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Related papers: Late Central Engine Activity in GRB 180205A

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Intense flares that occur at late times relative to the prompt phase have been observed by the $Swift$ satellite in the X-ray afterglows of gamma-ray bursts (GRBs). Here, we present a detailed analysis on the fall back accretion process to…

High Energy Astrophysical Phenomena · Physics 2015-08-19 Y. B. Yu , X. F. Wu , Y. F. Huang , D. M. Coward , G. Stratta , B. Gendre , E. J. Howell

We present very early ground-based optical follow-up observations of GRB~140423A, which was discovered by \emph{Swift}/BAT and by {\it Fermi}/GBM. Its broadband afterglow was monitored by {\it Swift}/XRT and ground-based optical telescopes…

We present the time-resolved optical emission of gamma-ray bursts GRB 060904B and GRB 070420 during their prompt and early afterglow phases. We used time resolved photometry from optical data taken by the TAROT telescope and time resolved…

Astrophysics · Physics 2009-11-13 A. Klotz , B. Gendre , G. Stratta , A. Galli , A. Corsi , B. Preger , S. Cutini , A. Pelangeon , J. L. Atteia , M. Boer , L. Piro

We report on a detection of an early rising phase of optical afterglow (OA) of a long GRB 090726. We resolve a complicated profile of the optical light curve. We also investigate the relation of the optical and X-ray emission of this event.…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 V. Simon , C. Polasek , M. Jelinek , R. Hudec , J. Strobl

The optical afterglow of GRB 010222 was observed using the recently installed 2-m telescope at the Indian Astronomical Observatory, Hanle, and the telescopes at the Vainu Bappu Observatory, Kavalur, beginning ~ 0.6 day after the detection…

Astrophysics · Physics 2007-05-23 R. Cowsik , T. P. Prabhu , G. C. Anupama , B. C. Bhatt , D. K. Sahu , S. Ambika , Padmakar , S. G. Bhargavi

GRB050904 is very interesting since it is by far the most distant GRB event known to date($z=6.29$). It was reported that during the prompt high energy emission phase, a very bright optical flare was detected, and it was temporal coincident…

Astrophysics · Physics 2009-11-13 D. M. Wei , T. Yan , Y. Z. Fan

We present the results of a detailed spectral and temporal analysis of Swift and XMM-Newton observations of the high redshift (z=3.969) GRB 050730. The X-ray afterglow of GRB 050730 was found to decline with time with superimposed intense…

We present the simultaneous Swift and Fermi observations of the bright GRB100728A and its afterglow. The early X-ray emission is dominated by a vigorous flaring activity continuing until 1 ks after the burst. In the same time interval high…

High Energy Astrophysical Phenomena · Physics 2015-05-28 The Fermi Collaboration , L. Piro

We present a multiwavelength study of GRB 151027A. This is the 999th GRB detected by the Swift satellite and it has a densely sampled emission in the X-ray and optical band and has been observed and detected in the radio up to 140 days…

(Abridged) We report on observations of the optical and NIR afterglow of GRB020405. Ground-based optical observations started about 1 day after the GRB and spanned a period of ~10 days; archival HST data extended the coverage up to 70 days…

We report on the very early time search for an optical afterglow from GRB 971227 with the Livermore Optical Transient Imaging System (LOTIS). LOTIS began imaging the `Original' BATSE error box of GRB 971227 approximately 14 s after the…

GRB 080503, detected by Swift, belongs to the class of bursts whose prompt phase consists of an initial short spike followed by a longer soft tail. It did not show any transition to a regular afterglow at the end of the prompt emission but…

High Energy Astrophysical Phenomena · Physics 2015-06-04 R. Hascoët , F. Daigne , R. Mochkovitch

Gamma-ray burst (GRB) X-ray light curves exhibit a variety of complex temporal structures, such as flares and plateaus. The origin of flares seen in many GRB early afterglows is still uncertain. Here, we analyze a sample of 89 GRBs, 61 of…

High Energy Astrophysical Phenomena · Physics 2025-12-09 H. Dereli-Bégué , A. Pe'er , D. Bégué , F. Ryde , A. Gowri

We present the systematic analysis of the UVOT and XRT light curves for a sample of 26 Swift Gamma-Ray Bursts (GRBs). By comparing the optical/UV and X-ray light curves, we found that they are remarkably different during the first 500s…

The Swift X-ray Telescope (XRT) has discovered that flares are quite common in early X-ray afterglows of Gamma-Ray Bursts (GRBs), being observed in roughly 50% of afterglows with prompt followup observations. The flares range in fluence…

We report on the temporal and spectral characteristics of the early X-ray emission from the Gamma Ray Bursts GRB050126 and GRB050219A as observed by Swift. The X-ray light-curves of these 2 bursts both show remarkably steep early decays…

Astrophysics · Physics 2010-03-19 M. R. Goad

As indicated by the observed X-ray flares, a great amount of energy could be intermediately released from the postburst central engine of gamma-ray bursts (GRBs). As a natural consequence, the GRB external shock could be energized over and…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Liang-Duan Liu , A-Ming Chen

We discuss the current interpretations of the {\it Swift} GRB X-ray afterglows, mainly focusing on the sharp decline at the prompt tail emission, and the shallow decay afterward, which is then followed by the conventional pre-\emph{Swift}…

Astrophysics · Physics 2010-11-11 Yi-Zhong Fan

We present a photometric study of the optical counterpart of the long-duration Gamma Ray Burst (GRB) 030725, which triggered the HETE FREGATE and WXM instruments on July 25th, 2003, and lasted more than 160s. An optical counterpart was…

To reveal and understand astrophysical processes responsible for the Gamma Ray Burst (GRB) phenomenon, it is crucial to discover and understand relations between their observational properties. The presented study is performed in the GRB…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Maria Giovanna Dainotti , Michal Ostrowski , Richard Willingale