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Titolo:
The quiescent state broadband X-ray spectrum and variability of Mkn 421
Autore:
Guainazzi, M; Vacanti, G; Malizia, A; OFlaherty, KS; Palazzi, E; Parmar, AN;
Indirizzi:
Europeanwijk,e Agcy, Estec, Dept Space Sci, Div Astrophys, NL-2200 AG Noord European Space Agcy Noordwijk Netherlands NL-2200 AG s, NL-2200 AG Noord BeppoSAX Sci Data Ctr, I-00131 Rome, Italy BeppoSAX Sci Data Ctr Rome Italy I-00131 i Data Ctr, I-00131 Rome, Italy Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, EnglandUniv Southampton Southampton Hants England SO17 1BJ 7 1BJ, Hants, England CNR, Ist Tecnol & Studio Radiaz Extraterr, I-40129 Bologna, Italy CNR Bologna Italy I-40129 tudio Radiaz Extraterr, I-40129 Bologna, Italy
Titolo Testata:
ASTRONOMY AND ASTROPHYSICS
fascicolo: 1, volume: 342, anno: 1999,
pagine: 124 - 130
SICI:
0004-6361(199902)342:1<124:TQSBXS>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
BL LACERTAE OBJECTS; SELF-COMPTON MODELS; MULTIFREQUENCY OBSERVATIONS; ASTRONOMY SATELLITE; ABSORPTION FEATURE; RELATIVISTIC JETS; LAC OBJECTS; ON-BOARD; GALAXY;
Keywords:
X-rays : galaxies; galaxies : nuclei; galaxies : jets; galaxies : BL Lacertae objects: individual : Mkn 421; galaxies : active;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Guainazzi, M European2200ce Agcy, Estec, Dept Space Sci, Div Astrophys, Postbus 299, NL- European Space Agcy Postbus 299 Noordwijk Netherlands NL-2200 AG
Citazione:
M. Guainazzi et al., "The quiescent state broadband X-ray spectrum and variability of Mkn 421", ASTRON ASTR, 342(1), 1999, pp. 124-130

Abstract

The BL Lac object Mkn 421 was observed three times by the X-ray observatory BeppoSAX in consecutive days during 1997 April and May. The source was ina quiescent state, with an average 2-10 keV flux of 9.0 x 10(-11) erg cm(-2) s(-1) Flux variation by a factor of similar or equal to 2 on timescales as short as a few 10(4) s were more pronounced in the hard (i.e. above similar or equal to 3 keV) than in the soft X-rays. The broadband (0.1-40 keV) spectrum is concave and can be most easily explained with a power-law modelwhich steepens gradually with energy. In this framework, neither photoabsorption edges nor resonant absorption lines are required, strengthening the case against the ubiquity of such features in BL Lac objects, which had been previously suggested by Einstein observations. The broadband spectrum hardens with hard X-ray flux, mostly due to a flattening above similar or equal to 4 keV. This suggests that the relativistic highest energy electron distribution properties drive the X-ray spectral dynamics: either a stratification of the distribution in the jet with energy or inhomogeneities in the electron injection mechanism could be consistent with the observed variability pattern.

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Documento generato il 18/11/17 alle ore 03:41:37