کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1826409 | 1526464 | 2011 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
BL Lacs bright in γ rays
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موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
ابزار دقیق
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چکیده انگلیسی
In this preview we consider implications from the recent AGILE γ-ray detection of the BL Lac 0716+714 in September-October 2007, marked by two intense flaring episodes reaching peak fluxes of 200Ã10â8 photons cmâ2 sâ1 in the energy range 0.1-10 GeV. The source shows no evidence of emission lines or disk radiation, related to any surrounding gas; its pure non-thermal radiation is effectively represented in terms of the synchrotron-self Compton radiation in the Thomson regime, also supported by the observed quadratic relation of the γ-ray to the X-ray flux variations. With source parameters so derived, we find a total jet power of about 4Ã1045 erg sâ1, that makes 0716+714 one of the brightest gas-poor BL Lacs so far detected at γ-ray energies. Thus it provides an ideal benchmark to compare its intrinsic luminosity with the top power extractable from a maximally rotating black-hole via the Blandford-Znajek mechanism. With a mass close to 5Ã108Mâ for the associated BH, we find the source to remain close to the Blandford-Znajek threshold during the flare. Other gas-poor but weaker BL Lacs remain well below the threshold. These findings and those expected from FERMI will provide a powerful test of GR at work.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment - Volume 630, Issue 1, 21 February 2011, Pages 265-268
Journal: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment - Volume 630, Issue 1, 21 February 2011, Pages 265-268
نویسندگان
A. Paggi, V. Vittorini, A. Cavaliere, M. Tavani,