Abstract
Radio observational results at 232 MHz and multifrequency studies of supernova remnant (SNR) HB21 are presented. Its integrated flux density at 232 MHz is about 390 ± 30 Jy. Both the integrated spectral index and the spatial variations of spectral index of the remnant were calculated by combining the new map at 232 MHz with previously published maps made at 408, 1420, 2695, and 4750 MHz. The SNR has an integrated spectral index of about α = -0.43(S ν ∝ να) between 232 and 4750 MHz. In general the spectral index varies from –0.5 in southeast and west regions of the remnant to –0.3 in the central region and near the northwest edge. The new data of 232 MHz reveals that there is interaction between the remnant and the surrounding gas along the east edge of the remnant which causes the spectrum flattening at low frequency, while the very good agreement between the structure of X-ray emission and the central flat spectrum area suggests that the existence of thermal emission is the reason of spectrum flattening in the area.
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References
Anderson, M.C. and Rudnick, L.: 1993, Astrophys. J. 408, 514.
Baars, J.W.M., Genzel, R., Pauliny-Toth, I.I.K. and Witzel, A.: 1977, Astron. Astrophys. 61, 99.
Braun, R. and Walterbos, R.A.M.: 1985, Astron. Astrophys. 143, 307.
Brown, R.H. and Hazard, C.: 1953, Mon. Not. R. Astron. Soc. 113, 123.
Costain, C.H.: 1960, Mon. Not. R. Astron. Soc. 120, 248.
Crowther, J.H.: 1965, The Observatory 85, 110.
Duglas, J.N., et al.: 1996, Astron. J. 111, 1945.
Erkes, J.W. and Dickel, R.: 1969, Astron. J. 74, 840.
Fukui, Y. and Tatematsu, K.: 1988, IAU Colloquium 101, 261.
Haslam, C.G.T., Keen, N.J., Wilson, W.E., Graham, D.A. and Thomasson, P.: 1975, Astron. Astrophys. 39, 453.
Hill, I.E.: 1974, Mon. Not. R. Astron. Soc. 169, 59.
Han, W.J., Zhang, X.Z. and Zheng, Y.J.: 1993, in: Proceedings of International Symp. on Radio Propagation, p. 30.
Kundu, M.R.: 1971, Astrophys. J. 165, L55.
Kundu, M.R., Bcker, R.H. and Velusamy, T.: 1973, Astron. J. 78, 170.
Leahy, D.A.: 1987, Mon. Not. R. Astron. Soc. 228, 907.
Leahy, D.A., Zhang, X.Z., Wu, X.J. and Lin, J.L.: 1998, Astron. Astrophys. 369, 610.
Milne, D.K.: 1987, Aust. J. Phys. 40, 771-787.
Minknowski, R.: 1958, Rev. Mod. Phys. 30, 1048.
Reich, W., Furst, E. and Sieber: 1983, IAU Symposium 101, 377.
Tatematsu, K., Fukui, Y., Landecker, T.L. and Roger, R.S.: 1990, Astron. Astrophys. 237, 189.
Wakker, B.P. and Schwarz, U.J.: 1990, Astron. Astrophys. Suppl. 200, 312.
Wang, S.G.: 1987, in: Publications of Beijing Astronomical Observatory, p. 1.
Willis, A.G.: 1973, Astron. Astrophys. 26, 237.
Yang, Y.P., Zheng, Y.J., Zhang, X.Z., Chen, H.S., Wu, X.T. and Peng, B.: 1990, in: J.E. Baldwin and S.G. Wang (eds.), Proceedings of URSI/IAU Symp. on Radio Astronomical Seeing, p. 249.
Zhang, X., Han, Wenjun, and Zheng, Yijia: 1990, S.G. Wang (eds.), Proceedings of URSI/IAU Symp. on Radio Astronomical Seeing ibid, 184.
Zhang, X.: 1995, Annals of Shanghai Observatory, p. 291.
Zhang, X., Zheng, Y., Chen, H. and Wang, S.: 1993, Astron. Astrophys. Suppl. 99, 545.
Zhang, X., Zheng, Y., Chen, H., Wang, S., Cao, A., Peng, B. and Nan, R.: 1997a, Astron. Astrophys. Suppl. 121, 59.
Zhang, X., Zheng, Y., Landecker, T. and Higgs, L.: 1997b, Astron. Astrophys. 324, 641.
Zheng, Y.J. and Han, W.J.: 1993, in: Proceedings of 1993 International Symp. on Radio Propagation, p. 338.
Zhu, Jian: 1994, in thesis, p. 23.
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Zhang, X., Qian, S., Higgs, L. et al. Radio Observations at 232 MHz and Multifrequency Spectral Studies of SNR HB21. Astrophysics and Space Science 279, 355–366 (2002). https://doi.org/10.1023/A:1015186104111
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DOI: https://doi.org/10.1023/A:1015186104111