http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
GRB Early Afterglow Observations with the REM Robotic Telescope
Susanna Diana Vergani,Stefano Covino,Daniele Malesani,Cristiano Guidorzi,Paolo D’Avanzo,Eliana Palazzi 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.5
Gamma-ray bursts (GRBs) are thought to be produced by highly relativistic outflows. Although upper and lower limits for the outflow initial Lorentz factor Γ₀ are available, observational efforts to derive a direct determination of Γ₀ have so far failed or have provided ambiguous results. As a matter of fact, the shape of the early-time afterglow light curve is very sensitive to Γ₀, which determines the time of the afterglow peak, i.e., when the outflow and the shocked circumburst material share a comparable amount of energy. We now comment on the early-time observations of the near-infrared afterglows of GRB060418 and GRB060607A performed by the (REM) robotic telescope. For both events, the afterglow peak was singled out, which allowed us to determine the initial fireball Lorentz, Γ₀ ~ 400.
Swift Observations of GRB 060614
Vanessa Mangano,Giancarlo Cusumano,Daniele Malesani,Guido Chincarini 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.5
GRB 060614 is a remarkable nearby gamma-ray burst (GRB; z = 0.125) observed by the Swift space based observatory, and it has puzzling properties that challenge current progenitor models;its lack of any bright supernova down to very strict limits and its vanishing spectral lags are typical of short GRBs, strikingly at odds with the long (102 s) duration of this event. However, the burst presents optical, UV, and X-ray afterglows in remarkable agreement with standard jetted fireball models. In particular, spectral analysis of the Burst Alert Telescope (BAT) and the X-ray Telescope (XRT) data during the overlap time interval and after shows that the peak energy of the burst decays and crosses the XRT energy band within 500 s from the trigger. The afterglow shows a clear case of jet break, which is simultaneously detected at optical, UV, and X-ray wavelengths,possibly the best among Swift GRBs. Moreover, the Ultraviolet and Optical Telecope (UVOT)light curves possibly show evidence of the passage of the injection frequency across the optical band between 10 and 30 ks from the trigger.
Sakamoto, T.,Troja, E.,Aoki, K.,Guiriec, S.,Im, M.,Leloudas, G.,Malesani, D.,Melandri, A.,de Ugarte Postigo, A.,Urata, Y.,Xu, D.,D'Avanzo, P.,Gorosabel, J.,Jeon, Y.,Sá,nchez-Ramí,rez, R.,A IOP Publishing 2013 The Astrophysical journal Vol.766 No.1
<P>We present our successful Chandra program designed to identify, with subarcsecond accuracy, the X-ray afterglow of the short GRB 111117A, which was discovered by Swift and Fermi. Thanks to our rapid target of opportunity request, Chandra clearly detected the X-ray afterglow, though no optical afterglow was found in deep optical observations. The host galaxy was clearly detected in the optical and near-infrared band, with the best photometric redshift of z = 1.31(-0.23)(+0.46) (90% confidence), making it one of the highest known short gamma-ray burst ( GRB) redshifts. Furthermore, we see an offset of 1.0 +/- 0.2 arcsec, which corresponds to 8.4 +/- 1.7 kpc, between the host and the afterglow position. We discuss the importance of using Chandra for obtaining subarcsecond X-ray localizations of short GRB afterglows to study GRB environments.</P>
Colour variations in the GRB 120327A afterglow
Melandri, A.,Covino, S.,Zaninoni, E.,Campana, S.,Bolmer, J.,Cobb, B. E.,Gorosabel, J.,Kim, J.-W.,Kuin, P.,Kuroda, D.,Malesani, D.,Mundell, C. G.,Nappo, F.,Sbarufatti, B.,Smith, R. J.,Steele, I. A.,Top EDP Sciences 2017 Astronomy and astrophysics Vol.607 No.-