Famille, urbanisation et crise du logement en Algérie

Megdiche, Cyrille; Guetta, Maurice

doi:10.3406/socco.1990.967

Cited by 11 publications

(13 citation statements)

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“…4, which is similar to flares seen in e.g. GRB 051117A (Goad et al 2007), GRB 050713A (Guetta et al 2007) and 061121 (Page et al 2007).…”

Section: Spectral Evolutionsupporting

confidence: 72%

Correlated optical and X-ray flares in the afterglow of XRF 071031

Krühler,

Greiner,

McBreen

et al. 2009

Preprint

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We present a densely sampled early light curve of the optical/near-infrared (NIR) afterglow of the X-Ray Flash (XRF) 071031 at z=2.692. Simultaneous and continuous observations in seven photometric bands from g ′ to K S with GROND at the 2.2 m MPI/ESO telescope on LaSilla were performed between 4 minutes and 7 hours after the burst. The light curve consists of 547 individual points which allows us to study the early evolution of the optical transient associated with XRF 071031 in great detail. The optical/NIR light curve is dominated by an early increase in brightness which can be attributed to the apparent onset of the forward shock emission. There are several bumps which are superimposed onto the overall rise and decay. Significant flaring is also visible in the Swift X-Ray Telescope (XRT) light curve from early to late times. The availability of high quality, broadband data enables detailed studies of the connection between the X-ray and optical/NIR afterglow and its colour evolution during the first night post burst. We find evidence of spectral hardening in the optical bands contemporaneous with the emergence of the bumps from an underlying afterglow component. The bumps in the optical/NIR light curve can be associated with flares in the X-ray regime suggesting late central engine activity as the common origin.

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“…4, which is similar to flares seen in e.g. GRB 051117A (Goad et al 2007), GRB 050713A (Guetta et al 2007) and 061121 (Page et al 2007).…”

Section: Spectral Evolutionsupporting

confidence: 72%

Correlated optical and X-ray flares in the afterglow of XRF 071031

Krühler,

Greiner,

McBreen

et al. 2009

Preprint

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show abstract

“…The observed phenomenology has been found to be common to both long and short GRBs, and a number of studies have been aimed at establishing the origin of these X-ray rebrightenings. While in some cases the data are consistent with a refreshed (external) shock (Guetta et al 2007), the greater majority of the flares do require an extended activity of the inner engine, due to their fast temporal rise and decay (Zhang et al 2006;Lazzati & Perna 2007;Chincarini et al 2007;Falcone et al 2007) and as indicated by internal shock modeling (Maxham & Zhang 2009).…”

Section: Introductionmentioning

confidence: 85%

Flare-Less Long Gamma-Ray Bursts and the Properties of Their Massive Progenitor Stars

Perna

MacFadyen

2010

ApJ

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While there is mounting evidence that long gamma-ray bursts (GRBs) are associated with the collapse of massive stars, the detailed structure of their pre-supernova stage is still debatable. Particularly uncertain is the degree of mixing among shells of different composition, and hence the role of magnetic torques and convection in transporting angular momentum. Here we show that early-time afterglow observations with the Swift satellite place constraints on the allowed GRB pre-supernova models. In particular, they argue against pre-supernova models in which different elemental shells are unmixed. These types of models would produce energy injections into the GRB engine on timescales between several hundreds of seconds to a few hours. Flaring activity has not been observed in a large fraction of well monitored long GRBs. Therefore, if the progenitors of long GRBs have common properties, then the lack of flares indicates that the massive stars which produce GRBs are mostly well mixed, as expected in low-metallicity, rapidly rotating massive stars.

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“…The subject of X-ray flares in GRBs is an important one and a number of recent papers on Swift bursts have discussed flares, leading to a growing consensus that flares reflect late-time activity of the central source. Some important examples are Falcone et al (2006; the giant flare of GRB 050502B), Guetta et al (2007;GRB 050713A), and Burrows et al (2007) and Chincarini et al (2007) on the analysis of a statistical sample of Swift flares. This paper adds important new observational results and conclusions to the existing body of literature on flares.…”

Section: Discussionmentioning

confidence: 99%

GRB 060714: No Clear Dividing Line between Prompt Emission and X‐Ray Flares

Krimm

Granot

Marshall

et al. 2007

ApJ

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The long gamma-ray burst GRB 060714 was observed to exhibit a series of five X-ray flares beginning $70 s after the burst trigger T 0 and continuing until $T 0 þ 200 s. The first two flares were detected by the Burst Alert Telescope (BAT) on the Swift satellite, before Swift had slewed to the burst location, while the last three flares were strongly detected by the X-Ray Telescope (XRT) but only weakly detected by the BAT. This burst provides an unusual opportunity to track a complete sequence of flares over a wide energy range. The flares were very similar in their light curve morphology, showing power-law rise and fall components, and in most cases significant substructure. The flares also showed strong evolution with time, both spectrally and temporally. The small timescale and large amplitude variability observed are incompatible with an external shock origin for the flares, and support instead late-time sporadic activity either of the central source or of localized dissipation events within the outflow. We show that the flares in GRB 060714 cannot be the result of internal shocks in which the contrast in the Lorentz factor of the colliding shells is very small, and that this mechanism faces serious difficulties in most Swift GRBs. The morphological similarity of the flares and the prompt emission and the gradual and continual evolution of the flares with time makes it difficult and arbitrary to draw a dividing line between the prompt emission and the flares.

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Famille, urbanisation et crise du logement en Algérie

Cited by 11 publications

References 0 publications

Correlated optical and X-ray flares in the afterglow of XRF 071031

Correlated optical and X-ray flares in the afterglow of XRF 071031

Flare-Less Long Gamma-Ray Bursts and the Properties of Their Massive Progenitor Stars

GRB 060714: No Clear Dividing Line between Prompt Emission and X‐Ray Flares

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