We discuss the afterglow emission from a relativistic jet that is initially in the radiative regime in which the accelerated electrons are fast cooling. We note that such a “semiradiative” jet decelerates faster than an adiabatic jet does. We also take into account the effect of strong inverse-Compton scattering on the cooling frequency in the synchrotron component and therefore on the light cu...

The optical light curve of the afterglow following the gamma-ray burst GRB 990712 is reexamined. Recently published polarization measurements of that source require a collimated outflow geometry that in turn predicts a break in the light curve. We show that the V-band light curve is consistent with such a break and that the post-break light curve evolution is dominated by a supernova contributi...

transmission towers have been subjected to alternating loads caused by the galloping of iced conductors for a long time, and their fastening bolts are easy loosen or break, which seriously threatens safe operation lines. Through transverse vibration test M20 commonly used in towers, frequency amplitude changed, change law preload bolt joints is studied. The results show that with increase initi...

We revisit optical and radio afterglows arising from the shocks by relativistic conical ejecta running into pre-burst massive stellar winds. Under the homogeneous thin-shell approximation and the realistic treatment for lateral expansion of jets, our results show that a notable break of optical light curve within one decade in time indeed exists in most cases of our calculations by varying phys...

The afterglow emission that follows gamma-ray bursts (GRBs) contains valuable information about the circumburst medium and, therefore, about the GRB progenitor. Theoretical studies of GRB blast waves, however, are often limited to simple density profiles for the external medium (mostly constant density and power-law R−k ones). We argue that a large fraction of long-duration GRBs should take pla...

Context. The Swift discovery of the short burst GRB 090510 has raised considerable attention mainly because of two reasons: first, it had a bright optical afterglow, and second it is among the most energetic events detected so far within the entire GRB population (long plus short). The afterglow of GRB 090510 was observed with Swift/UVOT and Swift/XRT and evidence of a jet break around 1.5 ks a...

We report the discovery and subsequent multi-wavelength afterglow behaviour of the high redshift (z = 4.27) Gamma Ray Burst GRB 050505. This burst is the third most distant burst, measured by spectroscopic redshift, discovered after GRB 000131 (z = 4.50) and GRB 050904 (z = 6.29). GRB 050505 is a long GRB with a multipeaked γ-ray light curve, with a duration of T90 = 63±2 s and an inferred isot...

361 Figure 1. Log-log plot of the variance at a given scale, vs. that scale (similar to the power spectrum or a 2nd order structure function). It shows (scale-invariant) ARM cloud liquid water path data plus two computed radiation fields, IPA (“simple theory”) and MC (“better theory”). The MC curve, showing a scale break at the “radiative smoothing scale” 0 . 200-300 m for marine Sc, agrees wit...

We present all the Target of Opportunity (ToO) sub-millimeter observations of GRB 030329 taken by the Sub-millimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). This was by far the brightest sub-millimeter afterglow seen to date. The flux density at 850 μm was approximately constant up to a break that took place ∼7 days after the burst. This was consistent w...