INTEGRAL observations of the blazar Mrk 421 in outburst (Results of a multi-wavelength campaign)

G. G. Lichti; E. Bottacini; M. Ajello; P. Charlot; W. Collmar; A. Falcone; D. Horan; S. Huber; A. von Kienlin; A. Lähteenmäki; E. Lindfors; D. Morris; K. Nilsson; D. Petry; M. Rüger; A. Sillanpää; F. Spanier; M. Tornikoski

doi:10.1051/0004-6361:20079199

arXiv · 0805.2577

INTEGRAL observations of the blazar Mrk 421 in outburst (Results of a multi-wavelength campaign)

G. G. Lichti·E. Bottacini·M. Ajello·P. Charlot·W. Collmar·A. Falcone·D. Horan·S. Huber·A. von Kienlin·A. Lähteenmäki·E. Lindfors·D. Morris·K. Nilsson·D. Petry·M. Rüger·A. Sillanpää·F. Spanier·M. Tornikoski

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Abstract

We report the results of a multi-wavelength campaign on the blazar Mrk 421 during outburst. We observed four strong flares at X-ray energies that were not seen at other wavelengths (partially because of missing data). From the fastest rise in the X-rays, an upper limit could be derived on the extension of the emission region. A time lag between high-energy and low-energy X-rays was observed, which allowed an estimation of the magnetic-field strength. The spectral analysis of the X-rays revealed a slight spectral hardening of the low-energy (3 - 43 keV) spectral index. The hardness-ratio analysis of the Swift-XRT (0.2 - 10 keV) data indicated a small correlation with the intensity; i. e., a hard-to-soft evolution was observed. At the energies of IBIS/ISGRI (20 - 150 keV), such correlations are less obvious. A multiwavelength spectrum was composed and the X-ray and bolometric luminosities are calculated.

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G. G. Lichti, E. Bottacini, M. Ajello, P. Charlot, W. Collmar, A. Falcone, D. Horan, S. Huber, A. von Kienlin, A. Lähteenmäki, E. Lindfors, D. Morris, K. Nilsson, D. Petry, M. Rüger, A. Sillanpää, F. Spanier, M. Tornikoski. 2008-05-16. INTEGRAL observations of the blazar Mrk 421 in outburst (Results of a multi-wavelength campaign). https://doi.org/10.1051/0004-6361%3A20079199

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