Article

<i>Swift</i>Observations of GRB 070110: An Extraordinary X‐Ray Afterglow Powered by the Central Engine

E. TrojaDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKG. CusumanoINAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Sezione di Palermo, via Ugo la Malfa 153, 90146 Palermo, ItalyP. T. O’BrienDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKB. ZhangDepartment of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154B. SbarufattiINAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Sezione di Palermo, via Ugo la Malfa 153, 90146 Palermo, ItalyV. ManganoINAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Sezione di Palermo, via Ugo la Malfa 153, 90146 Palermo, ItalyR. WillingaleDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKG. ChincariniINAF-Osservatorio Astronomico di Brera, via Emilio Bianchi 46, I-23807 Merate (LC), ItalyJ. P. OsborneDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKF. E. MarshallNASA Goddard Space Flight Center, Greenbelt, MD 20771D. N. BurrowsDepartment of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802S. CampanaINAF-Osservatorio Astronomico di Brera, via Emilio Bianchi 46, I-23807 Merate (LC), ItalyN. GehrelsNASA Goddard Space Flight Center, Greenbelt, MD 20771C. GuidorziINAF-Osservatorio Astronomico di Brera, via Emilio Bianchi 46, I-23807 Merate (LC), ItalyH. A. KrimmNASA Goddard Space Flight Center, Greenbelt, MD 20771V. La ParolaINAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Sezione di Palermo, via Ugo la Malfa 153, 90146 Palermo, ItalyE. W. LiangDepartment of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154T. MineoINAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Sezione di Palermo, via Ugo la Malfa 153, 90146 Palermo, ItalyA. MorettiINAF-Osservatorio Astronomico di Brera, via Emilio Bianchi 46, I-23807 Merate (LC), ItalyK. L. PageDepartment of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UKP. RomanoUniversità degli studi di Milano-Bicocca, Dipartimento di Fisica, piazza delle Scienze 3, I-20126 Milan, ItalyG. TagliaferriINAF-Osservatorio Astronomico di Brera, via Emilio Bianchi 46, I-23807 Merate (LC), ItalyB. B. ZhangDepartment of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154M. J. PageMullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UKP. SchadyMullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK

2007en

ABI

Abstract

We present a detailed analysis of Swift multiwavelength observations of GRB 070110 and its remarkable afterglow. The early X-ray light curve, interpreted as the tail of the prompt emission, displays a spectral evolution already seen in other gamma-ray bursts. The optical afterglow shows a shallow decay up to $2 days after the burst, which is not consistent with standard afterglow models. The most intriguing feature is a very steep decay in the X-ray flux at $2 ; 10 4 s after the burst, ending an apparent plateau. The abrupt drop of the X-ray light curve rules out an external shock as the origin of the plateau in this burst and implies long-lasting activity of the central engine. The temporal and spectral properties of the plateau phase point toward a continuous central engine emission rather than the episodic emission of X-ray flares. We suggest that the observed X-ray plateau is powered by a spinning-down central engine, possibly a millisecond pulsar, which dissipates energy at an internal radius before depositing energy into the external shock.

Identifiers

DOI: 10.1086/519450

Citations and references

Cited by 40 references

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