Optical observations of GRB 050401 afterglow : a case for double-jet model |
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| Authors: | Atish Kamble Kuntal Misra D Bhattacharya Ram Sagar |
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| Institution: | Raman Research Institute, Bangalore –560 080, India;Astronomical Institute "Anton Pannekoek", Kruislaan 403, 1098 SJ Amsterdam, The Netherlands;Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital –263 129, India;Inter University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune –411 007, India |
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| Abstract: | The afterglow of GRB 050401 presents several novel and interesting features. (i) An initially faster decay in optical band than in X-rays. (ii) A break in the X-ray light curve after ～0.06 d with an unusual slope after the break. (iii)The X-ray afterglow does not show any spectral evolution across the break while the R -band light curve does not show any break. We have modelled the observed multiband evolution of the afterglow of GRB 050401 as originating in a two-component jet, and interpreting the break in X-ray light curve as due to lateral expansion of a narrow collimated outflow which dominates the X-ray emission. The optical emission is attributed to a wider jet component. Our model reproduces all the observed features of multiband afterglow of GRB 050401. We present optical observations of GRB 050401 using the 104-cm Sampurnanand Telescope at the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital. Results of the analysis of multiband data are presented and compared with GRB 030329, the first reported case of double jet. |
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| Keywords: | gamma-rays: bursts |
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