Hydrodynamics of Relativistic Blast Waves in a Density-Jump Medium and Their Emission Signature

Dai, Z. G.; Liu, Tan

doi:10.1086/339418

Cited by 307 publications

(420 citation statements)

References 48 publications

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“…Several modifications have been suggested to explain some of the observed fluctuations, flares, bumps and wiggles. Such modifications may include different density profiles and fluctuations (Wang & Loeb 2000;Ramirez-Ruiz et al 2001;Dai & Lu 2002;, energy injections (Rees & Meszaros 1998;Sari & Mészáros 2000;Granot et al 2003;Björnsson et al 2004;Jóhannesson et al 2006), jets with complex structure (Mészáros et al 1998;Kumar & Piran 2000;Rossi et al 2002), late engine activity (Dai & Lu 1998;Zhang & Mészáros 2002;Ramirez-Ruiz 2004), microlensing (Loeb & Perna 1998;Garnavich et al 2000;Ioka & Nakamura 2001) or dust echoes (Esin & Blandford 2000;Mészáros & Gruzinov 2000;Reichart 2001). Discerning the different scenarios is only possible through the analysis of the SEDs obtained with multiwavelength observations (see Sect.…”

Section: The Physics Of Grbs and Their Environmentsmentioning

confidence: 99%

Pre-ALMA observations of GRBs in the mm/submm range

Postigo

Lundgren

Martín

et al. 2012

A&A

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Context. Gamma-ray bursts (GRBs) generate an afterglow emission that can be detected from radio to X-rays during days, or even weeks after the initial explosion. The peak of this emission crosses the millimeter and submillimeter range during the first hours to days, making their study in this range crucial for constraining the models. Observations have been limited until now due to the low sensitivity of the observatories in this range. This situation will be greatly improved with the start of scientific operations of the Atacama Large Millimeter/submillimeter Array (ALMA). Aims. In this work we do a statistical analysis of the complete sample of mm/submm observations of GRB afterglows obtained before the beginning of scientific operations at ALMA. Methods. We present observations of 11 GRB afterglows obtained from the Atacama Pathfinder Experiment (APEX) and the SubMillimeter Array (SMA), as well as the first detection of a GRB with ALMA, still in the commissioning phase, and put them into context with a catalogue of all the observations that have been published until now in the spectral range that is covered by ALMA.Results. The catalogue of mm/submm observations collected here is the largest to date and is composed of 102 GRBs, of which 88 have afterglow observations, whereas the rest are host galaxy searches. With our programmes, we contributed with data of 11 GRBs and the discovery of 2 submm counterparts. In total, the full sample, including data from the literature, has 22 afterglow detections with redshifts ranging from 0.168 to 8.2. GRBs have been detected in mm/submm wavelengths with peak luminosities spanning 2.5 orders of magnitude, the most luminous reaching 10 33 erg s −1 Hz −1 . We observe a correlation between the X-ray brightness at 0.5 days and the mm/submm peak brightness. Finally we give a rough estimate of the distribution of peak flux densities of GRB afterglows, based on the current mm/submm sample. Conclusions. Observations in the mm/submm bands have been shown to be crucial for our understanding of the physics of GRBs, but have until now been limited by the sensitivity of the observatories. With the start of the operations at ALMA, the sensitivity has improved by more than an order of magnitude, opening a new era in the study of GRB afterglows and their host galaxies. Our estimates predict that, once completed, ALMA will detect up to ∼98% of the afterglows if observed during the passage of the peak synchrotron emission.

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Section: The Physics Of Grbs and Their Environmentsmentioning

confidence: 99%

Pre-ALMA observations of GRBs in the mm/submm range

Postigo

Lundgren

Martín

et al. 2012

A&A

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“…Variations in the external density provide a possible explanation for the temporal variability of the GRB afterglow light curves within the external shock framework (Lazzati et al 2002;Zhang et al 2006;Ioka et al 2005;Wang & Loeb 2000;Dai & Lu 2002). Such variations might be the result of the interstellar medium turbulence or variability in the winds from the progenitor.…”

Section: Inhomogeneous Density Profile Of the Ismmentioning

confidence: 99%

“…4.2, Rees & Mészáros 1998;Panaitescu 2005;Sari & Mészáros 2000;Panaitescu et al1998;Granot et al 2003;Kumar & Piran 2000), the ambient density profile into which the blast wave expands might not be homogeneous (see Sect. 4.3, Lazzati et al 2002;Zhang et al 2006;Ioka et al 2005;Wang & Loeb 2000;Dai & Lu 2002;Nakar & Granot 2007), or the jet may have an angular structure different from a top hat (see Sect. 4.4, Peng et al 2005;Granot et al 2006;Berger et al 2003;Racusin et al 2008).…”

Section: Introductionmentioning

confidence: 99%

The two-component jet of GRB 080413B

Filgas

Krühler

Greiner

et al. 2011

A&A

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Aims. The quick and precise localization of GRBs by the Swift telescope allows the early evolution of the afterglow light curve to be captured by ground-based telescopes. With GROND measurements we can investigate the optical/near-infrared light curve of the afterglow of gamma-ray burst 080413B in the context of late rebrightening. Methods. Multi-wavelength follow-up observations were performed on the afterglow of GRB 080413B. X-ray emission was detected by the X-ray telescope onboard the Swift satellite and obtained from the public archive. Optical and near-infrared photometry was performed with the seven-channel imager GROND mounted at the MPG/ESO 2.2 m telescope and additionally with the REM telescope, both in La Silla, Chile. The light curve model was constructed using the obtained broad-band data. Results. The broad-band light curve of the afterglow of GRB 080413B is well fitted with an on-axis two-component jet model. The narrow ultra-relativistic jet is responsible for the initial decay, while the rise of the moderately relativistic wider jet near its deceleration time is the cause of the rebrightening of the light curve. The later evolution of the optical/NIR light curve is then dominated by the wide component, the signature of which is almost negligible in the X-ray wavelengths. These components have opening angles of θ n ∼ 1.7 • and θ w ∼ 9 • , and Lorentz factors of Γ n > 188 and Γ w ∼ 18.5. We calculated the beaming-corrected energy release to be E γ = 7.9 × 10 48 erg.

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“…The early steep decays of the optical light curves (Akerlof et al 1999;Fox et al 2003b,a;Rykoff et al 2004) are interpreted as reverse shocks (Sari & Piran 1999a,b;Mészáros & Rees 1999;Kobayashi 2000). Some of the rebrightenings and bumps (Panaitescu et al 1998;Granot et al 2003;Guetta et al 2007) are attributed to refreshed shocks Panaitescu et al 1998), the others to density variations (Ramirez-Ruiz et al 2001;Dai & Lu 2002;Dai & Wu 2003;Panaitescu & Kumar 2004) or two-component jets (Berger et al 2003;Huang et al 2004;Peng et al 2005;Granot et al 2006;Racusin et al 2008;Filgas et al 2011b). However, with the latest generation of GRB instruments capable of high sampling in both time and energy domains, the modifications made to the standard model still fall short to explaining the observed afterglows consistently (e.g., Nardini et al 2011;Filgas et al 2011a).…”

Section: Introductionmentioning

confidence: 99%

GRB 091029: at the limit of the fireball scenario

Filgas

Greiner

Schady

et al. 2012

A&A

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Aims. Using high-quality, broad-band afterglow data for GRB 091029, we test the validity of the forward-shock model for gamma-ray burst afterglows. Methods. We used multi-wavelength (NIR to X-ray) follow-up observations obtained with the GROND, BOOTES-3/YA and Stardome optical ground-based telescopes, and the UVOT and the XRT onboard the Swift satellite. The resulting data of excellent accuracy allow us to construct a multi-wavelength light curve with relative photometric errors as low as 1%, as well as the well-sampled spectral energy distribution covering 5 decades in energy. Results. The optical/NIR and the X-ray light curves of the afterglow of GRB 091029 are almost totally decoupled. The X-ray light curve shows a shallow rise with a peak at ∼7 ks and a decay slope of α ∼ 1.2 afterwards, while the optical/NIR light curve shows a much steeper early rise with a peak around 400 s, followed by a shallow decay with temporal index of α ∼ 0.6, a bump and a steepening of the decay afterwards. The optical/NIR spectral index decreases gradually by over 0.3 before this bump, and then slowly increases again, while the X-ray spectral index remains constant throughout the observations. Conclusions. To explain the decoupled light curves in the X-ray and optical/NIR domains, a two-component outflow is proposed. Several models are tested, including continuous energy injection, components with different electron energy indices and components in two different stages of spectral evolution. Only the last model can explain both the decoupled light curves with asynchronous peaks and the peculiar SED evolution. However, this model has so many unknown free parameters that we are unable to reliably confirm or disprove its validity, making the afterglow of GRB 091029 difficult to explain in the framework of the simplest fireball model. This conclusion provides evidence that a scenario beyond the simplistic assumptions is needed to be able to model the growing number of well-sampled afterglow light curves.

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Hydrodynamics of Relativistic Blast Waves in a Density-Jump Medium and Their Emission Signature

Cited by 307 publications

References 48 publications

Pre-ALMA observations of GRBs in the mm/submm range

Pre-ALMA observations of GRBs in the mm/submm range

The two-component jet of GRB 080413B

GRB 091029: at the limit of the fireball scenario

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