Gamma-ray burst afterglow scaling relations for the full blast wave evolution

Hendrik J. Van Eerten, Andrew I. MacFadyen

    Research output: Contribution to journalArticle

    Abstract

    We demonstrate that gamma-ray burst afterglow spectra and light curves can be calculated for arbitrary explosion and radiation parameters by scaling the peak flux and the critical frequencies connecting different spectral regimes. Only one baseline calculation needs to be done for each jet opening angle and observer angle. These calculations are done numerically using high-resolution relativistic hydrodynamical afterglow blast wave simulations which include the two-dimensional dynamical features of expanding and decelerating afterglow blast waves. Any light curve can then be generated by applying scaling relations to the baseline calculations. As a result, it is now possible to fully fit for the shape of the jet break, e.g., at early-time X-ray and optical frequencies. In addition, late-time radio calorimetry can be improved since the general shape of the transition into the Sedov-Taylor regime is now known for arbitrary explosion parameters so the exact moment when the Sedov-Taylor asymptote is reached in the light curve is no longer relevant. When calculating the baselines, we find that the synchrotron critical frequency νm and the cooling break frequency νc are strongly affected by the jet break. The νm temporal slope quickly drops to the steep late-time Sedov-Taylor slope, while the cooling break νc first steepens and then rises to meet the level of its shallow late-time asymptote.

    Original languageEnglish (US)
    Article numberL30
    JournalAstrophysical Journal Letters
    Volume747
    Issue number2
    DOIs
    StatePublished - Mar 10 2012

    Fingerprint

    blasts
    afterglows
    gamma ray bursts
    light curve
    scaling
    asymptotes
    critical frequencies
    explosions
    explosion
    slopes
    cooling
    calorimetry
    synchrotrons
    heat measurement
    radio
    moments
    high resolution
    curves
    radiation
    simulation

    Keywords

    • gamma-ray burst: general
    • hydrodynamics
    • methods: numerical

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Gamma-ray burst afterglow scaling relations for the full blast wave evolution. / Van Eerten, Hendrik J.; MacFadyen, Andrew I.

    In: Astrophysical Journal Letters, Vol. 747, No. 2, L30, 10.03.2012.

    Research output: Contribution to journalArticle

    Van Eerten, Hendrik J. ; MacFadyen, Andrew I. / Gamma-ray burst afterglow scaling relations for the full blast wave evolution. In: Astrophysical Journal Letters. 2012 ; Vol. 747, No. 2.
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