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Titolo:
High temporal resolution XMM-Newton monitoring of PKS 2155-304
Autore:
Edelson, R; Griffiths, G; Markowitz, A; Sembay, S; Turner, MJL; Warwick, R;
Indirizzi:
Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA Univ Calif Los Angeles Los Angeles CA USA 90095 Los Angeles, CA 90095 USA Univ Leicester, X Ray Astron Grp, Leicester LE1 7RH, Leics, England Univ Leicester Leicester Leics England LE1 7RH er LE1 7RH, Leics, England
Titolo Testata:
ASTROPHYSICAL JOURNAL
fascicolo: 1, volume: 554, anno: 2001,
parte:, 1
pagine: 274 - 280
SICI:
0004-637X(20010610)554:1<274:HTRXMO>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACTIVE GALACTIC NUCLEI; LACERTAE OBJECT PKS-2155-304; SPECTRAL EVOLUTION; VARIABILITY; MARKARIAN-421; EMISSION; BLAZARS;
Keywords:
BL Lacertae objects : general; BL Lacertae objects : individual (PKS 2155-304); galaxies : active; methods : data analysis; X-rays : galaxies;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
18
Recensione:
Indirizzi per estratti:
Indirizzo: Edelson, R Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA Univ Calif Los Angeles Los Angeles CA USA 90095 , CA 90095 USA
Citazione:
R. Edelson et al., "High temporal resolution XMM-Newton monitoring of PKS 2155-304", ASTROPHYS J, 554(1), 2001, pp. 274-280

Abstract

The bright, strongly variable BL Lacertae object PKS 2155-304 was observedby XMM-Newton for two essentially uninterrupted periods of similar to 11 and 16 hr on 2000 May 30-31. The strongest variations occurred in the highest energy bands. After scaling for this effect, the three softest bands (0.1-1.7 keV) showed strong correlation with no measurable lag to reliable limits of \tau\ less than or similar to 0.3 hr. However, the hardest band (similar to3 keV) was less well correlated with the other three, especially on short timescales, showing deviations of similar to 10%-20% in similar to1 hr, although, again, no significant interband lag was detected. This result and examination of previous ASCA and BeppoSAX cross-correlation functions suggest that previous claims of soft lags on timescales of 0.3-4 hr could well be an artifact of periodic interruptions due to Earth occultation every 1.6 hr. Previous determinations of the magnetic field/bulk Lorentz factor were therefore premature since these data provide only a lower limit of B gamma (1/3) greater than or similar to 2.5 G. The hardest band encompasses thespectral region above the high-energy break; its enhanced variability could be indicating that the break energy of the synchrotron spectrum, and therefore of the underlying electron energy distribution, changes independentlyof the lower energies.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/10/20 alle ore 06:16:54