Nature of X‐Ray Flashes

Söderberg

Nakar

Cenko

et al. 2007

ApJ

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We present detailed optical, near-infrared, and radio observations of the X-ray flash XRF 050416a obtained with Palomar and Siding Springs Observatories, as well as the HST and VLA, placing this event among the best-studied X-ray flashes to date. In addition, we present an optical spectrum from Keck LRIS from which we measure the redshift of the burst, z ¼ 0:6528. At this redshift the isotropic-equivalent prompt energy release was about 10 51 ergs, and using a standard afterglow synchrotron model, we find that the blast wave kinetic energy is a factor of 10 larger, E K;iso % 10 52 ergs. The lack of an observed jet break to t $ 20 days indicates that the opening angle is j k 7 and the total beaming-corrected relativistic energy is k10 50 ergs. We further show that the burst produced a strong radio flare at t $ 40 days accompanied by an observed flattening in the X-ray band, which we attribute to an abrupt circumburst density jump or an episode of energy injection (from either a refreshed shock or off-axis ejecta). Late-time observations with HST show evidence for an associated supernova with peak optical luminosity roughly comparable to that of SN 1998bw. Next, we show that the host galaxy of XRF 050416a is actively forming stars at a rate of at least 2 M yr À1 with a luminosity of L B % 0:5L Ã and metallicity of Z $ 0:2Y0:8 Z . Finally, we discuss the nature of XRF 050416a in the context of short-hard GRBs and under the framework of off-axis and dirty fireball models for X-ray flashes.

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Section: Is Xrf 050416a a Short Burst?mentioning

confidence: 92%

A Spectacular Radio Flare from XRF 050416a at 40 Days and Implications for the Nature of X‐Ray Flashes

Söderberg

Nakar

Cenko

et al. 2007

ApJ

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“…This model also explains the [135,352] correlation, the different E iso would be due to the observer being at different angles relative to the jet axis. This hypothesis has been tested in a variety of ways [186,324,249,178]. Attempts to extend the universal θ −2 jet structure to include X-ray flashes ( §2.5), together with use of the Amati relation between the spectral peak energy E peak and E γ,iso ( §2.6), leads to the conclusion that a uniform top-hat model is preferred over a universal θ −2 jet model [250].…”

Section: Jetsmentioning

confidence: 99%

Gamma-ray bursts

2006

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Abstract. Gamma-ray bursts are the most luminous explosions in the Universe, and their origin and mechanism are the focus of intense research and debate. More than three decades after their discovery, and after pioneering breakthroughs from space and ground experiments, their study is entering a new phase with the recently launched Swift satellite. The interplay between these observations and theoretical models of the prompt gamma ray burst and its afterglow is reviewed.

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“…Indeed, Nakar & Piran (2005) have recently argued that the A02 correlation might be the result of selection effects, as a large number of GRBs (at least 50 per cent in the sample they considered) do not appear to follow it. Similar findings have been reported by Band & Preece (2005) who performed a more refined analysis and concluded that 88 per cent of BATSE bursts are not consistent with the A02 relation, and only at most 18 per cent could be consistent with it.…”

Section: Spread Of the Correlationsmentioning

confidence: 99%

“…No unique and robust interpretation of such results has been found so far (Zhang & Meszaros 2002;Schaefer 2003;Eichler & Levinson 2004;Liang, Dai & Wu 2004;Rees & Meszaros 2005). However, it is clear that if these correlations were to hold for the whole GRB population E-mail: celotti@sissa.it (see Nakar & Piran 2005;Band & Preece 2005;Friedman & Bloom 2005, for dissenting views), they could provide powerful clues to the physical origin of the prompt emission and have important repercussions on the potential cosmological use of GRBs.…”

Section: Introductionmentioning

confidence: 99%

Energetics-spectral correlations versus the BATSE gamma-ray bursts population

Bošnjak

Celotti

Longo

et al. 2008

Monthly Notices of the Royal Astronomical Society

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The proposed correlations between the energetics of gamma‐ray bursts (GRBs) and their spectral properties, namely the peak energy of their prompt emission, can broadly account for the observed fluence distribution of all ‘bright’ BATSE GRBs, under the hypothesis that the GRB rate is proportional to the star formation rate and that the observed distribution in peak energy is independent of redshift. The correlations can also be broadly consistent with the properties of the whole BATSE long GRB population for a peak energy distribution smoothly extending towards lower energies, and in agreement with the properties of a sample at ‘intermediate’ fluences and with the luminosity functions inferred from the GRB number counts. We discuss the constraints that this analysis imposes on the shape of such peak energy distribution, the opening angle distribution and the tightness of the proposed correlations.

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Survival probabilities in time-dependent random walks

Cited by 30 publications

References 25 publications

A Spectacular Radio Flare from XRF 050416a at 40 Days and Implications for the Nature of X‐Ray Flashes

A Spectacular Radio Flare from XRF 050416a at 40 Days and Implications for the Nature of X‐Ray Flashes

Gamma-ray bursts

Energetics-spectral correlations versus the BATSE gamma-ray bursts population

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