The Ep,i–Eiso correlation in gamma-ray bursts: updated observational status, re-analysis and main implications

By L. Amati. 2006

372 citations recorded by the source corpus.

The correlation between the cosmological rest-frame vF v spectrum peak energy, E p,i , and the isotropic-equivalent radiated energy, E iso , discovered by Amati et al. in 2002 and confirmed/extended by subsequent osbervations, is one of the most intriguing and debated observational evidences in gamma-ray burst (GRB) astrophysics. In this paper, I provide an update and a re-analysis of the E p,i -E iso correlation basing on an updated sample consisting of 41 long GRBs/X-ray flashes (XRFs) with firm estimates of z and observed peak energy, E p,obs , 12 GRB s with uncertain values of z and/or E p,obs , two short GRBs with firm estimates of z and E p,obs and the peculiar subenergetic events GRB 980425/SN1998bw and GRB 031203/SN20031w. In addition to standard correlation analysis and power-law fitting, the data analysis here reported includes modelling that accounts for sample variance. All 53 classical long GRBs and XRFs, including 11 Swift events with published spectral parameters and fluences, have E p,i and E iso values, or upper/lower limits, consistent with the correlation, which shows a chance probability as low as ∼7 x 10 -15 , a slope of ∼0.57 (∼0.5 when fitting by accounting for sample variance) and an extra-Poissonian logarithmic dispersion of ∼0.15, it extends over ∼5 orders of magnitude in E iso and ∼3 orders of magnitude in E p,i and holds from the closer to the higher z GRBs. Subenergetic GRBs (980425 and possibly 031203) and short GRBs are found to be inconsistent with the E p,i -E iso correlation, showing that it can be a powerful tool for discriminating different classes of GRBs and understanding their nature and differences. I also discuss the main implications of the updated E p,i -E iso correlation for the models of the physics and geometry of GRB emission, its use as a pseudo-redshift estimator and the tests of possible selection effects with GRBs of unknown redshift.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/1ab91f60a70fd1501bba224512b945fc7e137684

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In Astronomy and Astrophysics

1. Bing Zhang
2. E. Berger
3. Pawan Kumar
4. L. Amati
5. B. Metzger
6. T. Piran
7. Daniel J. Eisenstein
8. D. Weinberg

Citations in the corpus

• THE AFTERGLOW OF GRB 130427A FROM 1 TO 1016 GHz (2013, methodology): “…GRBs taken from the literature: Swift (from Butler & Kocevski 2007, using the most up-to-date catalogs online36), Konus (from a search of the GCN Circulars from 2005 onward), FermiGBM (from Goldstein et al. 2012 and Paciesas et al. 2012), and a variety of pre-Swift satellites from Amati (2006).”
• THE SECOND SWIFT BURST ALERT TELESCOPE GAMMA-RAY BURST CATALOG (2011, methodology): “We used the same cosmological parameters of Amati (2006) in the calculation of Eiso for the Swift GRBs. Table 13 summarizes the values of Esrcpeak and Eiso of Swift GRBs.”
• Observational probes of cosmic acceleration (2012, background): “GRBs are extremely diverse and highly beamed, but they exhibit correlations (Amati, 2006; Ghirlanda et al., 2006) between equivalent isotropic energy and spectral properties (such as the energy of peak intensity) or variability.”
• The physics of gamma-ray bursts & relativistic jets (2014, background): “Numerically, this relation can be written as Ep,z 100 keV = C ( Eγ,iso 1052 erg )m (102) with C ∼ (0.8 − 1) and m ∼ (0.4 − 0.6) (Amati, 2006).”
• AFTERGLOW OBSERVATIONS OF FERMI LARGE AREA TELESCOPE GAMMA-RAY BURSTS AND THE EMERGING CLASS OF HYPER-ENERGETIC EVENTS (2010, methodology): “…the empirical relation between the peak energy of the gamma-ray spectrum and the isotropic gamma-ray energy release (the Ep–Eγ,iso, or “Amati” relation; Amati 2006), MeV/GeV events detected by either the Gamma-Ray Burst Monitor (GBM, 8 keV – 40MeV; Meegan et al. 2009) or the Large Area Telescope…”
• A complete sample of bright Swift long gamma-ray bursts: testing the spectral-energy correlations (2011, background): “Li (2007), considered a sample of 48 GRBs (from Amati 2006, 2007) and investigated if the Epeak− Eiso correlation evolves with redshift, finding that it does, becoming steeper at higher redshifts.”
• A RADIO-SELECTED SAMPLE OF GAMMA-RAY BURST AFTERGLOWS (2011, neutral): “Abbreviations for the references are as follows: (1) Aleksić et al. 2010; (2) Chandra et al. 2010; (3) Amati 2006; (4) Antonelli et al. 2000; (5) Berger et al. 2005b; (6) Berger et al. 2007; (7) Bloom et al. 2001; (8) Butler et al. 2007; (9) Cardone et al. 2009; (10) Cenko et al. 2006; (11)…”
• GIANT AGN FLARES AND COSMIC RAY BURSTS (2008, background): “The typical isotropic equivalent energy of photons from a GRB is ≈ few×1053 erg (Amati 2006), so if GRBs are responsible for all the UHECRs, they must give a factor & 100 times more energy to UHECRs than to photons.”
• Extremely energetic Fermi Gamma-Ray Bursts obey spectral energy correlations (2009, neutral): “…by di ff erent instruments, each one having its own sensitivity and spectral response and thus covering di ff erent regions of the E p – fluence plane (Amati 2006a,b; Ghirlanda et al. 2008); b) by verifying its validity with large samples of GRBs with no measured redshift (Ghirlanda et al.…”
• Measuring the cosmological parameters with the Ep,i–Eiso correlation of gamma-ray bursts (2008, methodology): “As an example, the fit of the correlation with this method by using the Eiso values reported in Table 1 provides the following parameters value: m = 0.54±0.03, K = 98±7 and σext = 0.17 ± 0.02 (68% c.l.; consistent with the results reported by Amati 2006 for a smaller sample of 41 GRBs).”
• Short versus long gamma-ray bursts: spectra, energetics, and luminosities (2009, background): “The few short GRBs with measuredz and well determined spectral properties are inconsistent with theEpeak − Eiso correlation (Amati 2006, 2008), but it is worth exploring whether they are consistent with theEpeak−Liso relation.”
• Gamma-Ray Bursts in the Swift Era (2007, background): “…(the so-called Amati-relation,Ep ∝ E 1/2 iso , see Section 3.4 for more discussion), which is found generally valid among bursts (Amati et al. 2002; Amati 2006) and also within a same burst (Liang et al. 2004), Zhang et al. (2007a) generated a pseudo-burst that is about 8 timesless energetic.”