Abstract
We report the observation of nearest quasar 3C273 made with LASE instrument on November 20th, 1998 as a part of our continuing programme of balloon borne hard X-ray observations in the 20–200 keV band using high sensitivity Large Area Scintillation counter Experiment. Our data clearly show a steep spectrum in the 20–200 keV with power law spectral indexα = 2.26 ± 0.07. This is in complete contrast to the reported data from OSSE and BeppoSAX which suggest the value of 1.3 to 1.6 for the power law index in the X-ray energy band, but is quite consistent with the value derived for the high energy gamma ray data. A single power law fit in the X-ray and gamma ray energy bands points to a common origin of these photons and the absence of spectral break around 1 MeV as suggested in literature. We have reanalyzed the available data to study the temporal variability of the spectrum in the hard X-ray band. Our analysis reveals that 50 keV flux from the source, shows a strong modulation with a period of about 13.5 years. The analysis of the optical light curve of the source also supports the 5000 day period. We discuss the emission mechanism and the possible sites for X-ray photons along with the implications of the long term periodicity with respect to source geometry.
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References
Abramowicz, M. A. 1981,Nat.,294, 235.
Bassani, L.et al. 1992,Ap. J.,396, 504.
Begelman, M. C, Blandford, R. D., Rees M. J., 1980,Nat.,287, 307.
Bezler, M., Kendziorra, E., Staubert, R.et al. 1984,A&A,136, 351.
Boyer, C. S., Lampton, M., Mack, J. 1970,Ap. J.,161, L1.
Courvoisier, T. J. L.et al. 1987,A&A,176, 21.
Cappi, M., Matsuoka, M., 1997, Proc. 2nd Integral workshop ‘The Transparent Universe’, (ed.) Winkler, Courvoisier & Durouchoucx, ESA, SP-382,
Cappi, M. and Matsuoka, M. Otani, M., Leighly, K. M. 1998,PASJ,
D’Silva, J.A.R.et al. 1998,Nucl. Instrum. Methods,A412, 34.
Damle, S. V., Kunte, P. K., Naranan, S.et al. 1987,A&A,182, L1.
Davis, R. J., Muxlow, T. W. B., Unwin, S. C. 1991,Nat.,354, 374.
Dean, A. J., Bazzano, A., Court, A. J.et al. 1990,Ap. J.,349, 41.
DePaolis,et al. 2002,A&A,388, 470.
Dermer, C. D., Schlickeiser, R. 1993,Ap. J.,416, 458.
Fan, J. H., Romero, G. E., Lin, R. G. 2001,Acta Astronomica Sinica,42, 9.
Gaskell, C. M. 1996,Ap. J.,464, L107.
Ginzberg, V. L., Syrovatskii, S. I. 1964, inOrigin of Cosmic Rays (Pergamon Press)
Grandi, G.et al. 1997,A&A,325, L17.
Hayashida, N, Hirasawa, H., Ishikawa, F.et al. 1998,Ap. J.,504, L71.
Hermsen, W.et al. 1993,A & A 97, 97.
Honma, F., Matsumoto, R., Kato, S. 1991,PASJ,43, 147.
Johnson, W.N.et al. 1995,Ap. J.,445, 182.
King, A. R., Frank, J., Kolb, U., Ritter, H. 1997,Ap. J.,482, 919.
Kim, C. 2001,J. Astrophys. Astr.,22, 283.
Konigl, A. 1981,Ap. J.,243, 700.
Lasota, J. P 1989 In: (ed.)Accretion disks and Magnetic fields in Astrophysics, G. Belvedere, (Kluwer) p 273
Lasota, J. P., Pelat, D. 1991,A&A,249, 574.
Leach, C. M, McHardy, I. M., Papadakis, I. E., 1995,MNRAS,272, 221.
Litchi, G. G.et al. 1994, In:The Second Compton Symposium, (ed.) Fichtel, Gehrels & Norris, AIP, 611
Liu, F. K., Xie, G. Z., Bai, J. M. 1995,A &A,295, 1.
Liu, F. K., Liu, B. F, Xie, G. Z. 1997,A & A, SS123, 569.
Lobanov, A. P., Roland, J. 2002, In:Proc. 6th European VLBI network Symp., (ed.) Ross, Porcas, Labonov & Zensus, Bonn, p 121
Maisack, M.et al. 1989,Proc. ESLAB Symp.,SP-296, 975
Maisack, M., Kendziorra, E., Mony, B.et al. 1992,A & A. 262, 433.
Manchanda, R. K. 1998,Adv space Res.,21, 1019.
Manchanda, R. K. 2001,J. Astrophys. Astr,22, 145.
Maraschi, L.et al. 2000,Adv. Space Res.,25, 713.
Marshall, N., Warwick, R. S., Pounds, K. A. 1981,MNRAS,194, 987.
Matsumoto, R., Kato, S., Honma, F. 1989, In:Theory of accretion disks, (ed.) Meyer, Duschl, Frank and Meyer-Hofmeister, Kluwer, p 167
Me Hardy, I., Lawson, A., Newsam, A.et al. 1999,MNRAS,310, 571.
Mitra, A. 1991,Ap. J.,370, 345.
Mushotzky, M. 1982,Ap. J.,256, 92.
Nishikawa, D., Hayashi, S. Chamoto, N.et al. 1999,ICRC,3, 26.
Pietsch, W., Reppin, C, Trumper, J.et al. 1981,A & A,94, 234.
Primini, F. A., Cooke, B. A., Dobson, C. A.et al. 1979,Nat.,278, 234.
Protheroe, J., Bhat, C. L., Fleury, P.et al. 1998,ICRC,8, 317.
Ramos, E., Kafatos, M., Fruscione, A.et al. 1997,Ap. J.,482, 167.
Reiger, F M., Manheim, K. 2000,A & A,359, 948.
Ritter, H. 1988,A & A,124, 267.
Sambruna, R. M., Urry, C. M, Tavecchio, F.et al. 2001,A & A,549, L161
Shakura, N. I., Sunyaev, R. A. 1976,MNRAS,175, 613.
Sillanpaa, A., Haarala, S., Valtonen, M. J. 1988a,et al. Ap. J.,325, 628.
Sillanpaa, A., Haarala, S., Korhonen, T. 1988b,A & A Suppl Ser,72, 347.
Stockton, A., Farnhem, T. 1991,Ap. J.,368, 28.
Storchi-Bergmann, T., Eracleous, M., Ruiz, M. T.et al. 1997,Ap. J.,489, 87.
Sunyaev, R. A., Titarchuck, L. G. 1980,A & A,86, 121.
Taam, R. E., Lin, D. N. C. 1984,Ap. J.,287, 761
Turner, M. J. L., Courvoisier, T, Staubert, R.et al. 1995,Sp. Sci. Rev.,40, 623.
Ulrich, M. H., Courvoisier, T. J. L., Warnsteber, W. 1988,A & A,204, 21
Unwin, S., Wehrle, A., Lobonov, A. P.et al. 1997,Ap. J.,480, 1997
von Montigny, C.et al. 1993,A & A Suppl Ser.,97, 101.
Warrell, D. M., Mushotzky, R. F, Boldt, E. A.et al. 1979,Ap. J.,232, 683.
Wilkes, B. J., Elvis, M. 1987,Ap. J.,323, 243,
Williams, O. R., Turner, M. J. L., Stewart, G. C.et al. 1992,A & A. 285, 119.
Yu, Q., Lu, Y. 2001,A & A,377, 17.
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Manchanda, R.K. Spectral variability in hard X-rays and the evidence for a 13.5 years period in the bright quasar 3C273. J Astrophys Astron 23, 243–258 (2002). https://doi.org/10.1007/BF02702286
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DOI: https://doi.org/10.1007/BF02702286