Afterglow Emission from Naked Gamma-Ray Bursts

By Pawan Kumar, A. Panaitescu. 2000

366 citations recorded by the source corpus.

We calculate the afterglow emission for gamma-ray bursts (GRBs) going off in an extremely low density medium, referred to as naked bursts. Our results also apply to the case where the external medium density falls off sharply at some distance from the burst. The observed afterglow flux in this case originates at high latitudes, i.e., where the angle between the fluid velocity and the observer line of sight is greater than Γ-1. The observed peak frequency of the spectrum for naked bursts decreases with observer time as t-1, and the flux at the peak of the spectrum falls off as t-2. The 2-10 keV X-ray flux from a naked burst of average fluence should be observable by the Swift satellite for time duration of about 103 longer than the burst variability timescale. The high-latitude emission contributes to the early X-ray afterglow flux for any GRB, not just naked bursts, and can be separated from the shocked interstellar medium emission by their different spectral and temporal properties. Measurements of the high-latitude emission could be used to map the angular structure of GRB-producing shells.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5469cc7855367eff52b591b01b9ac9a500d4455c

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In Astronomy and Astrophysics

1. Bing Zhang
2. E. Berger
3. B. Metzger
4. Pawan Kumar
5. E. Nakar
6. E. Liang
7. E. Quataert
8. Binbin Zhang

Citations in the corpus

• The physics of gamma-ray bursts & relativistic jets (2014, background): “…simply the high latitude emission (described in §2.1) associated with the prompt γ-ray source at R >∼ 1015cm when the central engine turns off faster than the decline of the X-ray lightcurve (Kumar and Panaitescu, 2000a; Dermer, 2004; Zhang et al., 2006; Nousek et al., 2006; Liang et al., 2006a).”
• Gamma-Ray Bursts in the Swift Era (2007, background): “The generally accepted interpretation of the steep decay phse is the tail emission due to the so-called “curvature effect” (Fenimore et al. 1996; Kumar & Panaitescu 2000; Dermer 2004; Zhang et al. 2006; Panaitescu et al. 2006a; Dyks et al. 2005, for discussion of the curvature effect in the prompt…”
• Gamma-Ray Bursts in the Swift Era (2009, result): “…is consistent with an interpretation (Nousek et al. 2006, Zhang et al. 2006) in which the first break occurs when the slowly decaying emission from the forward shock becomes dominant over the steeply decaying tail emission of the prompt γ-rays as seen from large angles (Kumar and Panaitescu 2000).”
• Physical Processes Shaping Gamma-Ray Burst X-Ray Afterglow Light Curves: Theoretical Implications from the Swift X-Ray Telescope Observations (2005, background): “This is the so-called curvature effect (Fenimore et al. 1996; Kumar & Panaitescu 2000b; Dermer 2004; Dyks et al. 2005).”
• A unified picture of Galactic and cosmological fast radio bursts (2020, background): “Even if the maser mechanism is terminated suddenly when the shock is at some radius r, we will continue to receive radiation for at least a few times r/(2cΓ2s ), which drifts down in frequency as 1/t and the flux declines roughly as 1/t−2 (Kumar & Panaitescu 2000); t is the observer frame time.”
• Implications of the Lag-Luminosity Relationship for Unified Gamma-Ray Burst Paradigms (2002, background): “2001, ApJ, 546, L29 Salmonson, J. D., &Galama, T. J. 2002, ApJ, 569, 682 Scargle, J. D. 1981, ApJS, 45, 1 Soderberg, A.M., & Fenimore, E. E. 2001, in Proc.”
• THE HOST GALAXIES OF SWIFT DARK GAMMA-RAY BURSTS: OBSERVATIONAL CONSTRAINTS ON HIGHLY OBSCURED AND VERY HIGH REDSHIFT GRBs (2009, background): “GRBs exploding in galaxy halos or the intergalactic medium are predicted to have afterglows orders of magnitude fainter than those occurring in galactic disks (e.g., Kumar & Panaitescu 2000).”
• DISCERNING THE PHYSICAL ORIGINS OF COSMOLOGICAL GAMMA-RAY BURSTS BASED ON MULTIPLE OBSERVATIONAL CRITERIA: THE CASES OF z = 6.7 GRB 080913, z = 8.2 GRB 090423, AND SOME SHORT/HARD GRBs (2009, background): “A major issue of such a kinetic (high-latitude curvature effect) model is that the peak flux of the pulse drops rapidly with angle (Fenimore et al. 1996; Kumar & Panaitescu 2000), so that the flux is expected to be too low in softer bands to interpret the observed flux.”
• Testing the Curvature Effect and Internal Origin of Gamma-Ray Burst Prompt Emissions and X-Ray Flares with Swift Data (2006, background): “(1) (Kumar & Panaitescu 2000).”
• A Comprehensive Analysis of Swift XRT Data. II. Diverse Physical Origins of the Shallow Decay Segment (2007, background): “The normal decay phase could be missed in data fitting, if the normal decay segment is short, the data is sparse, or the jet break is not significant(e.g. Wei & Lu 2000; Kumar & Panaitescu 2000a; Gou et al. 2001).”
• Evidence for a Canonical Gamma-Ray Burst Afterglow Light Curve in the Swift XRT Data (2005, background): “We find that the most promising explanation for the initial fast flux decay ( 1) is that it is the tail of the prompt gamma-ray emission that is emitted from large angles ( > 1) relative to our line of sight (Kumar & Panaitescu 2000).”
• THE ULTRA-LONG GAMMA-RAY BURST 111209A: THE COLLAPSE OF A BLUE SUPERGIANT? (2012, background): “The choice of the Tend value is motivated by the fact that the sharp decline is usually interpreted as the high-latitude emission of the prompt phase, and its start time corresponds to the true end of the prompt phase (Kumar & Panaitescu 2000).”