Properties of Relativistic Jets in Gamma-Ray Burst Afterglows

By A. Panaitescu, P. Kumar. 2001

500 citations recorded by the source corpus.

We extend our calculation of physical parameters of gamma-ray burst (GRB) jets by modeling the broadband emission of the afterglows 970508, 980519, 991208, 000926, 000418, and 010222. Together with 990123, 990510, 991216, and 000301c, there are 10 well-observed afterglows for which the initial opening angle of the GRB jet can be constrained. The jet energies (after the GRB phase) obtained for this set of afterglows are within one decade around 5 × 1050 ergs. With the exception of 000418, which requires a jet wider than rad, the jet initial half-angle in the other cases ranges from 2° to 20°. We find that in half of the cases, a homogeneous ambient medium accommodates the afterglow emission better than the windlike r-2 profile medium expected around massive stars. The two types of media give fits of comparable quality in four cases, with a wind medium providing a better description only for 970508. The circumburst densities we obtain are in the 0.1-100 cm-3 range, with the exception of 990123, for which it is below 10-2 cm-3. If in all 10 cases the observed GRB durations are a good measure of the ejecta deceleration timescale, then the parameters obtained here lead to jet Lorentz factors at the deceleration radius between 70 and 300, anticorrelated with the jet initial aperture, and jet masses around 10-6 M☉ . Our results on the jet energy, opening Lorentz factor, and evacuation of material until breakout provide constraints on theoretical models of GRB jets.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/bb58cfee2b1185a547acda703a879f95580ea761

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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. Stan Woosley

In Nuclear and High Energy Physics

1. Bing Zhang
2. Pawan Kumar
3. B. Metzger
4. D. Giannios
5. E. Berger
6. A. Spitkovsky
7. Ramesh Narayan
8. J. McKinney

Citations in the corpus

• Relativistic Jets Shine through Shocks or Magnetic Reconnection (2015, background): “GRBs have efficiency f ∼ 0.1 − 1 in converting jet power into gamma-ray (prompt) emission (e.g., Berger et al.2000; Panaitescu & Kumar 2002; Yost et al. 2003; Granot et al. 2006; Nava et al. 2013).”
• The Cosmic Dispersion Measure from Gamma-Ray Burst Afterglows: Probing the Reionization History and the Burst Environment (2003, background): “3 (Dn/80 MHz) t mJy Dn ∼ 0.5n3 integration time s, and cm2 K .43 8 1t p 10 A /T p 2 # 10eff sys However, some GRBs have larger energy ergs and54E ∼ 10 lower density cm (Panaitescu & Kumar 2002).”
• A DECADE OF SHORT-DURATION GAMMA-RAY BURST BROADBAND AFTERGLOWS: ENERGETICS, CIRCUMBURST DENSITIES, AND JET OPENING ANGLES (2015, background): “…Berger et al. 2003; Friedman & Bloom 2005; Gehrels et al. 2008; Nysewander et al. 2009; Laskar et al. 2014), circumburst densities of≈ 0.1 − 100 cm−3 (Panaitescu & Kumar 2002; Yost et al. 2003), and opening angles of≈ 2 − 20◦ (Bloom et al. 2003; Frail et al. 2001; Friedman & Bloom 2005;…”
• Physical Processes Shaping Gamma-Ray Burst X-Ray Afterglow Light Curves: Theoretical Implications from the Swift X-Ray Telescope Observations (2005, methodology): “Previous analyses using late-time afterglow data (e.g., Panaitescu & Kumar 2002; Yost et al. 2003) have also suggested that most afterglow data are consistent with an ISMmodel rather than a windmodel.”
• Binary star progenitors of long gamma-ray bursts (2007, background): “However, from the analysis of GRB afterglows, a constant circumstellar medium density has been inferred in many cases (Chevalier & Li 2000; Panaitescu & Kumar 2001, 2002; Chevalier et al. 2004).”
• The afterglow of GRB 021004: surfing on density waves (2002, unknown): “(Panaitescu & Kumar 2002).”
• Gamma‐ray burst efficiency and possible physical processes shaping the early afterglow (2006, background): “Similar conclusion can be drawn by comparing previous results of Granot et al (1999), Wijers & Galama (1999), Freedman & Waxman (2001), Panaitescu & Kumar (2002) and LZ04.”
• A Comprehensive Analysis of Swift XRT Data. III. Jet Break Candidates in X-Ray and Optical Afterglow Light Curves (2007, background): “Previous broadband fits and statistical analyses suggest that e is typically around 0.1 (Wijers & Galama 1999; Panaitescu & Kumar 2002; Yost et al. 2003; Liang et al. 2004; Wu et al. 2004).10 Therefore, we take e = 0.1 for all the bursts.”
• Interpenetrating Plasma Shells: Near-Equipartition Magnetic Field Generation and Nonthermal Particle Acceleration (2003, background): “The obtained values of the equipartition parameter ( for ultra- and subrelativistic shocks) 2 3e ∼ 3 # 10 –3# 10B agree well with the values of inferred from GRB afterglowseB (Panaitescu & Kumar 2002).”
• THE MILLISECOND MAGNETAR CENTRAL ENGINE IN SHORT GRBs (2015, methodology): “In our calculations, the microphysics parameters of the shocks are assigned to standard values derived from the observations (e.g. Panaitescu & Kumar 2002; Yost et al. 2003): ǫe=0.1 and ǫB = 0.01.”
• AFTERGLOW OBSERVATIONS OF FERMI LARGE AREA TELESCOPE GAMMA-RAY BURSTS AND THE EMERGING CLASS OF HYPER-ENERGETIC EVENTS (2010, background): “Of the past GRBs with sufficient radio observations to estimate the circumburst density, the derived values span a large range from 1.9 × 10−3 cm−3 (GRB990123; Panaitescu & Kumar 2002) to 680 cm−3 (GRB050904; Frail et al. 2006).”
• The Hubble Diagram to Redshift >6 from 69 Gamma-Ray Bursts (2006, background): “For many bursts, the value of jet is based on a detailedmodel fitting of light curves in many energy bands (e.g., Panaitescu & Kumar 2002).”
• A complete reference of the analytical synchrotron external shock models of gamma-ray bursts (2013, background): “This is because the radiative loss fraction is at most ǫe (for fast cooling), which is constrained to be around 0.1 and lower (Panaitescu and Kumar, 2001, 2002; Yost et al., 2003)5.”
• Magnetic Field Generation in Collisionless Shocks: Pattern Growth and Transport (2003, background): “The existence of a strong magnetic field in the shocked external medium is required in order to explain the observed radiation in Gamma-Ray Burst afterglows as synchrotron radiation (e.g. Panaitescu & Kumar 2002).”
• Evidence for a Canonical Gamma-Ray Burst Afterglow Light Curve in the Swift XRT Data (2005, background): “…than several hours and therefore at t > tbreak;2) is typically estimated to be comparable to or smaller than that in the prompt gamma-ray emission (Panaitescu & Kumar 2002; Lloyd-Ronning & Zhang 2004), even when correcting for radiative losses from the afterglow shock at early times, implying a…”
• The Evolution of a Structured Relativistic Jet and Gamma-Ray Burst Afterglow Light Curves (2003, background): “…of the emergent jet, the density of the medium in the immediate vicinity of the GRB, etc., is that of comparing the observed afterglow light curve with the theoretically calculated flux (Wijers & Galama 1999; Granot, Piran, & Sari 1999b; Chevalier & Li 2000; Panaitescu & Kumar 2001a, 2001b, 2002).”
• Probing the cosmic reionization history and local environment of gamma‐ray bursts through radio dispersion (2003, methodology): “The isotropic equivalent (i.e. beaming-corrected) initial kinetic energy of the blastwave is fiducially E = 1053 erg from the most recent observational determinations (Panaitescu & Kumar 2001, 2002, Frail et al. 2001).”
• Model-independent Multivariable Gamma-Ray Burst Luminosity Indicator and Its Possible Cosmological Implications (2005, background): “…to several assumptions involved in the current Ghirlandarelation, such as constant medium density (which could vary in different bursts, e.g. Panaitescu & Kumar 2002), constant radiative efficiency (which also varies from burst to burst, e.g. Lloyd-Ronning & Zhang 2004; Bloom et al. 2003a…”
• Implications of the Lag-Luminosity Relationship for Unified Gamma-Ray Burst Paradigms (2002, background): “…can explain the break times, dynamic ranges in luminosity and gamma-ray energy, and in some cases the gamma-ray pulse behavior (Frail et al. 2001; Panaitescu & Kumar 2002; Wang & Wheeler 1998; Höflich et al. 1999; Nakamura 1999; Woosley et al. 1999; Salmonson 2001; Ioka & Nakamura 2001;…”