Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.sao.ru/cats/~satr/RFSymp/abs/05_Burenkov.pdf Дата изменения: Mon Oct 9 11:39:01 2006 Дата индексирования: Tue Oct 2 10:00:20 2012 Кодировка: Поисковые слова: annular solar eclipse

SPECTRAL MONITORING OF NGC 5548 IN 1996 ­ 2004
A.N. Burenkov1 , A.I. Shap ovalova1 , N.G. Bo chkarev2 , V.H. Chavushyan3 , S. Collin4 , V.T. Doroshenko2 , L. Pop oviґ5 , N. Borisov1 , L. Carrasco3 , D. Iliґ6 , J.R. Valdes3 , V.V. c c 1 2 Vlasuyk , V.E. Zhdanova Sp ecial Astrophysical Observatory of RAS, Nizhnij Arkhyz, 369167, Russia Sternb erg Astronomical Institute, University of Moscow, Universitetskij Prosp ect 13, Moscow 119899, Russia 3 Instituto Nacional de Astrofґ isica, Optica y Electrґ onica, Apartado Postal 51. C.P. 72000. Puebla, Pue., Mґ exico 4 LUTH, Observatoire de Paris, Section de Meudon, Place Janssen, 92195, Meudon, France 5 Astronomical Observatory, Volgina 7, 11160 Belgrade, Serbia 6 Department of Astronomy, Faculty of Mathematics, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia
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We present results of a sp ectral monitoring program of the Seyfert galaxy NGC 5548 with the 6m and 1m telescop es of SAO (Russia) and with the 2.1m telescop e of Guillermo Haro Observatory at Cananea, Mґ exico. Sp ectra were obtained with long-slit sp ectrograph, covering the sp ectral range (4000­7500) ° with a (4.5­15) ° resolution. We found that: A A ­ Both the flux in the lines and continuum gradually decreased, reaching minimum values during May-June 2002. In the minimum state, the wings of H and H b ecame extremely weak, corresp onding to a Sy1.8 typ e, not to a Sy1, as observed previously when the nucleus was brighter. ­ When the line profiles were decomp osed into variable and constant comp onents, the variable broad comp onent is well correlated with the continuum variation. It consists of a double p eaked structure with radial velo cities of ±1000 km/s relative to the narrow comp onent. A constant comp onent, whose presence is indep endent of the continuum flux variations, shows only narrow emission lines. The mean, rms, and the averaged over years, observed and difference line profiles of H and H reveal the same double p eaked structure at the same velo cities. The relative intensity of these p eaks changes with time. During 1996, the red p eak was the brightest, while in 1998­2002, the blue p eak b ecame the brighter one. Their radial velo cities vary in the range 500­1200 km/s. ­ In 2000­2002 a distinct third p eak app eared in the red wing of H and H line profiles. The radial velo city of this feature decreased b etween 2000 and 2002: by the observed profiles, from +(2500­2600) km/s to +2000 km/s and it is clearly seen on the difference profiles. ­ The fluxes of various parts of the line profiles are well correlated with each other and also with the continuum flux. The blue and red parts of the line profiles at the same radial velo cities vary in an almost identical manner. ­ Our results favor the formation of the broad Balmer lines in a turbulent accretion disc with large and moving "optically thick" inhomogeneities, capable of repro cessing the central source continuum. We made an attempt to investigate the variability of physical parameters in the BLR of NGC 5548 using the Boltzmann plot metho d given by Pop oviґ (2003). We applied the c metho d on the broad Balmer lines, and found that variability seen in lines is also present in the electron temp erature (T). We found that the average T for the considered p erio d was 10000K, and that it varies from 6000K (in 2002) till 15000K (in 1998). This variation


correlates with the optical continuum flux (r = 0.85) and may indicate existence of an accretion disk in the BLR of NGC 5548. We found that Partial Lo cal Thermo dynamical Equilibrium approximation is valid for at least one part of the BLR of NGC 5548. The detailed discussion of these results is done in our pap ers (Shap ovalova at al. 2004; Pop oviґ et al. 2005). c Acknow ledgements. This work was supp orted by grants from CONACYT 39560-F (Mexico), RFBR 06-02-16843 (Russia) and the Ministry of Science and Environment Protection of Serbia. References Pop oviґ L. C.: ApJ, 2003, 599, 140. c Pop oviґ L. C. et al.: Astro-ph/0511676, 2005 (in press). c Shap ovalova A. I. et al.: 2004, A&A, 422, 925.